Life Below Water (Encyclopedia of the UN Sustainable Development Goals) 3319985353, 9783319985350

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Encyclopedia of the UN Sustainable Development Goals Series Editor: Walter Leal Filho

Walter Leal Filho · Anabela Marisa Azul Luciana Brandli · Amanda Lange Salvia · Tony Wall Editors

Life Below Water

Encyclopedia of the UN Sustainable Development Goals Series Editor Walter Leal Filho

The problems related to the process of industrialization such as biodiversity depletion, climate change, and a worsening of health and living conditions, especially but not only in developing countries, intensify. Therefore, there is also an increasing need to search for integrated solutions to make development more sustainable. The current model of economic growth used by many countries is heavily based on the exploitation of natural resources, which is not viable. Evidence shows that a more careful, that is, a more sustainable, approach to the use of our limited resources is needed. The United Nations has acknowledged the problem, and among other measures, it produced a set of documents at the UN Conference on Sustainable Development (Rio+20), held in Rio de Janeiro, Brazil, in 2012. In 2015, the UN General Assembly approved the “2030 Agenda for Sustainable Development.” On January 1, 2016, the 17 Sustainable Development Goals (SDGs) of the Agenda officially came into force. These goals cover the three dimensions of sustainable development: economic growth, social inclusion, and environmental protection. There are to date no comprehensive publications addressing the SDGs in an integrated way. Therefore, the Encyclopedia of the UN Sustainable Development Goals is being published. It encompasses 17 volumes, each devoted to one of the 17 SDGs. More information about this series at https://www.springer.com/series/15893

Walter Leal Filho • Anabela Marisa Azul • Luciana Brandli • Amanda Lange Salvia • Tony Wall Editors

Life Below Water With 267 Figures and 73 Tables

Editors Walter Leal Filho European School of Sustainability Science and Research Hamburg University of Applied Sciences Hamburg, Germany Luciana Brandli Faculty of Engineering and Architecture Passo Fundo University Passo Fundo, Brazil

Anabela Marisa Azul Center for Neuroscience and Cell Biology Institute for Interdisciplinary Research University of Coimbra Coimbra, Portugal Amanda Lange Salvia University of Passo Fundo Passo Fundo, Brazil

Tony Wall Liverpool Business School Liverpool John Moores University Liverpool, UK

ISSN 2523-7403 ISSN 2523-7411 (electronic) ISBN 978-3-319-98535-0 ISBN 978-3-319-98536-7 (eBook) ISBN 978-3-319-98537-4 (print and electronic bundle) https://doi.org/10.1007/978-3-319-98536-7 © Springer Nature Switzerland AG 2022 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG. The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland

Series Preface

The United Nations General Assembly agreed and approved in September 2015 the document “2030 Agenda for Sustainable Development”, which contains a set of measures aiming to balance economic progress and protection of the environment, while at the same time remain aware of the need to address the many disparities still seen between industrialized and developing countries. The Agenda document consists of 17 Sustainable Development Goals (SDGs). These Goals build on the successes of the Millennium Development Goals, while including new areas such as climate change, economic inequality, innovation, sustainable consumption, peace and justice, among other priorities. The goals are interconnected – often the key to success on one will involve tackling issues more commonly associated with another. The 17 SDGs are: SDG 1, placing an emphasis on ending all forms of extreme poverty SDG 2, which aims to end hunger and achieve food security with improved nutrition SDG 3, focusing on ensuring healthy lives and promoting well-being for all SDG 4, touches on one of the most important areas, namely inclusive and quality education SDG 5, focusing on gender equality SDG 6, which emphasizes the need for clean water and sanitation SDG 7, advocates the need for affordable and clean energy SDG 8, sustaining inclusive and sustainable economic growth with productive and decent working conditions for all SDG 9, which intends to foster industry, innovation, and infrastructure SDG 10, being about reducing inequalities among countries SDG 11, an attempt to ensure that human settlements and cities are inclusive, safe, resilient, and sustainable SDG 12, with a focus on sustainable consumption and production patterns SDG 13, with an emphasis on the need for climate action SDG 14, raises the need to preserve life below water, especially rivers and oceans SDG 15, draws attention about the need for a greater care about life on land SDG 16, which advocates peace, justice, and strong institutions SDG 17, a cross-SDGs effort to foster the partnership for the goals and their delivery The SDGs and their specific objectives are very complex. The mandate of the Encyclopedia of the UN Sustainable Development Goals is, therefore, to v

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Series Preface

clarify and explain a wide range of terms associated with each SDG. It does so by gathering and presenting inputs provided by experts from across all areas of knowledge and from round the world, who explain each term and their implications, drawing also from the latest literature. With 17 volumes and involving in excess of 1,500 authors and contributors, the Encyclopedia of the UN Sustainable Development Goals is the largest editorial project on sustainable development ever undertaken. We hope that this publication will be helpful in fostering a broader understanding of the SDGs, and that this process may inspire and support a wide range of initiatives aimed at their implementation, thus realizing the “2030 Agenda for Sustainable Development”. Hamburg University of Applied Sciences Germany

Walter Leal Filho

Volume Preface

The world’s rivers and oceans cover more than 70% of our planet. They are a central component of the global ecosystem. Without them, life on Earth in its present form would not be possible. For instance, the substantial ecosystem services provided by the world’s oceans and rivers are the foundation of Earth’s ecological balance. For example, seas and oceans play an important role in the uptake and redistribution of natural and anthropogenic carbon dioxide (CO2) and heat. They are linked to other components of the climate system through the global exchange of water, energy, and carbon. Only healthy oceans can perform their climate-regulating function. Highly polluted and overexploited marine ecosystems lose their necessary resilience. However, as part of the global water cycle, they are also particularly vulnerable to external human impacts such as pollution from plastic waste; substance inputs from agriculture, industry, and transport; and pressures from overexploitation of resources and fish stocks. The protection of marine resources, their sustainable use, and the equitable sharing of the benefits from this use are essential factors for sustainable development and are core issues in the field of sustainability. The departing point of SDG 14 (Life Below Water), therefore, is to conserve and sustainably use oceans, seas, and marine resources for sustainable development. Among other things, SDG14 advocates that, by 2050, a prevention and significant reduction of all forms of marine pollution will take place, in particular from land-based activities and namely marine litter and nutrient pollution. It also defends the need to sustainably manage and protect marine and coastal ecosystems to avoid significant adverse impacts, including by strengthening their resilience, and taking measures to restore them so that the seas become healthy and productive again. SDG 14 also emphasizes that aquatic biodiversity is to be preserved, that man-made overfertilization (eutrophication) of water bodies is to be reduced to a minimum, and the concentrations of pollutants be addressed. There are various measures that may be implemented in order to implement SDG 14, for instance, by ensuring that small-scale artisanal fishers have access to marine resources and markets. Also, improvements in the conservation and sustainable use of the oceans and their resources may be supported through the implementation of the United Nations Convention on the Law of the Sea. The ongoing efforts to launch an international convention to protect the world’s oceans from littering with plastic waste are commendable, which may alleviate the substantial pressure they are under today. vii

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Volume Preface

With this volume, we attempt to emphasize and also showcase the advantages of embracing and implementing SDG14. To this purpose, it contains information on research, analyses, case studies, and practical experiences, which showcase many activities, projects, practical initiatives, and thoughts of various experts on how to foster the implementation of SDG14. We also hope that the chapters in this volume will provide a timely support towards the implementation of SDG 14 and will help to foster the ongoing global efforts towards protecting the oceans and other aquatic ecosystems. May 2022

Walter Leal Filho Anabela Marisa Azul Luciana Brandli Amanda Lange Salvia Tony Wall

List of Topics

Section Editor: Ana Marta Gonçalves

Section Editor: Ernesto Brugnoli

Defining and Measuring a Marine Species Population or Stock Harvested Rainwater as a Solution for Marine Pollution and Contaminated Groundwater Marine Microplastics: Chemical, Physical, Biological, and Social Perspectives Measuring Success: Indicators and Targets for SDG 14 Metal Contamination in Marine Resources

Biological Invasions as a Threat to Global Sustainability Cetacean Health: Global Environmental Threats

Section Editor: Anabela Marisa Azul Antarctic: Climate Change, Fisheries, and Governance Community-Based Research and Participatory Approaches in Support of SDG14 Estuaries: Dynamics, Biodiversity, and Impacts Maritime Spatial Planning and Sustainable Development Ocean Literacy for Sustainable Use of Oceans Globally Ocean(S) and Human Health: Risks and Opportunities Ocean-Related Effects of Climate Change on Society Ocean-Related Impacts of Climate Change on Economy Penguins: Diversity, Threats, and Role in Marine Ecosystems Pharmaceuticals Contamination: Problematic and Threats for the Aquatic System Tourist Traps: Assessing the Role of Tourism in Sustaining Life Below Water

Section Editor: Fernando Morgado Marine Animals and Human Care Toward Effective Conservation of the Marine Environment Saltmarshes: Ecology, Opportunities, and Challenges Stranding of Marine Animals: Effects of Environmental Variables Section Editor: Filipe Martinho Adaptation to Sea-Level Rise and Sustainable Development Goals Artisanal Fishing Gears and Sustainable Development Destructive Fishing Practices and Their Impact on the Marine Ecosystem Global Ocean Governance and Ocean Acidification Marine Modelling: Contributions, Advantages, and Areas of Application of Numerical Tools Metazoan Meiofauna: Benthic Assemblages for Sustainable Marine and Estuarine Ecosystems SDG 14 and Integrated Coastal Zone Management ix

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Sustainable Development Goals to Reduce and Prevent Marine Litter Sustainable Fishing Under SDG-14 Section Editor: Giulia Guerriero Co-management and Conservation Below Water in Australia Coral Triangle: Marine Biodiversity and Fisheries Sustainability Fish Farming Marine Ecosystems: Types, Their Importance, and Main Impacts Marine Protected Area and Biodiversity Conservation Nagoya Protocol on Access to and Benefit Sharing of Genetic Resources Plastics and Oceans: A Socio-ecological Perspective Responsible Ocean Governance: Key to the Implementation of SDG 14 Sustainable Tourism in the Context of the Blue Economy Types of Fisheries and Their Impact on Sustainable Development Goals Section Editor: Jessica Savage Resilient Oceans: Policies and Practices to Protect Marine Ecosystems Role of International Law in Effective Governance of the Marine Environment Spatial Data Collection for Conservation and Management of Coastal Habitats Sustainable Supply Chain Management and Life Below Water Trends and Patterns of the Seaweed Industry and Its Links with SDGs Section Editor: Luciana Brandli Deep Seabed Mining and Sustainable Development Goal 14 Marine Bioprospecting and Intellectual Property Section Editor: Melissa Jane Nursey-Bray Antarctica and NE Greenland: Marine Pollution in a Changing World

List of Topics

Coastal Zone and Wetland Ecosystem: Management Issues Conserving Coastal and Marine Areas for Sustainable Development: Opportunities and Constraints Conserving Marine Life in Sao Tome and Principe: Concerted Actions with Agenda 2030 Measuring Success of SDG 14: An Australian Perspective Section Editor: Natalie Hilmi Blue Bioeconomy and the Sustainable Development Goals Concepts of Marine Protected Area Conservation Target for Marine Biodiversity in Areas Beyond National Jurisdiction Environmental Governance in Context of the Marine Ecosystem: Considerations for Sustainability Promoting Coastal and Ocean Governance Through Ecosystem-Based Management Section Editors: Nathalie Hilmi and Luciana Brandli Role of Exclusive Economic Zones in Protecting Ocean Life Section Editor: Nidhi Nagabhatla Legal Approaches Toward the Achievement of SDG 14 United Nations Agreement on Marine Biodiversity Beyond National Jurisdiction Wetland Ecosystems and Marine Sustainability Section Editor: Saleem Mustafa Aquaculture: Farming Our Food in Water Artisanal Fisheries: Management and Sustainability Bycatch: Causes, Impacts, and Reduction of Incidental Captures Coastal Pollution: An Overview Effective Marine Conservation in the Global South: Key Considerations for Sustainability

List of Topics

Field Caging Transplants of Fish for Assessment and Monitoring in Aquatic Toxicology Impacts of COVID-19 Pandemic on Marine Resources and Livelihoods Macroalgae: Diversity and Conservation Management and Monitoring of Eutrophication: Trophic State Indexes on the Río de la Plata Northern Coast Sustainable Use of Marine Genetic Resources Section Editor: Teppo Vehanen CO2-Induced Ocean Acidification Coastal Nutrient Supply and Global Ocean Biogeochemistry Ecological and Economic Importance of Benthic Communities Ecology of Marine Fish Larvae Fisheries Management and Ecosystem Sustainability Fisheries Management: An Overview Nursery Areas for Marine Fish Plastic Pollution in Aquatic Ecosystems: From Research to Public Awareness Sustainable Coastal and Marine Ecotourism: Opportunities and Benefits

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Section Editor: Ulisses Azeiteiro Coastal Defenses and Engineering Works Diatoms and Their Ecological Importance Exploration and Production of Petroleum Harmful Algal Blooms: Effect on Coastal Marine Ecosystems Higher Education and Sustainable Development of Marine Resources Mangroves Conservation: Relevant Task to Achieve the SDG14 Nature and Occurrence of Hydrocarbons Photoinhibition: Fundamentals and Implications for Primary Productivity Role of Microphytobenthos in the Functioning of Estuarine and Coastal Ecosystems Traditional Fishing Community and Sustainable Development Section Editors: Walter Leal Filho, Ernesto Brugnoli and Anabela Marisa Azul Jellyfish, Global Changes, and Marine Ecosystem Services

About the Editors

Walter Leal Filho, is Professor and Director of the European School of Sustainability Science and Research, whose Headquarters are at the Hamburg University of Applied Sciences in Germany. He also holds the Chair of Environment and Technology at Manchester Metropolitan University, UK. He is founding editor of the International Journal of Sustainability in Higher Education and heads the Inter-University Sustainable Development Research Programme (IUSDRP), the world´s largest network of universities engaged on sustainable development research. He is also Editor-in-Chief of the World Sustainable Development series with Springer. Prof. Walter Leal serves on the editorial board of various journals. He has in excess of 400 publications to his credit, among which are groundbreaking books such as Universities as Living Labs for Sustainable Development: Supporting the Implementation of the Sustainable Development Goals, Social Responsibility and Sustainability, and Handbook of Sustainability Science and Research. He has nearly 30 years of field experience in project management and has a particular interest in the connections between sustainability, climate change adaptation, and human behavior.

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About the Editors

Anabela Marisa Azul is a Researcher at the Center for Neuroscience and Cell Biology (CNC) and Institute for Interdisciplinary Research of the University of Coimbra (UC, Portugal). She holds a Ph.D. in Biological Sciences, with specialization in Ecology (2002, UC), and pursued her investigation on biology and ecology of fungi to pinpoint the role of mycorrhizal symbiosis for sustainability of Mediterranean forests under different land use scenarios, at the Centre for Functional Ecology (CFE-UC), where she became an Associate Researcher (from 2009 to 2014). At CFE-UC, Marisa Azul developed a holistic approach that combined innovation in food production with sustainable development and public scientific awareness to multiple actors. At CNC, from 2014 onward, she focuses her investigation on basic research and participatory research dynamics to pinpoint links between fungimetabolism-health/disease-sustainability. She has coedited over 40 scientific publications and book chapters, coedited four books for children and two comics, and coproduced an animation. Luciana Brandli, is an Associate Professor at the University of Passo Fundo, Brazil, working in the Ph.D. Program in Civil and Environmental Engineering. Her current research interests include sustainability in higher education and green campus, management of urban infrastructure and sustainable cities, and the Agenda 2030 for Sustainable Development. She supervises a number of master’s and doctoral students on engineering, environment, and sustainability issues and has in excess of 300 publications, including books, book chapters, and papers in refereed journals.

About the Editors

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Amanda Lange Salvia has a degree in Environmental Engineering from the University of Passo Fundo, Brazil, and graduate studies focused on sustainable cities and universities. Her work focuses on the Sustainable Development Goals, the role of universities towards sustainability and the impacts of climate change. Amanda has experience with international studies assessing aspects related to the 2030 Agenda and sustainability in higher education. She is a reviewer for various journals and is also a member of the editorial board of the International Journal of Sustainability in Higher Education. Professor Tony Wall was the founder and head of the International Centre for Thriving, a globalscale collaboration between business, arts, health, and education to deliver sustainable transformation for the common good. He is now the curator of Impact Incubators at Liverpool Business School in the UK and visiting professor at Stockholm University. He is passionate about thriving and has published more than 200 works, including articles in quartile 1 journals such as Nature Communications, The International Journal of Human Resource Management, and Vocations and Learning, as well as global policy reports for the European Mentoring & Coaching Council in Brussels. Overall, his leadership and international impact in these areas have attracted numerous accolades including the prestigious Advance-HE National Teaching Fellowship and three Santander International Research Excellence Awards.

About the Section Editors

Ulisses M. Azeiteiro The Centre for Environmental and Marine Studies (CESAM) and Department of Biology University of Aveiro Aveiro, Portugal

Anabela Marisa Azul Center for Neuroscience and Cell Biology Institute for Interdisciplinary Research University of Coimbra Coimbra, Portugal

Luciana Brandli Faculty of Engineering and Architecture Passo Fundo University Passo Fundo, Brazil

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About the Section Editors

Ernesto Brugnoli Oceanografía y Ecología Marina Facultad de Ciencias Universidad de la República Montevideo, Uruguay Estación Científica COIBA-AIP Clayton, Panamá

Ana M. M. Gonçalves University of Coimbra, MARE – Marine and Environmental Sciences Centre Department of Life Sciences Coimbra, Portugal Department of Biology and CESAM – Centre for Environmental and Marine Studies University of Aveiro Aveiro, Portugal

Giulia Guerriero Dept of Biology & Interdept. Research Center for Environment (CIRAm) University of Naples Federico II Napoli, NA, Italy

Nathalie Hilmi Environmental Economics Centre Scientifique de Monaco Monaco, Monaco

About the Section Editors

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Walter Leal Filho European School of Sustainability Science and Research Hamburg University of Applied Sciences Hamburg, Germany

Filipe Martinho Centre for Functional Ecology (CFE) Department of Life Sciences University of Coimbra Coimbra, Portugal

Fernando Morgado The Centre for Environmental and Marine Studies (CESAM) and Department of Biology University of Aveiro Aveiro, Portugal

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About the Section Editors

Saleem Mustafa Borneo Marine Research Institute Universiti Malaysia Sabah, Kota Kinabalu Sabah, Malaysia

Nidhi Nagabhatla The United Nations University Institute on Comparative Regional Integration Studies (UNU-CRIS) Bruges, Belgium School of Earth, Environment & Society McMaster University Hamilton, ON, Canada Melissa Nursey-Bray Department of Geography Environment and Population School of Social Sciences Faculty of Arts, The University of Adelaide Adelaide, SA, Australia Jessica M. Savage Global Sustainable Development School for Cross Faculty Studies University of Warwick Coventry, UK

Teppo Vehanen Natural Resources Natural Resources Institute Finland Helsinki, Finland

Contributors

Diletta Acuti Department of Marketing, University of Portsmouth, Portsmouth, UK Helena Adão MARE – Marine and Environmental Sciences Centre, School of Sciences and Technology, University of Évora, Évora, Portugal C. Marisa R. Almeida CIIMAR—Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Matosinhos, Portugal Olga M. C. C. Ameixa CESAM – Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal Caleb Christian Amos School of Engineering, Western Sydney University, Sydney, NSW, Australia EnviroWater Sydney Pty Ltd, Sydney, NSW, Australia Australia-Bangladesh Research Centre, Daffodil International University (DIU), Dhaka, Bangladesh CSIRO Land and Water, Canberra, ACT, Australia José S. Antunes do Carmo Department of Civil Engineering, University of Coimbra, Coimbra, Portugal Francisco Arenas CIIMAR – Interdisciplinary Centre of Marine and Environmental Research of the University of Porto, Matosinhos, Portugal Rafael Arocena Sección Limnología, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay Md. Ashrafuzzaman University of Lisbon, Lisbon, Portugal Nova University of Lisbon, Lisbon, Portugal University of East Anglia, Norwich, UK Department of Anthropology, University of Chittagong, Chattogram, Bangladesh Edison Barbieri Instituto de Pesca - Governo do Estado de São Paulo Mariculture Division, São Paulo, Brazil xxi

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Prabal Barua Department of Environmental Sciences, Jahangirnagar University, Savar, Dhaka, Bangladesh Trond Bjørndal SNF Centre for Applied Research at NHH, Bergen, Norway Ángel Borja AZTI, Marine Research, Basque Research and Technology Alliance (BRTA), Pasaia, Spain Faculty of Marine Sciences, King Abdulaziz University, Jeddah, Saudi Arabia Heitor Oliveira Braga Department of Biology and CESAM – Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal CAPES Foundation, Ministry of Education of Brazil (BEX: 8926/13-1), Brasília, DF, Brazil Ana Brasão Escola de Ciências Económicas e das Organizaçções, Uniersidade Lusófona Humanidades e Tecnologias, Lisbon, Portugal Brígida Rocha Brito International Relations Department, Environmental Studies and International Cooperation, Universidade Autónoma de Lisboa, Lisbon, Portugal Ernesto Brugnoli Oceanografía y Ecología Marina, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay Estación Científica COIBA-AIP, Clayton, Panamá Bruna Kist Brusius Federal University of Santa Maria, Santa Maria, Brazil Lucía Cabrera-Lamanna Departamento de Ecología y Gestión Ambiental, Centro Universitario Regional Este, Universidad de la República, Maldonado, Uruguay Helena Calado Faculty of Science and Technology, University of the Azores, Ponta Delgada, Portugal Douglas A. Campbell Department of Biology, Mount Allison University, Sackville, NB, Canada Patrícia G. Cardoso Group of Endocrine Disruptors and Emergent Contaminants, Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Matosinhos, Portugal Miguel Carneiro Department of Sea and Marine Resources, Division of Modelling and Management of Fisheries Resources, Portuguese Institute for Sea and Atmosphere, Lisbon, Portugal Sabuj Kumar Chaudhuri Department of Library and Information Science, University of Calcutta, Kolkata, West Bengal, India Paulo de Tarso Chaves Department of Zoology, Federal University of Parana, Curitiba, Brazil Jakub Ciesielczuk Lincoln Centre for Ecological Justice, University of Lincoln, Lincoln, UK

Contributors

Contributors

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João Pedro Coelho Biology Department and CESAM and ECOMARE, Aveiro University, Aveiro, Portugal Peter Convey British Antarctic Survey, Natural Environment Research Council (NERC), Cambridge, UK Sarah Cook School of Engineering, University of Warwick, Coventry, UK School of Biosciences, University of Nottingham, Nottingham, UK Roland Cormier Helmholtz-Zentrum Hereon, Institute of Coastal Systems – Analysis and Modeling, Geesthacht, Germany João P. S. Correia Instituto Politécnico de Leiria and Flying Sharks, Peniche, Portugal Simonetta Corsolini Department of Physical, Earth and Environmental Sciences, University of Siena, Siena, Italy Institute of Polar Science (CNR-ISP, Italy), Siena, Italy Elizabeth J. Cottier-Cook Scottish Association for Marine Science, Scottish Marine Institute, Oban, UK Daniel Crespo MARE – Marine and Environmental Sciences Centre, ESTM, Polytechnic of Leiria, Peniche, Portugal CFE, Centre for Functional Ecology – Science for People and the Planet, Department of Life Sciences, University of Coimbra, Coimbra, Portugal CIIMAR – Interdisciplinary Centre of Marine and Environmental Research of the University of Porto, Matosinhos, Portugal Matías Bastián Crisóstomo Centre Scientifique de Monaco, Environmental Economics, Monaco, Monaco George Cummings World Federation Coral Reef Conservation, Mission Blue Partner, SDG 14 Ocean Ambassador, Austin, TX, USA Leticia Cotrim da Cunha Programa de Pós-Graduação em Oceanografia/ FAOC, Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, Brazil Brazilian Network for Ocean Acidification (BrOA), Rio Grande, Brazil Rede Clima, Sub-Rede Oceanos, INPE, São José dos Campos, Brazil Agnieszka Dąbrowska Laboratory of Spectroscopy and Intermolecular Interactions, Faculty of Chemistry, University of Warsaw, Warsaw, Poland Sizenando Nogueira de Abreu Centre for Environmental and Marine Studies (CESAM), Department of Biology, University of Aveiro, Aveiro, Portugal Lisa Simone de Grunt SUBMARINER Network for Blue Growth, Berlin, Germany Ronald Buss de Souza National Institute for Space Research, Center for Weather Forecast and Climate Studies, São José dos Campos, Brazil

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Ana Carolina Esteves Dias School of Environment, Enterprise and Development, University of Waterloo, Waterloo, ON, Canada João M. Dias Centre for Environmental and Marine Studies (CESAM) and Department of Physics, University of Aveiro, Aveiro, Portugal Marina Dolbeth CIIMAR – Interdisciplinary Centre of Marine and Environmental Research of the University of Porto, Matosinhos, Portugal Felix Kwabena Donkor College of Agriculture and Environmental Sciences (CAES), University of South Africa (UNISA), UNISA Science Campus, Johannesburg, South Africa Rui Pena dos Reis Geosciences Centre, Coimbra University, Coimbra, Portugal Michael Elliott Department of Biological and Marine Sciences, University of Hull, Hull, UK International Estuarine and Coastal Specialists Ltd, Leven, UK Saeid Eslamian Department of Water Engineering, College of Agriculture, Center of Excellence in Risk Management and Natural Hazards, Isfahan University, Isfahan, Iran Abentin Estim Borneo Marine Research Institute, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia Ana M. Faria MARE – Marine and Environmental Sciences Centre, ISPA – Instituto Universitário, Lisbon, Portugal Lora E. Fleming European Centre for Environment and Human Health, University of Exeter Medical School, Cornwall, UK Catarina Frazão Santos Marine and Environmental Sciences Centre, Faculdade de Ciências, Universidade de Lisboa, Cascais, Portugal Environmental Economics Knowledge Centre, Nova School of Business and Economics, Carcavelos, Portugal Gustavo Luís Furini OBSERVARE – Observatory of Foreign Relations at the Autonomous University of Lisbon (UAL), Lisbon, Portugal Charles Galdies Institute of Earth Systems, University of Malta, Msida, Malta Maria Ines Gameiro Law School, Lisbon NOVA University, Lisbon, Portugal DINAMIA’CET – Centre for Socioeconomic and Territorial Studies, ISCTE – Lisbon University Institute, Lisbon, Portugal CIMA – University of Algarve, Faro, Portugal José G. Garcia-Casanova Master’s Program in Energy and Environment, Metropolitan Autonomous University, Iztapalapa, Mexico

Contributors

Contributors

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Maéva Gauthier Community-based Research Laboratory, Department of Geography, University of Victoria, Victoria, BC, Canada Hong Ching Goh Department of Urban and Regional Planning, Faculty of Built Environment, Universiti Malaya, Kuala Lumpur, Malaysia Ana M. M. Gonçalves University of Coimbra, MARE-Marine and Environmental Sciences Centre, Department of Life Sciences, Coimbra, Portugal Department of Biology and CESAM – Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal Leandra Regina Gonçalves Oceanographic Institute at University of São Paulo, São Paulo, Brazil Zachary Greenberg Natural Science and Mathematics, Biochemistry and Physics, University of Texas at Dallas, Richardson, TX, USA Alexandra Harrington Albany Law School, Albany, NY, USA Nathalie Hilmi Environmental Economics, Centre Scientifique de Monaco, Monaco, Monaco Francesca Iandolo Department of Management, Sapienza Università di Roma, Rome, Italy Nirupa Jain Manda Institute of Technology, Bikaner, Rajasthan, India Trilok Kumar Jain International School of Business Management, Suresh Gyan Vihar University, Jaipur, India A. Saleem Khan Centre for Climate Change and Sustainability Studies, School of Habitat Studies, Tata Institute of Social Sciences (TISS), Deonar, Mumbai, Maharashtra, India Elizabeth A. Kirk Lincoln Centre for Ecological Justice, University of Lincoln, Lincoln, UK Johann Lavaud UMR 6539 LEMAR, Institut Européen de la Mer, Plouzané, France Sara Leston Center for Functional Ecology, Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal Wenhua Liu Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Science, Shantou University, Shantou, People’s Republic of China Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, People’s Republic of China Ansje J. Löhr Faculty of Science, Department of Environmental Sciences, Open University of the Netherlands, Heerlen, The Netherlands

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Priscila F. M. Lopes Department of Ecology, Fishing Ecology, Management and Economics Group, Federal University of Rio Grande do Norte, Natal, Brazil Ivana Lukic SUBMARINER Network for Blue Growth, Berlin, Germany Isaac Lyne Institute for Culture and Society, Western Sydney University, Sydney, NSW, Australia M. Mahmudul Islam Department of Coastal and Marine Fisheries, Sylhet Agricultural University, Sylhet, Bangladesh Dimitra B. Manou School of Law, Aristotle University of Thessaloniki, Thessaloniki, Greece Sónia Cotrim Marques MARE – Marine and Environmental Sciences Centre, ESTM, Polytechnic of Leiria, Leiria, Portugal Márcia Marques CESAM – Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal Jillian Marsh Victoria University, Melbourne, VC, Australia Beatriz Martinez Romera Faculty of Law, University of Copenhagen, Copenhagen, Denmark Filipe Martinho Centre for Functional Ecology (CFE), Department of Life Sciences, University of Coimbra, Coimbra, Portugal Irene Martins CIIMAR—Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Matosinhos, Portugal Rogélia Martins Department of Sea and Marine Resources, Division of Modelling and Management of Fisheries Resources, Portuguese Institute for Sea and Atmosphere, Lisbon, Portugal Lee Matthews International Centre for Corporate Social Responsibility, Nottingham University Business School, University of Nottingham, Nottingham, UK Osgur McDermott Long United Nations Environment Programme World Conservation Monitoring Centre, Cambridge, UK Chris J. McOwen United Nations Environment Programme World Conservation Monitoring Centre, Cambridge, UK Kevin Mearns College of Agriculture and Environmental Sciences, University of South Africa (UNISA), UNISA Science Campus, Florida, South Africa Fernando Morgado The Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, Aveiro, Portugal Pablo Muniz Oceanografía y Ecología Marina, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay

Contributors

Contributors

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Gordon Munro The Uniersity of British Columbia, Vancouer School of Economics, Vancouer, BC, Canada Joelson Musiello-Fernandes Department of Agricultural and Biological Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil Saleem Mustafa Borneo Marine Research Institute, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia Faizan Hasan Mustafa Faculty of Business, Economics and Accountancy, Universiti Malaysia Sabah, Sabah, Malaysia P. B. Myles International Tourism Development Specialist: Coastal and Marine Tourism in Nelson Mandela Bay, Port Elizabeth, South Africa Nidhi Nagabhatla The United Nations University Institute on Comparative Regional Integration Studies (UNU-CRIS), Bruges, Belgium School of Earth, Environment & Society, McMaster University, Hamilton, ON, Canada Prateep Kumar Nayak School of Environment, Enterprise and Development, University of Waterloo, Waterloo, ON, Canada Raquel A. F. Neves Research Group of Experimental and Applied Aquatic Ecology, Federal University of the State of Rio de Janeiro (UNIRIO), Rio de Janeiro, Brazil Margarida Nunes Center for Functional Ecology, Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal Melissa Nursey-Bray Department of Geography, Environment and Population School of Social Sciences, Faculty of Arts, The University of Adelaide, Adelaide, SA, Australia Vítor H. Oliveira Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, Aveiro, Portugal Mariana Palma University of Coimbra, Centre for Functional Ecology, Department of Life Sciences, Coimbra, Portugal Miguel Ângelo Pardal CFE, Centre for Functional Ecology – Science for People and the Planet, Department of Life Sciences, University of Coimbra, Coimbra, Portugal David M. Paterson Sediment Ecology Research Group, Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, Fife, UK Camila Pegorelli Faculty of Science and Technology, University of the Azores, Ponta Delgada, Portugal Awangku Hassanal Bahar Pengiran Bagul Faculty of Business, Economics and Accountancy, Universiti Malaysia Sabah, Sabah, Malaysia P. B. Myles: deceased.

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Contributors

Leonel Pereira Department of Life Sciences, MARE – Marine and Environmental Sciences Centre, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal Freedom-Kai Phillips University of Cambridge, Cambridge, UK Nuno Pimentel Instituto Dom Luiz, Lisbon University, Lisbon, Portugal Sisir Kanta Pradhan School of Environment, Enterprise and Development, University of Waterloo, Waterloo, ON, Canada Radisti A. Praptiwi Department of Biotechnology, Universitas Esa Unggul, Jakarta, Indonesia Centre for Sustainable Energy and Resources Management, Universitas Nasional, Jakarta, Indonesia Ana Lígia Primo Centre for Functional Ecology – Science for People and the Planet, Department of Life Sciences, University of Coimbra, Coimbra, Portugal Sara Pruckner United Nations Environment Programme World Conservation Monitoring Centre, Cambridge, UK Madeleine Pullman The School of Business, Portland State University, Portland, OR, USA Tony George Puthucherril Jindal Global Law School, O.P. Jindal Global University, Sonipat, India Eric J. Raes The Commonwealth Scientific and Industrial Research Organisation, Hobart, Australia Ocean Frontier Institute and Department of Oceanography, Dalhousie University, Halifax, NS, Canada Ataur Rahman School of Engineering, Western Sydney University, Sydney, NSW, Australia Syed Hafizur Rahman Department of Environmental Jahangirnagar University, Savar, Dhaka, Bangladesh

Sciences,

Sandra Ramos CIIMAR—Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Matosinhos, Portugal Hervé Raps Department of Medical Biology, Scientific Center of Monaco, Monaco, Monaco Marta Chantal Ribeiro Law of the Sea Research Group – Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Porto, Portugal João Rito University of Coimbra, Centre for Functional Ecology, Department of Life Sciences, Coimbra, Portugal Centre for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal

Contributors

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Elsa T. Rodrigues Centre for Functional Ecology (CFE), University of Coimbra, Coimbra, Portugal Krishna Roka Department of Sociology, Winona State University, Winona, MN, USA Shahbudin Saad Faculty of Science, International Islamic University Malaysia, Kuantan, Pahang, Malaysia Edmond Sanganyado Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Science, Shantou University, Shantou, People’s Republic of China Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, People’s Republic of China Subrata Sarker Department of Oceanography, Shahjalal University of Science and Technology, Sylhet, Bangladesh Jessica M. Savage Global Sustainable Development, School for Cross Faculty Studies, University of Warwick, Coventry, UK Angela Schultz-Zehden SUBMARINER Network for Blue Growth, Berlin, Germany Khomotso Semenya College of Agriculture and Environmental Sciences (CAES), University of South Africa (UNISA), Florida, South Africa João Serôdio Department of Biology and CESAM – Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal Rossita Shapawi Borneo Marine Research Institute, Universiti Malaysia Sabah, Kota Kinabalu, Sabah, Malaysia Pradeep A. Singh Ocean Governance, Institute for Advanced Sustainability Studies, Potsdam, Germany Fabiola S. Sosa-Rodriguez Head of the Research Area of Growth and Environment, Department of Economics, Metropolitan Autonomous University, Azcapotzalco, Mexico Ana I. Sousa CESAM – Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal Douglas J. Spieles McPhail Center for Environmental Studies, Denison University, Granville, OH, USA Henry Bikwibili Tantoh Department of Environmental Science, College of Agriculture and Environmental Science, University of South Africa, Pretoria, South Africa Department of Geography, Faculty of Arts, University of Bamenda, Bamenda, Cameroon Nicholas Theux-Lowen Environmental Economics, Centre Scientifique de Monaco, Monaco, Monaco

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Rachel Tiller SINTEF Ocean, Trondheim, Norway Phil N. Trathan British Antarctic Survey, Natural Environment Research Council (NERC), Cambridge, UK Frank Van Belleghem Faculty of Science, Department of Environmental Sciences, Open University of the Netherlands, Heerlen, The Netherlands C. van Zyl Department Applied Management, University of South Africa, UNISA, Pretoria, South Africa Ivan Viegas University of Coimbra, Centre for Functional Ecology, Department of Life Sciences, Coimbra, Portugal Hugo C. Vieira Centre for Environmental and Marine Studies (CESAM), Department of Biology, University of Aveiro, Aveiro, Portugal Chloe Wale McMaster University Hamilton Canada, Hamilton, ON, Canada Sarah M. Watson Melbourne Law School, University of Melbourne, Carlton, VIC, Australia Lauren V. Weatherdon United Nations Environment Programme World Conservation Monitoring Centre, Cambridge, UK José C. Xavier University of Coimbra, Marine and Environmental Science Centre (MARE-UC), Department of Life Sciences, Coimbra, Portugal British Antarctic Survey, Natural Environment Research Council (NERC), Cambridge, UK Luciana Yokoyama Xavier Oceanographic Institute at University of São Paulo, São Paulo, Brazil Godwin Yeboah Institute for Global Sustainable Development, School for Cross Faculty Studies, University of Warwick, Coventry, UK Kim Yeojin International Environmental Research Institute (IERI), Gwangju Institute of Science and Technology (GIST), Gwangju, Republic of Korea Participants of the CSIRO Oceans and Atmosphere ECR workshop Life Below Water CSIRO, Hobart, Tasmania, Australia

Contributors

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Activities in the Area

Introduction

▶ Deep Seabed Mining and Sustainable Development Goal 14

Climate change is one of the world’s greatest environmental challenges. It is now plain that the emission of greenhouse gases, associated with industrialization and economic growth from a world population that has increased sixfold in 200 years, is causing global warming at a rate that is unsustainable (Blair 2006). The Intergovernmental Panel on Climate Change (IPCC) reports that by 2100 anthropogenically induced climate change is likely to lead to a rise in global temperatures of 1.5
C to 2
C above pre-industrial levels (IPCC 2018; Sinay and Carter 2020). The term sea-level rise (SLR) generally designates the average long-term global rise of the ocean surface measured from the center of the earth, as derived from satellite observations. Relative SLR refers to long-term average SLR relative to the local land level, as derived from coastal tide gauges. Whereas, on a global scale, SLR is mainly due to an increase of the water mass and water volume of the oceans. This global SLR often termed Eustatic SLR (Dronkers 2020) and based on three major components: (1) the most important contribution to twentieth and twenty-first century SLR is likely to be thermal expansion of the ocean as it warms. Other contributions include (2) the melting of glaciers, changes in the mass of the Antarctic and Greenland ice sheets, and (3) changes in the terrestrial storage of water (Church 2001). Sea level is reported to have risen during the twentieth century by between 1 and 2 mm per

Adaptation to Sea-Level Rise and Sustainable Development Goals A. Saleem Khan Centre for Climate Change and Sustainability Studies, School of Habitat Studies, Tata Institute of Social Sciences (TISS), Deonar, Mumbai, Maharashtra, India

Synonyms Adjustment; The act of adapting; The state being of adapted

Definition Adaptation is defined as the process of adjustment to actual or expected climate and its effects. In human systems, adaptation seeks to moderate or avoid harm or exploit beneficial opportunities. In some natural systems, human intervention may facilitate adjustment to expected climate and its effects (IPCC 2014).

© Springer Nature Switzerland AG 2022 W. Leal Filho et al. (eds.), Life Below Water, Encyclopedia of the UN Sustainable Development Goals, https://doi.org/10.1007/978-3-319-98536-7

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Adaptation to Sea-Level Rise and Sustainable Development Goals

year and model predictions suggest the rise in global-mean sea level during the twenty-first century is likely to be in the range of 9–88 cm (Church et al. 2001; Lowe et al. 2006). However, IPCC in its fifth assessment report (AR5) estimated, global mean SLR for 2081–2100 relative to 1986–2005 will likely be in the range of 0.26– 0.55 m for RCP2.6, 0.32–0.63 m for RCP4.5, 0.33–0.63 m for RCP6.0, and 0.45–0.82 m for RCP8.5. These ranges are derived from CMIP5 climate projections in combination with processbased models and literature assessment of glacier and ice sheet contributions (Church et al. 2013; IPCC 2013; Ramachandran et al. 2017). Impacts of SLR are determined by the relative sea-level change, reflecting not only the globalmean trend in sea level, but also regional and local variations in sea level change and in geological uplift and subsidence (Church et al. 2008). Although sea levels have been rising slowly for centuries, global change driven increases in the rate of rise will result in increased exposure to coastlines and coastal systems around the world. In fact, SLR is predicted to have major effects on terrestrial and marine life and is considered to portend significant population displacements over the next century, particularly in the developing world (McGranahan et al. 2007). In particular, coastal areas are expected to suffer both from the impacts of SLR, as well as other impacts, in addition to already existing problems of coastal erosion, subsidence, pollution, land use pressures, and deterioration of ecosystems (El Raey et al. 1999). The immediate effect is submergence and increased flooding of coastal land, particularly during extreme events, as well as saltwater intrusion into surface and ground waters (Church et al. 2008). In addition, globally, approximately 400 million people live within 20 m of sea level and within 20 km of a coast (Small et al. 2000; Gornitz et al. 2001). Thus, the risks associated with sea-level changes are real but highly uncertain. Adequate attention must be given to respond to the impacts of SLR and climate change that are already occurring, while at the same time preparing for future impacts. It is important to understand the nature of those risks, where natural and human systems are

likely to be most vulnerable, and what may be achieved by adaptive responses (IPCC 2001). Appropriate strategies can lead to a significant amelioration of the impacts of SLR through both the mitigation of our emissions and also plans to adapt to the inevitable consequences of SLR (Church et al. 2008). A series of global assessments suggest that the impacts of SLR could be significant during the twenty-first century, unless there is an appropriate adaptive response (Nicholls 2002). Thus, the need for adaptation to climate change is recognized more and more. Even if we would succeed in mitigation of the emission of greenhouse gases, it will take several decades for the global warming trend to be stopped (Kwadijk et al. 2010). Adaptation is an important approach for protecting human health, ecosystems, and economic systems from the risks posed by climate variability and change, and for exploiting beneficial opportunities provided by a changing climate (Scheraga and Grambsch 1998). It is the fundamental conjunctive concept in human-environment relations. It is through the process of adaptation that humans and natural systems conjointly construct socio-ecological systems, or environments (Oliver-Smith 2009). The resilience and flexibility exhibited in the patterns of human settlements show an inherent desire and some measure of capacity to adapt. However, our understanding of human adaptive capacity is less developed than our understanding of responses by natural systems, which limits the degree to which we can quantify societal vulnerability in the world’s coastal regions (Nicholls et al. 2007; Boateng 2008). Thus, adaptation is believed to be one such significant measure/strategy that reduces vulnerability to actual or expected climate-change effects (Khan et al. 2012a).

Different Types of Adaptation Adaptation to climate change is defined as the adjustment of practices, processes, and structures to reduce the negative effects and take advantage of any opportunities associated with climate change. According to Smithers and Smit (1997), adaptation is described as “Changes in a system in response to some force or perturbation, in this case related to

Adaptation to Sea-Level Rise and Sustainable Development Goals

IPCC TAR

Anticipatory Adaptation

Takes place before impacts of climate change.

Autonomous Adaptation

Triggered by ecological changes in natural systems or welfare changes in human systems.

Planned Adaptation

Result of a deliberate policy decision, based on an awareness.

Private Adaptation

Initiated and implemented by individuals, households or private companies.

Public Adaptation

Initiated and implemented by governments at all levels.

Reactive Adaptation IPCC AR5

Incremental Adaptation Transformational Adaptation

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Takes place after impacts of climate change. Aim is to maintain the essence and integrity of a system or process at a given scale. Changes the fundamental attributes of a system in response to climate and its effects.

Adaptation to Sea-Level Rise and Sustainable Development Goals, Fig. 1 Classification of different types of adaptation by IPCC. (IPCC Intergovernmental Panel on

Climate Change, TAR Third Assessment Report, AR5 Assessment Report 5)

climate.” Whereas, Pielke (1998) defines adaptation as “adjustment in individual, group and institutional behavior in order to reduce society’s vulnerabilities to climate.” It is also defined as an adjustment in ecological, social, or economic systems in response to actual or expected stimuli and their effects or impacts. This term refers to changes in processes, practices and structures to moderate potential damages or to benefit from opportunities associated with climate change. Adaptation hence involves adjustments to decrease the vulnerability of communities, regions, and nations to climate variability and change and in promoting sustainable development (IPCC 2001). United Nations Development Programme (UNDP) states that adaptation is a process by which strategies to moderate, cope with and take advantage of the consequences of climatic events are enhanced, developed, and implemented (UNDP 2006). United Kingdom Climate Impact Programme (UKICP) explains adaptation as, the process or outcome of a process that leads to a reduction in harm or risk of harm, or realization of benefits associated with climate variability and climate change (UKICP 2004). However, IPCC in its Fifth Assessment Report defines adaptation as “The process of adjustment to actual or expected climate and its effects. In human systems, adaptation seeks to moderate or avoid harm or exploit

beneficial opportunities. In some natural systems, human intervention may facilitate adjustment to expected climate and its effects” (IPCC 2014). The IPCC (2001) in its Third Assessment Report (TAR) distinguishes several types of adaptation (Fig. 1) as: (i) Anticipatory adaptation: Adaptation that takes place before impacts of climate change are observed, and it is also referred to as proactive adaptation. (ii) Autonomous adaptation: Adaptation that does not constitute a conscious response to climatic stimuli but is triggered by ecological changes in natural systems and by market or welfare changes in human systems. Also referred as spontaneous adaptation. (iii) Planned adaptation: Adaptation that is the result of a deliberate policy decision, based on an awareness that conditions have changed or are about to change and that action is required to return to, maintain, or achieve a desired state. (iv) Private adaptation: Adaptation that is initiated and implemented by individuals, households, or private companies, and it is usually in the actor’s rational self-interest. (v) Public adaptation: Adaptation that is initiated and implemented by governments at

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all levels. Public adaptation is usually directed at collective needs. (vi) Reactive adaptation: Adaptation that takes place after impacts of climate change has been observed. It may be conclusive to state that adaptation can be spontaneous or planned and can involve enhancing the feasibility of social and economic activities to make them less vulnerable to climate. Whereas, IPCC in its Fifth Assessment Report (AR5) classified adaptation broadly as: (i) Incremental adaptation: Adaptation actions where the central aim is to maintain the essence and integrity of a system or process at a given scale. (ii) Transformational adaptation: Adaptation that changes the fundamental attributes of a system in response to climate and its effects (IPCC 2014).

Retreat Natural system effects are allowed to occur and human impacts are minimized by pulling back from the coast

Coastal Adaptation Strategies to Sea-Level Rise Coastal adaptation has become an increasingly important area of study as the significance of climate change rises and coastal hazards continue to damage coastal space and communities. A more realistic approach is to use existing methods and strategies of coastal adaptation that inform and meet new challenges of climate-change-induced vulnerabilities (Cheong 2010). Coastal climate adaptation theory has typically categorized adaptation approaches into three broad categories, which are “retreat,” “protect,” and “accommodate” (Fig. 2) (Nicholls et al. 2007). The clustering of solutions into these three categories is now widespread throughout many parts of the world (Gibbs 2016). The strategies are explained as: (a) Retreat: All-natural system effects are allowed to occur and human impacts are minimized by

Protect Natural system effects are controlled by soft or hard engineering, reducing human impacts in the zone that would be impacted without protection

Accommodate Natural system effects are allowed to occur and human impacts are minimized by adjusting human use of the coastal zone

Coastal Adaptation Strategies to Sea-Level Rise

Adaptation to Sea-Level Rise and Sustainable Development Goals, Fig. 2 Coastal adaptation strategies to sealevel rise

Adaptation to Sea-Level Rise and Sustainable Development Goals

pulling back from the coast (Nicholls 2003). This approach involves dis-establishing settled areas, and often moving structures that are situated at locations that are at risk to locations that are not at risk from future inundation. Besides migration and population resettlement, it includes options such as relocating buildings and infrastructure to higher grounds or further inland, spatial planning for no-development zones, managed plot and river realignment, and setback zones (Bott and Braun 2019). It discourages development in high-risk coastal areas and encourages development at low-risk inland areas that are usually at higher elevation. Such adaptation can be time-consuming and expensive, because development of the new site must be accompanied by a relocation policy. However, if planned proactively, it can be the most sustainable and effective adaptation to the uncertainty of future SLR (Lee 2014). (b) Protect: All-natural system effects are controlled by soft or hard engineering, reducing human impacts in the zone that would be impacted without protection (Nicholls 2003). Protection typically consists of “hard” structural measures such as dikes, seawalls and floodgates, but also “soft” structural options such as periodic beach nourishment and dune restoration, and more indigenous options such as afforestation, stone walls or coconut leaf walls (Bott and Braun 2019). It proposes hard structures to block the inflow of sea water, and protects facilities and critical infrastructure that would be difficult to move or relocate. It is advantageous to plan for protection of the maximum land area with the minimum required infrastructure. Soft protection involves the use of natural sedimentation and vegetation to form a buffer zone. It is relatively low-cost and eco-friendly, and can be provided by natural processes that can be accelerated through minimal human effort, such as wetland restoration or planning waterfront parks (Lee 2014). (c) Accommodate: All-natural system effects are allowed to occur and human impacts are min-

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imized by adjusting human use of the coastal zone (Nicholls 2003). Accommodate involves changes and modification in existing structures and in human behavior, which allow to sustain the use of land. Thus, accommodating can be translated into “living with risks.” It refers to top-down measures such as modification of land use and building styles, and early warning systems, as well as to community-based measures such as informal money pooling and collective workforce organization (Bott and Braun 2019). It might involve modifying existing infrastructure for adaptive land uses, raising the ground level or improving drainage facilities, encouraging salt resistant crops, restoring sand beaches, and improving flood warning systems (Lee 2014).

Coastal Adaptation Approaches to Sea-Level Rise Strategy is defined as a plan of action designed to achieve a long-term or overall aim, whereas approach is defined as a way of doing or an act of approaching. In this context, the emerging approaches to address coastal adaptation to SLR can be broadly classified as engineering or infrastructure-based adaptation, ecosystem-based adaptation (EbA), and community-based adaptation (CbA) (Fig. 3). Each has its specific emphasis; the first is on recognizing the potential of hard structures that protects the coastal Infrastructures and second on harnessing the management of ecosystems as a means to provide goods and services in the face of climate change. Whereas, third is on empowering local communities to reduce their vulnerabilities. The extent that both CbA and EbA stress the relevance of local specificities; recognize the role of ecosystem goods and services in people-centered adaptation; and operate at scale, building from the bottom up. However, together, both approaches have a better chance to forcefully address short-comings of the mainstream top-down, “hard” infrastructurebased approach to adaptation, and promote more balanced and integrated approaches (Girot et al. 2012).

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Adaptation to Sea-Level Rise and Sustainable Development Goals, Fig. 3 Coastal adaptation approaches to sea-level rise

Engineering/ Infrastructurebased Adaptation

Ecosystem-based Adaptation

Community-based Adaptation

(a) Engineering/Infrastructure-based Adaptation: The major impacts of SLR on infrastructure systems in coastal areas are coastal flooding, coastal erosion, land subsidence, and saltwater intrusion (Almedia and Mostafavi 2016). These impacts will affect various infrastructure systems (e.g., trans port such as ports, roads, rail, airports; power and water supply; storm water, sewerage, tourist infrastructures, etc.). However, Climate impacts on coastal industries and infrastructures vary considerably depending on geographical location, associated weather and climate, and specific composition of industries within particular coastal regions (IPCC 2013). Adaptation strategies can involve operations and management, investments in infrastructure, and policy solutions. Strategies can be developed at the sector, citywide, or infrastructure-shed scales. Storm surge barriers, adaptive land management, coastal zone policies, and revised standards and regulations offer the potential for protection against enhanced flooding associated with SLR. Effective adaptation measures can bring near-term benefits such as increased resource-use efficiency (Rosenzweig et al. 2011). An innovative adaptation measures such as green

infrastructure, coastal renewable energy, and emerging coastal management practices, designing new coastal drainage system, incorporating climate change impacts, including SLR into planning for new infrastructure, protecting water supply systems from saltwater contamination, Incorporating wetland protection into infrastructure planning, Develop adaptive storm water management practices, Managing realignment and deliberately realign engineering structures, etc. (Tillmann and Siemann 2011) are some of the engineering/Infrastructure-based adaptation of coastal systems to changing climate in general and SLR in particular. However implementation of engineering/infrastructure adaptation strategies is daunting tasks and it requires efficient engineering plan, practical application in the field, and effective utilization of both human and technological resources and adequate funding. Assessment of innovative financing approaches to implement infrastructure adaptation decisions is another dimension that future studies need to address (Almedia and Mostafavi 2016). Proposals for coastal infrastructure as adaptations to SLR are shifting toward the inclusion of a wider range of options, with a greater interest in using

Adaptation to Sea-Level Rise and Sustainable Development Goals

dynamic landforms as engineered components of infrastructure (Jonkman et al. 2013; Hill 2015). A comprehensive set of specific contributions including the design of a multijurisdictional stakeholder–scientist process, the development of state-of-the-art scientific projections and mapping targeted to the needs of managers of critical infrastructure, and the development of a region-wide risk management approach to adaptation is needed (Rosenzweig et al. 2011). Furthermore, a constellation of efforts is required that are both infrastructure and location-specific and eloped and employed together, with coordination among many different public- and private-sector entities (Zimmerman and Faris 2010). To cite an example for Engineering/ Infrastructure-based adaptation, the Thames barrier near London, which protects the city from storm surges pushing up the river, is a marvel of modern engineering, with rotating gates that allow operators to control the flow of the river. Thames Barrier and associated flood dikes could, with fairly modest modification, be expected to provide a good standard of flood protection through to 2070, based on best estimates of SLR. (b) Ecosystem-based Adaptation (EbA): EbA is the use of biodiversity and ecosystem services as part of an overall adaptation strategy to help people to adapt to the adverse effects of climate change. EbA uses the range of opportunities for the sustainable management, conservation, and restoration of ecosystems to provide services that enable people to adapt to the impacts of climate change. It aims to maintain and increase the resilience and reduce the vulnerability of ecosystems and people in the face of the adverse effects of climate change (IPCC 2014). It identifies and implements a range of strategies for the management, conservation, and restoration of ecosystems to ensure that they continue to provide the services that enable people to adapt to the impacts of climate change (IUCN 2009). As adaptation is needed for the sectors of society facing the impacts of climate change, it is necessary to consider the

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vulnerability and role of ecosystems in a sustained provision of ecosystem services to these sectors (Vignola et al. 2009). Coastal ecosystems, which lie at the interface between marine and terrestrial ecosystems and provide an assortment of ecosystem services to different groups, rightly illustrate the challenges (Granek et al. 2010). For example, coastal ecosystems like wetlands, mangroves, coral reefs, oyster reefs, and barrier beaches all provide natural shoreline protection from storms and flooding in addition to their many other services (CBD 2009). However, a range of EbA approaches can build resilience by improving the conservation, protection and management of biodiversity and ecosystem services in coastal areas. Ecosystem restoration, Establishment and management of protected areas, Ecosystem restoration, Managed realignment and coastal setbacks, Sustainable fisheries management, etc. (USAID 2018). A key advantage of EbA as an adaptation option is the retention (if an ecosystem is conserved as part of an EbA project) or production (if an ecosystem is restored) of a range of ecosystem functions and services that are provided along with the targeted adaptation service– often referred to as “co-benefits” of EbA (Jones et al. 2020). Importantly, EbA requires collective action among governments, communities, conservation and development organizations, and other stakeholders to plan and empower action that will enhance environmental and community resilience to climate- change impacts (UNFCCC 2008). Thus, EbA is an emerging option that can offset anticipated ecosystem losses and improve coastal planning for SLR because it provides benefits beyond climate change stressors (Sierra-Correa and Kintz 2015). Adaptation of mangrove ecosystem to SLR through Joint Mangrove Management (JMM) and Integrated Mangrove Fisheries and Farming System (IMFFS) at Pichavaram Mangrove region of Tamil Nadu, India, represents one of the best examples of EbA to SLR.

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(c) Community-based Adaptation (CbA): It is a local, community-driven adaptation. CbA focuses attention on empowering and promoting the adaptive capacity of communities. It is an approach that takes context, culture, knowledge, agency, and preferences of communities as strengths (IPCC 2014). CbA is about empowering vulnerable communities and their local governments and service providers to understand and analyze how the climate is and will continue to impact on their lives, make informed and anticipatory decisions on priority adaptation actions, and constantly adjust their livelihood and risk management strategies in response to new and uncertain circumstances (CARE 2011). It generates adaptation strategies through participatory processes, involving local stakeholders and development and disaster risk–reduction practitioners. It builds on existing cultural norms and addresses local development concerns that make people vulnerable to the impacts of climate change in the first place (Ayers and Forsyth 2009). For example communities in the coastal areas tend to be dependent on climate sensitive resources and coastal people do not have the means to adapt fast enough (Ziervogel et al. 2006). These communities are generally very poor, depend on natural resources and occupy areas already prone to shocks such as floods or droughts. Identifying appropriate adaptation options should then follow, building on information about existing community capacity, knowledge and practices used to cope with climate hazards (Huq 2008). Very importantly, social learning process needs to identify the best practices through participatory processes for CbA. Thus, through an understanding of how people might cope and adapt to predicted climate change and climate induced SLR, meaningful measures can be taken to reduce their vulnerability (Khan 2013). CbA experiences emphasize that it is important to understand a community’s unique perception of their adaptive capacities in order to identify useful

solutions and that scientific and technical information on anticipated coastal climate impacts need to be translated into a suitable language and format that allows people to be able to participate in adaptation decisionmaking and planning (IPCC 2001). Thus, community capacity to understand climate risk issues, effectively use of available information, develop the necessary institutions and networks, plan and build appropriate climate change adaptation actions and, evaluate and monitor these to learn from experience is an essential prerequisite for effective adaptation (IFRC 2009; Khan et al. 2020). Capacity building to climate change adaptation at the community level and scaling it up into the policy perspective through application of Sustainable Livelihood Approach (SLA) of fishing communities at Chilika lagoon in Odisha, India, is a good example for CbA to SLR. SLA plays a lead role in analyzing adaptive capacity to climate change through livelihood assets analysis at the community level.

Mainstreaming Coastal Adaptation Strategies and Sustainable Development Goals Mainstreaming involves the integration of policies and measures that address climate change into development planning and ongoing sectoral decision-making, so as to ensure the long-term sustainability of investments as well as to reduce the sensitivity of development activities to both today’s and tomorrow’s climate (Klein 2002; Huq et al. 2003; Agrawala 2005). Mainstreaming take place at the national, subnational, and local levels. Optimally, it is an iterative process that adjusts based on the assessment of outcomes and builds on multistakeholder input from a range of governmental and nongovernmental actors (Olhoff and Schaer 2010; UNDP and UNEP 2011). Mainstreaming can increase the likelihood of success of development under a changing climate. It can lead to

Adaptation to Sea-Level Rise and Sustainable Development Goals

enhanced results across programmatic objectives, contribute to more efficient use of financial and nonfinancial resources, and improve the sustainability and scale of adaptation efforts (Mogelgaard et al. 2018). It is important to recognize that climate change adaptation presents a fundamental challenge to managing the coastal resources and should be mainstreamed into coastal management and development at all levels. To reduce vulnerability and to enhance resilience to projected scenarios of SLR, mainstreaming adaptation is considered as one of the appropriate responses as a coastal management option (Khan et al. 2012b). SLR and climate change will not occur in vacuum, and these responses need to be placed within an ICZM framework (Integrated Coastal Zone Management) (Bijlsma et al. 1996) and also understanding climate change (SLR) in the coastal zone is a fundamental component to ICZM. In terms of responding to climate change, ICZM can be seen as an essential institutional mechanism that can deal with all competing pressures on the coast, including short, medium, and long-term issues (Kavikumar 2005). It provides a framework within which flexible responses can be developed to deal with the inherent uncertainty about the future, including rates and magnitude of climate change. In addition, it must anticipate and respond to the needs of coastal communities, public participation, and stakeholder involvement in the planning and implementation of ICZM are considered essential (Klein 2002). An agenda for collaborative learning about mainstreaming, for instance, could prove invaluable. Such an agenda could contribute to overcoming the artificial divide between the Community-based Adaptation approaches from the Ecosystem-based Adaptation approach, thus complementing the dominant infrastructure-based approach to adaptation (hard adaptation) espoused by many major international financial institutions. A common agenda is probably the best way of making the case for an inclusive approach to adaptation which empowers communities, and manages ecosystems in a way that enhances resilience and adaptation over time (Girot et al. 2012).

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Climate change adaptation, disaster risk reduction, and hazard assessment are strongly linked, and it is evident that this intersection is a strategic planning challenge for coastal communities. It is in this nexus of climate change adaptation and disaster risk reduction where some of the major challenges exist for local governments and planners (Sinay and Carter 2020). Furthermore, mainstreaming Sustainable Development Goals (SDGs) into the climate policy framework require sound policymaking at national and subnational levels in sectors that are core to sustainable development and climate change (TERI 2020). SDG Goal 11 Sustainable Cites and Communities (Target: Adaptation to climate change, resilience to disasters, and develop and implement, in line with the Sendai Framework for Disaster Risk Reduction); SDG Goal 13 Climate Actions (Target: strengthen resilience, Integrate climate change measures into national policies, strategies and planning, Improve education, awareness-raising and human and institutional capacity on climate change adaptation); SDG Goal 14 – Life below water (Target: Sustainably manage and protect marine and coastal ecosystems to avoid significant adverse impacts, including by strengthening their resilience, and take action for their restoration) (UN 2015) are some of the major SDGs that par in line with coastal adaptation and management strategies. Thus, these links between development and adaptation have resulted in calls to tackle the two issues in an integrated way to mainstream climate change adaptation into development support and development planning (Ayers et al. 2013). Importantly, mainstreaming should create no regrets opportunities for achieving development that is resilient to current and future climate impacts for the most vulnerable groups, and avoid potential tradeoffs between adaptation and development strategies that could result in maladaptation in the future (Klein et al. 2003; Ayers and Huq 2009; Ayers et al. 2013). Policy frameworks which require community consultation or participatory approaches can facilitate the inclusion of local community groups in climate change planning processes (Archer et al. 2014) and integrated community approaches to climate

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Adaptation to Sea-Level Rise and Sustainable Development Goals

Integrated Coastal Zone Management (ICZM)

Other Coastal Developmental Policies

SDG 11 Sustainable Cites and Communities

Mainstreaming coastal adaptation to SLR

Sendai Framework for Disaster Risk Reduction

SDG 13 Climate Actions

SDG 14 Life Below Water

Adaptation to Sea-Level Rise and Sustainable Development Goals, Fig. 4 Outline of mainstreaming coastal adaptation strategies and sustainable development goals

change adaptation through the formulation and mainstreaming of adaptation plans warrants urgent attention (UNDP 2012). Figure 4 outlines coastal adaptation strategies and SDGs.

Conclusion Climate change-induced SLR is one of the greatest challenges of the low-lying coastal regions of the world. Rising seas, more frequent storms, and other climate-driven coastal hazards necessitate adaptation planning measures to protect people and property (Reiblich et al. 2019). It is considered as one of the most appropriate response measures to face this global challenge, and it requires a pragmatic approach that’s locally suitable (Ramachandran et al. 2017). Adaptation responses are initiated by individuals or organizations and can be seen as efforts to manage system resilience, that is, to maintain, enhance, or change socio-ecological system function and structure (Nelson 2011; Keys et al. 2014). There are numerous approaches and academic debate (Termeer et al. 2017), surrounding climate change adaptation strategies and plans and how they support the

implementation of sustainability in practice. They range from approaches designed to embed adaptation into existing development planning, policy, and decision-making (Cuevas et al. 2016), aligning adaptation with sustainable development (Brown 2011), to transformative changes in governance that facilitate larger scale, step changes to improve our social and ecological resilience to climate change (Fazey et al. 2018; Brown et al. 2017). In order to address SDGs in general and SDG Goal 14 (Life Below Water) in particular through the lens of adaptation to SLR, this study outlines the following: 1. Different types of adaptation: IPCC has classified different types of adaptation as anticipatory adaptation, autonomous adaptation, planned adaptation, private adaptation, public adaptation, reactive adaptation, incremental adaptation and transformational adaptation. However, adaptation to SLR by the coastal systems could be a combination of all the above and/or one or more. Nevertheless, anticipatory and planned adaptation gains more attention as it provides more opportunities to prepare and cope with rising sea levels.

Adaptation to Sea-Level Rise and Sustainable Development Goals

2. Coastal adaptations strategies to sea-level rise: IPCC has recommended protect, retreat and accommodate are three major coastal adaptations strategies to address SLR. It is important that coastal regions begin preparations for adaptation to SLR, because there are opportunities to avoid adverse impacts by acting now (Dronkers et al. 1990). Given that SLR will likely continue into the future, the promotion and implementation of these adaptation strategies is necessary to ensure community resilience (Dvorak et al. 2018). 3. Coastal adaptation approaches to sea-level rise: There are number of ways, adaptation strategies are implemented; however, the infrastructure-based adaptation, ecosystem-based adaptation, and community-based adaptation are three emerging approaches to address coastal adaptation to SLR. Integrated approaches (Engineering/Infrastructure adaptations, EbA and CbA) have gained traction over recent years, and coastal policymakers and planners are increasingly promoting an integrated approach to respond to SLR and coastal challenges. These integrated approaches have the potential to benefit coastal infrastructures, coastal communities, and coastal ecosystems and their services. 4. Mainstreaming coastal adaptation strategies and sustainable development goals: Mainstreaming adaptation into development planning has been promoted as an effective way to respond to climate change (Lebel et al. 2012). Identifying windows of opportunity and understanding how they operate in this way can support sustainability and adaptation mainstreaming and dynamic adaptation pathway approaches to help deliver transformational change necessary for sustainable adaptation to climate change in coastlines worldwide (Brown et al. 2017).

Cross-References ▶ Artisanal Fisheries: Management and Sustainability ▶ Coastal Defenses and Engineering Works

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▶ Community-Based Research and Participatory Approaches in support of SDG14 ▶ Mangroves Conservation: Relevant Task to Achieve the SDG14 ▶ Traditional Fishing Community and Sustainable Development Acknowledgments The author is grateful to Centre for Climate Change and Sustainability Studies, School of Habitat Studies, and the management of Tata Institute of Social Sciences, Mumbai, India, for the generous support and encouragements.

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Lee Y (2014) Coastal planning strategies for adaptation to sea level rise: a case study of Mokpo, Korea. J Build Constr Plan Res 2(1):74–81 Lowe JA, Gregory JM, Ridley J, Huybrechts P, Nicholls RJ, Collins M (2006) The role of sea- level rise and the Greenland Ice Sheet in dangerous climate change: implications for the stabilization of climate. In: Schellnhuber HJ, Cramer W, Nakicenovic N, Wigley T, Yohe G (eds) Avoiding dangerous climate change. Cambridge University Press, New York McGranahan G, Balk D, Anderson B (2007) The rising tide: assessing the risks of climate change and human settlements in low elevation coastal zones. Environ Urban 19(17):17–37 Mogelgaard K. Dinshaw A, Ginoya N, Gutiérrez M, Preethan P, Waslander J (2018) From planning to action: mainstreaming climate change adaptation into development. Working paper. World Resources Institute, Washington, DC Nelson DR (2011) Adaptation and resilience: responding to a changing climate. WIIREs Clim Change 2(1):113–120 Nicholls RJ (2002) Analysis of global impacts of sea-level rise: a case study of flooding. Phys Chem Earth A/B/C 27(32–34):1455–1466 Nicholls RJ (2003) Case study on sea-level rise impacts. OECD workshop on the benefits of climate policy: improving information for policy makers. Working Party on Global and Structural Policies. https://www. oecd.org/env/cc/2483213.pdf. Accessed 29 Oct 2020 Nicholls RJ, Wong PP, Burkett VR, Codignotto JO, Hay JE, McLean R, Ragoonaden S, Woodroffe CD (2007) Coastal systems and low-lying areas. In: Parry ML, Canziani OF, Palutikof JP, van der Linden PJ, Hanson CE (eds) Climate change: impacts, adaptation and vulnerability. Contribution of working group II to the fourth assessment report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, UK Olhoff A, Schaer C (2010) Screening tools and guidelines to support the mainstreaming of climate change adapatation into development assistance: a stock taking report. United Nations Development Programme, New York Oliver-Smith A (2009) Sea level rise and the vulnerability of coastal peoples responding to the local challenges of global climate change in the 21st century. InterSecTions ‘Interdisciplinary Security ConnecTions’ Publication Series of UNU-EHS No. 7/2009. UNU Institute for Environment and Human Security (UNU-EHS) UN Campus, Bonn Pielke RA (1998) Rethinking the role of adaptation in climate policy. Glob Environ Chang 8(2):159–170 Ramachandran A, Khan AS, Prasnnahvenkatesh R, Palanivelu K, Jayanthi N (2017) Projection of climate change induced sea level rise for the coasts of Tamil Nadu and Puducherry, India using SimCLIM: a first step towards planning adaptation policies. J Coast Conserv 21:731–742 Reiblich J, Hartge E, Wedding LM, Killian S, Verutes GM (2019) Bridging climate science, law, and policy to

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14 advance coastal adaptation planning. Mar Policy 104: 125–134 Rosenzweig C, Solecki WD, Blake R, Bowman M, Faris C, Gornitz V, Horton R, Jacob K, LeBlanc A, Leichenko R, Linkin M, Major D, O’Grady M, Patrick L, Sussman E, Yohe G, Zimmerman R (2011) Developing coastal adaptation to climate change in the New York City infrastructure-shed: process, approach, tools, and strategies. Clim Chang 106(1):93–127 Scheraga JD, Grambsch AE (1998) Risks, opportunities, and adaptation to climate change. Clim Res 11(1):85– 95 Sierra-Correa PC, Kintz CJR (2015) Ecosystem-based adaptation for improving coastal planning for sealevel rise: a systematic review for mangrove coasts. Mar Policy 51:385–393 Sinay L, Carter RWB (2020) Climate change adaptation options for coastal communities and local governments. Climate 8(7):1–15 Small C, Gornitz V, Cohen JE (2000) Coastal hazards and the global distribution of human population. Environ Geosci 7:3–12 Smithers J, Smit B (1997) Human adaptation to climatic variability and change. Glob Environ Chang 7(2):129– 146 TERI (2020) Mainstreaming sustainable development and enhancing climate resilience: new opportunities for states in India. https://www.teriin.org/projects/nfa/ files/working-paper-subnational-action.pdf. Accessed 29 Oct 2020 Termeer CJ, Dewulf A, Biesbroek GR (2017) Transformational change: governance interventions for climate change adaptation from a continuous change perspective. J Environ Plan Manag 60:558–576 Tillmann P, Siemann D (2011) Climate change effects and adaptation approaches in marine and coastal ecosystems of the north pacific landscape conservation cooperative region. A compilation of scientific literature final report. National Wildlife Federation, U.S. Fish and Wildlife Service Region 1 Science Applications Program. https://www.nwf.org/~/media/PDFs/GlobalWarming/2014/Marine-Report/NPLCC_Marine_Cli mate-Effects_Final.pdf. Accessed 29 Oct 2020 UKCIP (2004) Contextual framework of the costing guidelines. In: Costing the impacts of climate change in the UK. United Kingdom Climate Impact Program (UKCIP), Oxford, UK UN (2015) Transforming our world: the 2030 Agenda for Sustainable Development. Resolution adopted by the General Assembly on 25 September 2015. https:// www.un.org/ga/search/view_doc.asp?symbol¼A/ RES/70/1&Lang¼E. Accessed 29 Oct 2020 UNDP (2006) Adaptation policy framework for climate change. In: Adaptation to climate change. United Nations Development Program (UNDP), New York UNDP (2012) Sea-level rise. Vanuatu – LDCF Project Identification Form (12 October 2012). United Nations Development Program (UNDP). https://www.adaptation-undp.

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Adjustment ▶ Adaptation to Sea-Level Rise and Sustainable Development Goals

Aichit Target 11 ▶ Concepts of Marine Protected Area

Alluvial Plain ▶ Wetland Ecosystems and Marine Sustainability

Antarctic: Climate Change, Fisheries, and Governance

Antarctic Continent ▶ Antarctic: Climate Change, Fisheries, and Governance

Antarctic: Climate Change, Fisheries, and Governance José C. Xavier1,2 and Peter Convey2 1 University of Coimbra, Marine and Environmental Science Centre (MARE-UC), Department of Life Sciences, Coimbra, Portugal 2 British Antarctic Survey, Natural Environment Research Council (NERC), Cambridge, UK

Synonyms Antarctic continent; Southern Ocean

Definition The continent of Antarctica has an area of c. 1.4 million km2, and the surrounding Southern Ocean (waters south of the Antarctic Polar Front) comprises 9.6% of the world’s oceans, both possessing significant environmental, scientific, historic, educational, and intrinsic values (Burton-Johnson et al. 2016; Hughes et al. 2018; Xavier et al. 2016b). Antarctica is the coldest, windiest, and driest continent on Earth, with temperatures in parts of its central icy plateau descending below 90
C (Cassano 2013; Scambos et al. 2018). Antarctica includes about 10% of the planet’s land surface and its ice contains about 70% of its freshwater (Kennicutt II et al. 2014; Walton 2013). It became isolated from other continents around 25–35 My ago, in the final stages of the breakup of Gondwana (Convey et al. 2018; Storey 2013), and this has led to high levels of endemism, particularly of certain marine groups such as fish and crustaceans (Xavier and Peck 2015), and many terrestrial

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groups (Pugh and Convey 2008). Antarctica hosts a wide diversity and abundance of species, particularly but not only in the marine environment (Convey 2017; De Broyer and Jażdżewska 2014). The Antarctic Treaty governs the region south of the 60
parallel of latitude, with its main objectives being to ensure peaceful use of Antarctica, promote international scientific cooperation and deliver environmental protection (Bennett et al. 2015; Berkman 2009; Hughes et al. 2018).

Introduction Importance of the Antarctic Region to the Planet Antarctica and the Southern Ocean have profound influences on the rest of Planet Earth, including on sea level, ocean circulation, climate, and marine productivity (IPCC 2013; Rintoul et al. 2018; Sarmiento et al. 2004) (Fig. 1). Furthermore, parts of these regions are among those that have been changing faster than any other regions on Earth in recent decades (Convey et al. 2012; Convey and Peck 2019; IPCC 2018; Turner et al. 2009, 2014), where important scientific and technological challenges have yet to be addressed (Chown and Brooks 2019; Kennicutt II et al. 2014, 2016; Xavier et al. 2016a). Life in the Antarctic and Southern Ocean (Fig. 2) faces extreme environmental conditions, including chronic low temperatures, high winds, seasonally intense solar radiation and sea-ice, and freezing and/or desiccation stress (Peck et al. 2006; Xavier and Peck 2015). In terrestrial habitats, the Antarctic is characterized by long winters and short summers. Terrestrial and freshwater organisms face considerable and unpredictable thermal variation particularly in summer. Although accumulated thermal energy sums are low to very low, even in comparison with the Arctic, spatial variability in Antarctic terrestrial ecosystems is very high on multiple physical scales (Convey et al. 2012; Peck et al. 2006). Apart from one species of scavenging bird (snowy sheathbill Chionis albus) that is

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Antarctic: Climate Change, Fisheries, and Governance

Antarctic: Climate Change, Fisheries, and Governance, Fig. 1 Map of Antarctica and the surrounding regions, with some key locations noted. (Adapted from De Broyer and Koubbi (2014) and Xavier et al. (2016c))

associated with marine vertebrate colonies and aggregations, there are no native terrestrial vertebrates in the Antarctic continent. The true terrestrial fauna consists entirely of invertebrates, with the largest being two species of chironomid midge (c. 0.5 cm in length, 80% of the grazing pressure upon phytoplankton. These Authors also suggested, already in 1999, that the annual pelagic primary and secondary productions are likely to increase in the future as a consequence of reduction and thinning of sea ice cover due to global warming.

Hydrurga leptonyx; c Antarctic minke whale Balaenoptera bonaerensis; and d killer whale Orcinus orca. (Photo Simonetta Corsolini)

Box 2 Insight into Polar Key Species

Krill are pelagic shrimps belonging to the order of Euphausiacea and different species are present in the oceans. These zooplanktonic Crustaceans are omnivorous and feed preferably on diatoms. Two species are present in the Southern Ocean: the ice krill Euphausia crystallorophias and the larger Antarctic krill Euphausia superba. The Thysanoessa inermis is an arctic and subarctic species and it is dominant in the Greenland seawaters. All these species are caught in Polar Oceans for different use, including sport fishing, aquarium food, aquaculture, krill oil pills, colorant and a flavoring additive to fish and other products for human consumption, food additive, krill hydrolysate, low-fluoride krill paste, and (continued)

Antarctica and NE Greenland: Marine Pollution in a Changing World

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Antarctica and NE Greenland: Marine Pollution in a Changing World, Fig. 8 Arctic marine birds and mammals: a fulmars and gulls; b northern fulmar Fulmarus

Box 2 (continued)

krill protein concentrates (Nicol and Endo 1997). The Antarctic silverfish Pleuragramma antarctica is another key species in the Southern Ocean ecosystems and it is considered a link between lower and higher trophic levels (Bottaro et al. 2009). It is the only full pelagic fish of the Southern Ocean (Kailola et al. 1993); its embryonated eggs and larvae live in the pack ice cavities (Bottaro et al. 2009). This fish feed on eggs, larvae, or adults of copepods, euphausiids, polychaetes, and chaetognaths depending on their life stage as they forage on larger food items with increasing size (Dewitt et al. 1990). The polar cod Boreogadus saida is a key species of the Arctic food webs and it links the lower with the higher trophic levels

glacialis; c polar bear Ursus maritimus; d fin whale Balaenoptera physalus. (Photo Simonetta Corsolini)

(Hop and Gjøsæter 2013); larvae and juveniles are associated to the pack ice and live in its cavities (Scott et al. 1999), and adults can show a pelagic behavior living under the ice (Hop and Gjøsæter 2013) or a benthic behavior (Falk-Petersen et al. 1986).

The polar key species spend their early life stage under the pack ice and are part of the cryopelagic community; it includes organisms of different trophic levels from phytoplankton to zooplankton, and fish. Diatoms are the most represented phytoplankton organisms in Polar Regions and they can be found under and inside the pack ice where the light is firstly available in Spring to start the primary production. Energy is then immediately available for other organisms like larvae and adults of copepods, Euphausiacea, and fish that feed directly or indirectly on this food resource. Survival in the extreme and cold

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Antarctica and NE Greenland: Marine Pollution in a Changing World

Antarctica and NE Greenland: Marine Pollution in a Changing World, Fig. 9 The Antarctic pack ice in November; the color of the ice is due to the presence of the cryopelagic community. (Photo Simonetta Corsolini)

environment of the Southern Ocean is energetically expensive, thus primary production is inefficiently converted into animal biomass in krillbased food-webs (Hempel 1985). In Summer, the progressive ice melting allow first phytoplankton and then zooplankton to bloom. These are the first steps of the Spring and Summer blooms, allowing the Polar ecosystems to function; most of marine organisms have to feed and complete their reproductive cycle during the Summer months to be able to overwinter. The cryopelagic community (Fig. 9) play a fundamental role in the Polar marine ecosystems and at the same time in the POP transfer from ice to trophic webs. In fact, those contaminants trapped in the ice are released in the water column during Summer melting and are then available to be bioaccumulated by the cryopelagic organisms and all those species living under and in the pack. This mechanism of POP transfer from the abiotic compartment to the trophic web of Polar ecosystems can be enhanced by the global change as the increasing melting of ice can remobilize contaminants previously trapped in it (Figs. 1 and 4). The same mechanism allows contaminants trapped in the continental freshwater ice to reach the ocean when huge icebergs calve from the ice shelves; these events have been increased during the last decades due to global warming and a possible increase of POP concentration was reported in the Ross Sea fish (Cincinelli et al. 2016; Corsolini et al. 2016a).

Strategy Against Cold of Marine Organisms: Why Are They a Risk Factor for Bioaccumulation? Polar marine organisms show interesting strategies of adaptations to the extreme cold climate. Among them, they accumulate lipids with different functions: protection from the cold, buoyancy, energy reserve for overwintering. For instance, marine birds and mammals accumulate subcutaneous fat (blubber in marine mammals) during Summer months to protect themselves from cold. Krill also accumulate lipids as energy reserve for overwintering: in autumn the lipid content peaks to 39.2% of dry mass to decrease to 10.5% of dry mass after overwintering (Hagen et al. 1996), and 70% of this content are triacylglycerol (Hagen et al. 2001). In other invertebrates, lipids are regulator of buoyancy (Visser and Jónasdóttir 1999). In the Southern Ocean, Notothenioid fish lack of swim bladder: their cartilaginous skeleton and the presence of fat accumulations allow buoyancy. The skin is also covered by lipids. The silverfish and another important Antarctic species, the Dissostichus mawsoni, both widely distributed and of high ecological value, are neutrally buoyant: both of them have important lipid deposits involved in buoyancy, although different mechanisms of storage exists in these species (Eastman 1988): the silverfish stores lipids in large subcutaneous and intermuscular sacs and uses them for

Antarctica and NE Greenland: Marine Pollution in a Changing World

buoyancy; the D. mawsoni stores lipids in adipose cells and in subcutaneous and muscular deposits (4.7–4.8% body weight, respectively) (Eastman 1988). Most of these buoyancy lipids are triacylglycerols in both species and may be also used as energy reserve (Eastman 1988). In the Arctic Ocean, most of the lipid content of B. saida is represented by triacylglycerols (58.4  6.3%) (Scott et al. 1999). Contaminants such as POPs show lipoaffinity, especially to triacylglycerols and other nonpolar or low-polar lipids that in organisms are used for energy reserve (Haedrich et al. 2020). Thus POPs accumulate in the lipid component of the tissues or in the free lipid fraction and they can be detected in both them (de Boer 1988; Haedrich et al. 2020). Lipids are transferred from low trophic levels including plankton to top predators from Spring within the summer semester (FalkPetersen et al. 1987). All these ecological features are important when studying the POP bioaccumulation in Polar marine environments: low trophic levels are rich in lipids, thus POPs can biomagnify starting from low levels of the food webs. The benthic-pelagic coupling of the marine ecosystems includes important and crucial processes that allow the exchange of energy and mass between the pelagic and benthic zones. These processes are important in the Polar Oceans where, for instance, fish are mostly benthopelagic (except the silverfish in Antarctica and few species, e.g. B. saida, in the Arctic). Together with the mass and energy transfer, also contaminants may be transferred and then sink in the sediments or enter benthic food webs. In the Anthropocene, an adaptive strategy that makes species tolerant to life in the extreme climate of Polar Regions is becoming a potential risk, fostering the bioaccumulation of lipophilic contaminants and toxic substances such as POPs. These mechanisms are important when considering that polar trophic webs are krill-centered (Everson 1977): most of the organisms feed directly or indirectly on krill, which is a highly rich food able to provide the necessary energy to organisms living in these extreme environments.

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Contamination of Polar Marine Ecosystems: General Considerations The presence of contaminants in the Antarctic region was first reported in penguins and crabeater seal in the 1960s (Sladen et al. 1966) and, since then, there has been a growing interest in the study and monitoring of POPs in abiotic and biotic compartments of these ecosystems. For many decades, the Southern Ocean was considered as the last uncontaminated area of our planet; now we know that contaminants can be detected in those ecosystems, although usually at very low levels (Corsolini and Focardi 2000; Corsolini 2009; Bengtson Nash 2011). This awareness has grown in recent years, because researches have shown that the Arctic acts as a final reservoir (being a cold trap) for many POPs (AMAP 2002, 2015, 2017), and Antarctic could be a final sink as well (Corsolini and Focardi 2000). The scientific evidences suggest that contaminants may be higher in the Arctic rather than in the Antarctic region likely because their different geography (as described in the previous section) and other factors, e.g.: most of the planet’s human population (87.5%) live in the Northern Hemisphere and the human impact on natural resources is highest between 5
N and 50
N (Kummu and Varis 2011); lands are source of air particles that can carry pollutants and the Northern Hemisphere is covered by 40% landmass and 60% water while the Southern Hemisphere by 20% landmass and 80% water (NASA 2019); an air inorganic pollution belt was reported to exist across the Northern Hemisphere between the Polar Circle and the Tropic of Cancer in Summer (Naranjo 2006); the air masses are mixed between the Hemispheres very slowly, thus pollutants from the Northern one can reach the Antarctic region later respect to the Greenlandic Arctic. Abiotic Polar Compartments: Are They Polluted? The presence of POPs and persistent plastic materials (PPMs) in the marine abiotic compartments (seawater, sediments, near-surface air, pack ice) of the Southern Ocean and Greenland Sea including NEG fjord system is low in the Southern Ocean

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Antarctica and NE Greenland: Marine Pollution in a Changing World

compared to other latitudes, and, in some areas of the NEG seawaters, is comparable or higher than in more anthropized areas (Hallanger and Gabrielsen 2018). In the Southern Ocean, POPs (for a review, see Fuoco et al. 2009) and PPMs (for a review, see Waller et al. 2017) were reported in marine sediments, seawater, and pack ice. PPMs including micro- to macro-plastics were recorded in deepsea sediments and surface waters (Waller et al. 2017) at levels likely negligible on a regional scale, though perhaps significant on a local scale (Waller et al. 2017). Very little is known on the POP presence in NEG marine ecosystems: the periodical reports of the Arctic Monitoring and Assessment Program do not mention much data in this area (AMAP 2002, 2009, 2015, 2017; Hung et al. 2016). Some flame retardants were detected in high volume air samples collected at Zeppelin and Villum Research Station (NEG) with values below the detection limits (0.4 pg/m3) (Vorkamp et al. 2015). PPMs were reported in the NEG seawater abiotic compartments (Greenland Sea) (for a review, see Hallanger and Gabrielsen 2018). Macro-plastics were detected on the sea surface in the Euro-Arctic from the Barents Sea and Fram Strait (Bergmann et al. 2016), and in the Greenland Sea (Jiang et al. 2020) at a lower density than at mid-latitude (Hallanger and Gabrielsen 2018). It was proposed that sea ice may delay or prevent the spreading of floating litter to the Arctic and/or that the distance to populated areas may limit their dispersion to Arctic regions (Bergmann et al. 2016). Anyway, an increasing of PPMs in the Arctic including the NEG seawaters is expected in the future (Tekman et al. 2017). Box 3 Persistent Plastic Materials (PPMs)

PPMs include all kind of plastic items released into the environment, from nanoto macro-scale dimension, including all chemical origin and sources. PPMs can be released into the Polar marine environment from ships (passenger ferries, cargo, fishing vessels, etc.) as well as scientific research

stations, although a distant source may not be excluded through atmospheric and ocean transport.

Are Polar Organisms Contaminated? The bioaccumulation of POPs in organisms is driven by physical, chemical, biological, and ecological factors. It was reported that POPs with a lower biomagnification potential tend to dominate in polar organisms and the biomagnification process is larger in Antarctic than sub-Arctic areas (Corsolini and Sarà 2017). These patterns are linked to the chemical structure of molecules and their physical-chemical properties, that affect their bioaccumulation. Concentrations in Antarctic marine organisms are generally in the range of dozens to hundreds pg/g of wet tissue and dozens ng/g in resident predators like Adèlie penguins (Corsolini et al. 2011). Levels are of the same order of magnitude also in NEG marine organisms (Corsolini et al. 2016b) except the top predator Greenland shark (Somniosus microcephalus) which bioaccumulate POPs at concentrations of at least one order of magnitude higher (Hobson et al. 1994; McKinney et al. 2012; Strid et al. 2013; Corsolini et al. 2014; Mckinney et al. 2015; Ademollo et al. 2018; Cotronei et al. 2018). Unfortunately little is known on the presence of POPs (AMAP 2002, 2009, 2015, 2017) or PPMs (Morgana et al. 2018) in organisms from NEG seawaters. The increasing human population will have a dramatic impact on the marine environments globally as the use of resources, the release of persistent pollutants including POPs, PPMs, and inorganic persistent contaminants will increase if no regulations will be agreed and abided by humankinds. Moreover, the production and use of chemicals of emerging concern (CECs: e.g., brominated and chlorinated flame retardants, per- and polyfluoroalkyl substances, organophosphate-based flame retardants and plasticizers, pharmaceuticals, and personal care products) will also contribute to contamination in the Polar Regions (AMAP 2017).

Antarctica and NE Greenland: Marine Pollution in a Changing World

Among CECs, some of them are legacy and some others are recently produced and used contaminants (AMAP 2017). Other causes of concern include the impact of increasing scientific, fishing, and touristic activities in the Southern Ocean. Tourism in Polar Regions has increased since the last few decades and some areas are impacted by human presence (e.g. Antarctic Peninsula region, Svalbard, Greenland except NEG so far). Increasing tourism in Antarctica started three decades ago when only very few ships could reach the Antarctic coasts and tourists could land under the supervision of personnel of the scientific stations only; return flights without landing were also organized. Moreover, the effects of climate change will also be of great concern in the present and near future times: it may affect human presence and activities in Polar Regions and directly or indirectly the POP transport and release. In this scenario, the human impacts might be responsible of the decline of a population, but in these ecosystems such events can have unpredictable and devastating effects on marine ecosystems; moreover, synergic effects among contaminants and between contaminants and climate change can be predicted. The sustainable use of our planet and oceans is our current challenge to avoid uncontrolled exploitation and damage of the oceans including the polar ones.

Future Challenges The ecological and ecotoxicological issues in the Polar Regions including the preservation of the structure and functioning of their ecosystems are intrinsic of three goals of the United Nations’ Sustainable Development Goals (United Nations 2015): Goal 14 - Conserve and sustainably use the oceans, seas, and marine resources for sustainable development; Goal 12 - Ensure sustainable consumption and production patterns; Goal 13 - Take urgent action to combat climate change and its impacts. Due to the key role of the Polar Regions in the global equilibrium of climate, ecosystems, and resources, their sustainable use is of prime importance; this key role was recognized by the European Union in 2016 (European Commission 2016). Much remains to be studied and understood in different research fields, and these lacking

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knowledge may play an important role in the sustainable use of these marine environments. Practical Issues The research efforts and outputs in Polar Regions and mainly in the Southern Ocean and NE Greenland seawaters are lower than for other regions of the world in relation to the extreme environmental conditions, the limited number of facilities allowing sampling and temporary housing, and the high amount of funds needed. The research on POPs in the Arctic region have produced a great amount of data and knowledge, also facilitated by the existence of the Arctic Monitoring and Assessment Programme (AMAP, https://www.amap.no/), one of six Working Groups of the Arctic Council (https:// arctic-council.org/en/); with respect to climate and pollution issues, AMAP has published highly quality reports on the status of the Arctic since its establishment in 1991. Only information on contamination of NE Greenland is scarce due to the limited access. The national and international collaborations are a priority in extreme working conditions and should be promoted and managed. These help researchers to collaborate more closely, to share knowledge, expertize, facilities, and maximize efforts and results. The research on POP presence in abiotic and biotic compartments of ecosystems are often carried out by different research groups with specific expertise, while it is important to apply integrated approach to understand the POP transfer between compartments and mechanisms at each ecological level. A multidisciplinary and international approach to research in Antarctica would help also to standardize some technical aspects, e.g., the methods of sampling and analysis. The Action Group on Input Pathways of Persistent Organic Pollutants to Antarctica (ImPACT) of the Scientific Committee on Antarctic Research (SCAR) aims to facilitate coordinated research on chemical inputs to the Antarctic region; it is among its focus the identification of avenues for structuring the ImPACT Action Group towards the establishment of an Antarctic Monitoring and Assessment Programme (AnMAP) body (https:// www.scar.org/science/impact/about/). These will

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Antarctica and NE Greenland: Marine Pollution in a Changing World

be the challenges for research in Antarctica and Southern Ocean for the near future. POPs and Climate Change The relationship between the climate change and POP transport and distribution to Polar Regions needs major and increasing investigations. It would be important to study if, how, and to what extent the climate parameters (weather conditions, air or seawater temperature, sea ice extent, salinity) affect the POP concentrations, distribution, and trend over a period, and to assess possible correlations. These research should also take into account that climate change may affect the structure of trophic webs, which, in turn, may affect the availability of usual prey thus forcing organisms to feed on different food items. A change in the diet and/or a shift of trophic level may cause different POP bioaccumulation. The changing environment may affect both the POP distribution in the ecosystem and the entrance level in the trophic webs and effects could not be detectable in a short period, mainly in the Southern Ocean where contamination events are delayed respect to the Arctic. Chemicals of Emerging Antarctic Concern (CEAnC) The Stockholm Convention controls 35 families of POPs, but at least 350,000 chemicals were registered for production and use and new compounds are continuously synthetized (Wang et al. 2020). Among them, 3421 chemicals are reported to be potential chemicals of emerging Arctic concern (CEAC) (Muir et al. 2019). Following the AMAP data, CEAC include per- and polyfluoroalkyl substances, non-PBDE brominated flame retardants, chlorinated flame retardants, organophosphatebased flame retardants and plasticizers, phthalates, short-chain chlorinated paraffins, siloxanes, pharmaceuticals and personal care products, polychlorinated naphthalenes, hexachlorobutadiene, current-use pesticides, pentachlorophenol and pentachloroanisole, organotins, polycyclic aromatic hydrocarbons, new unintentionally generated PCBs, marine plastics, and microplastics (AMAP 2017). All these chemicals can also be chemicals of emerging Antarctic concern (CEAnC).

Box 4 Stockholm Convention on Persistent Organic Pollutants (SC-POPs, http://chm. pops.int/)

The SC-POPs is a global treaty under the United Nation Environment Program (UNEP) with the aim to protect the global environment and humans from the adverse effects of POPs. It aims to regulate and finally eliminate POPs. Chemicals can be included in the list of POPs of interest to the Convention when the scientific evidences demonstrate they are persistent in the environment, thus they show potential to long range transport (LRTP) and to accumulate in organisms including humans eliciting toxic effects. The SC-POPs was adopted on 22/5/2001 and entered into force in 17/5/2004; today 152 countries signed it of the 184 Parties.

The legacy POPs are still hazardous to the ecosystems due to their toxic effects, and novel contaminants may pose a new risk: in the Arctic, the CEAC have been detected in different compartments since recent years although concentrations are lower than the legacy POPs (AMAP 2017). In the Southern Ocean, some novel POPs were detected in both abiotic and biotic samples (e.g., Schiavone et al. 2010; Pozo et al. 2017; Corsolini et al. 2020; Kim et al. 2020), confirming they can be transported in this remote region. The possible synergic effects with legacy POPs both in the environment and organisms can be unpredictable, especially under changing climatic conditions.

Cross-References ▶ Antarctic: Climate Change, Fisheries, and Governance ▶ Coastal Pollution: An Overview ▶ Ocean-Related Effects of Climate Change on Society ▶ Ocean-Related Impacts of Climate Change on Economy

Antarctica and NE Greenland: Marine Pollution in a Changing World

▶ Penguins: Diversity, Threats, and Role in Marine Ecosystems ▶ Tourist Traps: Assessing the Role of Tourism in Sustaining Life Below Water

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Antarctica and NE Greenland: Marine Pollution in a Changing World half century. Appl Geogr 31:495–507. https://doi.org/ 10.1016/j.apgeog.2010.10.009 Lund Paulsen M, Müller O, Larsen A et al (2019) Biological transformation of Arctic dissolved organic matter in a NE Greenland fjord. Limnol Oceanogr 64:1014– 1033. https://doi.org/10.1002/lno.11091 Ma J, Hung H, Macdonald RW (2016) The influence of global climate change on the environmental fate of persistent organic pollutants: a review with emphasis on the Northern Hemisphere and the Arctic as a receptor. Glob Planet Chang 146:89–108. https://doi.org/10. 1016/J.GLOPLACHA.2016.09.011 McKinney MA, McMeans BC, Tomy GT et al (2012) Trophic transfer of contaminants in a changing arctic marine food web: Cumberland sound, Nunavut, Canada. Environ Sci Technol 46:9914–9922. https://doi. org/10.1021/es302761p Mckinney MA, Pedro S, Dietz R et al (2015) A review of ecological impacts of global climate change on persistent organic pollutant and mercury pathways and exposures in arctic marine ecosystems. Curr Zool 61:617– 628. https://doi.org/10.1093/czoolo/61.4.617 Morgana S, Ghigliotti L, Estévez-Calvar N et al (2018) Microplastics in the Arctic: a case study with subsurface water and fish samples off Northeast Greenland. Environ Pollut 242:1078–1086. https://doi.org/ 10.1016/j.envpol.2018.08.001 Muir D, Zhang X, de Wit CA et al (2019) Identifying further chemicals of emerging arctic concern based on ‘in silico’ screening of chemical inventories. Emerg Contam 5:201–210. https://doi.org/10.1016/j.emcon. 2019.05.005 Naranjo L (2006) On the trail of global pollution drift | Earthdata. In: NASA Earth Obs. https://earthdata.nasa. gov/learn/sensing-our-planet/on-the-trail-of-global-pol lution-drift. Accessed 23 Dec 2020 NASA (2019) Climate science investigations South Florida – temperature over time. In: Climate Science Investigations. http://www.ces.fau.edu/nasa/module-3/regionaltemperature/explanation-2.php. Accessed 23 Dec 2020 Nicol S, Endo Y (1997) Biology and fisheries history of the commercially harvested species. In: Krill fisheries of the world. Food and Agriculture Organization of the United Nations, Rome Pozo K, Martellini T, Corsolini S et al (2017) Persistent organic pollutants (POPs) in the atmosphere of coastal areas of the Ross Sea, Antarctica: indications for longterm downward trends. Chemosphere 178:458–465. https://doi.org/10.1016/j.chemosphere.2017.02.118 Rintoul SR, Da Silva CE (2019) Antarctic circumpolar current. In: Encyclopedia of ocean sciences (Third Edition), Reference Module in Earth Systems and Environmental Sciences. Elsevier Ltd, pp 248–261. https:// doi.org/10.1016/B978-0-12-409548-9.11298-9 Rysgaard S, Nielsen T, Hansen B (1999) Seasonal variation in nutrients, pelagic primary production and grazing in a high-Arctic coastal marine ecosystem, Young Sound, Northeast Greenland. Mar Ecol Prog Ser 179:13–25. https://doi.org/10.3354/meps179013

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Schiavone A, Kannan K, Horii Y et al (2010) Polybrominated diphenyl ethers, polychlorinated naphthalenes and polycyclic musks in human fat from Italy: comparison to polychlorinated biphenyls and organochlorine pesticides. Environ Pollut 158:599–606. https://doi.org/10.1016/j.envpol.2009.08.011 Scott CL, Falk-Petersen S, Sargent JR et al (1999) Lipids and trophic interactions of ice fauna and pelagic zooplankton in the marginal ice zone of the Barents Sea. Polar Biol 21:65–70. https://doi.org/10.1007/ s003000050335 Sladen WJL, Menzie CM, ReichelL WL (1966) DDT residues in Adelie penguins and a crabeater seal from Antarctica. Nature 210:670–673. https://doi.org/10. 1038/210670a0 Strid A, Bruhn C, Sverko E et al (2013) Brominated and chlorinated flame retardants in liver of Greenland shark (Somniosus microcephalus). Chemosphere 91:222– 228. https://doi.org/10.1016/j.chemosphere.2012.12. 059 Tekman MB, Krumpen T, Bergmann M (2017) Marine litter on deep Arctic seafloor continues to increase and spreads to the North at the HAUSGARTEN observatory. Deep Res Part I Oceanogr Res Pap 120:88–99. https://doi.org/10.1016/j.dsr.2016.12.011 Trathan P, Forcada J, Murphy E (2007) Environmental forcing and Southern Ocean marine predator populations: effects of climate change and variability. Philos Trans R Soc B Biol Sci 362:2351–2365. https:// doi.org/10.1098/rstb.2006.1953 United Nations (2015) Transforming our world: the 2030 Agenda for Sustainable Development Transforming our world: the 2030 Agenda for Sustainable Development Preamble Visser AW, Jónasdóttir SH (1999) Lipids, buoyancy and the seasonal vertical migration of Calanus finmarchicus. Fish Oceanogr 8:100–106. https://doi. org/10.1046/j.1365-2419.1999.00001.x Vorkamp K, Bossi R, Rigét FF et al (2015) Novel brominated flame retardants and dechlorane plus in Greenland air and biota. Environ Pollut 196:284–291. https:// doi.org/10.1016/j.envpol.2014.10.007 Waller CL, Griffiths HJ, Waluda CM et al (2017) Microplastics in the Antarctic marine system: an emerging area of research. Sci Total Environ 598:220–227 Wang Z, Walker GW, Muir DCG, Nagatani-Yoshida K (2020) Toward a global understanding of chemical pollution: a first comprehensive analysis of national and regional chemical inventories. Environ Sci Technol 54:2575–2584. https://doi.org/10.1021/acs.est. 9b06379 Wania F (2003) Assessing the potential of persistent organic chemicals for long-range transport and accumulation in polar regions. Environ Sci Technol. https:// doi.org/10.1021/es026019e Wania F, Mackay D (1993) Global fractionation and cold condensation of low volatility organochlorine compounds in polar regions. Ambio 22:10–18. https://doi. org/10.2307/4314030

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Anthropogenic Factors

Anthropogenic Factors ▶ Environmental Governance in Context of the Marine Ecosystem: Considerations for Sustainability

also implies individual or corporate ownership of the stock being cultivated, the planning, development and operation of aquaculture systems, sites, facilities and practices, and the production and transport” (FAO 2010).

Introduction

Anthropogenic Impact to Cetaceans ▶ Cetacean Threats

Health:

Global

Environmental

Aquaculture: Farming Our Food in Water Mariana Palma and Ivan Viegas University of Coimbra, Centre for Functional Ecology, Department of Life Sciences, Coimbra, Portugal

Synonyms Mariculture; Pisciculture

Definition Due to the diversity and complexity of processes and organisms involved in the practice of aquaculture, a comprehensive definition has always been difficult to achieve. At first, a clear distinction from capture fisheries needed to be drawn; however, the degree of intervention over the farming/culture process and the issue of the ownership of the stock have always made whatever definition a work in process. According to the Food and Agriculture Organization of the United Nations (FAO), aquaculture has been defined as “the farming of aquatic organisms including fish, molluscs, crustaceans and aquatic plants. Farming implies some sort of intervention in the rearing process to enhance production, such as regular stocking, feeding and protection from predators. Farming

Basic Principles Aquaculture was considered until recently as part of fisheries sciences. As the aquaculture practice evolved over the recent decades, the two activities began to accumulate considerable differences in its basic principles, development, and management. As previously defined, aquaculture is an activity in which aquatic organisms are cultured under varying levels of control over their life cycle. In the case of some species, complete control is enforced over a closed life cycle, which implies an overall supervision in all steps of the process. For finfish species such control spans from broodstock maintenance, controlled reproduction, gamete selection and hatching, larvae rearing and subsequent switch from live food to inert pellets, juvenile grow-out phase, and finishing strategies (desired size, quality enhancement, pigment adjustments, etc.). Despite being now considered as completely different activities, the steady growth of aquaculture as an industry is intimately connected to capture fisheries since it still relies heavily on fishmeal and fish oils for feed production (Tacon et al. 2011). On the other hand, aquaculture has been also used to enhance fisheries stocks and/or help recover depleted stocks for both commercial and recreational purposes (Bostock et al. 2010). Man depended on hunting and fishing for basic subsistence since the Neolithic period. However, following technological advances from the industrial revolution and booming demand particularly after World War II, fisheries efforts were strongly increased, and fish stocks have declined abruptly ever since (Pauly and Zeller 2017). Aquaculture arose then as a way to improve or create new stocks for human consumption. In contrast to fisheries, aquaculture is in general only subjected to national jurisdiction, leaving few chances of

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international conflicts related with rights and ownership. Presently is well recognized the potential of aquaculture to improve income and nutrition in developing regions; to be integrated with other types of cultures (animal or crop) recycling its by-products; and to be optimized to fulfill the market demands in several aspects (quantity, size, processing, availability). The biological basis of aquaculture also reinforces the efficiency of this activity to produce animal protein for human consumption. When compared with other farmed animals such as cattle, poultry, and pork, cold-blooded animals have lower energy requirements for body temperature maintenance and locomotion, using efficiently the feed intake for growth and body weight gain. Generally, low trophic feeders are produced with lower production costs than higher trophic feeders even if at the end of the value chain, market place and price may not always reflect this principle (Pillay and Kutty 2005). Historical Perspective The rise of aquaculture remains shrouded by uncertainly, although it is generally accepted it dawned in China, between 2000 and 1000 years BC, with common carp (Cyprinus carpio) husbandry. The first published record on aquaculture was The Classic of Fish Culture, a book written by Fan Lai in 475 BC. This monography was the first to describe the ponds and methods of fish propagation. Since then, common carp culture spread significantly in China and neighboring countries. During Tang Dynasty (618–906 AD), due to restrictions in common carp rearing, new carp species were introduced in aquaculture systems leading to the first description of what is currently known as polyculture. In 1243, Chow Mit published Kwei Sin Chek Shik describing fry collection from natural waters. From 1368 to 1644, during the Ming Dynasty, the complete process of aquaculture was described and published (Stickney and Treece 2012). There are also several documented evidences that civilizations such as the Egyptians or the Romans exerted some level of control over flooded areas, trapping and enclosing fish that would be later harvested in a controlled manner.

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Some of these practices are still used in the Nile Delta. Recently, archaeological evidence uncovered an intricate system designed by the Gunditjmara Aboriginal people in Australia consisting of channels and weirs constructed from the abundant local volcanic rock. This design would manage water flows from nearby Lake Condah trapping eel for subsequent management and harvest as food source. These systems are thought to have around 6000 years old, and this location, the Budj Bim Cultural Landscape, was recognized as Australia’s World Heritage site in 2019 on the basis of being the first known attempt to culture fish species. Aquaculture activity has been developed in several countries, and currently around 500 species of plants, algae, and animals are cultivated all over the world. Somewhere along its long history, aquaculture became a science and is now a well-established multidisciplinary area of knowledge and research. The first scientific journal solely dedicated to this field was released in May 1972 (Aquaculture, Elsevier). It was stated in its debuting editorial that aquaculture would be the promising solution to sustain the increasing human population. Aquaculture is actually an important research and socioeconomic activity worldwide, crucial to the fulfillment of several of the UN 2030 Sustainable Development Goals. State of the Art The State of World Fisheries and Aquaculture is a flagship publication of FAO. It is set to provide policymakers, civil society, and those whose livelihoods depend on the sector a comprehensive, objective, and global view of capture fisheries and aquaculture. In its latest edition (FAO 2018a), it is referred that aquaculture continues to be the fastest-growing food production sector, even if at lower average annual rates (5.8% during the period 2000–2016) than observed in the 1980s (11.3%) and 1990s (10.0%). Nevertheless, aquaculture was in 2016 responsible for a global production of 80.0 million tons of seafood, 12% of which destined to non-food purposes. Farmed production included 54.1 million tons of finfish, 17.1 million tons of mollusks, 7.9 million tons of

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crustaceans, and, in addition, 30.1 million tons of aquatic plants. China is responsible for producing more than all other countries combined since 1991 (~60% of global production in 2016). Other major producers in 2016 were India, Indonesia, Vietnam, Bangladesh, Egypt, and Norway. Farmed aquatic plants are becoming increasingly relevant and reached a production of 30.1 million tons and included mostly seaweeds plus a much smaller production volume of microalgae.

Main Types of Aquaculture Aquaculture production has strongly increased over the last 50 years, contributing about 50% of the global fish-food supply. Production methods and strategies are diverse, as are the number of species and types of habitats occupied, ranging from freshwater to marine environments, and also including several types of transitional waters (coastal lagoons, estuaries, deltas, and other types of brackish water systems). Within this variety of environments aquaculture may be classified according to the type of species cultured that include aquatic plants and algae, crustaceans (crabs, lobsters, shrimps, prawns), finfish (diadromous, freshwater, and marine fish), mollusks (abalone, clams, cockles, oysters scallops), and cuttlefish (octopus, squid) as well as other aquatic invertebrates (e.g., sea urchins) and various other species (e.g., frogs, turtles). Asia is the region with the higher global production, with China being responsible for more than half of the total worldwide production, followed by Indonesia, India, and Vietnam. Aquaculture products can be broken down according to how they are processed/distributed/stored before reaching their target markets: live, fresh, chilled, or frozen; dried, prepared, preserved, or cured. Some of the production also serves non-food purposes, as is the example of the production of raw ingredients for feed such as fishmeal and fish oil (FAO 2018a). Finfish Driven by consumer preference, 68% of total production (excluding aquatic plants; by weight) is

Aquaculture: Farming Our Food in Water

for fish species (FAO 2018a). Freshwater fish aquaculture is dominated by the production of tilapia, perch, carp, and catfish (including Pangasius) (Bostock et al. 2010). These species perform well in captivity and can be cultured under flexible regimes both in terms of environmental parameters, stocking densities, and nutritional requirements, thus its impressive production over the last decades. The common carp (Cyprinus carpio) is the finfish species with the oldest history in aquaculture and is nowadays cultured all over the world, Asia being its biggest producer (Pillay and Kutty 2005). Around 24,000 tons of carp products (all species) are traded yearly within Europe (FAO 2018b), while the production of grass carp (Ctenopharyngodon idellus), silver carp (Hypophthalmichthys molitrix), and common carp, (Cyprinus carpio) represent more than 30% of total finfish production worldwide (FAO 2018a). Salmon and trout species are the marine finfish with higher production outputs (Bostock et al. 2010). Salmonid culture started much later than carp culture but contributed with significant advances and improvements to the overall aquaculture technique. Former salmonid culture systems were developed to create juveniles to restock depleted areas or introduce the species into new fisheries areas. Only few decades ago salmonids started to be grown until commercial size for direct human consumption (Pillay and Kutty 2005). The current worldwide production of Atlantic salmon (Salmo salar), for example, exceeds one million tons per year and is mainly sold to Japan, the European Union, and North America (FAO 2018c). Salmonid species, such as the Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss), represented approximately 6% of total finfish production in 2016 (FAO 2018a). As a consequence of the decrease of several fish stocks and diminishing quotas, but also due to consumerdriven strategies, the aquaculture industry has been actively diversifying the range of species cultured which now include flatfish (flounder, sole, plaice), grouper, meagre, seabass, and seabream, with prospects to diversify even further.

Aquaculture: Farming Our Food in Water

Crustaceans Shrimps and prawns are the major representative groups of cultured crustaceans that in 2016 represented 10% of the overall production (excluding aquatic plants; by weight) (FAO 2018a). Shrimps appeared in aquaculture as a secondary species in fish production systems in Asia. They only earned some attention after the strong increase in market demand. World production is dominated by the giant tiger prawn (Penaeus monodon), followed by the oriental shrimp (Penaeus chinensis), the whiteleg shrimp (Penaeus vannamei), and the giant freshwater prawn (Macrobrachium rosenbergii) (Pillay and Kutty 2005). Shrimps and prawns are the group with the second highest production value, from total aquaculture production (Bostock et al. 2010). The heightened market demand pushed producers to develop culture systems for crayfish, lobster, and crabs; however, only crayfish have a significant culture production, particularly the redswamp (or Louisiana) crayfish (Procambarus clarkii). The only crab species cultured at a commercial scale is the mud crab (Scylla serrate), produced in Southeast Asia and Australia (Pillay and Kutty 2005). Mollusks Mollusks integrate a diverse group of invertebrate animals that includes oysters, clams, mussels, scallops, abalones, and octopus, all with commercial value but with varying production efforts. If taken together, this group of species represented in 2016 21% of the overall production (excluding aquatic plants; by weight) (FAO 2018a). Oysters contribute with the higher production output, especially due to the Japanese oyster (Crassostrea gigas) production. Clams are the second representative group, followed by scallops and mussels. Improvements in oyster production lead to a dramatic increase in shellfish production, from 1.8 million tons in 1990 to 7.5 million tons in 2000. Hanging culture methods, allowed farmers to significantly decrease the production time and increase survival rates. These improvements on oyster culture also pushed the development of scallop production. Mussel production became significant in Spain in the early 1900s. Former

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mussel production systems were based on the collection of spat using poles. Few years later, the raft production system was introduced promoting a fast increase in production (Rheault 2012). The potential of cephalopods species for aquaculture continues to draw the attention of researchers. Octopus and squid have good growth and food conversion rates, which can lead to high production ratios and cost-effectiveness. However, cephalopod culture is still limited by their highly selective feeding requirements, mainly in the early stages of development. Although culture has not been possible to develop until the commercial level, it was already established in small scales, leaving open the opportunity to develop new approaches in this field (Vidal et al. 2014).

Key Issues for Aquaculture The current need to provide food to the increasing world population will require seeking for tools that will help develop effective and sustainable aquaculture production systems. Technical development and improvement should be driven toward higher production rates and better efficiency in the use of the resources (feed, water, land) and at the same time providing income while boosting the resilience of the communities. The informed diagnosis of the bottlenecks limiting such development should reveal the major issues behind the future of aquaculture. The following section discusses just a few of them with no particular order of importance between them or increased relevance in comparison to many others left unaddressed. Broodstock Management and Selective Breeding Broodstock management is a key step to begin and complete the entire life cycle of aquatic organisms in aquaculture systems. It encompasses three main steps of the production process: selection of fish with the adequate hereditary qualities; rearing them to reach a well-matured stage; and further selection of animals able to reproduce and produce healthy offspring. Broodstock is generally kept in tanks with optimal environmental

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conditions and low densities to ensure gamete and fry production at high quantity and quality (Migaud et al. 2013). Maternities could work as an independent business that supply other producers or be integrated in growth/production systems. If considered as starting ground for most aquaculture operations, effective broodstock management involves delicate and technically complex protocols for controlled spawning, larval rearing, and subsequent weaning normally under highly controlled abiotic parameters. These strategies have proven to maintain and improve the stock while avoiding inbreeding, increasing fecundity, and extend gamete conservation. Considered to be one of the most critical steps into developing healthy juveniles is the transition from live feed to formulated inert diets which normally encompass strict physical, chemical, and nutritional parameters which can be highly speciesspecific. Besides that, the provision of such juveniles must be accompanied by tight health control (microbial management, parasites, bath treatments), biosecurity validation, and adequate transport conditions. The most challenging (and potentially rewarding) species in this context is tunas and lobsters (Masuma et al. 2011; Hall et al. 2013; Partridge 2013). The production of these species largely depends on supply of wild juveniles. Contrary to terrestrial farmed animals which have been selected to enhance certain characteristics (like milk yield in cows or wool in sheep) for centuries, the fact is that for farmed aquatic species, this process has hardly begun. The selective breeding (also known as artificial selection) takes place through many generations for developing particular traits (phenotypes) in organisms. This process has been recently assisted and accelerated by many emerging methods for genetic profiling and improvement which differ in selection strategy, traits selected, and numbers of generations depending on species and objectives (growth, feeding efficiency, product quality, edible yield, shape, and disease resistance). The Atlantic salmon (Salmo salar) had been successfully selected to increase body weight, feed conversion rate, and increase resistance to bacterial and viral diseases. Other fish species, such as rainbow trout (Oncorhynchus mykiss) and cyprinids, have been

Aquaculture: Farming Our Food in Water

selected to increase the growth rate and the tolerance to environmental conditions respectively (Gjedrem et al. 2012). Oysters have been selectively bred to improve disease resistance and more recently to enhance resilience to environmental acidification (Fitzer et al. 2019). Also some species of shrimps have been bred to improve growth rate and disease resistance (Gjedrem et al. 2012). Genetically Modified Organisms As widely accepted in agronomy, the production of genetically modified organisms (GMO) can also be applied to aquaculture species to improve overall production efficiency. Genetic manipulation can be optimized toward improvement of growth and efficiency of feed conversion, enhance organoleptic characteristics of the fillet, increase resistance to diseases, and increase tolerance to environmental conditions, among others (FAO 2019a). The first aquatic species to be described and produced as genetically modified were the rainbow trout in 1984 and the goldfish in 1985. Currently, several species of fish are genetically modified for aquaculture production; however, production is dominated by the Atlantic salmon (Salmo salar), the Coho salmon (Oncorhynchus kisutch), tilapia (Oreochromis spp.), channel catfish (Ictalurus punctatus), and the African catfish (Clarias gariepinus). The use of transgenic organisms is subjected to different regulations depending on the region/country and will not be discussed in detail. Nevertheless the huge potential of GMOs to boost aquaculture production and food security and improve economic benefits, it must previously consider its possible effects to human health, biodiversity, and animal welfare. In general, it is crucial to prepare and disseminate accurate and plain information to the general public, producers, and policymakers to increase consumer awareness (Beardmore and Porter 2003). In another context, GMO can assist in producing more affordable and nutritious feeds. As the industry shifts away from using marine-derived ingredients and attempts to use more sustainable sources of ingredients for feed formulation, new challenges arise to the feed manufacturing industry, particularly in the case of carnivorous fish.

Aquaculture: Farming Our Food in Water

Genetic engineering to enhance the composition of plants (Napier and Sayanova 2020) may assist in developing ingredients that are rich in nutritional value, cost-effective, and environmentally compatible. That is the case for astaxanthin and related carotenoids or anthocyanins, components used as pigments/colorants for feeds but with proven antioxidant and nutraceutical action. Fish oil is highly rich in these fatty acids but vegetable oils are not. However, by transferring genes from the marine unicellular organisms responsible for the synthesis of EPA and DHA in the aquatic environments, it has been possible to engineer plants to synthesize omega-3 fatty acids. Genetically modified Camelina sativa (a relative of rapeseed) has been incorporated into several fish feeds and tested in growth trials in Atlantic salmon or gilthead seabream with promising results. The accumulation of EPA and DHA in seed oil has been shown to be a stable trait, and levels of these fatty acids in fish flesh attested for the efficacy of this novel plant-based source of EPA and DHA (Betancor et al. 2015, 2016). Environmental Impact Evaluating the environmental impact of aquaculture is a complex issue that can be assessed from different angles, always with its pros and cons. All of these must be put in perspective and evaluated, and decision-making should take into account all stakeholders. Those whose livelihoods depend on the aquaculture activity and those concerned with sustainable aquaculture are supporting aquaculture’s transformation (Mustafa and Shapawi 2015). Wastewater and Pollution

Nitrogen and phosphorous production is transversal to all animal production systems. However, it occurs in variable amounts, depending on the fish species and life stage, the type of diet, and the type of aquaculture system. Animals naturally produce nitrogen-derived products after food digestion which increases with the protein composition of the aquafeeds and the stocking densities. These factors combined have major impact on fish welfare (Conceição et al. 2012). There are some solutions that can help control or completely eliminate

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the nitrogenous discharges, resulting in few or nonsignificant environmental impact. Integrated multi-trophic aquaculture systems can be a sustainable solution, since plants can efficiently use metabolic by-products produced by animals and use them in their regular physiological mechanisms. Recirculating aquaculture systems also allow the recovery and reuse of the aquaculture waste (Granada et al. 2016). The widespread use of antibiotics and other chemicals in aquaculture can additionally raise environmental problems, in particular in production systems without effluent treatment, with direct contact with watercourses or with infiltration to the soil. Problems of bacterial resistance had been described in some sediments due to the continued use of antibiotics in aquaculture and its impacts on the environment. Other contaminants can also be released by aquacultures, such as veterinary drugs, pesticides, and metals. These contaminants could be absorbed and metabolized and then excreted or accumulated by the cultured organisms. Bioaccumulation and bioamplification (increase in the concentration of a substance along the food chain) of these pollutants in animals can lead to environmental problems and restrain human supply. Assessment of contaminants levels and profiles are of utmost importance to determine safety levels to meet food safety and quality requirements (HLPE 2014). Land and water use by aquaculture can also raise environmental questions, though this issue is strongly dependent on the type of production system and its location. Land-based systems usually demand both more land and water than sea cage systems. However if they are implemented in nonarable yields and use water-recirculating systems and kept with good productivity levels, the total environmental impact could be less than the one caused due to capture from wild stocks. Impact on Biodiversity

Although aquaculture is often used to restore depleted natural resources, under certain circumstances this activity could affect biodiversity. Albeit strongly dependent on the type of aquaculture system, it is possible that some animals could escape from the production tanks and become

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invasive to areas where they are nonnative. Escape can occur by cage or net ruptures in pens installed in water bodies and in ponds during flooding. Since most of the farmed species are genetically different from their wild counterparts, the escapees can produce offspring less suited to live in the wild. These non-indigenous individuals can also compete with the native species, shifting the environmental balance and threat viability of the wild populations (Glover et al. 2012). Intensively cultured animals are also generally more susceptible to diseases due to the higher stocking densities and stress. Although animal health problems are usually avoided with quarantine of new stocks, maintenance of water quality, and preventing stress, it is possible to have some health issues that can be treated with simpler solutions or using drugs. Therefore, escapees from aquaculture tanks can introduce diseases and parasites into the wild populations. Closed aquaculture systems are suggested to deal with both the disease and escape issues. The completely controlled environment allows the producer to supervise all the production steps and take measures as required to prevent major problems. Depending on the type of aquaculture, the land use/conversion and water use could also affect local resource and biodiversity. Moreover, animals grown in coastal waters, net pens, or ponds depend on the use of resources provided by the sensitive coastal environment (HLPE 2014). Nutrition A healthy and complete human diet should comprise all the essential nutrients. Aquaculture products like fish and seafood can provide a significant amount of these nutrients, such as essential amino acids (proteins), fatty acids (lipids), vitamins, and minerals. Fish fillet, for example, has a unique lipid composition, including long-chain polyunsaturated fatty acids that have been extensively described as beneficial for the adult health and child development. Regarding micronutrients, aquaculture products are in general considered a good source of vitamins (D, B) and minerals (calcium, phosphorus, iodine, zinc, iron, and selenium). Consumption of these products can help balance human nutrition and nourishing in

Aquaculture: Farming Our Food in Water

particular in more vulnerable populations in an affordable and accessible manner. The increased production has led to global per capita consumption of fish reaching about 20 kg/year in 2016. This represents about 17.4% of the global population’s intake of animal proteins and 7% of all proteins consumed. Estimates indicate a further growth in per capita consumption, with the share of aquaculture production in total available food fish supply overtaking that of capture fisheries (FAO 2019b). Protein from aquatic animals has higher digestibility than the protein derived from vegetable sources, contributing significantly to the overall protein intake in human diet. All taken into account, to meet the demand for fish and seafood during the 2020 decade, an extra supply of 30 million tons must be produced (Cai and Leung 2017). Different species have different nutritional values, and within the same species, nutritional value also changes. Despite the huge contribution of aquaculture products to a healthy diet, they can also expose consumers to toxins and health hazards. Exposure to microalgae toxins may also occur, in particular from shellfish consumption. In aquaculture systems, in particular the closed ones like recirculating aquaculture systems, it is easier to control and keep record of water parameters and fish health. Aquaculture systems can then provide products of high quality, with wellestablished security parameters and constant organoleptic characteristics (HLPE 2014).

Future Directions Current development of aquaculture and its expected increase in the near future will require the implementation of strategies that allow achieving environmental, commercial, and business demands. Generally, improvements can be made on key technical factors, namely, on the selection/improvement of the farming system, the resources-use policies (land, water and energy), the animal health and welfare management, cultured species, optimal use of the raw materials (aquafeeds, seeds, and infrastructures), and production management (escapes, yearly

Aquaculture: Farming Our Food in Water

production, and disease control). Research should also focus on diversifying farmed species, closing the life cycle of more species, diet optimization, better animal-health practices, improved product quality control, and better marketing and distribution strategies. Development of differentiated products for niche markets or innovative processing techniques will also increase the economic and social positioning of aquaculture. Labels for sustainable production and provenience/authenticity certificates should be adopted to promote confidence and loyalty of consumers. Market and environmental constant changes should always be seized as a way to improve, innovate, or adapt to the new conditions. Gathering all the partners from the several sectors involved in these projects will improve awareness, experience exchange, and decrease failure chances. As a worldwide activity with variable socioeconomic importance in different regions, the future of aquaculture production should also be toward designing of small-scale productions, as a mean to improve income and food availability to disadvantaged communities. Moreover, as a source of high-quality food, and a sustainable option to fisheries products, it is essential to increase public awareness about the nutritional quality and safety level of aquaculture products.

Cross-References ▶ Pisciculture

References Beardmore JA, Porter JS (2003) Genetically modified organisms and aquaculture. FAO fisheries circular no. 989 FIRI/C989(En). Food and Agriculture Organization of the United Nations, Rome Betancor MB, Sprague M, Sayanova O, Usher S, Campbell PJ, Napier JA, Caballero MJ, Tocher DR (2015) Evaluation of a high-EPA oil from transgenic Camelina sativa in feeds for Atlantic salmon (Salmo salar L.): effects on tissue fatty acid composition, histology and gene expression. Aquaculture 444:1–12. https://doi. org/10.1016/j.aquaculture.2015.03.020 Betancor MB, Sprague M, Montero D, Usher S, Sayanova O, Campbell PJ, Napier JA, Caballero MJ,

51 Izquierdo M, Tocher DR (2016) Replacement of marine fish oil with de novo Omega-3 oils from transgenic Camelina sativa in feeds for Gilthead Sea bream (Sparus aurata L.). Lipids 51:1171–1191. https://doi. org/10.1007/s11745-017-4248-z Bostock J, McAndrew B, Richards R, Jauncey K, Telfer T, Lorenzen K, Little D, Ross L, Handisyde N, Gatward I, Corner R (2010) Aquaculture: global status and trends. Philos Trans R Soc B Biol Sci 365:2897–2912. https:// doi.org/10.1098/rstb.2010.0170 Cai J, Leung PS (2017) Short-term projection of global fish demand and supply gaps. FAO fisheries and aquaculture technical paper no. 607. FAO, Rome Conceição LEC, Aragão C, Dias J, Costas B, Terova G, Martins C, Tort L (2012) Dietary nitrogen and fish welfare. Fish Physiol Biochem 38:119–141. https:// doi.org/10.1007/s10695-011-9592-y FAO - Food and Agriculture Organization of the United Nations (2010) FAO term portal, entry: 1222, collection: aquaculture FAO. http://www.fao.org/faoterm. Accessed 29 Jun 2018 FAO - Food and Agriculture Organization of the United Nations (2018a) The state of world fisheries and aquaculture 2018 - meeting the sustainable development goals, Rome FAO - Food and Agriculture Organization of the United Nations (2018b) Cultured Aquatic Species Information Programme – Cyprinus carpio. http://www.fao.org/ fishery/culturedspecies/Cyprinus_carpio/ en#tcNA00D6. Accessed 22 Jun 2018 FAO - Food and Agriculture Organization of the United Nations (2018c) Cultured Aquatic Species Information Programme – Salmo salar. http://www.fao.org/fishery/ culturedspecies/Salmo_salar/en#tcNA0050. Accessed 22 Jun 2018 FAO (2019a) The state of the World’s aquatic genetic resources for food and agriculture. FAO commission on genetic resources for food and agriculture assessments, Rome FAO (2019b) FAO yearbook. Fishery and aquaculture statistics 2017/FAO annuaire. Statistiques des pêches et de l’aquaculture 2017/FAO anuario. Estadísticas de Pesca y acuicultura 2017, Rome Fitzer SC, McGill RAR, Torres Gabarda S, Hughes B, Dove M, O'Connor W, Byrne M (2019) Selectively bred oysters can alter their biomineralization pathways, promoting resilience to environmental acidification. Glob Chang Biol 25:4105–4115. https://doi.org/10. 1111/gcb.14818 Gjedrem T, Robinson N, Rye M (2012) The importance of selective breeding in aquaculture to meet future demands for animal protein: a review. Aquaculture 350-353:117–129. https://doi.org/10.1016/j.aquacultu re.2012.04.008 Glover KA, Quintela M, Wennevik V, Besnier F, Sørvik AGE, Skaala Ø (2012) Three decades of farmed escapees in the wild: a spatio-temporal analysis of Atlantic Salmon population genetic structure throughout Norway. PLoS One 7:e43129

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52 Granada L, Sousa N, Lopes S, Lemos MFL (2016) Is integrated multitrophic aquaculture the solution to the sectors’ major challenges? – a review. Rev Aquac 8:283–300. https://doi.org/10.1111/raq.12093 Hall MR, Kenway M, Salmon M, Francis D, Goulden EF, Høj L (2013) Chapter 9 - Palinurid lobster larval rearing for closed-cycle hatchery production. In: Allan G, Burnell G (eds) Advances in aquaculture hatchery technology. Woodhead Publishing, pp 289–328 HLPE (2014) Sustainable fisheries and aquaculture for food security and nutrition. A report by the high level panel of experts on food security and nutrition of the committee on world food security, Rome Migaud H, Bell G, Cabrita E, McAndrew B, Davie A, Bobe J, Herráez MP, Carrillo M (2013) Gamete quality and broodstock management in temperate fish. Rev Aquac 5:S194–S223. https://doi.org/10.1111/raq.12025 Masuma S, Takebe T, Sakakura Y (2011) A review of the broodstock management and larviculture of the Pacific northern bluefin tuna in Japan. Aquaculture 315:2–8. https://doi.org/10.1016/j.aquaculture.2010.05.030 Mustafa S, Shapawi R (2015) Aquaculture ecosystems: Adaptability & Sustainability. Wiley-Blackwell, West Sussex Napier JA, Sayanova O (2020) Nutritional enhancement in plants – green and greener. Curr Opin Biotechnol 61:122–127. https://doi.org/10.1016/j.copbio.2019.12. 010 Partridge GJ (2013) Chapter 15 – closed-cycle hatchery production of tuna. In: Allan G, Burnell G (eds) Advances in aquaculture hatchery technology. Woodhead Publishing, pp 457–497 Pauly D, Zeller D (2017) Comments on FAOs state of world fisheries and aquaculture (SOFIA 2016). Mar Policy 77:176–181. https://doi.org/10.1016/j.marpol .2017.01.006 Pillay TVR, Kutty MN (2005) Aquaculture principles and practices, 2nd edn. Blackwell Publishing Ltd Rheault R (2012) Shellfish Aquaculture) In: Stickney JH (ed) Aquaculture production systems. WileyBlackwell/Wiley, pp 79–118 Stickney RR, Treece GD (2012) History of Aquaculture) In: Stickney JH (ed) Aquaculture production systems. Wiley-Blackwell/Wiley, pp 15–50 Tacon AGJ, Hasan MR, Metian M (2011) Demand and supply of feed ingredients for farmed fish and crustaceans trends and prospects. FAO fisheries and aquaculture technical paper no. 564. FAO, Rome Vidal EAG, Villanueva R, Andrade JP, Gleadall IG, Iglesias J, Koueta N, Rosas C, Segawa S, Grasse B, Franco-Santos RM, Albertin CB, Caamal-Monsreal C, Chimal ME, Edsinger-Gonzales E, Gallardo P, Le Pabic C, Pascual C, Roumbedakis K, Wood J (2014) Chapter one - cephalopod culture: current status of main biological models and research priorities. In: Vidal EAG (ed) Advances in marine biology. Academic Press, pp 1–98. https://doi.org/10.1016/B9780-12-800287-2.00001-9

Artisanal Fisheries: Management and Sustainability

Artisanal Fisheries: Management and Sustainability Filipe Martinho Centre for Functional Ecology (CFE), Department of Life Sciences, University of Coimbra, Coimbra, Portugal

Definitions Artisanal fisheries can be broadly characterized as the dynamic and evolving smallest viable fishing units within a country or region. This concept is applied to numerous and diverse labor-intensive and seasonally variable small-scale local fisheries, which are characterized by the use of various fishing gears and based on relatively small capital investments, providing fish and fish products mainly to domestic markets and for subsistence consumption (Farrugio et al. 1993; FAO 2004). In the marine environment, artisanal fisheries are mostly restricted to the continental shelf (75% of the licensed boats/crews), and the results had a direct implication for the design of management actions regarding total catches, discards, and bycatch. In contrast with more traditional approaches, the advent of mobile technologies and handheld

Artisanal Fisheries: Management and Sustainability, Fig. 3 Example of the traditional beach seine fishery – Arte-Xávega in Portugal. From the top left panel, clockwise: fishermen preparing the nets for another haul; ground

crews sorting of the fish catches on the beach; crews cleaning the nets; vessel ready for being deployed into the surf. (All photos by Filipe Martinho)

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devices (i.e., smartphones, tablets) has provided an opportunity for improved data exchange and communication between fishermen, management agencies, and researchers, overcoming the longstanding shortage of funds and human power allocated to data collection. A notable example is a toolkit developed by the FAO for small-scale fisheries data collection, which comprises a generic database (OPEN ARTFISH – Open Approaches, Rules and Techniques for Fisheries statistical monitoring) and a mobile phone application to facilitate the implementation of cost-effective and sustainable routine data collection, storage, and analysis (FAO 2017a). When in full implementation, this will enable a faster and more costeffective means for data acquisition, transfer and analysis in artisanal fisheries worldwide, and their integration in fishery management plans.

A Future for Artisanal Fisheries Due to the importance of this activity worldwide as a source of protein, livelihoods of local communities, trade and alleviation of poverty, joint efforts should be directed toward increasing the knowledge and adjusting existing practices to fulfill the objective of achieving true environmental, social, and economic sustainability in artisanal fisheries. Recently, the FAO proposed a set of indicators to provide reliable and validated information on small-scale fisheries to decisionmakers, which include production and resource utilization, employment, efficiency, economic contribution, food security and nutrition, trade, social development, environmental impacts, institutional arrangements, and the type of fishery involved (FAO 2017b). These indicators have also provided the opportunity to identify gaps in knowledge and contribute to the proposal of research agendas in the nearby future. In more detail, focus should be given to: • Increasing co-governance and participatory management • Improving monitoring plans for assessing catches, bycatch, and discards • Funding of research and data collection programs

Artisanal Fisheries: Management and Sustainability

• Implementing sustainable practices (reduction of discards, adapt fishing gears, certification) • Valorizing uncommon and/or low value species • Adopting a multidisciplinary point of view in fisheries management; • Bridging the gap between research and action

Cross-References ▶ Biological Invasions as a Threat to Global Sustainability ▶ Bycatch: Causes, Impacts, and Reduction of Incidental Captures ▶ Concepts of Marine Protected Area ▶ Fisheries Management: An Overview ▶ Nursery Areas for Marine Fish ▶ Traditional Fishing Community and Sustainable Development ▶ Types of Fisheries and Their Impact on Sustainable Development Goals

References Aguado SH, Segado IS, Pitcher TJ (2016) Towards sustainable fisheries a multi-criteria participatory approach to assessing indicators of sustainable fishing communities: a case study from Cartagena (Spain). Mar Policy 65:97– 106. https://doi.org/10.1016/j.marpol.2015.12.024 Allison EH, Beveridge MCM, van Brakel M (2009) Climate change, small-scale fisheries and smallholder aquaculture. In: Wramner P, Cullberg M, Ackefors H (eds) Fisheries, sustainability and development. Royal Swedish Academy of Agriculture and Forestry, Stockholm Almeida OT, Lorenzen K, McGrath DG (2002) The role of the fisheries sector in the regional economy of the Brazilian Amazon. In: Second international large rivers symposium. FAO, Rome Baeta F, Costa MJ, Cabral HN (2009) Trammel nets’ ghost fishing off the Portuguese central coast. Fish Res 1–23. https://doi.org/10.1016/j.fishres.2009.03.009 Baran E, Tous P (2000) Artisanal fishing, sustainable development and co-management of resources: analysis of a successful project in West Africa. IUCN, Gland/ Cambridge, pp 1–45 Battaglia P, Romeo T, Consoli P et al (2010) Characterization of the artisanal fishery and its socio-economic aspects in the central Mediterranean Sea (Aeolian Islands, Italy). Fish Res 102:87–97. https://doi.org/10. 1016/j.fishres.2009.10.013 Beck M, Heck K, Able K et al (2001) The identification, conservation, and management of estuarine and marine

Artisanal Fisheries: Management and Sustainability nurseries for fish and invertebrates. Bioscience 51:633– 641 Brander K (2010) Impacts of climate change on fisheries. J Mar Syst 79:389–402. https://doi.org/10.1016/j. jmarsys.2008.12.015 Brown J, Macfadyen G (2007) Ghost fishing in European waters: impacts and management responses. Mar Policy 31:488–504. https://doi.org/10.1016/j.marpol. 2006.10.007 Carvalho N, Edwards-Jones G, Isidro E (2011) Defining scale in fisheries: small versus large-scale fishing operations in the Azores. Fish Res 109:360–369. https://doi. org/10.1016/j.fishres.2011.03.006 Cheung WWL, Lam VWY, Sarmiento JL et al (2010) Large-scale redistribution of maximum fisheries catch potential in the global ocean under climate change. Glob Chang Biol 16:24–35. https://doi.org/10.1111/j. 1365-2486.2009.01995.x Chuenpagdee R (2012) Global partnership for small-scale fisheries research: too big to ignore. SPC Tradit Mar Res Manag Knowl Inform Bull 29:22–25 Colloca F, Crespi V, Cerasi S, Coppola SR (2004) Structure and evolution of the artisanal fishery in a southern Italian coastal area. Fish Res 69:359–369. https://doi. org/10.1016/j.fishres.2004.06.014 EU Parliament (2012) On small-scale coastal fishing, artisanal fishing and the reform of the common fisheries policy (Rapporteur João Ferreira). Fisheries committee report A7-0291/2012, pp 1–26 FAO (1999) Indicators for sustainable development of marine capture fisheries, FAO technical guidelines for responsible fisheries. FAO, Rome, pp 1–76 FAO (2004) A research agenda for small-scale fisheries. FAO Regional Office for Asia and the Pacific, Bangkok, pp 1–44 FAO (2005) Increasing the contribution of small-scale fisheries to poverty alleviation and food security, FAO technical guidelines for responsible fisheries. FAO, Rome, pp 1–97 FAO (2007) Building adaptive capacity to climate change. Policies to sustain livelihoods and Fisheries, New directions in fisheries – a series of policy briefs on development issues no 8. FAO Sustainable Fisheries Livelihoods Programme, Rome, pp 1–16 FAO (2009) Global conference on small-scale fisheries – securing sustainable small-scale fisheries: bringing together responsible fisheries and social development. FAO, Rome FAO (2011) Review of the state of the world fishery resources: inland fisheries, FAO fisheries and aquaculture circular. FAO, Rome, pp 1–110 FAO (2017a) Open ARTFISH and the FAO ODK mobile phone application: toolkit for small-scale fisheries routine data collection. FAO, Rome, pp 1–120 FAO (2017b) Improving our knowledge on small-scale fisheries: data needs and methodologies. Food and Agriculture Organization, Rome, pp 1–104 Farrugio H, Oliver P, Biagi F (1993) An overview of the history, knowledge, recent and future research trends in Mediterranean fisheries. Sci Mar 57:105–119

61 Garcia SM, Cochrane K (2005) Ecosystem approach to fisheries: a review of implementation guidelines. ICES J Mar Sci 62:311–318. https://doi.org/10.1016/j. icesjms.2004.12.003 Garcia SM, Zerbi A, Aliaume C et al (2003) The ecosystem approach to fisheries: issues, terminology, principles, institutional foundations, implementation and outlook, FAO fisheries technical paper no. 443. FAO, Rome, pp 1–76 García-Flórez L, Morales J, Gaspar MB et al (2014) A novel and simple approach to define artisanal fisheries in Europe. Mar Policy 44:152–159. https://doi.org/10. 1016/j.marpol.2013.08.021 Granek EF, Brown MA (2005) Co-management approach to marine conservation in Mohéli, Comoros Islands. Conserv Biol 19:1724–1732. https://doi.org/10.1111/j. 1523-1739.2005.00301.x Hilborn R, Stokes K, Maguire J-J et al (2004) When can marine reserves improve fisheries management? Ocean Coast Manag 47:197–205. https://doi.org/10.1016/j. ocecoaman.2004.04.001 ICSF – International Collective in Support of Fishworkers (2015) Voluntary guidelines for securing sustainable small-scale fisheries in the context of food security and poverty eradication. 1–24. ISBN 978 93 80802 46 6 Jennings S, Kaiser K, Reynolds JD (2001) Fishers: socioeconomics and human ecology. In: Marine fisheries ecology. Wiley-Blackwell, Maiden, 432 p Lloret J, Cowx IG, Cabral H, et al (2016) Small-scale coastal fisheries in European Seas are not what they were: ecological, social and economic changes. Mar Policy (in press). https://doi.org/10.1016/j.marpol. 2016.11.007 Mangi SC, Roberts CM (2006) Quantifying the environmental impacts of artisanal fishing gear on Kenya’s coral reef ecosystems. Mar Pollut Bull 52:1646–1660. https://doi.org/10.1016/j.marpolbul.2006.06.006 Martinho F, Cabral HN, Azeiteiro UM, Pardal MA (2012) Estuarine nurseries for marine fish: connecting recruitment variability with sustainable fisheries management. Manag Environ Qual Int J 23:414–433. https:// doi.org/10.1108/14777831211232236 Martinho F, van der Veer HW, Cabral HN, Pardal MA (2013) Juvenile nursery colonization patterns for the European flounder (Platichthys flesus): a latitudinal approach. J Sea Res 84:61–69. https://doi.org/10. 1016/j.seares.2013.07.014 Morgan LE, Chuenpagdee R (2003) Shifting gears: addressing the collateral impacts of fishing methods in US waters, Pew science series on conservation and the environment. Island Press, Washington, DC, 42 pp Morrongiello JR, Walsh CT, Gray CA et al (2014) Environmental change drives long-term recruitment and growth variation in an estuarine fish. Glob Chang Biol 20:1844–1860. https://doi.org/10.1111/gcb.12545 Ndhlovu N, Saito O, Djalante R, Yagi N (2017) Assessing the sensitivity of small-scale fishery groups to climate change in Lake Kariba, Zimbabwe. Sustain For 9:2209. https://doi.org/10.1080/14693062.2007.9685637

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62 Neves J, Martinho F, Pardal MA (2018) Effect of illegal glass eel (Anguilla anguilla) fishery on estuarine fish stocks: a case study in the Mondego Estuary, Portugal. Mar Freshw Res. https://doi.org/10.1071/ MF17364 Oliveira Júnior JGC, Silva LPS, Malhado ACM et al (2016) Artisanal fisheries research: a need for globalization? PLoS One 11:e0150689. https://doi.org/10. 1371/journal.pone.0150689.s001 Pauly D (1997) Small-scale fisheries in the tropics: marginality, marginalization, and some implications for fisheries management. Global trends: fisheries management American Fisheries Society symposium 20, Bethesda, pp 1–10 Pauly D (2006) Major trends in small-scale marine fisheries, with emphasis on developing countries, and some implications for the social sciences. MAST 4:7–22 Pauly D, Zeller D (2015) Catch reconstructions reveal that global marine fisheries catches are higher than reported and declining. Nat Commun 7:1–9. https://doi.org/10. 1038/ncomms10244 Pauly D, Zeller D (2016) Toward a comprehensive estimate of global marine fisheries catches. In: Pauly D, Zeller D (eds) Global atlas of marine fisheries: a critical appraisal of catches and ecosystem impacts. Island Press, Washington, DC, pp 171–181 Pitcher TJ, Preikshot D (2001) RAPFISH: a rapid appraisal technique to evaluate the sustainability status of fisheries. Fish Res 49:255–270 Pomeroy R, Phang KHW, Ramdass K et al (2015) Moving towards an ecosystem approach to fisheries management in the Coral Triangle region. Mar Policy 51:211– 219. https://doi.org/10.1016/j.marpol.2014.08.013 Pörtner HO, Peck MA (2010) Climate change effects on fishes and fisheries: towards a cause-and-effect understanding. J Fish Biol 77:1745–1779. https://doi.org/10. 1111/j.1095-8649.2010.02783.x Revenga C, Brunner J, Henninger N, Kassem K, Payne R (2000) Pilot analysis of global ecosystems: freshwater systems. World Resources Institute, Washington, DC Rice J, Ridgeway L (2010) Conservation of biodiversity and fisheries management. In: Grafton RQ, Hilborn R, Squires D, Tait M, Williams M (eds) Handbook of marine fisheries conservation and management. Oxford University Press, New York, 785 p Rijnsdorp AD, Peck MA, Engelhard GH et al (2009) Resolving the effect of climate change on fish populations. ICES J Mar Sci 66:1570–1583. https:// doi.org/10.1093/icesjms/fsp056 Rosenberg AA, Bigford TE, Leathery S et al (2000) Ecosystem approaches to fishery management through essential fish habitat. Bull Mar Sci 66:535–542 Rudd MA, Tupper MH, Folmer H, van Kooten GC (2003) Policy analysis for tropical marine reserves: challenges and directions. Fish Fish 4:65–85 Sharpe DMT, Hendry AP (2009) Life history change in commercially exploited fish stocks: an analysis of trends across studies. Evol Appl 2:260–275. https:// doi.org/10.1139/f57-034

Artisanal Fishing Gears and Sustainable Development Shester GG, Micheli F (2011) Conservation challenges for small-scale fisheries: bycatch and habitat impacts of traps and gillnets. Biol Conserv 144:1673–1681. https://doi.org/10.1016/j.biocon.2011.02.023 Smith LED, Khoa SN, Lorenzen K (2005) Livelihood functions of inland fisheries: policy implications in developing countries. Water Policy 7:359–383. https://doi.org/10.2166/wp.2005.0023 Steele JH (1998) Regime shifts in marine ecosystems. Ecol Appl 8:S33–S36 TAB – The Technical Advisory Body for Fisheries Management (2006) Livelihood approaches and fisheries management in the Lower Mekong Basin. Mekong fisheries management recommendation no. 5, pp 1–12 Trimble M, Plummer R (2018) Participatory evaluation in times of governance transition: the case of small-scale fisheries in Uruguay. Ocean Coast Manag 161:74–83. https://doi.org/10.1016/j.ocecoaman.2018.04.027 Walters CJ, Martell SJD (2004) Fisheries ecology and management. Princeton University Press, Princeton WCED (1987) Our common future. World Conference on Environment and Development. Oxford University Press, Oxford, p 400 Zeller D, Harper S, Zylich K, Pauly D (2015) Synthesis of underreported small-scale fisheries catch in Pacific island waters. Coral Reefs 34:25–39. https://doi.org/ 10.1016/j.fishres.2010.10.024

Artisanal Fishing Gears and Sustainable Development Rogélia Martins and Miguel Carneiro Department of Sea and Marine Resources, Division of Modelling and Management of Fisheries Resources, Portuguese Institute for Sea and Atmosphere, Lisbon, Portugal

Definitions Fishing is an ancient activity that remains very similar to practices a long time ago. Some of the devices, gears and fishing methods, are still very similar. The main developments and transformations in fisheries started by the end of the nineteenth century with the introduction of powered engines and new materials, thinner, more resistant, more durable, and often cheaper. However, for the most cases, the development of fishing technology had no, or almost none, relation with the discovery of new gears or fishing methods; the

Artisanal Fishing Gears and Sustainable Development

knowledge and the ancient fishermen traditions were only improved. Fishing activity is understood as the catching or collecting of any living being from the aquatic environment, where it permanently lives including fish, crustaceans, mollusks, mammals, plants, or other aquatic organisms. Artisanal fishing uses the fishing gears and methods that have been traditionally used with some improvements, such as those resulting from the utilization of new materials, powered engines, and several devices (mechanical hauling, echo sounders, navigation equipment, etc.). The diversity of fishing gears and methods currently used in local artisanal fishing is large and variable, depending on the season, the geographic location, the targeted species, and the fishing grounds (Gabriel et al. 2005). Fishing gear may be considered as an artifact specifically constructed for fishing and reflects the knowledge, adaptation, inventive spirit, innovation, and improvement of fishermen engaged in this activity. Fishing method can be defined as the process or the tactics that the fisherman uses to capture the prey.

Introduction Artisanal fisheries and of those whose livelihoods depend on them are a key aspect of the UN Sustainable Development Goals (SDG), in particular SDG 14 – Life Below Water, given not only their high contribution for global fishery production and people involved but also for the reduced discards, fuel consumption, and damage to aquatic habitats, which contribute to a more sustainable use of marine and freshwater resources. Given that this sector is usually distanced from political decision centers (Pauly 1997; Zeller et al. 2015), SDG 14 reinforces the need to provide access for smallscale artisanal fishers to marine resources and markets while also contributing to reducing illegal, unreported, and unregulated fisheries and to increasing the number of stocks under biologically sustainable levels. Focusing on the social, environmental, and economic facets of artisanal fisheries will ensure that this activity meets its full potential to contribute toward sustainable development.

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Artisanal fisheries are characterized by a multiplicity of gears used, which differ in complexity, capture methods, selectivity, and catch efficiency. In this work, gears and methods of fishing are grouped following the classification by von Brandt (1972) revised by Gabriel et al. (2005). For each group, a very general and succinct description of some artisanal fishing gears is done (FAO 2018). Sometimes it is difficult to classify certain gears within a category, because they have intermediate characteristics or are used in different operating modes. In this case, the classification results from a compromise between the characteristics of the gear and the operating mode used. The names given to each type of gear reflect either the target species or the method in which the gear is used.

Harvesting Harvesting is considered, and certainly is, the oldest fishing method practiced by man from prehistoric times and is still the simplest way of catching fish, crustaceans, mollusks, echinoderms, polychaetes, and aquatic plants, among others. It is an activity in which one only uses the hand, the foot, trained animals, or tools not specifically constructed for fishing. The tools used in this capture method are simple, typically working as a hand extension and not causing serious injury to the prey. The catching is usually made on foot during low tide. In some cases, however, it may be practiced in more or less deep waters using diving equipment, both at sea and in inland waters. Nowadays, this fishing method still plays an important role in many fishing communities but is also practiced in specific places by holidaymakers and hobby fishermen such as the hunters and collectors of the past.

Grappling and Wounding Gear This method of fishing arose as a result of man’s having developed and mastered the construction and use of pitching instruments; this group includes methods in which the prey is captured

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by a perforating instrument with the intention of causing a deep wound. The instruments used may or may not act in solidarity with the operator’s hand; thus, they can be pushed, thrown, or shot. They include harpoons, spears, arrows, prongs, tongs, clamps, rakes, etc. This fishing method is commonly carried out in shallow waters, from the shore or from a boat, mainly in inland waters to catch fish (e.g., lampreys, eels, flat fishes), mollusks (e.g., razor clam), polychaetes, etc.

Stupefying Devices This group encompasses methods of capture in which paralyzing or stunning and numbness of the prey is caused. These methods can be exerted by mechanical, chemical, or electrical action. The simplest mechanical method is by throwing stones which are considered as the first long-range weapon of prehistoric man, and it is used, even in modern times, in fisheries. Fishing with explosives is another example of mechanical means and when used in small quantities can scare or stun the fish avoiding it to flee before completely surrounded. Chemical methods include the use of ichthyotoxic plants and poisons (e.g., lime, sodium hypochlorite). Deoxygenation/suffocation is also included in “chemical” methods where the fish is suffocated by mud and can be easily caught. Electricity can be used in sea fisheries in combination with fishing gears to improve their efficiency.

Lines This group includes fishing methods and gears that are essentially characterized by the existence of lines, in which most cases are provided with one or more hooks that are usually baited with natural or artificial lure to attract the fish. There are several types of fishing lines from the simplest ones, with or without hooks, which catch only one fish at a time, to the more complicated devices intended to catch several fish at the same time called longlines. These gears are generally

Artisanal Fishing Gears and Sustainable Development

operated in a very wide range of depths, either in inland and seawaters. They can be employed without boat, directly from the coastline. Fish caught by this fishing method is considered of better quality than that captured by other methods. Line without hooks is a very simple method of fishing consisting of a line to which the lure is attached and the prey holds the bait until it is withdrawn. This type of fishing is used to catch fish (e.g., eels), crustaceans (e.g., crayfish), and cephalopods (e.g., cuttlefish). Line with hooks is characterized by the existence of a suspension line to which a hook is fixed. This set of line and hook can be used single or in groups of a few or several thousands (longlines); in the latter case, these basic units (thin line or snood and hook) are inserted in a common structure – the main line. Longlines may be vertical or horizontal when the main line is set parallel to the bottom or surface. The hook, which is one of the oldest fishing tools used by man, is now currently a steel artifact, with or without a barb. A wide variety of size, type of hooks, and baits can be used, depending on the fishing ground and the target species. This fishing gear is considered one of the most selective fishing methods. Hand lines, the simplest form of fishing lines, has one or a few hooks and is hand-operated, with or without the aid of a pole or rod, and can be used for fishing in the bottom, mid-water, or surface, from shore or vessel. Natural or artificial bait can be used. A jigging line is a specific vertical hand line with a weight at the end and equipped with one or two crowns of barbless hooks (jig), where the number of jigs is variable. This fishing method relies on the action of attracting the prey by a jerky up-and-down movement. Jigging with a handheld jig is still in use, but this type of fishing is now largely mechanical, using a jigging machine. This fishing gear has been used for catching fishes (e.g., cod, bluefish, burbot) and cephalopods (e.g., squids, cuttlefish, octopus). Set longlines represents a subgroup that comprises the longlines which are generally placed on or near the bottom. The number and dimensions of hooks and the distance of snoods on the main line as well as their lengths depend on the target

Artisanal Fishing Gears and Sustainable Development

species, usually bottom or demersal species. Nowadays, the main line and snoods are often made of monofilaments because of their lower visibility and small diameter that improve the efficiency of the longlines. Drift lines are devices kept near the surface or at a certain depth by means of regularly distributed buoys (floats) and drift freely with the water flows. They may or not be attached to the boat while they are still. The snoods are usually longer and more spaced than on the set-lines. It is mainly used for the capture of pelagic species. Today, the most important drifting longline in commercial use is probably the tuna line that, according to tradition, is said to have been invented by the Japanese more than 250 years ago (Gabriel et al. 2005). Troll lines include fishing lines that are towed at the surface or at the subsurface either by vessels or by the fisherman at the shore. Natural bait or, more often, artificial bait is used. They are employed in marine and freshwater fishing, and their use goes back to ancient times.

Traps This group includes passive fishing gears and methods in which the prey (fish, mollusk, or crustacean) is caught when seeking refuge and food or is simply confused with labyrinthic structures and where the exit is prevented or made difficult by the

Artisanal Fishing Gears and Sustainable Development, Fig. 1 Earthenware and plastic pots for catching octopus. (Photo: Miguel Carneiro)

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existence of special devices introduced for this purpose. The traps are constructed of various materials and may have very different shapes and one or several entrances/openings; they may also drive and prevent the prey from continuing its normal course. They are often located in places of possible prey concentration or interception of their migratory routes. They are usually bottomed singly or in groups, with or without bait, and signaled to the surface by appropriate buoys. Their designations differ with either the region, shape, or target species. Hiding traps take advantage of the fact that some species look for places to shelter and therefore function as hiding places allowing free entrance and exit. For catching octopus (Fig. 1), earthenware pots are traditionally used, and in some areas shells of large gastropods or bivalves are still used instead of these pots. This type of traps is also used for catching fish and crustaceans, for example, eels, catfish, and crayfish (in freshwater). These traps can be set either simply or on longline system. Barriers are a type of fixed fishing gears more or less efficient that pose obstacles to the normal progression of fish. They are generally vertical walls or barriers and labyrinths arranged to facilitate the entrance of fish into a particular area or device from which is difficult to exit. They may be also equipped with bags. This type of fishing gear can be made of various materials such as stakes,

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reeds, tree branches, netting, stone walls, etc. Stone walls are known in many parts of the world, and they may be considered as “living fossils of the oldest fishing gear” (Gabriel et al. 2005). They are often used in areas where the currents or variations in water level are significant but also in areas of preferential passage of certain species. This type of traps commonly operates in inland and shallow waters, with strong tide effects, and retains the fish during their displacement with the tidal movements. Baskets include structures presenting different designs (box-like or baskets of varying shape and size), constructed of various materials (wood, metal, fishing net, etc.). They may be rigid or flexible and disassembled or not and have one or more openings. They are usually placed at the bottom, with or without bait, either single or in fleets (several traps each one connected by a branch line to a main line). These gears are operated in a very wide range of depths either in inland, estuarine, or seawaters. They are used to catch many species of crustaceans, octopus, and fishes. Trapping gear usually includes large gears with various types of retaining devices, anchored or fixed on stakes, can have guiding panels made of netting to lead the fish into the catching chamber and may be set or floating. They are mainly used to catch fish that are alive at capture and therefore in excellent condition. They are generally operated in coastal zones and shallow waters, either in inland, estuarine, or seawaters. This type of fishing gear is typically used for catching tuna swimming near the coastline during its migrations for spawning. It has been also used to catch different species as salmon, herring, sardines, and cod, among others.

Aerial Traps These traps take advantage of the behavior of some fish species that tend to jump out of the water when they face an obstacle or feel in danger. Various artifacts, such as boxes, rafts, small boats, or nets, are used to artificially trigger this reaction

Artisanal Fishing Gears and Sustainable Development

and to catch the jumping fish. Mullets, salmon, and flying fish, for example, can be captured this way. They are generally set in coastal zones, either in inland, estuarine, or seawaters.

Gillnets These passive fishing gears are constituted by single-walled net, mounted on two ropes: an upper flotation rope with buoys (headrope) and a lower one with weights (footrope). The position of the net in the water column can be modified by altering the number and size of buoys and weights; these nets can be used single or, more usually, in fleets, with length range from a few tens of meters to several kilometers. These gears, according to the fishery for which they are intended and the equipment used, may catch species in the bottom, mid-water, or surface and be fixed to the bottom (bottom set gill nets) or float freely (drift gill nets) attached or not to the vessel. These nets may be used in inland and seawaters to catch pelagic, demersal, and benthic species. The gillnet length, height, and the mesh size depend on the target species (Fig. 2). They are constructed to catch fish by gilling and have a high degree of selectivity both in terms of fish species and fish size which is determined by the mesh size.

Tangle Nets The nets of this group are made up of single, double, or triple walled (trammel nets) and specifically designed to entangle the fish or crustaceans. These nets are mounted together on the same frame ropes. Trammel nets may be fixed to the bottom (bottom trammel) or float freely (drift trammel). In trammel nets, between the two wide-mesh stretched outer walls, a rather loose interior netting with smaller mesh is inserted (named lint or lintnet), so the capture process does not depend so much on mesh size as on gillnets, because the prey is entangled itself in

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Artisanal Fishing Gears and Sustainable Development, Fig. 2 Gillnet with gilled striped red mullet. (Photo: Miguel Carneiro)

the net webbing due to the slack of the netting; hence, it is less selective than gillnets but more effective. Several types of nets can be combined in one fishing gear (e.g., trammel nets combined with gillnets). In this case, the upper part of the net consists of one wall (gillnet) to catch pelagic species and the lower part of three walls of netting (trammel net) for bottom fishes.

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Falling Gear This group includes fishing gears consisting of nets (hand and boat cast nets) or rigid structures (cover pots, lantern, and cover nets), which operate falling on the prey covering it. For instance, hand cast nets are today used over the world. These fishing gears are generally used in inland and shallow marine waters and can be deployed from the shore or from a boat.

Drive-In Nets Lift Nets This group includes fishing gears of various types complemented by several artifacts to drive the prey to the main gear. These gears may be stationary or mobile generally operating in shallow waters. The fish is driven into them by different means including casting stones into water, noise, swimming or diving fishermen, attracting light, frightening lines, and other methods.

This group includes fishing gears essentially made up of net of appropriate shape and size which is quickly lifted when the prey is over it. The horizontal net panel or bag shaped is submerged to the desired depth, and the fish lying on it are retained when the net is drawn up from the water. Decoys such as light or bait

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are often used to attract the prey to the net opening. These gears can be operated manually or mechanically in inland, on shore, or on board of vessels in seawaters. Lift nets are generally used to catch small pelagic species.

Bagnets Included in this group are bags, where the inlet aperture is held rigidly open during the fishing operation. The prey that enters, more or less voluntarily, is caught by filtering. Bagnets can be small nets operated by hand (scoop baskets) or larger ones (gape nets with or without wings) mostly mechanically operated. These gears are generally operated in shallow waters, in inland, or at sea and used from the shore or from a vessel. They are usually used to catch fish and crustaceans.

Dragged Gear This group comprises fishing gears consisting of towed nets with a large bag, sometimes with extended opening by small wings, and typically active gears (i.e., the gear moves toward the prey to be able to catch it). Dragged gears include two main types: dredges and trawls. Depending on their type, they may operate at the bottom, midwater, or surface (pelagic). Dredges are fishing gears that revolve the bottom, usually to catch shellfish. The catches are retained in a bag constructed of netting, strong fabric, or wire mesh or by metallic bars which allows eliminating water, sand, and sludge. The bag is connected to a rigid structure of varying shape and dimensions having a bar at the bottom with or without teeth. The teeth of the former dredges penetrate in the substrate to capture the animals buried into the seabed such as clams, cockles, etc. The latter scrape the surface of the bottom to catch mussels, oysters, or sea cucumber. Dredges can be operated by hand, generally equipped with a longer or shorter wooden handle operated by a fisherman in shallow waters (Fig. 3).

Artisanal Fishing Gears and Sustainable Development

Heavier and larger dredges are towed by boats and mainly operate in coastal areas but sometimes also in deeper waters on the continental shelf. Bottom trawls: the typical trawls are planned and equipped to fish at the bottom; they are nets with a cone-shaped body, usually extended forward from the opening by two lateral wings, and end in a bag or cod-end where the catch is retained. The mesh size in the cod-end is used to regulate the size and the species to be captured. Bottom trawls are towed by vessels and can operate in a very wide range of depths mainly at sea but in some cases also in inland waters. The target species are bottom and demersal fish and crustaceans. Beam trawl is the simplest type of the modern bottom trawls. In these trawls, the horizontal opening is typically maintained by a wooden or metal rod/beam. Usually the vertical opening is provided by two iron hoops/wheels, which also facilitate the movement over the bottom. These gears usually have no wings and are mainly used for catching shrimps and flatfish. They can be operated in inland and seawaters. Otter trawls are bottom trawls towed by a single vessel and generally have a cone-shaped body with a wide opening between the two wings. The horizontal opening of the net is obtained by two relatively heavy otter boards, and the vertical opening is obtained with floats on the upper rope (float line) and weights on the groundrope. They can operate in a wide range of depths mainly at sea but also, in some cases, in inland waters to catch benthic and demersal species (e.g., fishes, shrimps).

Seine Nets This group includes gears essentially consisting of very long wings with a bunt or a central bag often of reduced size, when compared to the wing size. These gears have a headrope with floats on the surface and a footrope with weights. The ends of the wings are connected to long hauling ropes. The method of capture is by surrounding a certain area with a fixed place from which the gear is set and hauled. Hauling can be done to the shore or to

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Artisanal Fishing Gears and Sustainable Development, Fig. 3 Dredge to be operated by hand. (Photo: Miguel Carneiro)

a vessel and is used in inland and in marine waters. The target species are demersal and pelagic ones. Beach seines are nets operated from the shore and are often set from the boat. One hauling rope remains on shore, while the net is set in a curved path and the second hauling rope is brought back to the beach and then the net hauling is started. The hauling ropes are simultaneously towed from the beach leading to a decrease of the surrounding area and the fish herding in front of the bag or bunt of the gear. They are specially used for catching seasonal pelagic species. The beach seines are a very old fishing method in coastal areas and traditionally are hauled manually; however, nowadays shore-anchored pulleys, tractors, or even animals are used to make hauling easier. Boat seine operates in a similar way as the beach seine, but in this case, the whole operation is done with one or two boats. One of the hauling ropes is anchored with a signaling buoy or fixed to

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one of the boats, and the other boat sets the net by describing a circle back to the fixed place; then the net is hauled into the boat hauling simultaneously the two hauling ropes. The general arrangement plan (two wings, body, and bag) of these nets resembles the typical trawl nets. However, the encircling action of these nets is very important for the efficiency of the haul. They can operate in inland or in seawaters at the bottom, mid-water, or surface to catch demersal and pelagic species.

Surrounding Nets These gears function as netting walls, placed vertically in the water due to the presence of a float line on top, which is kept on the surface, and a lead line at the bottom. When operating, these nets surround the fish shoal from the sides and from underneath, thus preventing them from escaping.

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This group includes subsurface fishing gears mainly used to catch pelagic species. Lampara is constituted by two lateral wings with wide mesh and a central bunt or bag with smaller mesh to retain the catch and a lead line much shorter than the float line. In contrast to the seine nets, the lampara nets are sometimes called “purse seines with bag.” The net is mostly operated with a single boat. The fishing operation starts by fastening one wing to a buoy, followed by surrounding the fish shoal; the boat returns to the buoy and begins the simultaneous hauling of the two wings. Purse seine is constituted by a long wall of netting with the same mesh size and a lead line equal or slightly longer than the float line. It has also mounted on the lead line a set of rings through which runs a rope called purse line, which allows the complete closing of the net underneath, preventing the escape of the prey. The purse seine is operated with one or two vessels, and light may be used to attract the target species. It is set around a detected fish shoal, and after that the net is closed underneath the shoal by hauling the purse line.

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The use of traditional and artisanal gears in artisanal fisheries is thus seamlessly aligned with the UN SDG 14 since they contribute to maintaining and increasing coastal fish stocks, given their higher selectivity and lower discards. Additionally, nearly 90% of the fishermen of our planet are enrolled in artisanal fisheries, which are highly important in the development of local coastal communities, contributing to their sustainable development by increasing the number of jobs and increasing the ethical access of food. In this sense, fostering artisanal fishing practices (and gears), together with specific management procedures, will surely contribute to achieving their full potential as a sustainable fishing practice, whose high cultural and traditional importance cannot be disregarded.

Cross-References ▶ Artisanal Fisheries: Management and Sustainability ▶ Destructive Fishing Practices and Their Impact on the Marine Ecosystem

Conclusions

References

The most relevant of artisanal fisheries is the use of all categories of fishing gears in combination with fishing methods, the fewer negative impacts on the ecosystem, the utilization of more selective and less destructive fishing gears, and the generation of less bycatch. Additionally, the high number of fishing gears and methods used in artisanal fisheries allows fishermen to diversify the target species, thus preventing the overfishing of some fish stocks. Furthermore, the small fishery communities have lower mobility and are very dependent on the local resources and environmental quality, which lead to a more responsible fishing activity and give a contribution to cultural heritage and environmental knowledge.

FAO (2018) Fishing Gear type Fact Sheets. http://www. fao.org/fishery/geartype/search/en. Accessed 15 June 2018 Gabriel O, Lange K, Dahm E et al (eds) (2005) Fish catching methods of the world, 4th edn. Blackwell Publishing, Oxford, p 523 Pauly D (1997) Small-scale fisheries in the tropics: marginality, marginalization, and some implications for fisheries management. Global trends: fisheries management American Fisheries Society symposium 20, Bethesda, pp 1–10 Von Brand A (1972) Fish catching methods of the world – revised and enlarged (2nd ed). The Fisherman’s Library. Fishing News (Books) Ltd, p 240 Zeller D, Harper S, Zylich K, Pauly D (2015) Synthesis of underreported small-scale fisheries catch in Pacific island waters. Coral Reefs 34:25–39. https://doi.org/ 10.1016/j.fishres.2010.10.024

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Benthic Communities

Bioinvasions

▶ Ecological and Economic Importance of Benthic Communities

▶ Biological Invasions as a Threat to Global Sustainability

Biological Diversity Benthic Microalgae ▶ Role of Microphytobenthos in the Functioning of Estuarine and Coastal Ecosystems

Benthonic Communities ▶ Ecological and Economic Importance of Benthic Communities

▶ Concepts of Marine Protected Area

Biological Invasions a s a Threat to Global Sustainability Daniel Crespo MARE – Marine and Environmental Sciences Centre, ESTM, Polytechnic of Leiria, Peniche, Portugal CFE, Centre for Functional Ecology – Science for People and the Planet, Department of Life Sciences, University of Coimbra, Coimbra, Portugal CIIMAR – Interdisciplinary Centre of Marine and Environmental Research of the University of Porto, Matosinhos, Portugal

Biodiversity ▶ Coastal Zone and Wetland Ecosystem: Management Issues ▶ Marine Bioprospecting and Intellectual Property ▶ Ocean(S) and Human Health: Risks and Opportunities

Synonyms Bioinvasions; Exotic species; Invasive alien species; Introduced species; Non-indigenous invasive species; Non-native invasive species

© Springer Nature Switzerland AG 2022 W. Leal Filho et al. (eds.), Life Below Water, Encyclopedia of the UN Sustainable Development Goals, https://doi.org/10.1007/978-3-319-98536-7

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Definitions

naturalized, fitting within the category of cryptogenic. Cryptogenic species are those which origins—native or non-native—remain undisclosed (Carlton 1996b). Usually, invasive species display opportunist behavior and r-selected life strategy: several generations/year, with short periods between spawning activity, and a large investment in reproduction and recruitment (Sakai et al. 2001). However, the invasion potential will be dependent not only on species traits but also on propagule pressure and the characteristics of the invaded habitat (Sakai et al. 2001; Byers 2002; Simberloff 2009). The introduced species find similar niches to their native areas, but in the absence of their native predators, parasites, or competitors, they became able to thrive as invaders and successfully overcame sequential stages of arrival, establishment, and integration (Vermeij 1996; Sakai et al. 2001; Blackburn et al. 2011). Although any organism can be potentially invasive, public awareness is biased toward animals and plants as main invaders. Nevertheless, bacteria or fungus can also be considered as highly impacting invaders, due to their pathogenic properties (Caldwell et al. 2007; Strayer 2010). Management of biological invasions implies a multilevel approach, with the contribution of several stakeholders, and should be framed under the scope of the 2030 Agenda for Sustainable Development (United Nations 2015), as an issue that crosses several of the Sustainable Development Goals (SDG). Biological invasions are scrutinized by distinct expertise’s, such as socio-economic sciences, ecology, engineering, or biochemistry, which reveals the complexity of this topic (Robertson et al. 2020).

Invasive alien species: alien species that threaten ecosystems, habitats, and species (Convention on Biological Diversity 2001). Therefore, the process of biological invasion can be described as the introduction of species in biogeographic areas outside their native range, with harmful consequences to the invaded ecosystem (Vermeij 1996; Grosholz and Ruiz 2009).

Introduction Biological invasions are currently emerging as one of the most serious threats for aquatic systems, although their impacts are not always easy to follow. The most striking feature of an invasive species is the ability to outcompete native counterparts and occupy their abandoned niches, thus reducing biodiversity by dominance of the invaded habitat (Sakai et al. 2001; Gallardo et al. 2016). Invasive species are responsible for disruptions in native biological communities and, ultimately, in global biodiversity, by aggressive consumption of local resources, predation and competition, introduction of pathogens, and altered abiotic conditions (Charles and Dukes 2007; Strayer 2010). The invasive character of the species will depend on the spreading success of the introduced, affecting other species, the ecosystem and human health, and economy (Grosholz and Ruiz 2009; Katsanevakis et al. 2014). Not all introduced species have invasive behavior, and only species that show highly efficient reproductive behavior and dispersion, with harmful effects, are termed invasive (Vermeij 1996; Crowley et al. 2017). Species can be introduced and became naturalized without ever becoming invasive. Regarding abiotic conditions, many invaders act as ecosystem engineers, by physically modifying the invaded habitat (Grosholz and Ruiz 2009; Gutiérrez et al. 2014). The introduction may be accidental or deliberate but is usually related to human activities. Not all invasive species have origin in distant geographic areas, and simultaneously, several invaders are not perceived as such because they are for long

Threats: Why Are Invasive Species a Nuisance? Biological invasions are serious threats to global biodiversity and are among the most important drivers of change within ecosystems, next to habitat modification and overexploitation (Convention on Biological Diversity 2001; Millennium Ecosystem Assessment 2005). It is a common belief, especially among non-specialists, that

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invasive species threaten the ecosystems by dominance of the invaded communities. Biological invasions are frequently responsible for monotonous communities, excluding native species due to direct competition on resources such as food or space, by predation or parasitism, through niche displacement or by hybridization with native species. Therefore, the human-mediated transport of species across the globe, with its subsequent invasive consequences, is responsible for the reduction of local, regional, and global biodiversity due to the homogenization of biological communities (Ruiz et al. 1997; Seebens et al. 2017). Fundamentally, the impact of biological invasions can be divided into two large groups (Fig. 1): Ecological impacts: For long, the study of biological invasions focused on the effects on native species, especially on their demographic traits. Nevertheless, ecologists are shifting the attention to cumulative effects on the ecosystem,

particularly on how certain ecosystem functions are modified upon the arrival of an invader (Simberloff et al. 2013). The ecological effects of invading species are due to direct and indirect biotic mediation: (a) the invaders’ activities may have a direct influence on ecosystem process rates, for example such as bioturbation activities or nutrient generation by infaunal invertebrates (Crespo et al. 2018), or, on the other hand, (b) invaders influence other biotic and abiotic proponents that are themselves responsible for the change in ecological process, such as the influence of the Nile perch, that reduced native phytoplanktivores and detritivores populations, and allowed the increase of algal blooms and macrophytes (Simberloff et al. 2013); also, the effects of invaders can be described either by assimilatory-dissimilatory mechanisms (uptake and release of energy and materials) (Sousa et al. 2012) or by physical ecosystem engineering (organismal-mediated physical environmental

Impacts Ecological

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Bio olo ogical

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Ecolog gica al proces oc cesses s

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Ecosy system m engin neering

Preven ntion and mitiigation

Direct effect

Human intervention

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Biological link

Economic link

Biological Invasions a s a Threat to Global Sustainability, Fig. 1 Ecological and economic impacts of biological invasions

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Biological Invasions a s a Threat to Global Sustainability

modification) (Gutiérrez et al. 2014), or both. It is fundamental to understand that the net effects of invasions are due to the combination of both kinds of mediation and the aforementioned mechanisms. Therefore, biological invasions not only transform the relative abundance of species among native communities, but are also responsible for effects along trophic cascades, with alterations in energy and matter flows within the food web, in nutrient cycles, and in the physical structure of habitats and erosion regimes (Simberloff et al. 2013). Economic impacts: Biological invasions affect economy under different perspectives. The first is related with the ecological impacts per se. Changes in ecosystem functioning affect ecosystem services, which are the benefits offered by natural systems to human populations. This include provisioning services (food, crops, timber, fresh water, etc.), regulating services (air quality, climate regulation, water cycling, waste treatment, natural pest regulation, pollination, erosion prevention, etc.), cultural services (non-material services as aesthetical values, tourism and recreation, cultural heritage, etc.), and supporting services (soil formation, photosynthesis, and nutrient cycle) (Millennium Ecosystem Assessment 2005). Although hard to quantify, the loss of those services by the introduction of alien species will result in monetary losses, as most of them are tangible goods (Pimentel et al. 2007). The second source of economical nuisance due to invasive species will be the cost in prevention and mitigation of invasion effects (Simberloff et al. 2013; Jardine and Sanchirico 2018). There is also the cost associated with pathogens, introduced directly or along with their hosts, affecting human health, which is one of the main concerns and expenses in human societies (Pasko and Goldberg 2014). There are invasive species, especially aquatic fouling invertebrates, that are associated with malfunctioning of several industrial facilities or other man-made infrastructures, such as water transport systems or harbor structures (Matthews and McMahon 1999; Sorte et al. 2010; Piola and Hopkins 2012). These impacts are addressed under the field of engineering, not without associated costs. The global cost to

economy associated with invasive species is estimated in at least 5% GNP (Pimentel et al. 2007). Other estimations refer 20% of food production lost due to alien species (Caldwell et al. 2007). The perception of invasion by managers and stakeholders is often delayed in relation to the invasion’s starting moment (Seebens et al. 2017), because many introduced species have innocuous populations for extended periods, before causing harm to the invaded ecosystem. This will impair the efficiency in the eradication of invaders and in the mitigation of their effects, increasing its costs and often with mediocre results. Late attempts to attack invasions episodes have frequently irreversible consequences. Biological invasions events need to be analyzed and understood from a broad perspective. Although biodiversity loss is the most perceived consequence of biological invasions, the range of effects of biological invasions spans across distinct fields, and should be handled by a holistic approach (Rodríguez-Labajos et al. 2009; Simberloff et al. 2013; Robertson et al. 2020). Biological invasions are even responsible for cultural consequences (Vermeij 1996) because several human practices have changed in order to incorporate those changes in the biota.

Are There “Good” Invaders? Is the negative perception of biological invaders justified? The public perception and awareness related to non-native species are highly dependent on the context (Rodríguez-Labajos et al. 2009). The same species could be simultaneously regarded as an asset or as a nuisance, depending on the stakeholders’ perspective. Most of the nonnative species that are perceived as valuable are often related to provisioning: food sources (e.g., the bivalve Ruditapes philippinarum, Fig. 2a) or as timber. Also, several species are valued by their aesthetical properties: this is clearly the case of exotic ornamental plants in gardens and animals as pets or zoological curiosities (Simberloff et al. 2013). Until recent decades, those species were regarded as important resources, and their dissemination was extensively human-mediated

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Biological Invasions a s a Threat to Global Sustainability, Fig. 2 Examples of invasive aquatic species. (a) Ruditapes philippinarum. (Photo credits: Daniel Crespo);

(b) Hemigrapsus sanguineus. (Photo credits: Lénia Rato); (c) Asparagopsis armata. (Photo credits: Carla O. Silva)

(Seebens et al. 2017). Beside these profitable uses of non-native species, some other positive effects are attributed to some invasive species. For instance, some species can create habitat for other species, occasionally contributing to a biodiversity increase. This is the case of some introduced trees or the empty shelves of bivalves. In other cases, some aquatic species can reduce the organic loads on water bodies, with benefits on the overall ecosystem functioning. Nevertheless, those examples are not enough to treat non-native species with disregard, as the risk of negative impacts is higher and because the number of successful invasions with negative consequences is increasing every year (Simberloff et al. 2013; Seebens et al. 2017). The discussion on the deliberated use of non-native species must carefully account for all their impacts (positive and negative), under a multidisciplinary assessment.

The Particular Case of Marine and Coastal Systems Oceans and coastal systems represent a special case among the habitats under invasive pressure. Oceans are connected, and the barriers that species may find are mostly related to distance and currents. Global commerce is responsible for reducing the effect of distance. Global climate change contributes to alterations in the currents’ patterns across the globe. Both factors contribute to an increase in invasion episodes along coastal and estuarine systems. Also, human activities along shores and estuaries contribute to the spread of non-native species. These can be transported as fouling communities of vessels hulls, within ballasts waters, or introduced as aquaculture stock, for fishing purposes, or as pets escape (Carlton 1996a; Ruiz et al. 1997; Williams and Grosholz

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2008). Also, the connection of waterways through channeling plays an important role in the dispersal of non-native species, including diverse taxa such as mollusks, bryozoans, crustacean, ctenophores, and vascular plants (Ruiz et al. 1997). It seems that estuaries and embayment’s suffer more successful invasions than open shores (Ruiz et al. 1997; Preisler et al. 2009). Ports within international routes are identified as epicenters of most marine invasions. This could be related to altered ecosystems and to the higher number of inoculations by non-native species, due to a higher number of human activities that occur within those semi-enclosed systems. Estuaries, in particular, suffer a two-side invasive pressure, either from inland waters or from the open-ocean human activities (Caldwell et al. 2007; Crespo et al. 2018). Also, it seems that the effects due to invasive events are more prominent in estuaries than in the open-ocean. This could be justified partially by the open nature of the ocean and the large size of marine populations, with enough dispersal and recruitment capacity to resist the pressure by invasive species (Ruiz et al. 1997). Between 1961 and 1995, the San Francisco Bay and Delta, suggested to be the world’s most invaded estuary, have recorded a new invasive species every 14 weeks, in average (Cohen and Carlton 1998), which is quite remarkable. Although this is an extreme example of an invasion rate, it shows the high susceptibility for invasions in estuarine systems. Quite often, invasive species are responsible for the accessory introduction of pathogens or parasites that affect not only human health (Pasko and Goldberg 2014), such as toxic dinoflagellates, but also native species or aquaculture stocks, such as polychaete Terebrasabella uncinata, which affected abalone farms in California (USA) (Culver and Kuris 2000; Williams and Grosholz 2008). Most of times, the introduction of invasive species turns out to be irreversible, especially in these ecosystems, due to ineffective eradication strategies and management: in comparison with land ecosystems, underwater work brings added difficulties that increase associated costs. Nevertheless, there are some cases where the efforts appeared to be fruitful (Williams and Grosholz 2008), such as the case

of T. uncinata (Culver and Kuris 2000). Yet, the eradication of these invasive polychaete implied the sacrifice of large amounts of its preferred host, the snail Tegula funebralis. This is an example that control and strict policies on the introduction of new species in these ecosystems is fundamental and preferable to eradication plans, with lower economic and ecological costs. Several countries have signed the Convention on Biodiversity and the Codes of Practice on the Introductions and Transfers of Marine Organisms (ICES – International Counsel for Exploration of the Seas), which defines clear strategies and guidelines on the transport and introduction of non-native species. Nevertheless, these are non-regulatory, and their effective application depends on the transposition to the legislation of each country, which may have differential levels of efficiency (Williams and Grosholz 2008).

Key Mechanisms in Biological Invasions Vectors of Invasive Species It is fundamental to identify the vectors that allow non-native species to expand their distribution areas, because is during this stage that prevention is more effective (Robertson et al. 2020). Species are naturally able to expand their range through biological dispersal mechanisms. This means that a population will have to face direct competition with other species in order to occupy new niches. This implies a slow spread of the species, which is only obvious at expanded time scales. Most times, species are not able to cross large biogeographic barriers by natural dispersal mechanisms (Ruiz et al. 1997). Therefore, this is only possible through human mediation, either by accidental or deliberate transport and introduction or by facilitating dispersal by removing previous barriers (Carlton 1996a; Vitousek et al. 1997). Since the beginning of mankind and especially after the invention of agriculture, human communities transported several species along with their expansion. The human dispersion across the globe was associated with the transport of several domesticated and selected species, either plants or animals, but also of parasites and microbial

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pathogenic species (Seebens et al. 2017). Nevertheless, it was during the European maritime expansion in the fifteenth century that started a new era of transport of goods and biological material across continents and within short time spans: this was the beginning of globalization, which is currently more intensive than ever before, and associated with the highest rates of non-native species’ introduction (Ruiz et al. 1997; Zenetos et al. 2012; Seebens et al. 2017). Once introduced, species can disperse as it would in their native ranges. If they find less resistance to invasion in the newly invaded areas due to the lack of predators, parasites or direct competitors, they will spread with prejudice to local communities. Global climate change favors successful invasions. While some introductions may fail to succeed due to local environmental conditions, global climate change, with the increase of the mean temperature and especially with the expansion of temperature ranges, offer increasing opportunities for invasive species to prevail in their new habitats (Stachowicz et al. 2002; Sorte et al. 2010; McDowell et al. 2014). This is obvious for tropical species that are introduced in temperate areas that now show a more favorable temperature regime due to climate change (Rahel and Olden 2008). Thermal pollution is also responsible for the local increase of water bodies’ temperature, thus allowing the persistence of species that were previously unable to survive in those locations (Simard et al. 2012). A similar mechanism could be described for salinity, which is modified under climate change scenarios: alterations in salinity offers the possibility of colonization by species previously barred from those locations (Crespo et al. 2017). Nevertheless, a successful invasion depends on several events, which involve modifications on donor regions (with increase on populations, making potential invaders more available for transport), on recipient regions (environmental and ecological changes that increase the susceptibility to be invaded), and changes in dispersion vectors (size and speed, or the appearance of new vectors), which concur to widening invasion windows (the interaction of adequate colonizing and longterm establishment conditions) (Carlton 1996a).

Several pathways are identified as major vectors for the introduction of alien species, and they can be interconnected. Although some pathways are exclusive for aquatic or terrestrial systems, or in less extent, through aerial transport, ultimately, the transport network transforms all the globe as a potential target for biological invasions (Caldwell et al. 2007; Rodríguez-Labajos et al. 2009). Most of the planet is covered by oceans and even in land rivers play an important role as a communication way. The largest share of the world’s intercontinental commerce is based upon maritime shipping, thus creating limitless opportunities for the transportation of species across long distances, which raises the potential for invasion events (Carlton 1996a; Seebens et al. 2017). Below are listed the vectors that are commonly responsible for the introduction of invasive/alien species into aquatic systems: Transport within ballast water: Large cargo ships use ballast water for stability purposes. The water is loaded when necessary and released once the cargo weight is enough to offer stability to the vessel. This means that huge amounts of water could be transported across large distances and within those several species that could become invaders. This is probably the most important vector of introduction of new species in marine and estuarine habitats, and a large array of species (from bacteria to fishes) can be transported in this way (Carlton 1996a; Ruiz et al. 1997). Transport of hull fouling species: Many marine sessile species (especially crustaceans and mollusks) can colonize the hull and propellers of all kinds of ships and boats, which means that those species are able to travel long distances and disperse across large geographical areas. Channelization of water: The building of new channels for water diversion allows species to disperse across previously isolated systems, many times linking intracontinental drainage systems. Also, navigation channels linking seas and other large water bodies create wide open pathways for mobile species to expand their limits. The Suez Canal is a paradigmatic example, which allowed a significant modification in the Mediterranean species communities (Ruiz et al. 1997; Zenetos et al. 2012). The event was well

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described in scientific literature and named after the architect of the canal, Ferdinand de Lesseps, as the Lessepsian invasion. Also, the creation of new water bodies and channels or the enlargement of those already existent offer new empty niches that are occupied by species that outcompete others in the colonization process, which is usually the case of the invasive species. Tourism and recreational use of water bodies: The use of water courses for recreational activities such as fishing, boating, or other water sports, may facilitate the introduction of the species in previously uninvaded areas. This includes the use of invasive species as bait or the introduction of species as a food resource and fishing target (several predatory species have been introduced for recreational fishing in water reservoirs, with significant impacts on local communities, such as trout (Rahel and Olden 2008) or lion fish (Pasko and Goldberg 2014)), or simply the naïve transport of specimens as a tourist curiosity. Aquarium hobby and released pets: Pet owners often release their unwanted pets into the wild (Seebens et al. 2017). For example, in the Mediterranean, at least 18 species might have been introduced through aquarium trade (Zenetos et al. 2012). Another high-profile example is the Burmese python, released into Florida’s Everglades wetlands (USA), with a considerable impact on local communities (Pasko and Goldberg 2014) Aquaculture: This activity is responsible for an intensive transport of species across the globe, with many species being bred that have distant origins. Several categories of aquaculture do not use fully enclosed systems, which allows the escape of specimens into the wild. Those specimens can raise and mediate successful invasion events. The Atlantic oyster Crassostrea virginica was introduced on the Pacific Coast of the USA in the late nineteenth century (Ruiz et al. 1997). Several other species traveled as hitchhikers during this transport and are now important invaders on the west coast. Transport of goods and persons as conveyers: Several alien species are transported inadvertently along with natural resources as wood or food, for example as insects that contaminate those goods,

or also as seeds or propagules attached to domesticated animals and live stocks (Seebens et al. 2017). Humans are also able to carry alien species across large distances attached to footwear or clothes, for example. Stages of Invasions The above-mentioned vectors allow the transport of species from their native ranges to new territories, and represent the first steps on a succession of stages, more or less related to human mediation, that species must override for a successful invasion: transport, arrival, establishment, and integration (Vermeij 1996; Blackburn et al. 2011; Ricciardi 2012). The related terminology of the population shifts along with the crossing of those barriers. The transport stage needs to overcome geographical barriers and is usually highly dependent on human activities. The arrival or the introduction implies the entrance of the species into the new habitat, and to be successful, the population must flee from captivity or cultivation. Both stages are highly intertwined, and the species or the population is yet named as nonnative or alien. Most organisms fail to surpass these stages, yet, if the alien organisms became able to survive and reproduce, they reach the establishment stage and are now called introduced. The ability to reproduce turns the population into a naturalized population. Now, the naturalized population can sustain its demography without the input from the original source. Once the population is able to overcome dispersal and environmental barriers, it reaches the integration stage, when ecological links with native species are created, and once it shows the characteristic reproductive behavior with harmful impacts it is called invasive (Vermeij 1996; Blackburn et al. 2011). A phenomenon described for biological invasion events is the lag phase: this will be the time between the arrival and the establishment, after which occurs a rapid expansion of the invasive population, only contained by the invaded system carrying capacity. The duration of the lag phase is widely variable: it could be almost inexistent, or it could take several years or decades since arrival for an invasion to become fully

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installed, and it is shorter for animals than for plants. This has several implications on the management of biological invasions, because the impact and risk of invasion may become seriously sub-evaluated during this phase. In other cases, if not detected due to low numbers, it could represent a lost opportunity for the eradication of the population while still small, when the chances of successfully removing the infestation are highest (Caldwell et al. 2007; Williams and Grosholz 2008; Ricciardi 2012). Biologically, this lag time could be necessary for the invasive population to suffer a period of adaptation under selective pressures (post-invasion evolutionary response), thus increasing the population fit before becoming a fully invasive species (Caldwell et al. 2007).

Single-parent reproduction and vegetative reproduction. Phenotypic plasticity and genetic variability, physiological tolerance to a wide range on environmental conditions: Invasive species are often characterized as able to adapt their growth to several different environmental conditions, although this trait is under debate (McMahon 2002). Human commensalism: invasive episodes are usually related to human activities and production for consumption, such as the widely dispersed Ruditapes philippinarum (Fig. 2a) (Lopes et al. 2018). Although these traits could describe several invasive species, some of those can be also found in native populations that in the end are replaced by those invasive competitors. So, it seems that r-selected traits (rapid population growth, early maturity, short life spans, high fecundities and dispersal abilities) are more relevant for invasive species success, which means that, even if less adapted to extreme conditions, they are able to reach high densities faster than their competitors (McMahon 2002). This means that after catastrophic events, those invaders are the first to occupy the depleted niches. The populations of invaders are usually good performers in habitats where frequent massive dieoffs occur: those habitats are promptly recolonized by invaders due to their r-selected traits. There are some hypotheses that may justify the efficiency of invaders when compared with native communities (Caldwell et al. 2007; Ricciardi 2012). Preadaptation theory preconizes that invading species will succeed if they are already equipped with the equipment to face the new environment. This theory justifies the high invasive success of human-related species: they are already adapted to modified habitats and when introduced in new habitats where human mediation occurred, there is a high probability of a successful invasion. One of the most compelling theories is the novel weapons hypothesis (Callaway and Ridenour 2004): this theory postulates that introduced species bring novel biochemical weapons into the invaded habitats. The same

Characteristics of Invaders and Invaded Habitats There is a set of features that seem associated with invasive species. Nevertheless, some of those traits could be found in native species or in introduced species without invasive behavior. Therefore, the invasion potential depends on the relationship between the invader and the invaded habitat, which in turn could be a very contextdependent interaction (Gallardo et al. 2016). Some of the traits often associated with invasive species are (Ricciardi 2012): Fast growth: larger than related species and early reproduction – species show high production rates, with early sexual maturation, therefore giving rise to new generations faster than its competitors. Efficient dispersal mechanisms: invasive species often show specialized dispersal mechanisms that allow them to spread their offspring, seeds or propagules across larger areas. Opportunistic and generalist (polyphagy and eurytrophy): successful invaders are usually opportunistic, able to live in habitats less suitable to other species. This trait is related with the generalist feeding behavior, which means that these species can feed on several food sources (in the case of animals) (e.g., the invasive crab Hemigrapuss sanguineus (Fig. 2b)) (Bouwmeester et al. 2019).

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weapons are no concern in native grounds because competing species have co-evolved in the presence of those factors. An interesting example is the invasive red algae Asparagopsis armata (Fig. 2c) which exudates bioactive compounds into the water (Paul et al. 2006). Another interesting hypothesis is the invasional meltdown, described to justify the invasion potential of mutualistic invaders: positive feedback between introduced species can be responsible for the invasion success of some. Nevertheless, the success of an invasion depends not only on the species traits but also on the susceptibility of the invaded habitat which is accounted in this next theory. The empty niche hypothesis assumes that invasive species can give a better use of resources that native species use inefficiently. Therefore, by using new niches or by capitalizing the underused existent niches, the invaders can outcompete native species. This theory is closely related with the biotic resistance hypothesis (Stachowicz and Byrnes 2006), where species-rich communities offer higher resistance to invasion events, either due to already fulfilled niches (and therefore competition over similar resources) or due to predation by higher trophic levels. This means that after catastrophic events, such as floods or fires, or due to intensive pollutants release, habitats with low biodiversity levels show a higher potential to be invaded by non-native species. Another theory is the enemy release hypothesis (Torchin et al. 2003): under this concept, the invader, when removed from its native habitat and introduced in new areas, does not bring along its native topdown regulators, and therefore the pressures exerted in the native range are reduced in the new territories. This theory is enhanced under the evolution of increased competitive ability hypothesis (Blossey and Notzold 1995), which states that, under an evolutionary perspective, without their native selective pressures, invasive populations no longer have to support costly defenses, thereby re-routing their resources toward a better performance in growth and reproduction in the invaded range. Other evolutionary mechanisms that are also associated with the success of invasions are hybridization and founder effects (Caldwell et al. 2007, pg. 86–87).

None of those theories and concepts are mutually exclusive neither universally valid, and each invasion event is site- and opportunity-specific. The potential for an invasion to occur depends on the species, on the habitat, and on a wide range of factors that can be described under the scope of several of the previous theories. This reinforces the need to produce more and better knowledge on invasion science to better understand and predict these phenomena.

Prevention and Mitigation As a worldwide threat to ecosystems and economy, invasive species must be managed in order to minimize their impacts. The Convention on Biological Diversity (signed in 2010 by most world governments) clearly states, in its “target 9,” that “by 2020, invasive alien species and pathways are identified and prioritized, priority species are controlled or eradicated and measures are in place to manage pathways to prevent their introduction and establishment.” This international agreement is reinforced by 2030 Agenda for Sustainable Development (2015), which engages the prevention of biological invasions in the SDG 15: this SDG asks governments to include prevention measures to reduce the introduction and the impact on biological invaders by 2020. The efforts should be played within two levels: prevention and mitigation. Prevention is the obvious first line of defense against biological invasions (Caldwell et al. 2007; Ricciardi 2012; Simberloff et al. 2013). This is the most effective and cost-efficient option, with better results, and depends on the proper identification of the introduction vectors (Carlton 1996a; Simberloff et al. 2013). International borders must be controlled under tight biosecurity measures to avoid the intentional and non-deliberate transport of certain species. The example of mid-ocean ballast water exchange is a good, practical example of preventive measures, with reduced cost (Lavoie et al. 1999; Simberloff et al. 2013). Another potential technique to reduce the load of non-native species on ballast water could be based on water heating (Rigby et al. 1999). For prevention to be effective,

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it is not only necessary to comply with regulations, but also of utmost importance to transmit information about the risks and how to proceed against invasive species (Darrigran and Damborenea 2015). Dedicated management on local habitats could also present a preventive role, by increasing local resistance to invasion (Ricciardi 2012). Nevertheless, prevention is not a universal shield against invaders. Even if international conventions and local regulations were thoroughly enforced, still, it would be impossible to prevent all invasion episodes. Therefore, it is necessary to engage in the mitigation of invasions’ impacts. This will follow a successive chain of early detection, rapid response, eradication or containment and long-term management in the case of failure of previous steps. Early detection will allow a prompt eradication, more efficient and less onerous than longterm management programs. Novel molecular techniques allow the detection of alien species even before they reach adult stages (Simberloff et al. 2013; Darrigran and Damborenea 2015). Smaller populations are easier to target for elimination, while recently introduced populations do not have the time to establish strong ecological links with native communities, reducing the risk of unpredicted ecological risks. Once established, invasive populations are hard to eradicate and therefore the associated costs increase. Nevertheless, there are still active measures to be taken under the long-term management strategies, in order to maintain invasive populations under less hostile levels, such as mechanical (e.g., hunting, fishing, harvesting), chemical (e.g., pesticides, “BioBullets ®”) or biological (by the introduction of a non-native predator, parasite or herbivore) control (Ricciardi 2012; Pasko and Goldberg 2014). In this stage, besides higher costs, there are higher associated risks, like the elimination of non-target species, chemical contamination of the ecosystem or unpredictable outcomes with the introduction of a biological control. The inevitability of eradication plans included in the context of rapid response or long-term management strategies when facing invasive species is often confronted with the unwillingness of

stakeholders to comply with such intents (Simberloff et al. 2013). Also, those actions may be responsible for the loss of non-target species, either directly or by the loss of ecological interactions with invaders. Another challenge imposed by mitigation plans is the necessity of permanent monitoring, due to the risk of re-invasion. The elaboration of both preventive and mitigation strategies should rely on the scientific knowledge on invasive species, their vectors and their impacts, and on the characteristics of the recipient habitat, under the penalty of inefficiency and resource waste.

Future Directions It is fundamental to recognize biological invasions as one of the most deleterious threats to biodiversity in terrestrial and marine ecosystems. Although this concept is already installed within the scientific community, public outreach will play a crucial part in the minimization of the problem. Raising awareness within stakeholders and human populations increase prevention and early detection abilities. On the side of researchers, it is necessary to compile more information on the several components of biological invasions (species, populations and their traits, vectors, and source and invaded habitats) in order to produce models with higher predictive power. This means that, despite the technological improvement on preventive and mitigative tasks, there is still room for refinement.

Key Issues Invasive species represent a pervasive threat, with ecological and economic consequences, and are recognized in international agreements as the Convention on Biological Diversity and the 2030 Agenda for Sustainable Development. They represent a threat to fundamental ecosystem services and also are costly to regulate and mitigate. They are highly related to human activities and the recognition of their vectors and pathways play a crucial role in the design of preventive and

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mitigation plans. There are several traits that associated with biological invaders, although the characteristics of the invaded habitat influence the success of a potential invasion. The management of this intricate global issue depends on the lessons learned so far.

Convention on Biological Diversity (2001) Invasive Alien species: status, impacts and trends of alien species that threaten ecosystems, habitats and species Crespo D, Leston S, Martinho F et al (2017) Survival of Corbicula fluminea (Müller, 1774) in a natural salinity and temperature gradient: a field experiment in a temperate estuary. Hydrobiologia 784:337–347. https:// doi.org/10.1007/s10750-016-2887-3 Crespo D, Solan M, Leston S et al (2018) Ecological consequences of invasion across the freshwater-marine transition in a warming world. Ecol Evol 8. https://doi. org/10.7910/DVN/3ITBSH, https://doi.org/10.1002/ ece3.3652 Crowley SL, Hinchliffe S, McDonald RA (2017) Conflict in invasive species management. Front Ecol Environ 15:133–141. https://doi.org/10.1002/fee.1471 Culver CS, Kuris AM (2000) The apparent eradication of a locally established introduced marine pest. Biol Invasions 2:245–253. https://doi.org/10.1023/ A:1010082407254 Darrigran G, Damborenea C (2015) Strategies and measures to prevent spread of invasive species. In: Boltovskoy D (ed) Limnoperna fortunei, Invading Nature- Springer Series in Invasion Ecology 10. Springer, Cham Gallardo B, Clavero M, Sánchez MI, Vilà M (2016) Global ecological impacts of invasive species in aquatic ecosystems. Glob Chang Biol 22:151–163. https://doi.org/ 10.1111/gcb.13004 Grosholz ED, Ruiz GM (2009) Multitrophic effects of invasions in marine and estuarine systems. In: Rilov G, Crooks JA (eds) Biological invasions in marine ecosystems. Springer, Berlin/Heidelberg, pp 305–324 Gutiérrez JL, Jones CG, Sousa R (2014) Toward an integrated ecosystem perspective of invasive species impacts. Acta Oecol 54:131–138. https://doi.org/10. 1016/j.actao.2013.10.003 Jardine SL, Sanchirico JN (2018) Estimating the cost of invasive species control. J Environ Econ Manag 87: 242–257. https://doi.org/10.1016/j.jeem.2017.07.004 Katsanevakis S, Wallentinus I, Zenetos A et al (2014) Impacts of invasive alien marine species on ecosystem services and biodiversity: a pan-European review. Aquat Invasions 9:391–423. https://doi.org/10.3391/ ai.2014.9.4.01 Lavoie DM, Smith LD, Ruiz GM (1999) The potential for intracoastal transfer of non-indigenous species in the ballast water of ships. Estuar Coast Shelf Sci 48:551– 564. https://doi.org/10.1006/ecss.1999.0467 Lopes ML, Rodrigues JP, Crespo D et al (2018) Functional traits of a native and an invasive clam of the genus Ruditapes occurring in sympatry in a coastal lagoon. Sci Rep 8:16901. https://doi.org/10.1038/s41598-01834556-8 Matthews M, McMahon R (1999) Effects of temperature and temperature acclimation on survival of zebra mussels (Dreissena polymorpha) and Asian Clams (Corbicula fluminea) under extreme hypoxia. J Molluscan Stud 65:317–325

Cross-References ▶ Aquaculture: Farming Our Food in Water ▶ Coastal Pollution: An Overview ▶ Promoting Coastal and Ocean Governance Through Ecosystem-Based Management ▶ Sustainable Tourism in the Context of the Blue Economy

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Seebens H, Blackburn TM, Dyer EE et al (2017) No saturation in the accumulation of alien species worldwide. Nat Commun 8. https://doi.org/10.1038/ ncomms14435 Simard A, Paquet A, Jutras C et al (2012) North American range extension of the invasive Asian clam in a St. Lawrence River power station thermal plume. Aquat Invasions 7:81–89. https://doi.org/10.3391/ai.2012.7.1.009 Simberloff D (2009) The role of propagule pressure in biological invasions. Annu Rev Ecol Evol Syst 40:81–102. https://doi.org/10.1146/annurev.ecolsys.110308.120304 Simberloff D, Martin J-L, Genovesi P et al (2013) Impacts of biological invasions: what’s what and the way forward. Trends Ecol Evol 28:58–66. https://doi.org/10. 1016/j.tree.2012.07.013 Sorte CJB, Williams SL, Zerebecki RA (2010) Ocean warming increases threat of invasive species in a marine fouling community. Ecology 91:2198–2204. https://doi.org/10.1890/10-0238.1 Sousa R, Varandas S, Cortes R et al (2012) Massive dieoffs of freshwater bivalves as resource pulses. Ann Limnol Int J Limnol 48:105–112. https://doi.org/10. 1051/limn/2012003 Stachowicz J, Byrnes J (2006) Species diversity, invasion success, and ecosystem functioning: disentangling the influence of resource competition, facilitation, and extrinsic factors. Mar Ecol Prog Ser 311:251–262. https://doi.org/10.3354/meps311251 Stachowicz JJ, Terwin JR, Whitlatch RB, Osman RW (2002) Linking climate change and biological invasions: ocean warming facilitates nonindigenous species invasions. Proc Natl Acad Sci U S A 99:15497–15500. https://doi.org/10.1073/pnas.242437499 Strayer DL (2010) Alien species in fresh waters: ecological effects, interactions with other stressors, and prospects for the future. Freshw Biol 55:152–174. https://doi.org/ 10.1111/j.1365-2427.2009.02380.x Torchin ME, Lafferty KD, Dobson AP et al (2003) Introduced species and their missing parasites. Nature 421: 628–630. https://doi.org/10.1038/nature01346.1 United Nations (2015) Transforming our world: the 2030 Agenda for Sustainable Development. A/RES/70/1 Vermeij GJ (1996) An agenda for invasion biology. Biol Conserv 78:3–9. https://doi.org/10.1016/0006-3207 (96)00013-4 Vitousek PM, Mooney HA, Lubchenco J, Melillo JM (1997) Human domination of Earth’ s ecosystems. Science 277:494–499. https://doi.org/10.1126/science. 277.5325.494 Williams SL, Grosholz ED (2008) The invasive species challenge in estuarine and coastal environments: marrying management and science. Estuar Coasts 31:3–20. https://doi.org/10.1007/s12237-007-9031-6 Zenetos Α, Gofas S, Morri C et al (2012) Alien species in the Mediterranean Sea by 2012. A contribution to the application of European Union’s Marine Strategy Framework Directive (MSFD). Part 2. Introduction trends and pathways. Mediterr Mar Sci 13:328. https://doi.org/10.12681/mms.327

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Biological Nuisances ▶ Harmful Algal Blooms: Effect on Coastal Marine Ecosystems

Biological Population ▶ Defining and Measuring a Marine Species Population or Stock

Biological Nuisances

environment for these sectors are allocated, considering also its impacts on and interrelations with the marine environment as well as with other economic activities, following the triad of social, environmental, and economic objectives (Ehler and Douvere 2009). Multiuse may be part of MSP and is gaining more traction in recent years, signifying a more efficient use of marine space, combining maritime economic activities such as aquaculture and tourism, or offshore wind energy and seaweed farming (Schupp et al. 2019).

Introduction: What Is the Blue Bioeconomy?

Blue Bioeconomy and the Sustainable Development Goals Lisa Simone de Grunt, Angela Schultz-Zehden and Ivana Lukic SUBMARINER Network for Blue Growth, Berlin, Germany

Definitions The Blue Economy may be understood as any economic activity that uses marine resources and/or takes place in or on the ocean. Blue Economy sectors, for instance, include tourism, shipping and transport, renewable energy, fisheries, and the Blue Bioeconomy (World Bank 2017; European Commission 2018). The latter includes economic activities such as aquaculture, mussel, and algae cultivation, blue biotechnology, as well as using waste and side stream valorization to develop new and innovative products – for human food and animal feed for aqua- or agriculture, bioenergy, pharmaceuticals, and many other applications (Beyer et al. 2017). The focus of both the Blue Economy as well as the Blue Bioeconomy is on the sustainable exploitation of marine resources and maintaining marine ecosystem health, with a clear direction to improving livelihoods from both a financial as well as a social perspective. Maritime Spatial Planning (MSP) ensures that the most optimal sites in the marine

As the global population is increasing and the challenges posed by climate change (e.g., diminishing fossil fuels and natural resources, food security, pollution, emissions, and plastics) are becoming more evident, the role of the oceans in the well-being of the global environment is becoming more important than ever. Sustainability and the circular economy are no longer catch phrases but form an intrinsic part of the shift towards a more responsible and ecosystem-based global society and economy. For many of those with an interest in the role of the oceans, the term Blue Economy may be clear, but what is meant by the Blue BioEconomy, and why is it so important? The Blue Economy is the part of the global economy that is built on the sustainable use of ocean resources for maintaining ocean ecosystem health; economic growth; as well as improved livelihoods and jobs, following the triad of sustainability indicators (i.e., social, economic, and environmental) (World Bank 2017). It covers maritime related sectors such as energy (both renewable and nonrenewable); sediment and mineral extraction and sea-bed mining; coastal and maritime tourism; transport; as well as the blue bioeconomy, which does not only encompass fishery and aquaculture, but the entire field of economizing living aquatic resources (such as algae, mollusks, etc.). As part of the Blue Economy, the Blue Bioeconomy is of crucial importance to further drive the global economy and to ensure that it is becoming more sustainable, as well as inclusive.

Blue Bioeconomy and the Sustainable Development Goals

The Value Chains of the Blue Bioeconomy Defined as the sustainable (commercial) use of living or renewable aquatic bioresources (such as algae, mussels, (jelly)fish, etc.), a wide variety of economic activities, products, and services make up the Blue Bioeconomy: for example, food for human consumption, feed for aquaculture or agriculture, bioenergy, pharmaceuticals, nutraceuticals and cosmetics, or bio-based chemicals, materials or other types of products (Beyer et al. 2017). It is a relatively young concept driven by increasing interest, knowledge, and rapid technological developments, and its potential is gaining increased recognition across the globe as many sectors are moving from the research and development stage to commercialization. According to Bio Market Insights, “aquatic biomass used in developing these products can include shellfish, crustaceans, algae, fishery residues and the like, and with oceans constituting 72% of the surface of the planet and constituting more than 95% of the biosphere (the global ecological system), the potential really is huge” (Upton 2019). What is meant by the value chain of such sectors covers the phases from initial prospecting all the way up to consumption, as illustrated in Fig. 1. The Blue Bioeconomy covers a wide range of sectors, products, and services. Mussel farming, for instance, is done not only to produce human food, but also fertilizer for grain production, feed for the poultry and fish feed sectors and can be used in biogas production. The global annual production of mussels exceeds 1.5 million tons, over half of which is produced and consumed in Europe. Farming mussels may also serve as a

Transformation technologies

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possible measure to counteract eutrophication, since they take up nutrients such as nitrogen and phosphorus (SUBMARINER Network 2019). Fish aquaculture is the world’s most popular source of animal protein, with an average annual growth of 8.8% since 1980. The sector provides almost 50% of all globally consumed fish and shellfish, and by 2050, the capacity of the sector is expected to double (Jorquera and Nordén 2017). Sustainable fish aquaculture (both for human consumption and for the production of fish feed) uses production methods including sustainable fish feed and technologies that do not pollute the marine environment, nor deplete or permanently damage other marine species or ecosystem components, as the sector is dedicated to following a sustainable feed-supply chain. As part of the Blue Bioeconomy’s commitment to closing the nutrient loop, the aquaculture sector is becoming increasingly dedicated to developing innovative uses and/or applications from nonquota fish, underutilized side or even waste streams, as well as discarded capture fishes, to transform them into products such as roe, fish oil, bones, or skins for highly valuable markets and products. In addition, nonquota fish and discarded capture fishes may also be used to feed cultivated species, which in turn leads to pollution avoidance and thus less waste ending up in the marine environment. In addition to sectors like aquaculture and mussel farming, cultivating macroalgae, or seaweed, is also a crucial part of the Blue Bioeconomy. There is a long tradition of using macroalgae for different purposes, including for food and animal feed production, as fertilizer and soil conditioner in agriculture, and as biomaterial. Seaweed can

Added value innovative products / Pilot scale production

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Marketing and branding

VC / BA / Banks

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Blue Bioeconomy and the Sustainable Development Goals, Fig. 1 Simplified Bioresources Value Chain based on Blue Bio Alliance (2016). Source: Author (2020)

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also be used to produce nutraceuticals and antioxidants and can be used for energy production. In addition, cultivating algae may contribute in removing nutrients and carbon from the marine environment, hereby mitigating effects of climate change, eutrophication, and pollution abatement. According to the Blue Economy Report 2019, “Worldwide, algae production has markedly increased over the last two decades from an amount of 10.5 Mt (wet weight) in 2000 to 31.2 Mt in 2016 (. . .) with an estimated market value of $1,073 millions. China, producing 47% of the total algae biomass in 2016, is the main algae biomass supplier at the global level. In Europe, the production has been stable over time with the EU contributing to 0.2% and the EEA contributing to 0.8% of the global production. Norway, France and Ireland are the main European producers of algae biomass” (European Commission 2019a). Marine biotechnology, the application of science and technology to marine organisms with the aim of producing new knowledge, goods, and services, is a sector that shows great possibilities in the shift towards a bio-based economy. New uses and applications from marine organisms accelerate the Blue Bioeconomy and play a crucial role in creating new sustainable business models (Vieira, Costa Leal, Calado 2020). The sector has considerable potential to help address global challenges regarding health, food security, industrial and environmental sustainability, as well as in protecting and preserving marine resources for future generations. Applications of marine biotechnology can be found not only in the food and feed industry, but also in the medical, pharmaceutical, and cosmetics industries. A growth rate of 12% is estimated for the marine biotechnology sector, consolidating a market of around €2.4 billion annually (Leary et al. 2009). According to the European Marine Board, “Marine biotechnology is essential to satisfy the growing demand for healthy products from fisheries and aquaculture in a sustainable way” (European Marine Board 2010). According to estimates by the United Nations, by the year 2050 the global population is expected to have increased to 9.8 billion people. These people will all need to be fed and there will be a

Blue Bioeconomy and the Sustainable Development Goals

major need for resources to provide for food (including a focus on proteins, fats, carbohydrates, and micronutrients such as fatty acids, minerals, and vitamins) as well as nonfood products such as energy, industrial applications as well as pharmaceuticals, cosmetics, etc. Traditional economic growth models and industries and markets around the world are not sustainable, neither in the economic, nor in the environmental or social sense, since they are ultimately based on the depletion of natural resources. Economies that focus on the inclusion of Blue Bioeconomy sectors can provide more sustainable alternatives, especially considering fisheries and aquaculture, as today only a small percentage of total fish catches is used for human consumption and the production of other marine resources such as algae and mussels are still under-developed sectors. Of course, realism will prohibit anyone from predicting a future where all our food will come from the oceans, which is also why some experts emphasize the need to create meaningful integrated systems between terrestrial and marine food and feed production systems. This means that the interactions between land and sea must also be continuously considered in the Blue Bioeconomy, as a balance must be achieved between nutrients that come from the land to the sea, and the nutrients that are brought on to land from the marine space, for food, feed, and other applications, in the form of fish, algae, mussels, and the like (Visser et al. 2020). The promise of the bioeconomy shaping new global economic systems is grounded in its interdisciplinary approach, as it is focused specifically on addressing the full value chains from prospecting to consumption, as well as considering cumulative impacts of production systems for a wide range of marine sectors (Lewandowski 2018). Challenges and Opportunities: Spotlight on the Baltic Sea Region The recently established European Blue Bioeconomy Forum categorizes the challenges facing the Blue Bioeconomy into policy; environment and regulation; finance and business development; consumers and supply chains; and technology and innovation

Blue Bioeconomy and the Sustainable Development Goals

(European Commission 2019a). Many enterprises in Blue Bioeconomy sectors are either already commercially viable or show great promise, although there are several challenges to overcome. In many countries, challenges across sectors may include outdated legislation, underdeveloped markets and infrastructure, and a lack of technological advancements. Concrete examples of such challenges are, for instance, a lack of specially equipped boats, advanced processing plants, or cooling or storing facilities. In addition, there are still early market challenges to be overcome in several Blue Bioeconomy sectors, such as investment skepticism, high start-up costs, and difficulties in scaling up production processes (Upton 2019). The Baltic Sea Region has traditionally been characterized by a highly developed agricultural and fisheries sector, high-level research and infrastructure, as well as technological knowledge and skills and enjoys the fruits of a long and strong tradition of transnational cooperation. At the same time, the Baltic Sea itself is characterized by a high level of eutrophication. The notoriously poor quality of Baltic marine waters is not only a challenge but has also served as a driver for the development of the Blue Bioeconomy in the region. It thus has the potential to solidify its position as a model region for identifying and promoting new sustainable value chains that are not only more environmentally friendly, but also socially valuable as they can stimulate the local, regional, and national economies and provide new employment opportunities also in rural and coastal areas. The solutions found in the Baltic Sea Region can also serve as reference points to other regions throughout the world, not in the least as they are often well-documented (see “www.submarinernetwork.eu”: the Blue Platform), as well as, for instance, in national research strategies. According to the Nordic Council of Ministers and Sustainia, the Nordic and Baltic countries of Europe can make an important contribution to reaching the Sustainable Development Goals: ... the region has a high environmental skill and knowledge base, as well as many commercial interests that for a large part show good practices in the marine, agricultural and forestry sectors. Connecting this expertise with the abundant bio-based resources,

87 the Baltic Sea Region can make an important contribution to reaching the Sustainable Development Goals and mitigating climate change through further developing the bioeconomy. (Nordic Council of Ministers 2017)

Some of the challenges experienced in Blue Bioeconomy sectors also refer to the ecosystem services that they provide, such as nutrient removal, eutrophication mitigation, and bioremediation, which are not compensated for. This often plays a part in the difficulty enterprises in these sectors experience in their efforts to become commercially profitable, and thus economically sustainable, as they provide an ecosystem service in addition to generally trying to run a profitable business. According to the SUBMARINER Roadmap for the Blue Bioeconomy, “if the Baltic Sea Region countries are serious about reaching their nutrient reduction targets as well as good environmental status in general, transparent economic assessment of ecosystem services is needed to substantiate any proposed financial incentives for those who contribute to achieving them” (Przedrzymirska et al. 2015). It has been suggested by experts that ecosystem services payment schemes may provide part of a solution, but to date few such schemes for Blue Bioeconomy sectors have been introduced, although, for instance, on the Seychelles and in Tanzania, Payments for Ecosystem Services (PES) programs are being developed or implemented. Countries around the world are developing national and sectoral strategies that are generally “greener” and aim to realize economies that are less dependent on finite resources, have fewer negative impacts, and are generally more sustainable. Following this trend, public bodies can and should further adapt their procurement policies and national legislation to increase support for and increasingly prioritize the development of value chains that advance fossil-free products and services, hereby also driving the demand side and effectively contributing to creating markets for Blue Bioeconomy sectors (Nordic Council of Ministers 2017). According to the Ocean Solutions Report from 2017, regulatory frameworks for aquaculture, for instance, “need to be modernized and adapted to novel technologies in

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order to drive the implementation of sustainable farming systems with minimal environmental impact,” and regulations “need to change so that blue catch crops get the same status and become subject to the same rules as green catch crops” (Jorquera and Nordén 2017). The policy paper “Aquaculture Legislation: Recommendations” (Ikauniece et al. 2020) argues that, for instance, Finland can be considered as a good practice in view of the fact that several national planning documents make reference to the ambition to use fish feed produced from Baltic Sea fish, as feed in Baltic Sea fish farming. The government thus foresees to provide incentives to aquaculture farms which reduce nutrient loading and apply circular economy principles, like RAS (Recirculating Aquaculture Systems) and using Baltic Sea Fish Feed as a compensatory measure (Ikauniece et al. 2020). The Need to Establish Strong Networks Realizing a sustainable Blue Bioeconomy requires strong cooperation between a wide variety of different types of stakeholders, including a critical mass of experts, researchers, producers, technology developers, business support actors, entrepreneurs and farmers, politicians and policymakers, academia, finance actors, NGOs, as well as consumers, to take a collaborative approach to pave the way towards creating sustainable commercial markets for Blue Bioeconomy sectors. As marine ecosystems are not defined by national administrative borders, and the effects, impacts, and interconnectivities of maritime activities are inherently transnational, such cooperation would per definition need to be both crosssectoral as well as transnational. Moreover, Blue Bioeconomy product development chains are often transnational as well, with one company or one country, using resources from another. What is needed is joint knowledge, experience, and technology exchange, as well as joint knowledge, experience, and technology generation. Countries cannot singularly provide all the resources and expertise necessary to complete the transformation from idea to product: a collaborative effort is needed to secure a sufficient and continuous amount of cost-efficient biomass (including mussels, algae, nonquota fish, side streams), as well as the necessary technology and logistical chains necessary to realize sustainable

Blue Bioeconomy and the Sustainable Development Goals

markets. Cooperation between sectors and countries is also crucial since products cannot be developed without a market demand in place, which is a dilemma that must be approached from a transnational perspective, since many of the challenges from the production side are highly similar across countries and sectors. The SUBMARINER Network for Blue Growth EEIG, a flagship umbrella project of the EU Strategy for the Baltic Sea Region, was established in 2013 and has since developed into the leading transnational hub in the Baltic for promoting sustainable and innovative uses of marine resources. It is unique in its set-up and wide scope, as similar networks tend to only bring together stakeholders of a single category, such as entrepreneurs or public bodies, or they primarily focus on single sectors of the Blue Bioeconomy (e.g., with only a focus on aquaculture or offshore wind energy). The SUBMARINER Network however has a broad focus including all sectors of the Blue Bioeconomy and it brings together authorities and research and innovation actors – both public and private – across the Baltic Sea Region, integrating perspectives from local to transnational scale and different scientific and economic spheres. Under the network, two voluntary working groups have been established, one on mussel cultivation and one on sustainable fish aquaculture. These working groups bring together a wide variety of actors, from researchers and planners, to actual farmers and processors. Together, its members discuss the challenges they face and the strategic opportunities which they want to invest in. This is an example of how bringing together a group of diverse actors in the Blue Bioeconomy is helping to advance the sectors further, as the actors can speak with a singular voice and so influence policy making, for instance, through the development of joint recommendations for a sector. The SUBMARINER Network has achieved many feats, including a comprehensive Blue Bioeconomy actors mapping across the Baltic Sea Region; providing support with the realization of product development chains; the realization of better technologies adapted to Baltic Sea characteristics; as well as ultimately contributing to an increased

Blue Bioeconomy and the Sustainable Development Goals

awareness of potential new products and services. It also shapes and influences policy developments both at the national and on the Baltic and EU level, for instance, through the future HELCOM Baltic Sea Action Plan and the European Commission’s Bioeconomy Agenda. To illustrate the need for the network, one only has to consider the fact that in 2010 only a handful of companies were active in the Baltic Blue Bioeconomy, whereas in 2020, hundreds are now in existence. In 2021, the network will publish an updated Roadmap for the Blue Bioeconomy, highlighting urgent action points for Blue Bioeconomy actors and sectors. It will focus on the Baltic Sea Region, but like its predecessor is expected to also be highly relevant for any actor operating in global Blue Bioeconomy sectors. Its current edition, updated in 2015, presents a unique and comprehensive sustainability assessment for the full value chains of several innovative and sustainable uses of Baltic marine resources, including macroalgae, mussel cultivation, blue biotechnology and fish aquaculture, as well as reed harvesting, large-scale microalgae cultivation, wave energy, and combinations with offshore wind parks (Przedrzymirska et al. 2015).

How to Plan (for) the Blue Bioeconomy With the global population growing rapidly, the oceans are getting busier as more maritime economic activities take up increasing amounts of space in an effort to accommodate the increase in global citizen needs. Many past and on-going research and results from projects on blue bioeconomy sectors have shown that in order for the Blue Bioeconomy to thrive and contribute to sustainable growth, it is necessary to identify optimal sites where such production can take place in a sustainable way. Determining how to best allocate areas suitable for aquaculture, mussels, algae cultivation activities, and the like requires a synthesis of a large number of up-to-date measurements and subsequent analyses of a multitude of abiotic and biotic environmental variables. Lukic et al. (2018) suggest that in order to properly assess spatial requirements both for existing and future maritime economic activities, maritime

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spatial planners need to have access to the best available, up to date and relevant data, information and tools, so that they can efficiently allocate marine space and consider also the implications of new developments and trends in maritime sectors. Maritime Spatial Planning also has a role in encouraging such developments and allows for the operationalization of visions and strategies for the marine space. In the policy paper “Aquaculture Legislation: Recommendations,” Ikauniece et al. (2020) present another example of how national spatial plans may include Blue Bioeconomy considerations: In Finland, a spatial plan for aquaculture has been approved in 2014 after 6 years of development. Its principles include the allowance of aquaculture farms in areas with good or satisfactory water quality, to place them at least at 500 m distance from summer cottages, as well as allowing larger fish farms further offshore in order to improve profitability. The idea is to put the offshore farms out in summer and to take them back or to submerge them during the winter period. The spatial plan was well received with many people applying for new licenses and farms, resulting in already some new aquaculture farms with almost 2.000 tons higher production. (Ikauniece et al. 2020)

Maritime Spatial Planning and Optimal Site Selection Maritime Spatial Planning (MSP) is defined as a “public process of analyzing and allocating the spatial and temporal distribution of human activities in marine areas to achieve ecological, economic, and social objectives that are usually specified through a political process” (Ehler and Douvere 2009). Generally, MSP is seen as an integrative process to cope with the increasing demand for maritime space from traditional and emerging sectors, while preserving the proper functioning of the marine ecosystems, that is, following an ecosystem-based approach. They key feature of MSP is that it considers the integration of maritime sectors with each other so that it both employs a cross-sectoral, as well as a crossborder perspective. The challenges faced by the Blue Bioeconomy are highly interconnected and a holistic approach is needed to tackle these in an efficient way. MSP represents a move from solely traditional single sector planning to a more

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integrated approach to the planning of the sea. It is thus in line with the concept of the Blue Bioeconomy which itself represents a more integrated approach to development of maritime sectors. Based on lessons learned from numerous MSP projects and national initiatives, the allocation of optimal sites for Blue Bioeconomy sectors must be approached with consideration of other synergetic or conflicting sectors, the marine environment’s carrying capacity, as well as a holistic consideration of the three pillars of sustainability. As an example, Estonia has, for instance, taken into account the potential for seaweed and mussel cultivation in their national maritime spatial plan, showing a commitment to the potential of the Blue Bioeconomy and taking it into account in current planning decisions.

Multiuse

In the last 5 years, the concept of ocean multiuse has been gaining popularity, advocated by MSP and research projects. It is defined as a concept where two or more ocean uses are: (. . .) intentionally sharing marine resources in close geographic proximity. It is an umbrella term that covers many combinations of maritime activities and represents a radical change from the concept of exclusive resource rights – to the inclusive sharing of marine resources and space by one or more activities. The degree of connectivity between different maritime uses can vary with respect to spatial, temporal, provisioning, and functional dimensions – ranging from two uses merely sharing the “same” maritime space (co-location), to shared platforms and other infrastructure. Therefore, multiuse is not limited to the joint use of installations, but also encompasses joint activities. (Schupp et al. 2019).

Multiuse can contribute to a more efficient use of maritime space as it promotes the co-location of two or more maritime sectors, for instance, offshore wind energy together with mussel farming, or aquaculture sites together with marine and coastal tourism. The need for multiuse will no doubt increase as the oceans are becoming busier, but realizing multiuse sites may not always be possible in a straightforward way, since existing multiuse projects and pilots in Europe and beyond have already shown that in order for maritime economic activities to share the same maritime

space, this must be made more attractive than operating a single maritime economic activity in that space. In other words, multiuse should create additional economic benefits, if it is to be seen as an attractive endeavor by investors and developers. Multiuse may lead to suboptimal sites for one of the combined sectors in question, but the total benefit is still higher than allowing only a singular use in the given marine space, as there is also a value to be attached to space which is left free for future demands currently unknown. In planning for the Blue Bioeconomy, what is also needed is an integrated view of aqua- and agriculture. The nutrient run-off from agriculture has to be put into the overall regional equation of nutrient run-offs, also potentially deriving from aquaculture. Thus, it may well be possible that agriculture gets “less” quota, to the benefit of aquaculture, as, relatively speaking, it produces less nutrient leakage than agriculture. The MUSES project (Multi-Use in European Seas) has contributed key research in the field of multiuse, with high relevance also for sea basins outside of Europe, for instance, through its Ocean Multi-Use Action Plan of 2018 (Schultz-Zehden et al. 2018).

The Blue Bioeconomy and the SDGs The Blue Bioeconomy is clearly linked to the United Nations Decade of Ocean Science for Sustainable Development (2021–2030) (UNESCO IOC 2018) which aims to “support efforts to reverse the cycle of decline in ocean health and gather ocean stakeholders worldwide behind a common framework that will ensure ocean science can fully support countries in creating improved conditions for sustainable development of the ocean.” The concept is also in line with the Paris Agreement of COP21 under the United Nations Framework Convention on Climate Change (adopted 2015) (Bell et al. 2015) which aims to strengthen the global response to climate change by keeping global temperature rise below 2 degrees Celsius above preindustrial levels. Across the globe, the oceans are getting increased attention in light of “greener” political agendas

Blue Bioeconomy and the Sustainable Development Goals

and national plans and strategies that seem to indicate a desire to strengthen their best efforts in realizing more sustainable economies (OECD 2016). According to the Global Ocean Science Report, “the main ocean science challenges of our time are interdisciplinary, involving natural and social sciences to investigate issues such as ocean acidification, micro-plastics, hypoxia, blue carbon, blue growth and governance (UNESCO IOC 2017)”. The Blue Bioeconomy is also of crucial importance in realizing the ambitions of the United Nations Sustainable Development Goals (SDGs) (United Nations 2019), including #6 Zero Hunger, #8 Decent Work and Economic Growth, #9 Industry, Innovation and Infrastructure, #12 Responsible Consumption and Production, #13 Climate Action, as well as #14 Life below Water. As many global fish stocks are becoming increasingly depleted and as rapid population growth is making it hard for traditional agricultural systems to keep up, Blue Bioeconomy sectors such as aquaculture and macroalgae and mussel farming are becoming increasingly important. They provide marine-based sources of both food for human consumption and fish feed focused on more sustainable value chains. As such, Blue Bioeconomy sectors strongly contribute to realizing the SDGs, for instance, through reducing global hunger, providing economic growth and employment and achieving more responsible production and consumption patterns. In addition, they also contribute to more environmentally focused SDGs, such as climate action and improvement of the health of marine environments. Macroalgae and mussel cultivation may, for instance, counteract eutrophication and mitigate nutrient loading (SUBMARINER Network 2012). The cultivation of algae is also very important in light of renewable energy, as on-going research, for instance, on using microalgae for transport fuels or developing biomethane from macroalgae are paving the way for a society that emits less carbon (some say even carbon-neutral fuels) and relies far less on finite resources: When cultivated with proper attention to power, carbon, and nutrient sources, microalgae can produce a variety of biopetroleum products, including carbon neutral biofuels for transportation and long-

91 lived, potentially carbon-negative construction materials for the built environment. In addition to mitigating and potentially reversing the effects of fossil CO2 emissions directly, microalgae can play an important indirect role. (Greene 2018)

Mussel farming also contributes especially to SDG #14, as it reduces nutrient concentrations and recycles nutrients to new biomass, hereby improving water quality, and the sector produces marine proteins for human consumption and feed production with a lower climate impact, since the sector uses less energy than traditional sectors, thereby contributing to SDG #13. In addition, blue biotechnology is a strong ally to realizing the SDGs, as illustrated by an assessment done by the Baltic Blue Biotechnology Alliance, a consortium of research and technology institutes, technology parks and innovation companies, which showed that each of its “cases” (SMEs and start-ups) contributed to four SDGs on average (GEOMAR Helmholtz Centre for Ocean Research 2019). Figure 2 shows that sustainability is a top priority for the Alliance, as all cases contributes to more than one SDG. The size of the boxes in the figure corresponds to the number of Alliance cases supporting the SDGs. The Blue Bioeconomy and the Society of the Future Along with its potential to close the nutrient loop from agriculture, aquaculture, and other sectors, the Blue Bioeconomy also has the potential to create many employment opportunities and a generally healthier and more prosperous society. Additional benefits of realizing a global sustainable Blue Bioeconomy include increased employment not only in cities, but also especially in rural areas, for instance, for fishermen that are having to deal with depleted fish stocks, as well as a reduced dependence on imports and exports, since the Blue Bioeconomy promotes local or regional production and consumption. The Blue Growth Agenda of the European Commission has identified five highly promising blue sectors that are projected to make major contributions to economic growth and employment opportunities, including aquaculture, coastal and maritime tourism, marine biotechnology, and ocean energy

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Blue Bioeconomy and the Sustainable Development Goals

Blue Bioeconomy and the Sustainable Development Goals, Fig. 2 Baltic Blue Biotechnology Alliance: contribution of cases to the SDGs. Source: Baltic Blue Biotechnology Alliance (2019)

(European Commission 2017). In addition, the European Commission’s Bioeconomy Strategy also emphasizes that there should be a comprehensive approach to addressing the ecological, environmental, energy, food supply, and natural resource challenges faced by Europe and the world (European Commission 2012). The European Union’s Green Deal aims for Europe to become the world’s first climate-neutral continent and foresees a future where the European Union is a “modern, resource-efficient and competitive economy, where there are no net emissions of greenhouse gases by 2050” and where “environmental challenges are turned into opportunities.” The Green Deal also makes specific reference to the creation of a sustainable Blue Economy which should serve to tackle pressures from climate change and will alleviate the demands on Europe’s terrestrial spaces. The Green Deal reads: “The sector can contribute by improving the use of aquatic and marine resources and, for example, by promoting the production and use of new sources of protein that can relieve pressure on agricultural land. More generally, lasting solutions to climate change require greater attention to naturebased solutions including healthy and resilient seas and oceans” (European Commission 2019a).

For Small Island Developing States (SIDS) as well as generally ocean-dependent communities across the globe, the ocean economy is often synonymous with the national economy. Aligning these economies with the principles of a sustainable Blue Economy is increasingly prolific on political agendas. SIDS and developing nations generally have additional barriers and bottlenecks for realizing a sustainable Blue Economy, such as vulnerability to natural disasters, poverty, underdeveloped infrastructure, illegal, unreported, and unregulated (IUU) fishing or remoteness. Thus, the Blue Economy in such nations is often linked to the creation of financial injections and incentives to boost blue economy sectors, including but not limited to fisheries or tourism, but, for instance, also including more emergent sectors such as aquaculture or biotechnology. Ocean-facing communities are increasingly forced to diversify their economies in an effort to increase a shared and sustainable prosperity for their citizens. Islands such as Cabo Verde are, for instance, adapting to this new future with the development of a “Blue Growth Charter,” which is a “government wide agenda. . . with a significant focus on its ocean resources” (Lanthén and Beyersdorff 2017).

Blue Bioeconomy and the Sustainable Development Goals

The marine environment has the potential to realize many new employment opportunities and economic growth, and the (Blue) Bioeconomy is a key driver in taking this potential to the next level. As traditional resources are dwindling, higher pressures are put on both terrestrial as well as marine resources in an effort to meet growing global demands for food, feed, and energy. Such biomass production needs to be approached in a holistic and sustainable way, necessitating a review of traditional value chains and making both production as well as consumption more sustainable, from an environmental perspective, as well as from a social and economic viewpoint – as the growing population across the world will also require the creation of new employment opportunities (Lewandowski, 2018). In Europe, the Blue Economy includes 5.4 million jobs that are either directly or indirectly related to the ocean, of which around 20% include jobs in fisheries, aquaculture, and food processing, and this number is estimated to double by the year 2030. According to the Organisation for Economic Cooperation and Development (OECD): Ocean industries also have the potential to make an important contribution to employment growth. In 2030, they are anticipated to employ approximately 40 million full-time equivalent jobs in the businessas-usual scenario. The fastest growth in jobs is expected to occur in offshore wind energy, marine aquaculture, fish processing and port activities. (OECD 2016)

This means that many companies and institutions are eager to attract young(er) people into their sectors and measures must be taken to ensure that future job creation will be organized in a sustainable way. According to the “Career Guide: Blue Economy Joby for Young People” (Militos Consulting SA 2019), young people must be encouraged, and enterprises and institutions as well, to realize a future workforce, especially considering that there are currently almost 14 million young people between 15 and 29 years old in Europe that have not or are not pursuing education, employment or training. Careers in Blue Bioeconomy sectors must be promoted, and investments must be made in research to realize advanced technologies to

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support market creation in order for innovative research to be integrated into the entrepreneurial world, allowing private companies to make the shift from the start-up stage to full commercialization. Knowledge about the world’s marine ecosystems and the resources that they contain is increasing rapidly in recent years, enabling the possibility to more accurately predict changes and enabling more science-based planning of ocean space and maritime economic activities (UNESCOC IOC 2019). However, more research is needed continuously, as much is still unknown about the oceans, as expressed aptly in the adage “we know more about the moon than about what’s below the surface of our oceans,” as the entirety of the global ocean floor has been mapped, but only 0.05% has been mapped at resolutions of less than five kilometers (Copley 2015). Though the ocean in the past has been relatively unexplored and some may say taken for granted, it is now clear that anthropogenic activities are impacting the marine environment in unforeseen and irreversible ways. According to the report “Innovating for sustainable growth: a Bioeconomy for Europe,” ocean and coastal areas are now recognized as “major contributors to the global economy and fundamental to global well-being through direct economic activities, provision of ecosystem services, and as home to the majority of the world’s population” (European Commission 2012). Equally important is the need to create more support for the sectors and enhanced consumer awareness when it comes to both the production as well as the demand/consumer side of the Blue Bioeconomy. Consumers are becoming more environmentally conscious and are a key driver in the shift to more sustainable production and consumption patterns. According to the Annual Economic Report on EU Blue Economy (2018), it will be crucial to increase the visibility of the role of the marine environment in the global economy, including its potential for innovation, in an effort to pave the way for increased consumer demands for products and services from sustainable marine resources (Przedrzymirska et al. 2015). Including youth in Blue Bioeconomy cooperation will ensure that the sectors will remain strong and secure and will encourage increased synergies

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not only between different age groups, but also between countries and between sectors – and making sure that this continuous into future generations. Creating the jobs and influencing the consumers of the future will also require significant investments in increasing ocean literacy to stimulate a greater understanding of and appreciation for the marine environment and the benefits it can and does provide. Such investments will need to be directed towards education from young ages to life-long-learning and re-training, including, for instance, primary school education as well as organizing awareness raising campaigns for general citizens. Consumer demand for Blue Bioeconomy products and services needs to be stimulated, with a focus on regional production, sustainable consumption, rural development, etc. Across the globe, numerous on-going ocean literacy initiatives are pointing out that consumers must be provided with the information necessary to increase their understanding of the environmental and sustainability benefits of Blue Bioeconomy products, which may, in turn, also justify a potentially higher price tag. An online survey among 30.000 respondents across 60 countries showed that 66% of consumers “say they are willing to pay more for sustainable brands – up from 55% in 2014 and 50% in 2013” (Nielsen 2015). Outlook The Blue Bioeconomy can contribute to the realization of many of the SDGs, as the oceans and seas can provide economic prosperity, food security, climate action, as well as more sustainable production and consumption patterns. What is needed are innovative and creative ideas to promote, accelerate, and shape the future of the Blue Bioeconomy and highlight the vital role of the marine environment for the well-being of the world, its environment, and its citizens. The Blue Bioeconomy promises the creation of a global society and economy that is built on sustainable value chains that succeed in combining economic growth with environmental and social considerations. The creation of new and sustainable value chains based on marine resources for

Blue Bioeconomy and the Sustainable Development Goals

applications in human food, pharmaceuticals, the feed industry, industrial, cosmetics, and energy applications will create sustainable economic growth and new employment opportunities. These value chains will also contribute to preventing further climate change and fighting its effects (including reducing global emission levels such as CO2), realize increased resource efficiency and food security, as well as support the realization of alternatives to fish stock depletion and unsustainable farming practices. It must however be stressed that Blue Bioeconomy activities in turn depend on all maritime activities and thus the link with the broader macroeconomic environment must always be considered (European Commission 2018). To increase and strengthen the competitiveness of countries and regions across the globe, investing in Blue Bioeconomy sectors may just provide the golden ticket, but what is needed are investments in research and demonstration pilots to develop innovative production technologies along the full value chains of the Blue Bioeconomy sectors, along with investments in creating sustainable markets for the sectors. According to Upton (2019), investments must be de-risked for many Blue Bioeconomy sectors through making demonstrations of the feasibility and cost-effectiveness possible. In essence, innovation is seen as a key driving force in all stages of the Blue Bioeconomy value chains, including for harvest and extraction; cultivation, processing and refining; as well as in technology development, transport, and the delivery of equipment along all stages of the value chains (EUMOFA 2018). According to the Organisation for Economic Co-operation and Development (OECD), “innovations in advanced materials, subsea engineering and technology, sensors and imaging, satellite technologies, computerization and big data analytics, autonomous systems, biotechnology and nanotechnology – every sector of the ocean economy – stand to be affected by these technological advances” (OECD 2016). In order to cope with increasing global pressures, all actors must come together to radically change approaches to production and consumption patterns and jointly develop strategic research priorities, legislative interventions, and opportunities

Blue Bioeconomy and the Sustainable Development Goals

to create sustainable markets for Blue Bioeconomy sectors (European Commission 2019a). Research priorities should include advancements in technologies for the mass production and processing of marine resources, both for human food production, feedstock, pharmaceuticals, and other applications. As demonstrated by the commitments to implement the Sustainable Development Goals, challenges posed by climate change, a growing world population, depleting natural resources, worrying environmental health and food security concerns must be tackled sooner rather than later – and the Blue Bioeconomy is part of the solution.

Cross-References ▶ Aquaculture: Farming Our Food in Water ▶ Higher Education and Sustainable Development of Marine Resources ▶ Legal Approaches Toward the Achievement of SDG 14 ▶ Macroalgae: Diversity and Conservation ▶ Maritime Spatial Planning and Sustainable Development ▶ Measuring Success: Indicators and Targets for SDG 14 ▶ Ocean Literacy for Sustainable Use of Oceans Globally ▶ Ocean Sustainability ▶ Responsible Ocean Governance: Key to the Implementation of SDG 14

References Bell E et al (2015) United Nations / framework convention on climate change (2015) adoption of the Paris agreement, 21st conference of the parties. United Nations, Paris Beyer C, Schultz-Zehden A et al (2017) Towards an implementation strategy for the sustainable blue growth agenda for the BSR. Available at: https://op.europa. eu/en/publication-detail/-/publication/60adf799-4f1911e7-a5ca-01aa75ed71a1/language-en Accessed 11 January 2021 Copley J (2015). Just how little do we know about the ocean floor? In: Scientific American. http://www. scientificamerican.com/article/just-how-little-do-weknow-about-the-ocean-floor/. Accessed 24 Apr 2020 Ehler C, Douvere F (2009) Marine spatial planning: a stepby-step approach toward ecosystem-based

95 management. Intergovernmental Oceanographic Commission and Man and the Biosphere Programme EUMOFA (2018) Blue bioeconomy: situation report and perspectives. Publications Office of the European Union, Luxembourg European Commission (2012) Innovating for sustainable growth: a bioeconomy for Europe. Publications Office of the European Union, Luxembourg, p 2012 European Commission (2018) The 2018 annual economic report on EU blue economy. European Union, 5. Available at: https://ec.europa.eu/maritimeaffairs/sites/ maritimeaffairs/files/2018-annual-economic-reporton-blue-economy_en.pdf. Accessed 11 Aug 2020 European Commission (2019a) Blue bioeconomy forum – roadmap for the blue bioeconomy. Publications Office of the European Union, Luxembourg European Commission (2019b) The EU blue economy report 2019. Publications Office of the European Union, Luxembourg European Commission (2019c) Communication from the commission to the European parliament, the European council, the council, the European economic and social committee and the committee of the regions: the European green Deal. Office for Official Publications of the European Communities, Luxembourg European Marine Board (2010) Marine biotechnology: a new vision and strategy for Europe. Marine Board-ESF Position Paper 15 European Union: European Commission (2017) Commission staff working document: report on the blue growth strategy: towards more sustainable growth and jobs in the blue economy. 31 March 2017, SWD (2017) 128 final. Available at: https://ec.europa.eu/ maritimeaffairs/sites/maritimeaffairs/files/swd-2017128_en.pdf. Accessed 24 Apr 2020 GEOMAR Helmholtz Centre for Ocean Research (2019). Baltic blue biotechnology alliance April 2019 state of play & future prospects. Available via SUBMARINER Network https://www.submariner-network.eu/images/ ALLIANCE_promotional_brochure_24pages_final_ WEB.pdf. Accessed 24 Apr 2020 Greene C (2018) Marine microalgae: achieving climate, energy, and food security in the 21st century’. Presentation at the Ocean Sciences Meeting, Portland, 11–16 February 2018 Ikauniece A et al (2020) Aquaculture legislation: recommendations. SUBMARINER Network, Berlin Jorquera R, Nordén A (2017) Ocean Solutions Report. Sustainable development solutions network Northern Europe. Publication number: 2017: 1 Lanthén E, Beyersdorff S (2017) Blue growth in large Ocean Nations. Conclusions for the Large Ocean Nations Forum in Malta, 2–4 October 2017 Leary D et al (2009) Marine genetic resources: a review of scientific and commercial interest. Mar Policy 33 (2):183–194 Lewandowski I (2018) Bioeconomy: shaping the transition to a sustainable, biobased economy. Springer Nature Publishing. Available via https://doi.org/10.1007/9783-319-68152-8. Accessed 10 Aug 2020

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96 Lukic I et al (2018) Maritime spatial planning for blue growth, Final technical study. Publications Office of the European Union, Luxembourg Militos Consulting SA (2019) Career guide: blue economy Joby for young people’ (output under the ‘blue generation’ project. Available in online format at: https://uatstaging.work Nielsen (2015) The sustainability imperative: new insights on consumer expectations’. New York: The Nielsen Company Nordic Council of Ministers and Sustainia (2017) Five principles for a sustainable bioeconomy in Nordic and Baltic countries. Available via BSR Bioeconomy http://bsrbioeconomy.net/5principles/Policybrief_5P. pdf. Accessed 24 Apr 2020 OECD (2016) The ocean economy in 2030. OECD Publishing, Paris Przedrzymirska J et al (eds) (2015) SUBMARINER roadmap. Towards a blue-green economy in the Baltic sea region, 2nd edn. Gdańsk, Poland Schultz-Zehden et al (2018) Ocean multi-use action plan. MUSES Project, Edinburgh Schupp F et al (2019) Towards a common understanding of ocean multi-use. Front Mar Sci 6:165 SUBMARINER Network (2012) SUBMARINER network compendium – an assessment of innovative and sustainable uses of Baltic marine resources. Poland, Maritime Institute Gdansk SUBMARINER Network (2019) Mussel farming in the Baltic Sea as an environmental measure. Available via SUBMARINER Network. https://www.submariner-network. eu/images/SUBMARINER_Paper_Mussel_farming_in_ the_Baltic_Sea_September_2019.pdf. Accessed 24 Apr 2020 UN IOC (2019). The science we need for the ocean we want: the United Nations decade of ocean science for sustainable development (2021–2030). Paris. Brochure 2018-7 (IOC/BRO/2018/7 Rev) UNESCO (2017) Global Ocean science report: the current status of ocean science around the world. UNESCO, IOC, Paris UNESCO IOC (2018). Revised roadmap for the UN decade of ocean science for sustainable development. In: 51st IOC Executive Council, Paris, 2018 United Nations (2019) The sustainable development goals report 2019. UN, New York Upton L (2019) Meet three European pioneers leading the blue bioeconomy revolution. Available via Bio Market Insights. https://biomarketinsights.com/meet-threeeuropean-pioneers-leading-the-blue-bioeconomy-revo lution/. Accessed 24 Apr 2020 Vieira H, Costa Leal M, Calado R (2020) Fifty shades of blue: how blue biotechnology is shaping the bioeconomy. In: Science and Society. Available via: https://doi.org/10.1016/j.tibtech.2020.03.011. Accessed 10 Aug 2020 Visser S et al (2020) How does the sea fit into the circular bio-economy? Available via Weblog Wageningen University & Research. https://weblog.wur.eu/biobased-

Blue Health economy/how-does-the-sea-fit-into-the-circular-bioeconomy/. Accessed on 24 Apr 2020 World Bank (2017) What is the blue economy? Infographic. https://www.worldbank.org/en/news/infographic/2017/ 06/06/blue-economy. Accessed 24 Apr 2020

Blue Health ▶ Ocean(S) and Human Health: Risks and Opportunities

Bottom Communities ▶ Ecological and Economic Importance of Benthic Communities

Brackish Waters ▶ Estuaries: Dynamics, Biodiversity, and Impacts

Bycatch: Causes, Impacts, and Reduction of Incidental Captures Paulo de Tarso Chaves Department of Zoology, Federal University of Parana, Curitiba, Brazil

Definitions Catch, from a fishery perspective, includes all living biological material, such as corals, jellyfish, tunicates, sponges, and other noncommercial organisms, retained or captured using fishing gear. Target catch is the catch of a species or species assemblage that is primarily sought in a particular fishery, such as shrimp, flounders, or cods. Incidental catch is the retained catch of non-targeted species, for example, aquatic mammals, turtles, and seabirds. Conversely, discards is that portion of the catch returned

Bycatch: Causes, Impacts, and Reduction of Incidental Captures

to the sea as a result of economic, legal, or personal considerations. Bycatch is the total catch of non-target animals. It can be explained assuming animals in a “species” sense; in this case, bycatch excludes the target species. In contrast, when considering animals in an “individual” sense, all individuals discarded after being caught, including juveniles and undersized organisms of target species, constitute bycatch, with no distintion between target and non-target species. Bycatch is usally thrown back to water, dead or dying, or likely to die. However, a fraction of the bycatch is commonly retained to be sold. Therefore, bycatch is the discarded catch plus incidental catch. Discarded catches frequently include non-marketable individuals of target species; hence, this proposal does not exclude the bycatch of the target species. Hereafter, bycatch is considered in such a broad sense: the total catch of non-target individuals, which implies discarding of target and non-target species, and retention of non-target species (incidental catch).

Introduction During fishing, many animals are retained by nets, traps, and baited lines. In addition to fish, crustaceans and mollusks, also mammals, birds, reptiles, as well as echinoderms and other invertebrates, are caught. Captures different from those targeted by fishers are known as bycatch (Kelleher 2005), an occurrence that can overcome the target resources (Costa et al. 2008). National Marine Fisheries Service (2011) does not distinguish between target and non-target species, and adds to bycatch any unobserved mortality due to a direct encounter with fishing gear. The retained catch of non-targeted species is considered a particular type of bycatch, the incidental catch (Alverson et al. 1994; Kelleher 2005). Conversely, discards is that portion of the catch returned to water as a result of economic, legal, or personal considerations (Alverson et al. op. cit.). Bycatch is common in marine fisheries. Raby et al. (2011) reviewed a total of 1,152 papers on

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bycatch and discarding and stated that 96% bycatch were from marine fisheries. However, bycatch also occurs in inland waters, where crocodiles, turtles, otter, and platypus are often killed by fishing (Raby et al. 2011; Serena et al. 2016). Bycatch is more commonly reported in commercial fisheries; as a result, research on bycatch and mitigation efforts have focused on large-scale industrial fisheries. But bycatch from recreational fishing can also have a significant effect on some non-target species Bell and Lyle 2016; Fisheries New Zealand 2020; and Serena et al. (2016) reported that, between 1980 and 2009, 56% of platypus deaths with an identifiable cause in Victoria, Australia, were due to drowning in traps or nets set by recreational fishers. Bycatch is accumulated because target and non-target species share a common habitat and are both vulnerable to the same fishing gear. For example, shrimp and fish occupy the benthic zone exposed to trawling (Broadhurst 2000; He 2007; Pina and Chaves 2009) (Fig. 1); crabs and octopods cohabit with lobsters in benthic zones exposed to gillnets and traps (Groeneveld et al. 2006; Giraldes et al. 2015); fish, turtles, penguins, and mammals use pelagic waters exposed to setnets during migratory movements (Cheng and Tien-Hsi 1997; Cardoso et al. 2011; FAO 2020). Low selectivity is the main cause of bycatch. Trawl nets go through a reduction in mesh size when used; consequently, several unintentional materials are captured, mainly small-sized benthic organisms. In contrast, traps and pots are less restrictive to individual size, but are strongly selective by habits; further, carnivorous mammals, reptiles, and cephalopods are attracted by baits destined for lobsters and crabs (Groeneveld et al. 2006; Serena et al. 2016). Bycatch and incidental captures are also accumulated when the fishing gear is deployed. Such gear commonly affects seabirds and pinnipeds, which are attracted by available food. Another incidental capture is that of dugongs, dolphins, and whales in control nets deployed to avoid sharks in coastal waters, common in Australia. Such captures are not linked to commercial or recreational fisheries, but are also classified as bycatch (Erbe and McPherson 2012). Similarly,

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Bycatch: Causes, Impacts, and Reduction of Incidental Captures

Bycatch: Causes, Impacts, and Reduction of Incidental Captures, Fig. 1 Shrimp trawling is a common source of bycatch, and fishers have to segregate the marketable and non-marketable products

the capture of non-target specimens in fisheries with a scientific purpose also constitutes a bycatch; for example, crustaceans caught in samplings for fish inventories, and vice versa. Thus far, the impact of scientific fishing efforts on the aquatic fauna has been neglected; further, the species and biomass that are affected by such fishing efforts remain unknown. Fishing grounds generally overlap with foraging areas, as in the case of wintering and breeding marine birds in southern Brazil (Bugoni et al. 2008). This cohabitation is stressed when aquatic predators such as sharks, dolphins, albatrosses, and petrels get caught on baited hooks or fish get entangled in the longlines and gillnets (Cardoso et al. 2011), or when platypus enters a trap after detecting the target resource, a crayfish (Serena et al. 2016). In fact, the gut contents of fish caught during shrimp trawling is commonly filled with shrimps and other invertebrates, demonstrating that the non-target capture was feeding on the target (Gomes and Chaves 2006).

Quantifying Bycatch The complete knowledge and quantification of bycatch effects on natural populations requires knowledge of life history, demographics,

population connectivity, and trophic interactions as well as ecological relationships between target and non-target species (Komoroske and Lewison 2015). The total volume of bycatch accumulated worldwide is unknown, in part because of the discards before landing. Most bycatch is discarded aboard for two reasons: low economic interest, depending on species, individual size, and sanitary conditions; and landing interdiction, varying among species, legal size, and period of the year. Estimated levels of discards from shrimp fisheries could reach at least 85% of the total bycatch (world estimates for 1983: 11.2 million t bycatch, 9.5 million t discards – Alverson et al. 1994). In Tasmania, gillnet fisheries discard over half of the commercial catch, with discard rates of 80% for non-target species (Bell and Lyle 2016). Physiological stress and injury by entanglement accelerate animal death. Indeed, high losses occur by predation on fish during the retention time, from a few minutes in recreational fisheries to several hours in commercial ones. Opportunistic carnivores, such as puffers and crabs, bite fish in gillnets and hooks, killing them and contributing to catch losses. Globally, total bycatch is estimated to represent 40.4% of global marine catches (Davies et al. 2009); however, a great part of bycatch capture is neglected by official statistics. Considering

Bycatch: Causes, Impacts, and Reduction of Incidental Captures

marine capture data, in 2014 (81.5 Mt) bycatch had summed 32.9 Mt (FAO 2016), a volume superior to that estimated in 1990 of 28 Mt (FAO 1996). Juvenile catches in industrial fisheries, especially those of small pelagics (e.g., sardines and anchovies), have not been adequately reflected in the estimates of most countries, while large-scale bycatch of turtles, cetaceans, pinnipeds, and seabirds are not generally quantified by any existing system or research (Davies et al. 2009). Information on incidental capture can be documented in the fishers' logbooks or by independent observer programs. However, these tools are not available for most fisheries and regions, particularly for artisanal and small-scale fisheries, a particularly data-poor sector. Research and other vessels conducting fishery-independent surveys can provide useful information on the identity and quantity of incidental captures (Kennelly 1995). For example, studies have recognized oceanographic conditions and habitat features associated with the distribution of loggerhead and leatherback turtles off Hawaii (Komoroske and Lewison 2015). The study promoted the NOAA-led program Turtlewatch, which created weekly maps depicting ocean areas where bycatch of both species was more likely to occur. Even so, by the known “observer effect,” observed fishers tend to follow best practice fishing principles, producing not 100% reliable data, which are subject to be underestimated (Davies et al. 2009).

Impacts Scientists agree that bycatch represents a risk for conservation. Many threatened, endangered, or protected species are exposed to non-target fishing that has affected their natural populations. Pelagic longlines used by industrial fleets, for example, are a primary source of mortality to seabirds and marine turtles. Some marine turtles are protected because they exhibit special life history characteristics, such as slow maturation, low fecundity, and high adult survivorship. Data compiled by Lenta and Squires (2017) indicate that incidental capture is the greatest direct threat

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to marine mammals, and in this group, the annual mortality reaches globally 665,000 individuals. The lobster gillnet fisheries constitute a major source of mortality that likely has seriously negative impacts on the depleted eastern Pacific hawksbill population (Liles et al. 2017). Sharks and rays are strongly vulnerable to baited hooks in pelagic and bottom longlines. They are also entangled by trammel nets and gillnets while trying to catch other fish (Costa and Chaves 2006) (Fig. 2). Hooks, gillnets, and traps also affect air-breathing species, such as reptiles, birds, and mammals, that will drown within a few minutes after retention (Bugoni et al. 2008; FAO 2009; Serena et al. 2016; Fisheries New Zealand 2020). In the case of turtles, juveniles (Cheng and Tien-Hsi 1997) and nesting females (Silva et al. 2010) are also a cause for concern. Low size selectivity of fishing gears such as trawl nets for shrimps has an impact on juvenile finfish and on adult crustaceans particularly crabs, on mollusks such as bivalves and gastropods, and on echinoderms, such as sand dollars and sea stars. Frequently, adults are caught during the spawning season. Unfortunately, laws implemented to protect breeding season of a target resource can neglect the life cycle of cohabitant species (Souza and Chaves 2007; Pina and Chaves 2009). Ecological disturbances can occur from bycatch. In northeastern Brazil, Giraldes et al. (2015) reported that decapod species caught in lobster fisheries play a role as detritivores, herbivores, and first consumers within the reef ecosystem. They are also natural prey items for reef fish species. Therefore, the removal of benthic organisms affects the abundance and fish species that occupy these habitats, generating cascading effects throughout the food web (Kennelly 1995). The quantification of the biological effects of bycatch is a multidisciplinary challenge. Komoroske and Lewison (2015) stated that bycatch affects all ecological levels, causing population decline, sinks populations of species, and changes food web interactions. Alverson et al. (1994) pointed out that the bycatch of species having life history strategies – with or without

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Bycatch: Causes, Impacts, and Reduction of Incidental Captures

Bycatch: Causes, Impacts, and Reduction of Incidental Captures, Fig. 2 Fishers throwing to the birds the invertebrates that landed with the main catch

parental care – and reproductive and natural mortality rates similar to that of target species, may have less impact than the capture, in which the life history features differ between bycatch species and target species. The impacts from bycatch are considerable not only for conservation, but also on economic indicators. Discards frequently include nonmarketable individuals of target species, for example, fish entangled in gillnets for a long time, resulting in unsatisfactory sanitary conditions. These catches are omitted in fishery assessments. Indeed, as a large proportion of bycatch takes as juvenile fish, the average weight of which is much lighter than the weight of the larger fish recorded in the statistics of landings. The ecological importance of these juveniles to the marine environment is therefore not adequately conveyed when expressed in weight; thus, the ecological impact of bycatch is potentially far greater than can be reflected in this current estimate (Davies et al. 2009).

Lenta and Squires (2017) argue that the costs of catching endangered species have to be internalized in fisheries costs. Discarded fish generally include small individuals of commercially valued species (Souza and Chaves 2007), having a significant impact on adult stocks and fisheries yield. Kennelly (1995) suggests that this may not have any detectable effect on subsequent stocks of fisheries if most juveniles would have died of natural causes. Normally, fishery interaction problems exist, in which, for example, discards from demersal trawling conflicts with other fisheries that target the bycatch species that are discarded by trawlers. Other economic implications from bycatch result from predation by non-target organisms on target organisms. In lobster trap-fishery, Groeneveld et al. (2006) observed that octopuses can enter traps, feed, and escape before lines are hauled. Gut contents showed that 80% of them had a preference for the bait. In these fisheries, bycatch benefits from lengthening the available time for escape.

Bycatch: Causes, Impacts, and Reduction of Incidental Captures

Currently, the costs of bycatch are not factored into the costs of fishing. For example, concerning the impacts of bycatch on marine mammals, seafood from fisheries with marine mammal bycatch seems to be overproduced and underpriced, with a negative public perception (Lenta and Squires 2017; FAO 2020). As commented by the FAO (2016), excessive bycatch is often a problem for fishers as it slows their catch sorting operations considerably, causing inferior catch quality, and in trawling fisheries, particularly, it increases fuel consumption. Economic losses are also registered in fishing gear. Non-target animals like pinnipeds and dolphins cut cables and nets. Destruction, accidental movements, and loss of fishing gears are currently attributed to entangled large fish and reptiles, too. Penguins and dolphins are generally avoided by professional gillnet fishers (Cardoso et al. 2011). Ethical implications must also be considered. Kennelly (1995) demonstrated that when hundreds of thousands of juvenile fish were bycatch, protests against commercial and recreational fisheries were recorded. At the consumer level, the capture of non-target species may disqualify a fish product from a specific label even when the bycatch species is not depleted (FAO 2016). In contrast, seabirds are simultaneously “beneficiaries” and victims. Coastal birds benefit from bycatch because a large part of small fish and invertebrates, those with no economic value, are discarded before landing. Studies cited by Tsukamoto et al. (2008) indicate that over 80% by weight of discards sink and that 14% of them are available to seabirds. These fish are generally benthic and are normally not accessible to pelagic predators, and thus, are exposed to scavenging by petrels, albatrosses, sharks, mammals, and other carnivores. Behavior of birds and dolphins suggests that they have learned to follow trawlers (Kennelly 1995). This unnatural food availability is responsible for the increased bird densities in certain coastal areas subjected to intense fishing efforts (Wagner and Boersma 2011) (Fig. 2). Simultaneously, in coastal and oceanic waters, penguins and other birds that forage underwater are caught by fishing gears when feeding on baited hooks, or on fish kept by gillnets and

hooks (Cardoso et New Zealand 2020).

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al.

2011;

Fisheries

Human Use of Bycatch The Nordic Council of Ministers NCM (2003) refers to bycatch as “the proportion of the catch that is taken on board, or brought to the surface by the vessel, which is subsequently thrown back to sea, dead or dying, or likely to die”. It assumes that all bycatch is discarded, which is not true. Although a bycatch definition could be “catch that is either unused or unmanaged” (Davies et al. 2009), these captures are frequently welcome by fishers. During benthic trawling, for example, several fish with economic value are caught, being an interesting byproduct of shrimp fisheries. Bluefish, mackerel, weakfish, and sharks feed on benthic invertebrates; thus, they occur together with seabob shrimp. Depending on their individual size, this byproduct is sometimes sold at a higher price than that of shrimps. In southern Brazil, Gomes and Chaves (2006) found that 35% of trawling bycatch species is locally marketed. However, the size of marketed individuals is larger than that of the samples of bycatch in shrimp fisheries. Conversely, gillnets for demersal fish, such as croaker and flatfish, can retain large shrimps, which are easily marketable. This commercial bycatch (Costa et al. 2008) includes cephalopods, crabs, and cartilaginous fish, varying according to the fishing gear employed. Octopus bycatch is currently an additional product of lobster-fishery that can be sold to increase earnings (Groeneveld et al. 2006). In contrast, in many fisheries, non-target organisms are poorly used. This is the case with lobster fisheries performed in northeastern Brazil, where the large crab Damithrax hispidus is even more abundant than the target spiny lobster, Panulirus echinatus; however, only the chelipeds from larger crabs are used, while the rest of the body is discarded on the beach (Giraldes et al. 2015). The use of bycatch extrapolates commercial purposes and can include cultural components, as is the case for cetaceans. In Gambia, Senegal, and Guinea-

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Bissau, Leeney et al. (2015) reported that dolphin bycatch is generally distributed among the community as food as well as for medicinal purposes and for traditional ceremonies. The landing of all bycatch, instead of discarding them, is controversial. The FAO (1996) assumes that the landing of bycatch is a fundamental solution to the bycatch and discard issue. In fact, the production of food to satisfy human and animal requirements is a global challenge. Martin (2017) suggests that a possible solution for the food crisis resides in making more with less, by using the enormous amount of protein discarded as bycatch. For this, Kennelly (1995) states that more diverse markets for such products need to be developed. In contrast, today, discards represent a traditional food for marine birds (Fig. 3). Consequently, SorianoRedondo et al. (2016) warn that the recent reform of the European Common Fisheries Policy, which intends to ban discards through the landing obligation of all catches, may force seabirds to seek alternative food sources. These authors found that the probability of bird interactions with longliners increases as the number of trawlers (many discards) decreases. Thus, the landing obligation of trawlers bycatch should be carefully monitored and counterbalanced with bycatch mitigation measures in the longline fleet.

Bycatch: Causes, Impacts, and Reduction of Incidental Captures, Fig. 3 Selling of bycatch: small pickled fish sold in Southeastern Brazil

Reducing Bycatch Supporting a better use of bycatch is welcome; however, this does not mean to support bycatch. Prize initiatives for the development of practical, innovative fishing gear (www.wwf.panda.org) designed to avoid unwished captures should be encouraged. Lenta and Squires (2017) cite an example of reward for reducing bycatch of marine mammals, the SmartGear prize. Policies on this matter are available in several countries, and new designs for gears are being developed to increase the survival of animals after release. In the tuna fishing industry, for example, Bugoni et al. (2008) found that mortality is particularly high when longline uses small hooks, as they are easier to be swallowed by birds. In addition, gear-based and non-gear adaptations are recommended by Willems et al. (2016) to further reduce the bycatch of small individuals. Incidental captures and bycatch are expected in all fisheries; further, adaptations in fishing gear as well as regulations created for their operation and overall bycatch quotas have been developed to avoid unwished catches. Technological adaptations explore differences between target and non-target animals according to their behavior or size (Broadhurst 2000; He 2007; Serena et al.

Bycatch: Causes, Impacts, and Reduction of Incidental Captures

2016; FAO 2018). Traps for crabs can add an extra opening to the roof of traps, improving the platypus’s and freshwater turtles’ ability to escape in a timely manner. In longline fishing, circle hooks are more effective for avoiding turtles than the conventional J-hook design. Circle hooks and traps designed to reduce bycatch and damage to traps are also being developed in shark sanctuaries. A decrease in bird apprehension by hooks can also be obtained by deploying weights, weighted lines, and longer secondary lines (Bugoni et al. 2008). Bycatch reduction devices (BRDs) in shrimp trawl nets consist of a particular mesh design on the top of the net, allowing fish to escape during trawling. In Suriname’s seabob shrimp fisheries, a reduction in the overall catch rate of rays was estimated at 36.1% using the alternate mesh design (Willems et al. 2016). In 1987 the US government passed a federal bycatch regulation that required all shrimp trawlers to use turtle excluder devices (TEDs) while fishing in US waters. TEDs are grids of bars with an opening either at the top or at the bottom of the trawl net; fish and turtles are excluded by behavior movements (FAO 2012). The use of a top-opening excluder device in trawling nets can also prevent the bycatch of mammals by promoting the escape of pinnipeds (FAO 2020). In terms of cetaceans, acoustic alarms (pingers) are efficient in gillnets. On the Australian coast, they are also used on shark control nets, preventing entanglement of humpback whales, dugongs, and dolphins. Erbe and McPherson (2012) state that the received sound level should be measured in the field at the time, rather than relying on the manufacturer specifications in combination with a simple sound propagation model. Juveniles cannot escape from traps as easily as adults can, as is the case with crab traps that catch platypus (Serena et al. 2016); thus, escaping from fishing gear can be harmful to these animals. In spite of this, Raby et al. (2011) consider mechanical adaptations to fishing gear a preferable solution to the requirement of pulling the gear and release the bycatch, a process that can exacerbate stress and injury among the fish. Bell and Lyle (2016) investigated how capture conditions,

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immediate mortality, and delayed mortality are affected by gillnet soak duration. The authors state that the maximum gillnet soak duration regulations implemented as a strategy to improve fishing practices appear to be effective for most species in facilitating high post-capture survival. Legal measures remain a subject of discussion and are still missing adequate data for support. In January 2018 the European Parliament voted to ban pulse trawling, which potentially reduces bycatch in flatfish fisheries. Stokstad (2018) explains that irrespective of the lack of clear effects of electric pulses, this type of trawling, although more selective than a typical trawling net, is harmful to non-target marine life. In fact, many sharks and rays, for example, are particularly sensitive to these electrical fields. In contrast, ICES (2018) argues that there is insufficient information available on the detection threshold of organisms to the electric pulse, or on adverse response thresholds, to quantitatively assess the potential effect of electrical exposure at the population level. A long-term experiment of the small spotted catshark Scyliorhinus canicula, one of the more common species in the southern North Sea, demonstrates that the feeding and reproductive behavior of this species was not altered by pulse exposure. Attention is also required for scientific studies to focus on fisheries. The use of electric fishing as a sampling method suffers from restrictions on water conductivity, flow rate, and depth (Bolin et al. 1989); it is not recommended as a unique sampling method in inventory studies (Oliveira et al. 2014). However, as individuals respond differently to the characteristics of electrical current, depending on species and body size, most of the capture is harvested alive. Hence, despite the stress imposed on the fish, electrofishing is a satisfactory method to reduce post-capture mortality (Bolin et al. op. cit.). In addition to technological adaptations, fishing routines can help reduce bycatch. Spatial measures may include zones reserved for traditional fishing activities or for specific gear types (FAO 2016). Longline fishing is restricted to operate after sunset as stipulated by Brazilian laws, in view of the low activity of seabirds in this period. Colored flags are expected to repel albatrosses and petrels during longline fishing, but still require

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legislation. Gillnetting closures of key areas in Tasmania, implemented in 2015, are cited by Bell and Lyle (2016) as a tool to reduce the probability of skate bycatch in its habitat. These authors argue that implementation of maximum soak duration regulations represents an effective step toward reducing bycatch mortality. Time/area closures can avoid bycatch in sensitive areas, reducing interactions between marine mammals and fishing gear. Although unpopular with fishers, this measure is highly recommended, particularly where marine mammals aggregate, such as breeding grounds (FAO 2020). Paradoxically, anthropogenic pressures on coastal environments can disturb fishing activities and indirectly contribute to conservation. This is observed in northeastern Brazil, where irresponsible tourism on a reef environment as a result of the tourism trade has been a strong driver of reduction in use of gillnets, benefiting the lobster population and accompanying bycatch decapods (Giraldes et al. 2015). Partnering with the fishing community has proven positive. As observed by Liles et al. (2017), spatiotemporal patterns in fishing effort and turtle bycatch in set nets at shallow depths with longer soak times during the peak lobster fishing season offer guidance for potential community-based mitigation strategies in lobster gillnet fisheries in El Salvador and Nicaragua. Surveys with anglers in general show that discards in noncommercial fisheries, and educational campaigns, such as the distribution of guides (FAO 2009) and line cutters and dehookers (Bugoni et al. 2008), are useful in guiding fishers on handling procedures for sea turtles and birds in general, improving survival after release. These campaigns as well as the implementation of monitoring programs and participation in local forums have proven effective (Silva et al. 2010). Social media hits for seabird-related outreach campaigns, and material and mitigation guidance toward amateur charter vessel operators are policies in New Zealand, which present an exceptional number of seabird species Fisheries New Zealand 2020. Incentives to decrease bycatch (e.g., for mammals) are also possible from consumer markets and

firms in the supply chain through eco-labeling, certification, and standards (Lenta and Squires 2017). Tax landings based on the observed level of bycatch on each fishing trip, or on representative trips in this time and area, are proposed. However, while the initial direct costs of bycatch reduction may be low, relatively high and largely fixed regulatory costs risk will need to request subsequent adjustments. The institutional and infrastructure costs to implement, monitor, and enforce mammal bycatch programs, for example, may be comparatively high. In Brazil, despite Brazilian legislation, a large proportion of the trawling fleet is unable to implement normative regulations on TEDs because their use is not economically and operationally viable (Silva et al. 2010). Top–down approaches to fishery management adopted for reducing bycatch, thereby reducing wastage and the ecosystem impacts of fisheries, can lead to significant yield losses for the fishing industry. As stated by Tsukamoto et al. (2008), any technology or policy aiming at a bycatch and discards reduction must consider fishers to compensate for the landing losses. For TEDs, Mukherjee and Segerson (2011) found that, over the period 1989–2003, the estimated harvest loss for the fishing industry was approximately 2% lower than that claimed by the industry. Small-scale fisheries, in particular, provide important livelihood support and poverty alleviation for coastal residents. Better multidisciplinary management would bring all sectors together to avoid reduced fishing efforts (FAO 2016).

Conclusions and the Way Forward The uncertainty in rate estimation impedes the development of effective mitigation strategies. There is ample opportunity for research on freshwater bycatch in developed countries as well as on commercial bycatch of freshwater fishing of developing countries. Techniques to reduce interactions between fishing gears and corals, sponges, and other structure-forming invertebrates are particularly strategic. Improving the understanding of post-release mortality is also necessary.

Bycatch: Causes, Impacts, and Reduction of Incidental Captures

Fishers’ behavior will determine the success or failure of bycatch management measures; therefore, the involvement of the fishing sector is necessary to obtain full cooperation. It includes recreational fisheries, by way of social media campaigns. Area closures aiming to avoid bycatch of threatened, endangered, or protected species in critical sites have to be subjects of research, considering social and economic communities concerned with fishing. Payments for ecosystem services can provide a form of reward for reducing and directly pricing bycatch. Subsidies that finance innovation, diffusion, and adoption of bycatch reducing technology can ultimately increase economic and ecological welfare. Bycatch is expected to link biology, oceanography, and ecology to engineering, sociology, and economics. It is a byproduct inherent to extractive activities that offer challenges in all environments and communities where fishing takes place. All fisheries worldwide are a cause for concern, with different human comprehension and management practices. They can be included as illegal, unreported, and/or unregulated fishing, directly linked with the Sustainable Development Goal 14, Conserve and sustainably use the oceans, seas, and marine resources for sustainable development, which, according to the United Nations (2019), remains one of the greatest threats to sustainable fisheries, the livelihoods of those who depend on them and marine ecosystems. Undoubtedly, ethical questions as well as conservational and economical questions, requesting multidisciplinary approaches to mitigate their effects, should be addressed.

Cross-References ▶ Artisanal Fisheries: Management and Sustainability ▶ Coral Triangle: Marine Biodiversity and Fisheries Sustainability ▶ Destructive Fishing Practices and Their Impact on the Marine Ecosystem ▶ Fisheries Management: An Overview

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and market responses. Mar Resour Econ 26(3): 173–189. https://doi.org/10.5950/0738-1360-26.3.173 National Marine Fisheries Service (2011) U.S. National Bycatch Report (eds: Karp WA, Desfosse LL, Brooke SG). U.S. Department of Commerce NOAA Technical Memorandum NMFS-F/SPO-117E, 508 p Nordic Council of Ministers (2003) Workshop on discarding in nordic fisheries. Sophienberg Castle, Rungsted, Denmark, 18–20 November 2002 Oliveira AG, Gomes LC, Latini JD, Agostinho AA (2014) Implications of using a variety of fishing strategies and sampling techniques across different biotopes to determine fish species composition and diversity. Nat Conserv 12:112–117. https://doi.org/10.1016/j. ncon.2014.08.004 Pina JV, Chaves PT (2009) Efeitos da pesca de arrasto camaroeiro sobre peixes em atividade reprodutiva: um estudo de caso no Sul do Brasil. Atlântica Rio Grande 31(1):99–106 Raby GD, Colotelo AH, Blouín-Demers GB, Cooke SJ (2011) Freshwater commercial bycatch: an understated conservation problem. Bioscience 61(4):271–280. https://doi.org/10.1525/bio.2011.61.4.7 Serena M, Grant R, Williams GA (2016) Reducing bycatch mortality in crustacean traps: effect of trap design on platypus and yabby retention rates. Fish Res 175:43–50 Silva ACCD, Castilhos JC, Santos EAP, Brondízio LS, Bugoni L (2010) Efforts to reduce sea turtle bycatch in the shrimp fishery in Northeastern Brazil through a co-management process. Ocean Coast Manag 53(9): 570–576 Soriano-Redondo A, Cortés V, Reyes-González JM, Guallar S, Bécares J, Rodrigues B, Arcos JM, González-Solís J (2016) Relative abundance and distribution of fisheries influence risk of seabird bycatch. Sci Rep 6:37373. https://doi.org/10.1038/srep37373 Souza LM, Chaves PT (2007) Atividade reprodutiva de peixes (Teleostei) e o defeso do arrasto de camarão no litoral norte de Santa Catarina, Brasil. Rev Bras Zool 24(4):1113–1121 Stokstad E (2018) Tensions flare over electric fishing in European Waters. Am Assoc Adv Sci. https://doi.org/ 10.1126/science.aat0249 Tsukamoto K, Kawamura T, Takeuchi T, Beard Jr TD, Kaiser MJ (eds) (2008) Fisheries for global welfare and environment, 5th world fisheries congress, pp 169–180. A review of bycatch and discard issue toward solution United Nations (2019) Special edition: progress towards the Sustainable Development Goals. Report of the Secretary-General. Economic and Social Council, E/2019/68, distr. 08 May 2019. https://undocs.org/E/ 2019/68. Accessed 3 Sept 2019 Wagner EL, Boersma PD (2011) Effects of fisheries on seabird community ecology. Rev Fish Sci 19:157–167 Willems T, Depestelea J, Backera A, Hostens K (2016) Ray bycatch in a tropical shrimp fishery: do bycatch reduction devices and turtle excluder devices effectively exclude rays? Fish Res 175:35–42

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Cetacean Conservation

Definition

▶ Cetacean Health: Global Environmental Threats

Cetaceans are aquatic mammals, large-headed, hairless, and torpedo-shaped mammals with a complex stomach comprising of at least four chambers. There are 90 species belonging to the order Cetacea; examples include dolphins, porpoises, and whales (Smith et al. 2003). Cetacean health encompasses the sum of all biological, social, and environmental interactions in which an individual, population, or community of cetaceans engage to manage or adapt to stress over time (Stephen 2014). Environmental threat represents a stressor that can cause adverse responses in organisms, ranging from molecular, tissue, organismal, to population level (Avila et al. 2018); examples of environmental threats include chemical pollution, climate change, overfishing, and bycatch. Environmental risk refers to the possibility of an organism or population to experience an adverse effect following exposure to an environmental threat, which can have direct effects, e.g., infectious diseases, injuries, and mortality, or indirect effects, e.g., changes in feeding, migratory, or reproductive behavior, on cetacean health (Jørgensen and Fath 2011).

Cetacean Diseases ▶ Cetacean Health: Global Environmental Threats

Cetacean Health: Global Environmental Threats Edmond Sanganyado and Wenhua Liu Guangdong Provincial Key Laboratory of Marine Biotechnology, Institute of Marine Science, Shantou University, Shantou, People’s Republic of China Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, People’s Republic of China

Synonyms Introduction Anthropogenic impact to cetaceans; Cetacean conservation; Cetacean diseases; Cetacean populations; Environmental threats to cetaceans

Cetacean health is the capacity of cetaceans to support biota and maintain habitat quality by

© Springer Nature Switzerland AG 2022 W. Leal Filho et al. (eds.), Life Below Water, Encyclopedia of the UN Sustainable Development Goals, https://doi.org/10.1007/978-3-319-98536-7

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functioning as vital members of the ecosystem. Cetaceans are a highly diverse group of species with varying body sizes, migratory patterns, foraging habits, and habitat niche. As apex predators, cetaceans play a vital role in maintaining biodiversity, ecosystem structure, function, and dynamics and regulating diseases (Estes et al. 2011). Cetaceans face multiple stressors that are caused by anthropogenic disturbances throughout their lifetime. These disturbances often affect their foraging, reproductive, and migratory opportunities which adversely affects their productivity, growth, and survival rates (Sanganyado et al. 2020). Hence, marine biologists, ecologists, environmental chemists, and marine conservation organizations continue to raise alarm on the decline of cetacean populations across the globe. Conservation and sustainable use of oceans, seas, and marine resources as required by the SDG 14 offers numerous benefits to cetaceans

Cetacean Health: Global Environmental Threats

(Fig. 1). Attaining SDG 14 can decrease disease prevalence, accidental deaths, and habitat degradation. Hence, cetacean health is a critical indicator of the progress made in achieving the Sustainable Development Goal 14. Traditionally, cetacean health was assessed based on mass strandings, population changes, and the presence of chemical contaminants in tissue (Hunt et al. 2013). Such health indicators envisioned health as the absence of disease. Today, physiological changes in cetaceans measured using advanced techniques such as bioanalysis, next-generation DNA sequencing, and photometry are widely used as biomarkers for assessing cetacean health (Derous et al. 2020). This article explores the concept of cetacean health, highlights the current techniques used in assessing cetacean health and their limitations, discusses the multiple stressors threatening cetaceans, and proposes a framework for assessing cetacean health.

Cetacean Health: Global Environmental Threats, Fig. 1 Health and ecological benefits to cetaceans of attaining the SDG 14 targets

Cetacean Health: Global Environmental Threats

Cetacean Health and Marine Ecosystem Services Marine ecosystem services refer to the direct and indirect benefits provided by marine ecosystems to humans (Cook et al. 2020). A marine ecosystem comprises of abiotic and biotic components that interact to promote and maintain nutrient and energy flow across the food web, biological productivity, and habitat quality (Barbier 2017). Ecosystem services are produced through these

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marine components and processes. Linking marine ecosystem function and structure to environmental processes and human is critical in developing marine conservation and management strategies. Cetaceans provide a critical physical link between marine ecosystems, ecosystem services, and economic systems. Cetaceans are grouped into two distinct suborders, Mysticeti and Odontoceti, according to their feeding habits (Table 1). Mysticeti (baleen whales, 14 species, and 4 families) are filter feeders that

Cetacean Health: Global Environmental Threats, Table 1 List of cetacean suborders, families, and species Order Cetacea

Suborder Mysticeti

Family Balaenidae (right whales) Neobalaenidae Eschrichtiidae Balaenopteridae

Odontoceti

Physeteridae Kogiidae Ziphiidae (beaked whales)

Platanistidae Iniidae Lipotidae Pontoporiidae Monodontidae Delphinidae

Phocoenidae (porpoises)

Species Balaena mysticetus, Eubalaena glacialis, Eubalaena japonica, Eubalaena australis Caperea marginata Eschrichtius robustus Balaenoptera acutorostrata, Balaenoptera bonaerensis, Balaenoptera borealis, Balaenoptera edeni, Balaenoptera musculus, Balaenoptera omurai, Balaenoptera physalus, Megaptera novaeangliae Physeter macrocephalus Kogia breviceps, Kogia sima Berardius arnuxii, Berardius bairdii, Berardius minimus, Hyperoodon ampullatus, Hyperoodon planifrons, Indopacetus pacificus, Mesoplodon bidens, Mesoplodon bowdoini, Mesoplodon carlhubbsi, Mesoplodon europaeus, Mesoplodon ginkgodens, Mesoplodon grayi, Mesoplodon hectori, Mesoplodon hotaula, Mesoplodon layardii, Mesoplodon mirus, Mesoplodon perrini, Mesoplodon peruvianus, Mesoplodon stejnegeri, Mesoplodon traversii, Mesoplodon densirostris, Tasmacetus shepherdi, Ziphius cavirostris Platanista gangetica Inia geoffrensis Lipotes vexillifer (possibly extinct) Pontoporia blainvillei Delphinapterus leucas, Monodon monoceros Cephalorhynchus commersonii, Cephalorhynchus eutropia, Cephalorhynchus heavisidii, Cephalorhynchus hectori, Delphinus delphis, Feresa attenuata, Globicephala macrorhynchus, Globicephala melas, Grampus griseus, Lagenodelphis hosei, Lagenorhynchus acutus, Lagenorhynchus albirostris, Lagenorhynchus australis, Lagenorhynchus cruciger, Lagenorhynchus obliquidens, Lagenorhynchus obscurus, Lissodelphis borealis, Lissodelphis peronii, Orcaella brevirostris, Orcaella heinsohni, Orcinus orca, Peponocephala electra, Pseudorca crassidens, Sousa teuszii, Sousa chinensis, Sousa plumbea, Sousa sahulensis, Sotalia fluviatilis, Sotalia guianensis, Stenella attenuata, Stenella clymene, Stenella coeruleoalba, Stenella frontalis, Stenella longirostris, Steno bredanensis, Tursiops aduncus, Tursiops truncates Neophocaena phocaenoides, Neophocaena asiaeorientalis, Phocoena dioptrica, Phocoena phocoena, Phocoena sinus, Phocoena spinipinnis, Phocoenoides dalli

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prey on small fish and primary producers such as zooplankton, while Odontoceti (toothed whales, 72 species, and 10 families) are predominantly carnivorous and feed on fish and invertebrates which they normally catch individually (Van Blaricom et al. 2013). The ecosystem services provided by cetaceans and marine ecosystems can be classified as provisioning, regulation and maintenance, or cultural services. Cetacean biomass directly provides provisioning services such as food products and oil products from whales (Barbier 2017). In contrast, cetacean foraging and reproductive habits directly provide regulation and maintenance services to the physical, chemical, and biological conditions of the marine ecosystem such as predator control, energy and nutrient cycling, and carbon sequestration but indirectly affect provisioning services such as fish harvests (Cook et al. 2020). For example, Odontoceti feeds on larger species which is critical for maintaining a healthy and balanced ecosystem. Maintaining the Odontoceti health is crucial because losing apex predators in an ecosystem (trophic downgrading) affects environmental processes such as disease dynamics, carbon sequestration, invasive species, and biogeochemical exchanges between sediments, water, and the atmosphere (Estes et al. 2011). Previous studies found that whales significantly increased primary productivity in their feeding and calving areas by releasing nitrogen-rich fecal plume near the surface where phytoplankton inhabit (Roman and McCarthy 2010; Roman et al. 2016). The life history and physiology of cetaceans often provides important cultural services such as aesthetics, cultural identity, bequest, and spiritual enrichment (Cook et al. 2020). Hence, cetacean health may influence the ecological productivity of marine ecosystems and the human benefits of ecosystems services by altering food chain and habitat connectivity, prey abundance and diversity, and the availability of goods and services (Barbier 2017).

Challenges in Assessing Cetacean Health Assessing cetacean health is challenging because of the complexity and the dynamic nature of health. Health is historically defined as the

Cetacean Health: Global Environmental Threats

absence of diseases or infirmity in an individual or population (Huber et al. 2011). As a result, cetacean health is often assessed based on the occurrence of adverse physiological changes in an individual species or vital population rates such as survival, productivity, or recruitment. The parameters often assessed in cetacean health include productivity, body weight, fecal output, abundance, and profitability. However, defining cetacean health as the absence of disease has five major limitations (Stephen 2014): (i) absence of diseases is not possible because of the ubiquity of parasites and pathogens in wildlife communities; (ii) absence of diseases does not afford a threshold for determining the biological changes that lead to disease, death, or recovery; (iii) healthy populations can have exposed, infected, or diseased individuals; (iv) it emphasizes understanding the causes of death or disease rather than the proactive maintenance of good cetacean health; (v) it ignores the socioecological factors that threaten the well-being of wildlife populations such as overfishing, habitat changes, and ocean- and land-use pressures. Cetacean health is often assessed at various levels of biological organization. At a molecular level, bioanalytical techniques employing highresolution mass spectrometers are often used to measure biomolecules such as hormones, lipids, and peptides as biomarkers of exposure or effect (Trego et al. 2018; Galligan et al. 2019). A biomarker is a measurable indicator of physiological or biological change in an individual species or population (Godard-Codding and Fossi 2018). Cetacean cell cultures obtained from lungs, skin, and liver are often used to measure cetacean health at a cellular level (Rajput et al. 2018; Huang et al. 2020). Ecologists often use body condition and reproductive history to measure cetacean health at an organism level. The body condition is often determined by measuring the weight and length of the cetaceans. In recent years, photometry has gained prominence in determining body conditions and reproductive rates of cetaceans (Hunt et al. 2013). At a population level, cetacean health is often measured using the population demographics and the spatial and temporal trends in population. Assessment of cetacean health increases in complexity from molecular to the population level.

Cetacean Health: Global Environmental Threats

Extrapolating changes observed at a molecular and cellular level to the individual or population health remains challenging since cetaceans are exposed to multiple stressors of natural and anthropogenic origin in a highly dynamic environment (Trego et al. 2020). Cetacean respond to external (e.g., nutritional conditions, pathogens, pollution, and predators) and internal (e.g., disease) stressors by thickening their blubber, forming large skeletal muscles, and altering their osmoregulation, blood glucose levels, and diving behavior which results in changes in cetacean metabolism (Suzuki et al. 2018). A previous study used capillary electrophoresis and liquid chromatography which were coupled to time-offlight mass spectrometers to measure changes in blood plasma metabolites in bottlenose dolphins (Suzuki et al. 2018). In addition to catch-andrelease and skin biopsy sampling, metabolomic analysis can be conducted using a noninvasive technique such as breathe analysis where cetacean breathe is collected (Aksenov et al. 2014). Recently, breathe analyses in cetaceans impacted by the Deepwater Horizon oil spill showed a significant association between levels of metabolites linked to lung damage such as arachidonic acid cascade metabolites and extent of lung damage as shown by sonography (Pasamontes et al. 2017). Besides changes in metabolites, cetaceans also respond to stressors by altering their gene expression and lipid profiles. Transcriptomics measures changes in RNA transcripts and identifies functional genes that are regulated differently following exposure to multiple stressors (Trego et al. 2020). The changes in gene expression are then used to infer potential changes in physiological processes downstream physiological. Lipid content in cetacean blubber often provides a good indication of nutrition conditions in a habitat. Hence, metabolomics, transcriptomics, and lipidomics provide powerful tools for linking molecular changes to organismal health using noninvasive or minimally invasive techniques.

Anthropogenic Threats to Cetacean Health In the past century, rapid industrialization and urbanization contributed to a significant increase

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in threats to cetacean health. Cetaceans face numerous threats such as chemical or noise pollution, climate change, overfishing, and loss of habitats (Table 2). The magnitude and types of stressor vary with location and time as the intensity and nature of human activities vary spatially and temporally (Simmonds 2018). For example, cetaceans inhabiting waters close to a busy port will be exposed to noise pollution. The intensity of the noise pollution will depend on time and proximity to the traffic route. New human activities introduce new threats to cetacean health. For example, the rapid development of the electronic industry in the Guangdong province resulted in an increase in the discharge of brominated flame retardants into the eastern Guangdong coastal waters (Sanganyado et al. 2018). The current push for offshore wind farms integrated with mariculture will also introduce new threats to cetaceans through loss of habitats or pollution (Nowacek et al. 2007). Multiple stressors often cause mortality and morbidity in cetaceans, and it is often difficult to identify the exact cause. Cetaceans are in constant interaction with the environment and often host various disease-causing agents or pathogens. Environmental changes such as pollution and climate change can alter the host-agent/pathogen balance resulting in disease manifestation by affecting the physiology of the host or increasing the load of the agent/pathogen. These changes can directly affect cetacean health due to an increase in morbidity and mortality or indirectly by affecting reproduction, migration, and feeding behavior. Both indirect and direct effects of environmental change affect the health of cetacean populations. In this article, five major global threats will be discussed: climate change, anthropogenic contaminants, fishing and related activities, noise pollution, and infectious diseases. Climate Change The ongoing alterations in chemical, physical, and biological processes due to climate change in marine ecosystems have drastic effects on cetacean populations. Climate change affects cetacean habitats as follows: alters sea temperatures, sea levels, ice extent, seawater chemistry (e.g., ocean acidity, salinity, and redox), seawater mixing,

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Cetacean Health: Global Environmental Threats, Table 2 An overview of the global threats to cetacean populations and their habitats. (Modified from Simmonds (2018). Used with permission of Elsevier)

Threat Climate change

Description Storm intensity changes Sea ice changes Changes in runoff water circulations Ozone depletion Climate change-driven changes in human activities, e.g., Increased shipping and fishing in Arctic waters Increased directed take of marine mammals Anthropogenic Nutrient pollution-eutrophication pollution Harmful algal blooms Oil spills Persistent organic pollutants, especially PCBs (but also potentially including brominated flame retardants and perfluorinated compounds) Heavy metals Non fishery-derived marine debris, including microdebris Fisheries/related Overfishing and prey-culling and depletion activities Mariculture Marine debris, including ghost nets Bycatch Noise pollution Seismic surveys Boat traffic (also causing ship strikes) Military sonar Construction Pathogen emergent disease Physical habitat Bottom trawling degradation Dredging Other destructive fishing techniques Reclamation Coastal construction Wind farms Dams and barrages Marine fossil fuel exploration/extraction Tourism Whale watching “Swim with” programs War-related Mines activities Munition dumps Introduced species Intentional takes Commercial whaling Other marine mammal takes for profit or food

Current knowledge statusa Habitat Population 2 1 2 1 2 1 2 1 3 1

3 3 3 2

1 2 2 2

2 2

2 2 3 2 1 3 1 1 1 1 1 2 2 2 1 1 1 1 2 2 2 1 1 1 3 3

3 3 0 3 3 0 3 3 3 3 3 1 3 3 3 3 3 3 2 3 3

a

Legend indicating the current knowledge status: 0, not applicable; 1, poorly understood; 2, moderately understood; and 3, well understood

precipitation, and ocean waves (Burgener et al. 2012). These physicochemical changes have severe implications on the biological processes in the environment as well as cetacean and

human behavior. Table 3 details the impact of climate change on human behavior and the possible implications to cetacean health. Loss of prey, changes in feeding and breeding locations and

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Cetacean Health: Global Environmental Threats, Table 3 Impact of climate change on human behavior and cetacean health. (From Alter et al. (2010). Used with permission from Elsevier) Change in physical or biological environment Diminishing sea ice

Decline of coral reef health Warming of high-latitude waters

Drought and decreasing precipitation

Warming of high-latitude terrestrial ecosystems Increase in storm severity Sea level rise

New focus on renewable energy sources

Potential change in human behavior Increased shipping

Impact on cetaceans Acoustic disturbance

Increased fishing pressure As ice-dependent pinnipeds decline, Arctic communities may shift hunting effort to cetaceans Increase in military presence Displacement of tourism to whale and dolphin-watching

Depletion of prey base; bycatch Direct hunt

Increase in aquaculture

Coastal eutrophication: Cetacean interactions with aquaculture operations may lead to harassment/culling Increase in bycatch

Increase in fisheries as target species move north Decline in food security may result in greater reliance on marine ecosystems for food Increase in human migration to coastal areas

Acoustic disturbance Harassment, acoustic disturbance

Species that may be affected Large whales inhabiting Arctic and subarctic waters Polar and subpolar cetaceans Arctic cetaceans subject to harvest

Arctic cetaceans Coastal tropical cetaceans in regions where coral reef tourism is prominent Coastal high-latitude species, particularly small, toothed cetaceans Polar and subpolar cetaceans

Prey depletion; direct catch of cetaceans for food

Tropical coastal cetaceans in EEZs of drought-prone nations Tropical coastal cetaceans in EEZs of drought-prone nations

Increase in desalination

Increase in urban and agricultural runoff, potential increases in tourism Localized disturbance

Increase in intensive agriculture

Increase in anoxic zones and potentially HABs

Increase in human densities and terrestrial activities (e.g., agriculture)

Increase in urban and agricultural runoff, potential increases in tourism

Construction of breakwaters, jetties, etc., may increase coastal noise propagation Coastal construction projects (dykes, etc.) to manage flooding Land acquisition and creation of marsh and wetlands Construction of wind, wave, and tidal generators

Acoustic disturbance

Coastal cetaceans

Habitat fragmentation

Coastal cetaceans (particularly estuarine and riverine)

Habitat loss; introduction of foreign contaminants and disease Acoustic disturbance; potential for habitat disruption or displacement; collisions Destruction of freshwater habitat for cetaceans and prey

Coastal cetaceans (particularly estuarine and riverine) Cetaceans in areas with high potential for renewable energy

Increase in hydroelectric power sources

Coastal cetaceans of droughtprone nations, particularly those that use shallow lagoon or bay habitat All coastal cetaceans in drought-prone nations, particularly those near river mouths Subpolar and polar coastal cetaceans

Riverine and estuarine cetaceans; species that depend on freshwater fish prey

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times, loss of habitats (e.g., Arctic cetaceans), and increased energy demands for thermoregulations have been observed (Simmonds 2017). Prey depletion has severe consequences to reproduction in cetaceans that synchronize their breeding with prey abundance for lactation and calf weaning (Simmonds and Eliott 2009). Hence, cetaceans might need to find better locations and times for breeding to adapt to climate change. In addition, the distribution and diversity of cetaceans is mainly influenced by the sea temperature. Hence, the changes in surface sea temperature can be expected to change the distribution of these cetaceans. A previous study estimated that by 2050 the cetacean richness will increase above 40
latitude but decrease at lower latitudes in both hemispheres (Kaschner et al. 2011). Vaquita (Phocoena sinus) inhabiting the Gulf of California are at risk because they cannot escape the warming waters since they are in a closed embayment (Simmonds and Eliott 2009). In another study, female sperm whales had lower reproductive rate following prolonged exposure to warm sea-surface temperatures (Simmonds and Eliott 2009). Warming sea-surface temperatures may increase disease prevalence in cetacean populations by (i) increasing disease susceptibility due to physiological stress, (ii) increasing disease transmission due to changes in cetacean migratory ranges and patterns, and (iii) promoting the emergence and proliferation of thermophilic pathogens (Simmonds and Eliott 2009). Anthropogenic Contaminants The presence of anthropogenic contaminants in the marine environments poses a health risk to cetaceans. Examples of anthropogenic contaminants include marine debris such as microplastics and chemical pollutants such as pharmaceuticals and personal care products, pesticides, brominated flame retardants, plasticizers, microplastics, potentially toxic elements, and inorganic nutrients (Shi et al. 2020). Anthropogenic contaminants arising from land-based activities primarily enter the marine ecosystem through a wastewater treatment plant, industrial, domestic, hospital, and agricultural effluent. Offshore activities such as mariculture, shipping, and oil drilling are an

Cetacean Health: Global Environmental Threats

additional source of anthropogenic contaminants such as heavy metals, antibiotics, organotins, and polycyclic aromatic hydrocarbons, respectively (Yu et al. 2020). Since cetaceans often have a long life span, have a high lipid content in their skin, inhabit contaminated coastal areas, and are at the top of the food web, they readily accumulate chemical pollutants, thus putting their health at risk (Sanganyado et al. 2018). Several organic pollutants detected in cetaceans have been shown to interfere with the endocrine system and hormonal activities in wildlife including cetaceans. Endocrine-disrupting chemicals such as polychlorinated biphenyls and organochlorine pesticides can disrupt enzyme coordination, protein binding, gene expression, and receptor activities which can lead to reproductive and developmental dysfunction (Tubbs and McDonough 2018). These chemicals present a considerable threat to cetaceans, especially to near threatened to critically endangered species whose continued existence is easily imperiled by perturbations in reproduction (Tubbs and McDonough 2018). For example, a previous study found reproductive dysfunction and failure in female common dolphins in the Northeast Atlantic was associated with high polychlorinated biphenyl concentrations in the blubber (Murphy et al. 2018). Anthropogenic contaminants have been shown to affect the immune system in cetaceans adversely. The cetacean immune system responds to pathogens through innate and adaptive immunity. Innate immunity involves the activity of phagocytic cells such as macrophages and neutrophils in the swift destruction of pathogens (Desforges et al. 2016). In contrast, lymphocytes such as the B and T cells play an active role in adaptive immunity to provide long-term protection to pathogens (Desforges et al. 2016). However, a previous study found increased polychlorinated biphenyl concentrations in bottlenose dolphins (Tursiops truncatus) were associated with a decrease in T-lymphocyte proliferation (Schwacke et al. 2012). Previous in vitro studies using immortalized fibroblast cell lines found polybrominated diphenyl ethers impaired innate immune response by altering prostaglandin

Cetacean Health: Global Environmental Threats

E receptors, increasing the secretion of interleukin-1β, and suppressing interleukin-10 (Rajput et al. 2018; Huang et al. 2020). These results suggested that exposure to organic pollutants increased the susceptibility of cetaceans to infectious disease. Fishing and Related Activities Fishing activities, directly and indirectly, threaten the survival of cetacean populations globally. Collision with fishing vessels, incidental catch (bycatch), entanglement with fishing gear, and lacerations from boat propellers directly injure cetaceans externally. It is estimated that more than 300,000 cetaceans worldwide are injured by bycatch annually (Burgener et al. 2012). Bycatch can decrease survival, reduce fecundity, and cause health problems in cetaceans. The injuries can range from skin abrasions to amputations depending on the species and fishing method. When a cetacean is entangled in shipping gear, it uses more energy to swim, struggles to feed or avoid predation, and becomes more susceptible to diseases. Fishing activities indirectly threaten cetacean populations by reducing the availability and changing the diversity of prey as well as degrading cetacean habitats. Prey depletion causes serious health problems since it limits nutrition. At least 13 Odontoceti species are struggling to cope with the depletion of food resources due to overfishing (Smith et al. 2003). Some fishing methods such as bottom trawling cause significant habitat degradation. Bottom trawling destabilizes marine benthos by resuspending and dispersing basal resources resulting in loss of food benthic organisms which have cascading effects to plankton and fish which are preyed by cetaceans. Cetaceans often avoid aquaculture areas because of the structures, equipment, high traffic, and deteriorated water quality (Watson-Capps and Mann 2005). Depending on the location of the structure, aquaculture can result in fragmentation of cetacean populations which can have drastic impacts on cetacean productivity. Aquaculture can also cause the depletion of plankton and discharge organic pollutants such as antibiotics. Hence, sustainable fishery activities are essential for cetacean conservation and management.

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Noise Pollution Cetaceans evolved to depend on sound as the main mechanism for communicating, navigating, foraging, and perceiving the environment. However, anthropogenic activities such as whalewatching, ship traffic, seismic survey air guns, and navy sonar disrupt the acoustics of the marine ecosystem (Parsons et al. 2008). Noise pollution can directly affect cetacean health by impeding hearing which has negative cascading effects on their socio-ecological interactions such as predation, reproduction, and migration (Nabi et al. 2018). Behavioral responses of cetaceans to noise vary from changes to breathing patterns, to ceasing vocalization, to deserting or avoiding the noisy areas (National Research Council 2003). The behavioral changes vary depending on internal and external factors, as shown in Fig. 2. Mass stranding of beaked whales was linked spatially and temporally to the usage of multiple highenergy, mid-range (1–10 kHz) sonars for activities such as military exercise (National Research Council 2003). Large ships emit low-frequency (0.02–0.2 kHz) noise which overlaps with the acoustic signals used by baleen whales to communicate. An increase in exposure to large ship noise was shown to increase fecal levels of glucocorticoids in Eubalaena glacialis (Rolland et al. 2012). However, studies mechanistically linking noise pollution and acoustic trauma are lacking. Infectious Diseases Cetaceans host diverse groups of pathogenic microorganisms such as bacteria and viruses. The main transmission routes for pathogens are dietary intake, dermal entry sometimes through skin injuries, and inhalation. In addition, transplacental infection of the respiratory system has been demonstrated in bottlenose dolphins (Fauquier et al. 2009). In sperm whales, a stranded neonate with cerebrum congestion and inflamed lymph nodes tested positive to Brucella sp. and morbillivirus in these tissues (West et al. 2015). The results suggested vertical transmission of the two pathogens in utero contributed to the pathology observed in the neonate. Table 4 shows the major pathogens that have been identified in cetaceans. Pathogens are sometimes specific to an order,

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Cetacean Health: Global Environmental Threats, Fig. 2 Factors influencing the behavioral response of cetaceans to noise pollution. (Adapted from National Research Council (2003). Used with permission of National Academies Press)

family, or species, for example, morbillivirus, poxvirus, and papillomavirus (West et al. 2015). Morbilliviruses, papillomaviruses, Toxoplasma gondii, and Brucella sp. have been linked to mass cetacean stranding, reduced reproduction, and increased virulence of other diseases (Van Bressem et al. 2009). However, other pathogens such as bacteria, fungi, and protozoa are opportunistic, which means they do not usually cause harm to the host unless the host has a compromised immune system. Understanding the prevalence of diseases in cetacean populations is important for conservation purposes. Current data on infectious diseases in cetaceans is often obtained through pathological studies on stranded animals or noninvasive analysis of scat, earwax, and exhaled breath. The host-pathogen balance in cetaceans is often affected by environmental stressors and the spatial configuration of the habitat.

Environmental stressors increase morbidity by promoting pathogen emergence, proliferation, and transmission as well as suppressing immunity. In addition, the dynamics of infectious diseases in wildlife habitats are often influenced by spatial and temporal heterogeneity (Parratt et al. 2016). Cetacean population density, connectivity, and migratory patterns influence the probability of the cetacean to encounter a pathogen. Hence, the spatial configuration of cetaceans can influence disease dynamics in the environment (Parratt et al. 2016). For example, in clustered populations, cetaceans can be infected through localized transmission. Pathogens face abiotic and biotic stress from local environmental conditions and predators, respectively. These stressors help to maintain the host-pathogen equilibrium. However, following fragmentation of the host population due to habitat loss, the pathogen stressors can be reduced, resulting in an increase

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Cetacean Health: Global Environmental Threats, Table 4 Examples of infectious diseases affecting cetaceans globally Pathogen Virus

Cetacean morbillivirus

Health effects A systemic infection is marked by lymphoid depletion, bronchointerstitial pneumonia, and nonsuppurative encephalitis

Herpesvirus

The health effects of herpes viruses are not well understood

Poxviruses

Chordopoxvirinae cause tattoo skin diseases that can last for years

Papillomaviruses

Papillomaviruses cause genital lesions and sometimes invasive carcinomas

Protozoa

Toxoplasma gondii

Bacteria

Brucella spp.

T. gondii is a parasitic protozoon that infects cetaceans. It may cause nonsuppurative encephalitis, abortion, or potentially lethal systemic diseases B. ceti is linked to skin diseases (e.g., lesions and abscesses), reproductive organ lesions, placentitis, abortions, pneumonia, meningitis, and necrosis

Erysipelothrix rhusiopathiae

E. rhusiopathiae causes dermatologic and septicemic erysipelas in cetaceans

pathogen load. Furthermore, habitat fragmentation together with chemical pollution can cause changes in pathogen community structure, composition, niches, and behavior which may increase transmission (Parratt et al. 2016).

Comments Mainly affects free-ranging cetaceans and has caused numerous global outbreaks among bottlenose dolphins, striped dolphins, and pilot whales Alphaherpes viruses are linked to proliferative dermatitis lesions and nonsuppurative encephalitis in bottlenose dolphins and nephritis in Blainville’s beaked whale Tattoo skin diseases may be lethal in neonates and calves but not in adult cetaceans. However, co-infection with other pathogens can result in systemic diseases and even death Genital warts caused by papillomaviruses are three times more prevalent in males than females, probably due to behavioral and hormonal differences. When severe, genital warts may negatively affect copulation T. gondii infects free-ranging cetaceans and has also been detected in pelagic cetaceans such as sperm whales and fin whales

Brucella spp. is transmitted through contact with infected materials such as aborted fetuses. It occurs primarily through ingestion but can occur through dermal contact or inhalation. Mother-child occurs during breeding and lactation They may cause little pathological changes but can lead to morbidity and mortality in cetaceans that have a compromised immune system or when the viral load is high

Reference Mazzariol et al. (2018))

C Mazzariol et al. (2018)

Van Bressem and Raga (2011)

Van Bressem and Raga (2011)

Mazzariol et al. (2018)

Nymo et al. (2011)

Mazzariol et al. (2018)

Conclusions and Future Directions Data on the impact of environmental stressors on cetacean health is critical for crafting conservation and management strategies. However, data on

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cetacean health remain scarce because of (i) ethical and legal restrictions in sampling threatened and near-threatened cetaceans; (ii) the diversity in cetacean physiology, life history, and behaviors; and (iii) multiplicity and distinctive modes of action of the environmental stressors cetaceans are exposed to in time and space. These limitations affect environmental monitoring programs that could offer risk assessment data and epidemiological data that could help predict population responses to stressors. Several noninvasive sampling techniques have been developed for determining the exposure or effects of environmental stressors. Examples of such techniques include scat, breathe, earwax, and sometimes biopsy sampling sample analysis. These samples can undergo chemical analysis to determine the accumulation of chemical contaminants or microplastics. With the development of high-resolution mass spectrometers, biotransformation products and a wide array of known and unknown contaminants can be determined using targeted and nontargeted screening (Cossaboon et al. 2019). Regular chemical and microplastics analysis can provide the “dose” data imperative for determining the risk posed by pollutants. The effects of these pollutants can be determined using cell cultures or biochemical analysis. Immobilized cell cultures are currently being used as models of chemical exposure in marine mammalian toxicity studies (Yajing et al. 2018; Huang et al. 2020). In recent years, the impact of environmental stressors has been assessed by determining the levels of stress and reproductive hormones in cetacean blood or blubber. However, extrapolating the data from biochemical analysis and cell culture to cetacean populations remains challenging due to their physiological complexity. Marine mammal protection areas have gained popularity as a conservation strategy. However, research on the role of protected areas in protecting cetacean health is still growing. Cetacean populations are under constant threat from various anthropogenic activities such as fishing, ocean sprawl, ship traffic, climate change, marine pollution, and military exercises. Environmental changes are altering marine habitats and availability of prey. Cetaceans respond to these

Cetacean Health: Global Environmental Threats

changes by shifting their feeding, breeding, and migratory behaviors which sometimes comes at a cost to their energetics. In addition, environmental changes have left cetaceans susceptible to infectious diseases. For example, chemical and noise pollution can compromise the cetacean immune system. Mass stranding linked to various environmental stressors has been reported globally. Overall, with the rapid urbanization and industrialization, there is a need for the development of comprehensive strategies to minimize or eliminate the environmental threats faced by cetaceans. Such an approach requires regular health assessment, and this can be achieved using noninvasive approaches. Overall, attaining SDG 14 could minimize anthropogenic threats to cetaceans.

Cross-References ▶ Marine Animals and Human Care Toward Effective Conservation of the Marine Environment ▶ Marine Ecosystems ▶ Stranding of Marine Animals: Effects of Environmental Variables

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119 Nabi G, McLaughlin RW, Hao Y et al (2018) The possible effects of anthropogenic acoustic pollution on marine mammals’ reproduction: an emerging threat to animal extinction. Environ Sci Pollut Res 25:19338–19345. https://doi.org/10.1007/s11356-018-2208-7 National Research Council (2003) Ocean noise and marine mammals. National Academies Press, Washington, DC Nowacek DP, Thorne LH, Johnston DW, Tyack PL (2007) Responses of cetaceans to anthropogenic noise. Mamm Rev 37:81–115. https://doi.org/10.1111/j.1365-2907. 2007.00104.x Nymo IH, Tryland M, Godfroid J (2011) A review of Brucella infection in marine mammals, with special emphasis on Brucella pinnipedialis in the hooded seal (Cystophora cristata). Vet Res 42:93. https://doi.org/ 10.1186/1297-9716-42-93 Parratt SR, Numminen E, Laine A-L (2016) Infectious disease dynamics in heterogeneous landscapes. Annu Rev Ecol Evol Syst 47:283–306. https://doi.org/10. 1146/annurev-ecolsys-121415-032321 Parsons ECM, Dolman SJ, Wright AJ et al (2008) Navy sonar and cetaceans: just how much does the gun need to smoke before we act? Mar Pollut Bull 56:1248– 1257. https://doi.org/10.1016/j.marpolbul.2008.04.025 Pasamontes A, Aksenov AA, Schivo M et al (2017) Noninvasive respiratory metabolite analysis associated with clinical disease in cetaceans: a Deepwater Horizon oil spill study. Environ Sci Technol 51:5737–5746. https:// doi.org/10.1021/acs.est.6b06482 Rajput IR, Xiao Z, Yajing S et al (2018) Establishment of pantropic spotted dolphin (Stenella attenuata) fibroblast cell line and potential influence of polybrominated diphenyl ethers (PBDEs) on cytokines response. Aquat Toxicol 203:1–9. https://doi.org/10.1016/j.aquatox. 2018.07.017 Rolland RM, Parks SE, Hunt KE et al (2012) Evidence that ship noise increases stress in right whales. Proc R Soc B Biol Sci 279:2363–2368. https://doi.org/10.1098/rspb. 2011.2429 Roman J, McCarthy JJ (2010) The whale pump: marine mammals enhance primary productivity in a coastal basin. PLoS One 5:e13255. https://doi.org/10.1371/ journal.pone.0013255 Roman J, Nevins J, Altabet M et al (2016) Endangered right whales enhance primary productivity in the Bay of Fundy. PLoS One 11:e0156553. https://doi.org/10. 1371/journal.pone.0156553 Sanganyado E, Rajput IR, Liu W (2018) Bioaccumulation of organic pollutants in Indo-Pacific humpback dolphin: a review on current knowledge and future prospects. Environ Pollut 237:111–125. https://doi.org/10. 1016/j.envpol.2018.01.055 Sanganyado E, Bi R, Teta C et al (2020) Toward an integrated framework for assessing micropollutants in marine mammals: challenges, progress, and opportunities. Crit Rev Environ Sci Technol 20:1–48. https://doi. org/10.1080/10643389.2020.1806663 Schwacke LH, Zolman ES, Balmer BC et al (2012) Anaemia, hypothyroidism and immune suppression

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120 associated with polychlorinated biphenyl exposure in bottlenose dolphins (Tursiops truncatus). Proc R Soc B Biol Sci 279:48–57. https://doi.org/10.1098/rspb.2011. 0665 Shi J, Sanganyado E, Wang L et al (2020) Organic pollutants in sedimentary microplastics from eastern Guangdong: spatial distribution and source identification. Ecotoxicol Environ Saf 193:110356. https://doi.org/ 10.1016/j.ecoenv.2020.110356 Simmonds MP (2017) Evaluating the welfare implications of climate change for cetaceans. In: Butterworth A (ed) Marine mammal welfare: human induced change in the marine environment and its impacts on marine mammal welfare. Springer, Cham, pp 125–135 Simmonds MP (2018) Marine mammals and multiple stressors. In: Marine mammal ecotoxicology. Elsevier, Oxford, UK, pp 459–470 Simmonds MP, Eliott WJ (2009) Climate change and cetaceans: concerns and recent developments. J Mar Biol Assoc UK 89:203–210. https://doi.org/10.1017/ S0025315408003196 Smith BD, Crespo EA, Notarbartolo di Sciara G (2003) Dolphins, whales and porpoises: 2002–2010 conservation action plan for the world’s cetaceans. https:// portals.iucn.org/library/sites/library/files/documents/ 2003-009.pdf Stephen C (2014) Toward a modernized definition of wildlife health. J Wildl Dis 50:427–430. https://doi.org/10. 7589/2013-11-305 Suzuki M, Yoshioka M, Ohno Y, Akune Y (2018) Plasma metabolomic analysis in mature female common bottlenose dolphins: profiling the characteristics of metabolites after overnight fasting by comparison with data in beagle dogs. Sci Rep 8:12030. https://doi. org/10.1038/s41598-018-30563-x Trego ML, Hoh E, Kellar NM et al (2018) Comprehensive screening links halogenated organic compounds with testosterone levels in male Delphinus delphis from the Southern California Bight. Environ Sci Technol 52: 3101–3109. https://doi.org/10.1021/acs.est.7b04652 Trego ML, Whitehead A, Kellar NM et al (2020) Tracking transcriptomic responses to endogenous and exogenous variation in cetaceans in the Southern California Bight. Conserv Physiol 7:coz018. https://doi.org/10.1093/ conphys/coz018 Tubbs CW, McDonough CE (2018) Reproductive impacts of endocrine-disrupting chemicals on wildlife species: implications for conservation of endangered species. Annu Rev Anim Biosci 6:287–304. https://doi.org/10. 1146/annurev-animal-030117-014547 Van Blaricom GR, Gerber LR, Brownell RL (2013) Marine mammals, extinctions of. In: Encyclopedia of biodiversity. Elsevier, London, pp 64–93 Van Bressem MF, Raga JA (2011) Viruses of cetaceans. Stud Viral Ecol Anim Host Syst 2:309–332. https://doi. org/10.1002/9781118025710.ch12 Van Bressem M-F, Raga JA, Di Guardo G et al (2009) Emerging infectious diseases in cetaceans worldwide and the possible role of environmental stressors. Dis

Cetacean Populations Aquat Org 86:143–157. https://doi.org/10.3354/ dao02101 Watson-Capps JJ, Mann J (2005) The effects of aquaculture on bottlenose dolphin (Tursiops sp.) ranging in Shark Bay, Western Australia. Biol Conserv 124:519– 526. https://doi.org/10.1016/j.biocon.2005.03.001 West KL, Levine G, Jacob J et al (2015) Coinfection and vertical transmission of Brucella and Morbillivirus in a neonatal sperm whale (Physeter macrocephalus) in Hawaii, USA. J Wildl Dis 51:227–232. https://doi. org/10.7589/2014-04-092 Yajing S, Rajput IR, Ying H et al (2018) Establishment and characterization of pygmy killer whale (Feresa attenuata) dermal fibroblast cell line. PLoS One 13: e0195128. https://doi.org/10.1371/journal.pone. 0195128 Yu X, He Q, Sanganyado E et al (2020) Chlorinated organic contaminants in fish from the South China Sea: assessing risk to Indo-Pacific humpback dolphin. Environ Pollut 263:114346. https://doi.org/10.1016/j. envpol.2020.114346

Cetacean Populations ▶ Cetacean Threats

Health:

Global

Environmental

Climate Change ▶ Jellyfish, Global Changes, and Marine Ecosystem Services

Climate Hazards ▶ Impacts of COVID-19 Pandemic on Marine Resources and Livelihoods

Climate Risks ▶ Impacts of COVID-19 Pandemic on Marine Resources and Livelihoods

CO2-Induced Ocean Acidification

CO2-Induced Ocean Acidification Ana M. Faria MARE – Marine and Environmental Sciences Centre, ISPA – Instituto Universitário, Lisbon, Portugal

Synonyms Elevated pCO2; Low pH

Definition The ocean is the largest natural reservoir of dissolved carbon, with an immense buffering capacity for changes in atmospheric carbon dioxide (CO2) concentrations and to regulate Earth’s surface temperature. However, the increasing atmospheric CO2 concentrations, caused mainly by anthropogenic emissions derived from fossil fuel burning, deforestation, and other human activities, have caused the ocean to absorb increasingly greater amounts of CO2, thus altering the ocean carbon chemistry through a process that became known as ocean acidification (Caldeira and Wickett 2003). The increased amounts of CO2 gas emitted into the atmosphere increase the partial pressure of CO2 (pCO2) in ocean surface waters, leading to increased dissolved inorganic carbon (DIC) and hydrogen ion (H+) concentrations (lower pH, more acidic) and other changes in chemical properties of seawater (e.g., reduced carbonate ion [CO32] concentrations).

Introduction Since the beginning of the Industrial Revolution, ocean surface waters took ~25% of the carbon generated by human activities, leading to a decrease of the surface-ocean total pH from 8.2 to 8.1 and an increase in atmospheric CO2 concentrations from 278 to 400 parts per million

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(ppm). If CO2 emissions continue as they stand, surface-ocean pH could fall by further ~0.3 units by the end of the twenty-first century, and atmospheric CO2 concentrations may reach 1000 ppm (Orr 2011). However, the actual magnitude of pH change will vary locally, and it will also depend on future CO2 emissions along the century. The Intergovernmental Panel on Climate Change (IPCC), established in 1988 by the World Meteorological Organization and United Nations Environment Programme, provides climate projections representative of a range of pathways, scenarios, or targets that reflect the relationship between gas emissions and our ability to reduce emissions. On its last Assessment Report (AR5), IPCC presents a series of Representative Concentration Pathways (RCPs), which are summarized as follows (IPCC 2013): RCP 2.6

RCP 4.5 RCP 6.0 RCP 8.5

Lowest emissions; atmospheric CO2 peaks at ~443 ppm in 2050, declining to ~421 ppm by 2100. Assumes active CO2 removal from the atmosphere Low emissions; atmospheric CO2 concentrations reach ~538 ppm by 2100 Moderate emissions; atmospheric CO2 concentrations reach ~670 ppm by 2100 High emissions; atmospheric CO2 concentrations reach ~936 ppm by 2100. Current emissions trend if no significant mitigation actions are taken (“business as usual”)

These scenarios are important scientific tools for predicting the influence of anthropogenic emissions on climate while reflecting the uncertainty inherent to the human influence on climate. Apart from models used to forecast climate change, the geological record also increments our knowledge about the impacts of ocean acidification upon marine life. During the PaleoceneEocene Thermal Maximum (~56 Myr ago) – the closest geological analogue to modern-day ocean acidification due to the volume of carbon

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released – global temperatures increased by about 5
C (McInerney and Wing 2011), while oceanic pH decreased (Zachos et al. 2005). Still, the overall rate of change in CO2 was much lower than the current increase in atmospheric CO2 (0.6–1.1 vs. 10 gigatons of carbon per year). Therefore, geological derived data can be compared with modern research data, but comparisons should be made cautiously as the climatic conditions preceding previous geological events were distinct (Zeebe and Ridgwell 2011). Undoubtedly, the greatest difference between past geological events with the Anthropocene is the rate at which the human-induced carbon perturbation occurs. The magnitude of ocean acidification fluctuates seasonally (Kwiatkowski and Orr 2018) and differs across latitudes and differs from oceanic and coastal areas, as also demonstrated by the geological record. pH and associated chemistry changes vary greatly in coastal sites than in the open ocean, mostly due to the influence of additional drivers other than atmospheric CO2, such as freshwater input (Salisbury et al. 2008), eutrophication (Cai et al. 2011), and upwelling events (Feely et al. 2008). These dynamic conditions may suggest that coastal waters organisms are adapted to tolerate low pH and will, therefore, be less susceptible to ocean acidification than those from the open ocean. However, it could also mean that these species are experiencing harmful pH thresholds. Moreover, ocean carbon chemistry is also expected to change with latitude, largely because CO2 becomes more soluble as water temperature declines. Thus, cold, high-latitude surface waters can retain more CO2 than warmer low-latitude surface waters (Barry et al. 2011). As carbonate minerals also dissolve faster in colder waters, high-latitude oceans are expected to become undersaturated first with respect to calcium carbonate (CaCO3) (Orr et al. 2005). All these changes in the carbonate chemistry will likely compromise the physiological processes of marine organisms (e.g., metabolism, calcification, photosynthesis, pH regulation) and consequently modify their population dynamics and, ultimately, the entire community structure (Nagelkerken and Connell 2015).

CO2-Induced Ocean Acidification

Ocean Acidification as a Global Threat to Marine Organisms Ocean acidification may affect biological processes through two main mechanisms. First, the extra-cellular pH of body fluids and the intracellular pH of various organs or unicellular organisms are usually tightly regulated, with many intracellular enzymes that control cellular physiology being pH-sensitive and displaying a pH optimum around the physiological range. Exposure to high CO2 can disrupt the acid-base status of many marine animals, leading to reduced respiratory efficiency, reduced enzyme activity, and metabolic depression, with potentially large effects on overall metabolic performance (Pörtner et al. 2011). Organisms can show compensatory mechanisms, but acid-base regulation is an energetic process, and a disruption caused by changing external CO2 levels will require energy to maintain aspects of extra- or intracellular balance. Studies on invertebrates and fish physiology showed that organisms require additional energy to maintain the acid-base balance at high pCO2. Thus, if a constant total energy budget is assumed, then increasing energetic investment into acidbase regulation may induce tradeoffs or impair basic life processes (Heuer and Grosell 2014). Other direct effects of ocean acidification could occur when one or several reactants in a key physiological process are carbon species, as during calcification and photosynthesis. For example, carbon dioxide (CO2) and bicarbonate (HCO3) are used in photosynthesis, while carbonate (CO32) is essential for building shells and skeletons. Hence, ocean acidification can stimulate primary production since the concentrations of both CO2 and HCO3 are larger at lower pH, but it may decrease calcification (Riebesell and Tortell 2011), suggesting that highly calciumcarbonate-dependent ecosystems (e.g., coral reefs, oyster, and mussel beds) are particularly vulnerable. This is the main reason why seminal research focused on calcifying invertebrates. Nowadays, the rapidly expanding body of research reveals consistent reductions in calcification, growth, and development of a range of calcified marine species (Kroeker et al. 2013). Coral

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reefs, calcifying algae, and polychaete structures habitats are deemed relevant to study due to their high biodiversity while providing coastal protection. Coral reefs are the best studied ecosystem and provide some of the best-known examples of calcareous structures. Ocean acidification not only hinders the process of calcification but also promotes its dissolution (Eyre et al. 2018). As calcium carbonate levels drop, existing coral structures dissolve. These include the living corals, but also the sediment platforms they build on top of, which is the bulk of the reefs. Surprisingly, some reefs are already experiencing this sediment dissolution, such as in Hawaii. In addition to coral reefs, shelled mollusks (bivalves and gastropods) have been studied extensively. These organisms also have an intrinsic economic value as a fishery, and they provide essential ecosystem services, including the formation of habitat structure for benthic organisms (e.g., mussel and oyster beds), water purification, and a food source for other organisms. The impacts of ocean acidification on these taxa are highly variable and species-specific and hinder any possible conclusion (Gazeau et al. 2013). However, while detrimental effects on adults remain uncertain, the most sensitive life-history stage seems to be the larvae (Kroeker et al. 2013). Disruption of physiological processes and altered mineral kinetics, associated with low carbonate saturation states and low pH in high CO2 waters, hinders the ability of pelagic larvae to normally develop shells and increases dissolution-induced mortality during the early settlement phase (Waldbusser et al. 2015). Crustaceans appear less sensitive to smaller increases in CO2 than other calcifiers (Kroeker et al. 2013; Wittman and Pörtner 2013), potentially because of their pH regulation abilities, less soluble form of calcium carbonate (CaCO3), and biological control of the calcification process. However, increase calcification may occur under reduced pH conditions. The metabolic investment in increased calcification may impact other physiological processes leading to reduced growth and increased mortality (Ries et al. 2009). The impacts of ocean acidification on echinoderms, and on sea urchins in particular, have also

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been widely addressed. Impacts on sea urchin’s fitness are neutral or negative and may include increased mortality, decreased fecundity or reduced fertilization success, and sublethal decreased growth rate. Additionally, the impact differs along sea urchin’s life cycle. Adults and gametes have higher resilience to ocean acidification than embryos, larvae, and juveniles (Dupont and Thorndyke 2014). Fish were considered to be resilient to ocean acidification as they can control internal pH in a high CO2 environment through active ion transport, mostly across the gills (Brauner and Baker 2009). This tight regulation of acid-base balance maintains the pH required for efficient cellular function in a high CO2 environment, but it may demand more energy. This balance is especially costly for early life stages due to the poor developed acid-base balance mechanisms, thus becoming the most studied life stage. The exposure to high CO2 levels influences calcification, behavior, and ion transport. Calcification in fish affects the formation and growth of otoliths, which are calcified structures located in the fish inner ear and responsible for sensing gravity, balance, linear acceleration, and sound. Low environmental pH increases otolith growth rate in some species (Checkley et al. 2009), thus compromising hearing and balance. Remarkably, changes in the concentrations of acid-base-relevant ions at higher CO2 levels may impair the function of GABA-A receptors, a major inhibitory neurotransmitter, which is probably responsible for a range of behavioral changes (Nilsson et al. 2012). These changes include impaired learning ability, sensory functions, or decision-making (such as lateralization – preference for left or right side), as well as disrupted anti-predator responses, boldness, and homing behavior (Heuer and Grosell 2014; Clements and Hunt 2015). The GABA-A receptor is an ion channel with conductance for chloride (Cl) and bicarbonate (HCO3), two ions involved on fish acid-base regulation. Given the ubiquity of GABA-A receptors in marine organisms, it is likely that elevated CO2 levels could cause behavioral abnormalities across marine taxa. Ultimately, behavioral and sensory changes may affect predator-prey interactions, dispersal, settlement,

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and habitat choice, with cascading implications at the community level (Nagelkerken and Munday 2016). Despite these evidence, other studies reported no effect of high CO2 levels on fish, thus suggesting a highly variable response to ocean acidification, as observed for almost every taxon. A few studies investigated cephalopod responses to ocean acidification. Cephalopods have a complex homeostatic machinery, and high CO2 may impair oxygen transport because hemocyanin – the respiratory pigment – is very sensitive to CO2 so blood oxygen transport can be easily disturbed to reduce activity (Pörtner 1994; Pörtner et al. 2004). For example, the Pacific jumbo squid Dosidicus gigas showed significant reduction of metabolic rates and activity under 1000 matm of CO2 (Rosa and Seibel 2008). Ocean acidification may also induce changes on statoliths, which are vital for balance and detecting movement (Kaplan et al. 2013). Also, the calcification rate of cuttlefish embryos and juveniles’ cuttlebone increased under high CO2 levels (Dorey et al. 2012). Moving on to holoplankton, the base of the food web. These organisms spend their whole life in the water column and are key components of marine food webs at several levels and of biogeochemical processes. Calcified and noncalcified holoplankton include bacterioplankton, protistoplankton (autotrophic – phytoplankton, mixotrophic and heterotrophic protists), and zooplankton. Some planktonic bacteria are photosynthetic, so they may be considered as phytoplankton, but most are heterotrophic, consuming organic matter. Therefore, bacteria intervene in the nutrient cycling at multiple levels. The response of bacteria to ocean acidification is understudied compared to the calcifying plankton. Bacteria colonize and degrade dead organisms so functioning as the ocean’s wastewater treatment plants. Simultaneously, bacteria release nutrients that are essential to the lower levels of the food web, such as nitrogen and phosphorus. Thus, acidification-induced changes at the community level will preclude that nutrient cycling within and between benthic and pelagic compartment will change (Riebesell and Tortell 2011).

CO2-Induced Ocean Acidification

Phytoplankton (e.g., cyanobacteria, coccolithophores, diatoms, autotrophic dinoflagellates) are the primary producers of most marine ecosystems. Ocean acidification may affect phytoplankton because CO2 is the substrate for photosynthesis and, like other substrates needed for growth, CO2 can limit photosynthetic rates if it is scarce. Also, ocean acidification and the inherent reduction in CO3 can affect the ability of calcified phytoplankton to build and maintain their carbonate-based structures (Riebesell and Tortell 2011). However, real impacts are difficult to predict because some species use carbon concentrating mechanisms to compensate for low CO2 availability and require variable energy investments. Carbon concentrating mechanisms induce carbon saturation in cells even when ambient CO2 levels are low (Mackey et al. 2015). It is therefore difficult to predict whether a cell’s photosynthetic rate will remain constant, increase due to higher substrate availability and/or less energy expenditure, or decrease due to adverse effects of lower pH. Photosynthetic responses to increased CO2 are diverse and vary between and within taxonomic groups and within phenotypes of the same species. However, there are no clear trends about the photosynthetic responses to elevated CO2 (Riebesell and Tortell 2011). Future research should encompass a broader suite of measurements to demonstrate how different physiological processes, other than photosynthesis, respond to ocean acidification. Zooplankton are a major food source for planktivorous animals, and they also support bacterial and phytoplankton production through their excretion of nitrogen and phosphorus compounds. Furthermore, the sedimentation and burial of fecal pellets and zooplankton carcasses act as a sink for CO2 that may mitigate CO2 emissions. Most studies focused on single-species laboratory experiments, as on pteropods and foraminifera that produce CaCO3 shells. Severe direct effects on some calcifying zooplankton were attributed to the increased energy requirements to acquire carbonate ions as building blocks for calcification (Riebesell and Tortell 2011). In contrast, non-calcifying zooplankton (e.g., copepods) are generally not directly affected by ocean acidification (Riebesell and Tortell 2011). However,

CO2-Induced Ocean Acidification

single-species studies provide little information on a broader scale given zooplankton’s pivotal role in marine ecosystems and the carbon cycle. Therefore, studies addressing impacts at the population and community levels are needed. In summary, it seems that species response to ocean acidification is more variable than anticipated. A part of the variability observed between studies investigating similar processes or life stages is likely due to distinct experimental designs, or intrinsic inter-population differences, or dependent on previous exposure (i.e., carryover effects). Understanding whether the remaining variation within taxonomic groups and life stages represents real biological differences among species, locally adapted populations, or acclimation capacities, or experimental error remains a critical area for future research.

Ocean Acidification as a Global Concern For many years, ocean acidification stood in the shadow of global warming and was known as “the other CO2 problem” (Doney et al. 2009). The first time many policy advisers became aware of ocean acidification was in 2005 when the Royal Society published a policy document entitled “Ocean acidification due to increasing atmospheric carbon dioxide.” This document recognized that ocean acidification is a significant threat to many calcifying organisms that would alter food chains and other ecosystem processes and lead to a reduction of biodiversity in the oceans. Since then, research in ocean acidification has increased exponentially and is currently among the top 3 global ocean research priorities (Rudd 2014). Several other policy-related publications attracted significant attention, of which stands the IPCC 4th Assessment Report on Climate Change published in 2007. Here, the IPCC recognizes the immediate and future threat of ocean acidification on ocean ecosystems. In 2009, the Monaco Declaration, which resulted from the Second Symposium on the Ocean in a High-CO2 World and endorsed by HSH Prince Albert II of Monaco, was signed by 155 scientists from 26 countries. This declaration called upon

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policymakers to support initiatives in multidisciplinary research, communication, and policy action. In 2012, at the United Nations Conference on Sustainable Development “Rio + 20” (Rio de Janeiro, June 2012), stakeholders, including United Nations bodies, intergovernmental organizations, and national governments, were urged to make commitments on delivering concrete results for sustainable development on a voluntary basis. There was substantial stakeholder input on ocean acidification resulting in a specific ocean acidification statement (number 166) in the Conference’s outcome document “The Future We Want.” One of the main outcomes of the Rio + 20 Conference was the agreement by Member States to launch a transparent intergovernmental process to develop a set of Sustainable Development Goals to be agreed by the General Assembly at its 68th session (2013–2014). The progress report of the Open Working Group of the UN General Assembly includes mention of ocean acidification, but this was a non-binding document. In September 2015, the UN General Assembly adopted the 2030 Agenda for Sustainable Development, and on 1 January 2016, the 17 Sustainable Development Goals of the 2030 Agenda officially came into force. Goal 14 – Life Below Water – aims at the conservation and sustainable use of the oceans, seas, and marine resources, and one of its targets is to minimize and address the impacts of ocean acidification, including through enhanced scientific cooperation at all levels. Several projects, both at the national and international level, have backed up these reports and goals. The first large-scale, multi-national project on ocean acidification was the European Commission’s “European Project on Ocean acidification” (EPOCA), in 2008–2012, which brought together more than 160 scientists from 32 countries to address scientific uncertainties on ocean acidification, including biogeochemical modelling, biological effects, and implications for marine biodiversity. A notable output was the publication of the book Ocean Acidification (Gattuso and Hansson 2011). A second EC project on ocean acidification was the MedSeA, which ran from 2011 to 2014, focused on its links to climate change in the Mediterranean Sea. In 2012, another

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initiative to enhance international science collaboration was established, the Global Ocean Acidification Observing Network. This initiative uses a network of hydrographic surveys, time-series stations, and volunteer observing ships which provide a strong foundation of observations of the carbonate chemistry throughout the world and of putative ecological changes. The work of Global Ocean Acidification Observing Network is guided by three high-level goals: (1) improve our understanding of global ocean acidification conditions; (2) increase our knowledge of ecosystem response to ocean acidification; and (3) acquire and exchange the data and information necessary to optimize the modelling of ocean acidification and its impacts. Other projects at the national level have included the German program Biological Impacts of Ocean acidification (BIOACID) that started in 2009 and ended in 2017; the US research support via NSF and NOAA and mandated by the 2009 Federal Ocean Acidification Research and Monitoring (FOARAM); the UK Ocean Acidification Research Programme (UK OCEAN ACIDIFICATION) that began in 2010; and other programs and projects in Australia, China, Japan, South Korea, Norway, and throughout the world. All these policy reports and national and international projects represent the public recognition of ocean acidification as a global threat to marine ecosystems and their impact on various economic sectors (e.g., fisheries, aquaculture, tourism) (Cooley and Doney 2009) and therefore in various coastal populations. Describing and quantifying the plausible consequences of ocean acidification on the society is still a challenge. Consequences will rely on the interactions within and between species, the resilience of ecosystems, and on the interaction of ocean acidification with other ocean stressors (Bopp et al. 2013). Additionally, it is difficult to put a monetary value on the wealth of marine ecosystem goods and services since many have an intangible value. Risks to economy and society may include disturbances to seafood resources and the deterioration of habitats, both of which could lead to losses to the fishing and tourism industry, decreased biodiversity, and threatened food security for populations relying

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to a large extent on seafood as a protein source. Fisheries and seafood industries represent both commercial and recreational interests that contribute an economic value via travel and purchase of permits and equipment. Furthermore, numerous jobs depend on fishery industries, from fishermen to affiliated industries such as processing, transportation, preparation, and sales. The existing economic literature on ocean acidification impacts is scarce and only assessed a partial set of the potentially impacted ecosystem services, with a focus on the direct-use values that are most easily addressed. One of the most wellknown case study reflecting a real impact of ocean acidification on seafood industry comes from the oyster hatcheries, off the northwest coast of the United States of America. Due to the naturally low and variable pH of upwelled water off this coast, there is strong evidence that additional acidification due to anthropogenic CO2 already has economic impacts in that region. Oyster hatcheries in Oregon and Washington have increasingly suffered high larval mortalities (up to 80%) since 2006, which threatened the viability of an industry valued around $280 million per year. The variable carbonate chemistry and pH of the hatchery water (due to periodic upwelling events) is a major factor affecting the success of larval production and mid-stage growth cohorts of the Pacific oyster Crassostrea gigas (Barton et al. 2012). The oyster hatcheries adapted their working practices to avoid using upwelled low pH seawater, either by re-circulating facilities seawater or by treating intake water during upwelling events. With these new practices, these oyster hatcheries are producing near to full capacity again.

Knowledge Gaps and Future Directions During the 2010s, laboratory studies have unequivocally shown that a wide range of marine organisms are sensitive to pH changes, affecting their physiology, fitness, and survival mostly, but not always, in a negative way. These studies have the advantage of isolating individual variables under controlled conditions, thus facilitating the interpretation of cause and effect. However, such

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studies only grasp the full extent of ocean acidification impacts. So, there are still knowledge gaps that are urgent to address by the scientific community. Ocean acidification won’t be the single stressor affecting marine organisms, since other stressor will act in tandem, as increasing temperature and deoxygenation. The biological effects of multiple stressors cannot be assumed to be additive. Indeed, impact may be amplified through synergism or diminished through antagonism effects. Therefore, research on the concurrent effects of ocean acidification and other stressors is still necessary to forecast the status of marine organisms and communities in the near future. The lack of complex manipulation experiments combining two or more stressors is justified by the high complexity involved. These experiments often require high technology to control the stressors. Additionally, there are experimental design challenges, such as replication or number of treatments, which limit more complex approaches. Despite a growing understanding of species’ vulnerabilities, most experimental approaches are on single organisms, failing to capture the true level of complexity of multispecies biological interactions, as predator-prey relationships and resource competition. As of 2018, it remains unclear how the direct effects of ocean acidification on individual species might scale up to impact population dynamics and communities. However, quantifying species interactions will be challenging as interactions will be affected by conditioning time, biotic interactions, and initial community composition. Moreover, perturbation experiments are usually run for short periods of time, lasting between a few hours or weeks. These studies provide valuable insights into the phenotypic responses but limit the potential of populations to adapt to lower ocean pH. So, long-term studies involving multiple generations will allow evaluating adaptive processes. This approach is more promising for organisms with short generation times, such as bacterio- and protistoplankton. All these limitations lower the confidence on the real impacts of ocean acidification on marine organisms, populations, communities,

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and ecosystems. Nevertheless, this “scaling-up” process from individual- to ecosystem-level effects is essential to understand the real effects of ocean acidification. Scientists have already begun to work on innovative approaches to capture longer-term and ecosystem-level effects to provide more realistic predictions of future ecosystem responses deemed more useful for stakeholders. One approach involves the study of benthic communities at natural volcanic CO2 vents, which provide insights on the effects of ocean acidification at the ecosystem level. This approach is a good opportunity to document species-species and species-environment interactions under low pH conditions. These species-environment interactions are relevant to acknowledge, as simple impacts upon key species may have cascading effects through the ecosystem (Hall-Spencer et al. 2008). However, experiments at natural volcanic CO2 vents need to be carefully interpreted as pCO2 and pH levels at these sites vary strongly and often exceed values projected for the next centuries. Also, many of the organisms inhabiting volcanic vents are motile or have a pelagic phase, so it is difficult to distinguish between local individuals and those which only recently colonized the area. Other innovative approach to work at the community level involves mesocosm enclosures (Riebesell et al. 2010). For example, the Free Ocean CO2 Enrichment (FOCE) systems inject CO2-enriched air into experimental units, and it enables overcoming some several drawbacks of laboratory and field studies. These experimental systems enable (1) precise control of CO2 enrichment by monitoring pH as an offset of ambient pH, (2) longer experiments with intact communities, and (3) to account the indirect effects mediated through interspecific relationships and food web structure 3) (Gattuso et al. 2014). These experimental systems are still expensive and logistically difficult to run in the field because it requires a great collaborative effort and an unlimited budget. Certainly, the integration of lab- and fieldbased observations with modelling tools (Murawski et al. 2010) will provide crucial new data and raise new and exciting research topics

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while improving our ability to predict the impact of global changes on marine ecosystems.

Cross-References ▶ Marine Ecosystems

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CO2-Induced Ocean Acidification Ocean acidification and temperature rise: effects on calcification during early development of the cuttlefish Sepia officinalis. Mar Biol 160:2007–2022. https://doi. org/10.1007/s00227-012-2059-6 Dupont S, Thorndyke MS (2014) Direct impacts of nearfuture ocean acidification on sea urchins. In FernándezPalacios JM, de Nascimento L, Hernández JC, Clemente S, González A, Díaz-González JP (eds.) Climate change perspective from the Atlantic: past, present and future, La Laguna, Servicio de Publicaciones, Universidad de La Laguna, pp. 461–485 Eyre BD, Cyronak T, Drupp P, De Carlo EH, Sachs JP, Andersson AJ (2018) Coral reefs will transition to net dissolving before end of century. Science 359:908–911. https://doi.org/10.1126/science.aao1118 Feely RA, Sabine CL, Hernandez-Ayon JM, Ianson D, Hales B (2008) Evidence for upwelling of corrosive “acidified” water onto the continental shelf. Science 320:1490–1492. https://doi.org/10.1126/science.1155676 Gattuso JP, Hansson L (2011) Ocean acidification. Oxford University Press, Oxford Gattuso JP, Kirkwood W, Barry JP, Cox E, Gazeau F, Hansson L, Hendriks I, Kline DI, Mahacek P, Martin S, McElhany P, Peltzer ET, Reeve J, Roberts D, Saderne V, Tait K, Widdicombe S, Brewer PG (2014) Free-ocean CO2 enrichment (FOCE) systems: present status and future developments. Biogeosciences 11:4057–4075. https://doi.org/10. 5194/bg-11-4057-2014 Gazeau F, Parker LM, Comeau S, Gattuso JP, O’Connor W, Martin S, Pörtner H-O, Ross P (2013) Impacts of ocean acidification on marine shelled molluscs. Mar Biol 160:2207–2245. https://doi.org/10.1007/s00227-0132219-3 Hall-Spencer JM, Rodolfo-Metalpa R, Martin S, Ransome E, Fine M et al (2008) Volcanic carbon dioxide vents show ecosystem effects of ocean acidification. Nature 454:96–99. https://doi.org/10.1038/nature 07051 Heuer RM, Grosell M (2014) Physiological impacts of elevated carbon dioxide and ocean acidification on fish. Am J Regul Integr Comp Physiol 307:1061–1084. https://doi.org/10.1152/ajpregu.00064.2014 IPCC (2013) Climate change 2013: the physical science basis. Contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change. Stocker TF, D Qin, GK Plattner, M Tignor, SK Allen, J Boschung, A Nauels, Y Xia, V Bex, PM Midgley (eds.). Cambridge University Press, Cambridge, UK/New York, 1535 pp Kaplan MB, Mooney TA, McCorkle DC, Cohen AL (2013) Adverse effects of ocean acidification on early development of squid (Doryteuthis pealeii). PLoS One 8:e63714. https://doi.org/10.1371/journal.pone.0063714 Kroeker KJ, Kordas RL, Crim RN, Hendriks IE, Ramajo L, Singh GS, Duarte CM (2013) Impacts of ocean acidification on marine organisms: quantifying sensitivities and interactions with warming. Glob Chang Biol 19:1884–1896. https://doi.org/10.1111/gcb.12179

Coastal Defenses and Engineering Works Kwiatkowski L, Orr J (2018) Diverging seasonal extremes for ocean acidification during the twenty-first century. Nat Clim Chang 8:141–145. https://doi.org/10.1038/ s41558-017-0054-0 Mackey KR, Morris JJ, Morel FM, Kranz SA (2015) Response of photosynthesis to ocean acidification. Oceanography 28:74–91. https://doi.org/10.5670/ oceanog.2015.33 McInerney FA, Wing SL (2011) The Paleocene-Eocene thermal maximum: a perturbation of carbon cycle, climate, and biospHere with implications for the future. In: Jeanloz R, Freeman KH (eds) Annual review of earth and planetary sciences, vol 39. Annual Reviews, Palo Alto, pp 489–516 Murawski SA, Steele JH, Taylor P, Fogarty MJ, Sissenwine MP, Ford M, Suchman C (2010) Why compare marine ecosystems? ICES J Mar Sci 67:1–9. https://doi.org/10. 1093/icesjms/fsp221 Nagelkerken I, Connell SD (2015) Global alteration of ocean ecosystem functioning due to increasing human CO2 emissions. Proc Natl Acad Sci USA 112(43):13272–13277. https://doi.org/10.1073/pnas .1510856112 Nagelkerken I, Munday P (2016) Animal behaviour shapes the ecological effects of ocean acidification and warming: moving from individual to community-level responses. Glob Chang Biol 22:974–989. https://doi. org/10.1111/gcb.13167 Nilsson GE, Dixson DL, Domenici P, McCormick MI, Sørensen C, Watson SA, Munday PL (2012) Nearfuture carbon dioxide levels alter fish behaviour by interfering with neurotransmitter function. Nat Clim Chang 2:201–204. https://doi.org/10.1038/nclima te1352 Orr J (2011) Recent and future changes in ocean carbonate chemistry. In: Gattuso JP, Hansson L (eds) Ocean acidification. Oxford University Press, Oxford Orr JC, Fabry VJ, Aumont O, Bopp L, Doney SC et al (2005) Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature 437:681–686. https://doi.org/10.1038/ nature04095 Pörtner H-O (1994) Coordination of metabolism, acid-base regulation and haemocyanin function in cephalopods. Mar Freshw Behav Physiol 25:131–148. https://doi. org/10.1080/10236249409378913 Pörtner H-O, Langenbuch M, Reipschlager A (2004) Biological impact of elevated ocean CO2 concentrations: lessons from animal physiology and earth history. J Oceanogr 60:705–718. https://doi.org/10.1007/ s10872-004-5763-0 Pörtner H-O, Gutowska M, Ishimatsu A, Lucassen M, Melzner F, Seibel B (2011) Effects of ocean acidification on nektonic organisms. In: Gattuso JP, Hansson L (eds) Ocean acidification. Oxford University Press, Oxford Riebesell U, Tortell P (2011) Effects of ocean acidification on pelagic organisms and ecosystems. In: Gattuso JP,

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Coastal Defenses and Engineering Works José S. Antunes do Carmo Department of Civil Engineering, University of Coimbra, Coimbra, Portugal

Synonyms Coastal management guidelines; Coastal processes; Future accommodation; Past and current protections; Public participation in decisionmaking

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Definitions Coastal zones are interface regions between the mainland and the sea that are dominated by (i) processes that originate in the drainage basins of tributaries, (ii) oceanographic and atmospheric processes, and (iii) anthropogenic activities at different orders of magnitude and scales (Aiello et al. 2013; Del Río et al. 2013; Antunes do Carmo 2017). Wind, waves, and currents erode the coast and deposit sediments on a continuous basis. The processes of erosion and deposition vary considerably with differences of time and space. In addition, the energy that reaches the coast can become high during storms, making coastal areas into areas of high vulnerability to natural hazards. Vulnerabilities and risks are controlled (as much as possible) by the construction of coastal defenses (Sterr 2008). Coastal defenses can be designed using hard or soft engineering techniques to minimize or even “eliminate” risks and thus protect local populations, although it is clear that this can be costly and time-consuming (Sterr 2008). Hard or soft defenses differ in terms of design, investment and maintenance costs, short-term efficiency, and environmental consequences. The basic concept of hard engineering, that relies on sea banks, sea walls, groin fields, and breakwaters, is to ensure safety at any cost by fixing or even advancing the shoreline and thus ignoring natural functions (Doody et al. 2004; EUROSION 2004). Such structural measures do not solve medium- and long-term problems, as they merely transfer the risk of erosion to other areas, thus increasing the risk of erosion in those areas and possibly increasing the risk of flooding (Manno et al. 2016). In contrast, soft engineering, such as buffer zones, beaches, and artificial dunes, may be more environmentally sustainable and can provide initial and long-term protection. However, sand nourishments have to be carried out regularly to maintain the coastline or control its retreat (Schipper et al. 2016). This work also aims to encourage coastal managers to implement new management concepts and thus prepare themselves with new protection

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approaches to meet the increased demand for accommodation alternatives in coastal areas.

Introduction As recipient bodies, the oceans and seas receive across their coastal zones the benefits of proper river basin management but also suffer from the harm associated with or resulting from inefficient management processes. In particular, low water quality, sediment extraction, and sediment retention in structures implanted in the fluvial systems are the most evident factors that affect the use, natural resources, and activities that may occur in the coastal zones (Antunes do Carmo 2019). These areas provide a number of ecosystem services or benefits, including coastal protection, fish production, recreation, and other economic and cultural values. In addition, they are abundant reservoirs of biodiversity and ecosystems upon which the functioning of the planet depends. Nevertheless, coastal habitats are facing increasing risks worldwide as a result of human activity. These habitats face the threats of nutrient pollution, resource depletion, and climate change caused primarily by human actions. These threats place further pressure on environmental systems, like biodiversity and natural infrastructure, while creating global socioeconomic problems, including health, safety, and financial risks (SDG Compass 2015). Although the status of the ocean and several of its resources and functions have been deteriorating over the past century, the degradation of ecosystem services may worsen significantly during the first half of this century and is a barrier to achieving the Millennium Development Goals (Millennium Ecosystem Assessment 2005). In fact, most coastal ecosystems are under noticeable stress, compromising the services they provide. Therefore, the need to implement SGD 14 and its seven targets and three means of implementation to transform human behavior toward sustainable practices, exploiting marine resources and taking action to preserve productive and resilient oceans and seas, is increasingly urgent (Schmidt et al. 2017).

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It is in this context that interventions in coastal zones, whether for increasing valuation or for implementing protective measures, should be better designed safeguarding the environment, ecosystem services, and marine resources for sustainable development.

Past Coastal Interventions From a procedural point of view, the implementation of works in the coastal zone until recently followed a very simple procedure. All interventions focused on the project, which was entirely managed by an engineer. The contribution of experts from different disciplinary areas and with different perspectives did not exist or was very limited (Fröhle and Kohlhase 2004). In fact, until the 1980s, the construction of public works in coastal areas essentially followed a procedure that consisted in delegating all responsibility for designing, formulating, and implementing a project to a coastal engineer. As Evans (1992) points out, at that time the coastal/civil engineer was “traditionally involved in the planning, construction, monitoring and maintenance of coastal defence works.” Therefore, the coastal engineer only interacted with the coastal decision-maker. The decision-maker, as well as the owner, generally representing a government entity or a construction/business company, independently contracted and oversaw coastal public works and assumed full responsibility for decisions and coastal work implementation relating to the project and for monitoring its behavior (Kamphuis 2005). Coastal science at that time was essentially physical (hydrodynamics, e.g., waves, storms, currents, tides, etc.). Some coastal public works projects that were executed in this context are noteworthy. Until the 1980s, the entire process was generally carried out in accordance with the procedures outlined above. The interventions were usually based on a structural project and lacked impact studies, environmental concerns, public consultation, and intervention/incorporation of input from local communities and stakeholders. A compilation of several case studies in Europe under these

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guidelines, and the lessons learned from these case studies, are detailed in EUROSION (2004). Seawalls, groins, and jetties are among many coastal works built at that time (Fig. 1). The residential areas shown in Fig. 1 are located on the Western Portuguese coast and are only maintained at the expense of hard engineering projects. Jetties constructed in the 1960s and extended in 2010 have maintained channel access to the Figueira da Foz port for navigation purposes, as shown in Fig. 1b. They have also acted as a barrier to net southerly longshore sediment transport, causing downdrift erosion. This led to the installation of a field of five groins immediately to the south (the downdrift side), which is visible in the lower part of Fig. 1b. After the last of these structures had been constructed, an increase in erosion occurred, which led to a significant retreat of the coastline, the destruction of beach supports, and an increase in the risk of damage to residential buildings, as shown in Fig. 2.

Innovative Solutions In terms of the sustainability of coastal spaces, the ineffectiveness of many of the solutions adopted in the past is now recognized. In fact, it is common knowledge that hard engineering defenses can be effective in the short term, when properly designed and constructed, but may not withstand extreme events, which are becoming more and more frequent. Since monitoring is constantly required and investment and monitoring costs are high, hard defenses destroy beach aesthetics (Antunes do Carmo et al. 2010). In this context, a new perspective has emerged, which has led to a deep reformulation of priorities and guidelines relating to coastal defenses. Accordingly, unlike coastal defenses built in the past, novel solutions to address coastal processes, as alternatives to traditional coastal protection structures (e.g., seawalls, rubble-mound breakwaters, and groins), are becoming increasingly important. The new concepts in force are in line with natural processes, adopting more ecological and environmentally friendly actions. The most common contemporary adaptation measures include

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Coastal Defenses and Engineering Works, Fig. 1 Urban seafronts located on the Western Portuguese coast, protected by sea walls, groins, and jetties. (a) North

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of Mira Beach (Courtesy of António Mota Lopes). (b) Figueira da Foz port (Adapted from Google Earth, October 2017)

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Coastal Defenses and Engineering Works, Fig. 2 Groin built at south of Figueira da Foz to protect the Gala coastal front (last groin near the lower boundary of

Fig. 1b. The zooms of the areas indicated in the figure above are shown below. The third zoom (A) shows that the groin base/root is partially destroyed (Source: author)

artificial sand nourishments, possibly with additional sand support measures; the building and rehabilitation of dunes; the creation and restoration of wetlands; the reinforcement or creation of submerged longitudinal bars; submerged breakwaters made of geotextile tubes; artificial or reinforced dunes; beach dewatering; buffer zones; and land-use restriction and zoning (Dronkers and Stojanovic 2016; Antunes do Carmo 2018). These novel approaches seek to strengthen the benefits of traditional natural defenses, such as beaches and natural dunes, and are typically marketed as having lower environmental impacts and costs and as being easier to implement

(Milligan and O’Riordan 2007; Cummings et al. 2012; Cheong et al. 2013). An example of a possible combination of these innovative approaches is shown in Fig. 3. Of course, these approaches need not be combined in the manner shown in Fig. 3. Rather, the right combination depends on the type of coast; cliff coasts, clayey bank coasts, intertidal/muddy coasts, sand dune coasts, and sandy coasts possibly call for different combinations. The goal is to maintain the aesthetics and sustainability of the coastal zone. In areas of increasing risk, this will only be possible through regular interventions, in accordance with guidelines established in the context of integrated coastal

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Coastal Defenses and Engineering Works, Fig. 3 Innovative approaches, combined to maximize energy dissipation and wave attenuation, with the goal of

stabilizing the beach and the dune system (Adapted from Cummings et al. 2012)

zone management (ICZM). Longer-lasting sustainability can be achieved by implementing interventions that effectively reduce wave energy prior to reaching the coastline. This is the main purpose of the submerged breakwater shown in Fig. 3. In fact, it is possible to guide the wave propagation by acting on the seabed in areas of the continental shelf where (frequent and storm) waves propagate in intermediate- and shallow-water conditions, forcing waves to rotate (refraction effect) and break in the water mass (away from the coastline), thus preventing all of the wave energy from being discharged on the beach and/or in natural defense systems (dunes). To preserve coastal dunes and stabilize the coastal foundation properly, one strategy recommends the use of artificial nourishments, possibly complemented with other types (preferable soft measures) of protections to prevent sand losses. The goal of this strategy is to protect the coast in an environmentally friendly and aesthetically pleasing manner. Examples of effective actions that protect the coast in this manner are presented in Oh and Shin (2006) and Taal et al. (2016). On this issue, the Leirosa case study has been an example of learning. This sand dune system has been the scene of three major dune rehabilitation interventions in the past 18 years. The first involved the reconstruction of the sand dunes followed by revegetation with Ammophila arenaria, as shown in Fig. 4 (Reis et al. 2005). The second intervention consisted of installing geotextile containers filled with sand (Reis et al.

2005), and the last one was implemented to stabilize the existing geotextile-reinforced sand dune system in the area where some encapsulated sand layers, mainly the bottom three, had partially opened up (Antunes do Carmo et al. 2010). This protection strategy allowed this stretch of the coast to remain more or less stable until 2014. However, the Hercules and Stephanie storms that struck the Portuguese coast in 2014 caused deep damages in this dune system, thus increasing the weaknesses that existed (Antunes do Carmo 2018). These events have taught us that the measures taken to protect the beach and dune system of Leirosa would not be sufficient, so we put forward a proposal to install a multifunctional submerged structure with characteristics to (1) protect the coastal zone, dissipating energy of waves, (2) create a calmer sea on the lee side of the structure, and (3) increase the surfing possibilities in the Leirosa area of Portugal. It should be noted that coastal defense structures incorporating multifunctionalities are, in general, well accepted by stakeholders (Evans et al. 2017). The proposed structure for Leirosa was tested for two reef geometries with different reef angles (45
and 66
). Wave data were obtained from a Datawell Directional Waverider buoy located about 5 km off the coastline, position 40
030 22“ N 8
57’ 22” W, at 25 m water depth. In order to propagate the incident wave, a Boussinesq-type model, COULWAVE (Lynett

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Coastal Defenses and Engineering Works, Fig. 4 Leirosa sand dune system: artificial reconstruction of the sand dunes followed by revegetation with Ammophila arenaria (Source: author)

and Liu 2008), was used. Figure 5 shows numerical results of wave heights and the wave breaking line for the common wave conditions: wave height H ¼ 1.5 m, period T ¼ 9.0 s, and a reef angle ¼ 45
(Ten Voorde et al. 2009; Mendonça et al. 2012a, b). Figure 5 shows the good performance of an artificial submerged reef taking advantage of the wave refraction effect. This structure also causes wave to break in the water mass (away from the coastline). Therefore, it is possible to not only increase the width of the beach (new position of the break line) but also take advantage of the generated wave characteristics (shoaling effects) for sports practices. This structure can be designed to meet current conditions and, if necessary, be further strengthened to take into account possible changes in coastal dynamics. Another concept that is on the agenda is the implementation of appropriate adaptation measures. In effect, adaptation measures that are less common today may become essential in the near future. These measures include the adaptation of drainage systems, building emergency flood shelters, and building on pilings, tidal houses,

houseboats, and floating houses (Junak 2016a, b; Antunes do Carmo 2018). An increasing reduction of living conditions in coastal areas and a demand for these types of housing are foreseeable, especially in the second half of the present century. Indeed, already today, (i) two-thirds of the world’s megacities are located on the coast, and more than half of the population of the 22 European Member States (that have a coastline) live less than 50 km from the sea (Neumann et al. 2015), and (ii) these narrow coastal strips correspond to only approximately 10% of the living space on Earth. According to Berger (2015), one billion people could live along the coasts, at or below 10-meter elevations, by the year 2060.

Paradigm Shift in Coastal Zone Governance Levels of Participation and Key Dimensions for the ICZM Success Reconciling current activities in coastal zones with the maintenance of healthy ecosystems

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Coastal Defenses and Engineering Works, Fig. 5 Wave heights and wave breaking line around the reef area (reef angle ¼ 45
; wave height H ¼ 1.5 m; and period T ¼ 9.0 s) (Adapted from Mendonça et al. 2012a, b)

requires monitoring, systematic evaluation, and the implementation of corrective measures. Indeed, it is generally understood, and practice has shown, that planned, preventative adaptation is more cost-effective and efficient in the long run than retroactive measures. Therefore, identifying and addressing the needs and gaps in policies and planning will strengthen the adaptive capacity of regions and local communities. In economic terms, the natural wealth of coastal zones and the wide diversity of activities taking place in them make these regions the main source of revenue for many countries. In fact, coastal zones are currently (i) important areas of food production, through agriculture, fishing, and aquaculture; (ii) the main tourist destinations in all continents; (iii) significant sources of mineral resources, including oil and natural gas; (iv) foci of industrial development and transport; and (v) abundant reservoirs of biodiversity and ecosystems, on which the functioning of the planet depends. However, some decreases in attractiveness and demand have been observed. These decreases contribute to the maintenance and sustainability of coastal ecosystems, but such behavior can also result in socially unsustainable conditions. The

unfavorable circumstances in coastal zones include (i) large concentrations of people and services in sensitive or risk areas, leading to commercialization in those areas; (ii) insufficient or inefficient services (housing, security, health, catering, banks, leisure, bathing, etc.) to mitigate the increased risk during high-demand seasons; (iii) scarcity (in quantity and quality) of water resources during seasons of increased demand and consumption; (iv) considerable specialization of some economic activities, directed to very specific users during very restricted periods of the year; (v) a poorly designed, nonexistent, or very permissive arrangement of spaces, with unbridled/abusive and uncontrolled occupations; (vi) considerable speculation and uncontrolled costs, which are often incompatible with the quality of the services provided; (vii) high stress/confusion, which is incompatible with rest (e.g., physical and mental recovery); and (viii) of least concern, the interests and well-being of the residents throughout the year. However, this panorama may be seen as only circumstantial and can be reversed only by the implementation of actions, management measures, and incentives that are sufficiently attractive and do not compromise the sustainability of

Coastal Defenses and Engineering Works

coastal zones. One of the key measures is the integration of relevant scientific areas, local communities, and all stakeholders into decisionmaking processes relating to coastal interventions. In fact, contemporary assessment processes are based on vulnerability indexes or coastal sensitivity, which are functions of several variables or physical parameters that require a diversified knowledge base and depth that goes beyond the pure domain of engineering. In order to be successful, managers must consider not only physical processes and economic interests but also the opinions and participation of citizens, stakeholders and local communities in planning processes, conservation projects, and coastal developments. Public participation is paramount to ensure the development and sustainability of coastal zones (Du et al. 2010). Therefore, the use of management strategies that address and consider the public perception of environmental risks, erosion effects, cyclones, tidal surges, and floods is appropriate. This is also recognized as the United Nations Framework Convention on Climate Change (UNFCCC) states: “Successful adaptation activities also call for the effective engagement of stakeholders including national, regional, multilateral and international organizations, the public and private sectors, and civil society - and the management of knowledge for adaptation at each step” (ONU 2018). Moreover, “effective engagement of stakeholders, including management of knowledge for adaptation, is vital in supporting all adaptation activities at each step in the process. Relevant multilateral, international, regional, national, subnational and local organizations, public and private sectors, civil society and other relevant stakeholders are invited to undertake and support enhanced action on adaptation at all levels” (ONU 2018). However, the inclusion of entities and people with a passive attitude is not enough. Managers must also reflect on the level of participation of the agents involved. As noted by Harvey and Caton (2010), “a key factor in the nature of the community’s role in coastal management is the power of the community within all stages of the planning and management process.” Harvey and Caton also illustrate, using two examples of

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management programs implemented on the Australian coast during the 1990s, that most community activities in coastal management fall into the areas of collaborative management and participation. This issue is also addressed by Guimarães et al. (2011), who establish the existence of seven levels of cooperation, which are defined as follows: passive, in which participants are informed of what will happen; informatory, in which participants’ questions are answered; consultation, where the participants are consulted and their perspectives are heard; incentives, in which people are offered incentives to participate; functional, in which groups are formed that aim to achieve defined objectives; interactive, in which people participate in joint analyses to define actions; and, finally, mobilizing participation, in which people participate by taking initiatives independently of external institutions. These levels of participation correspond to different levels of interaction and can be considered distinct stages in the decisionmaking process. A strategy consisting of five levels to increase community engagement is proposed in Herefordshire Council (2015). The levels are informing, consulting, involving, collaborating, and empowering. The techniques used at each level are also addressed. This brief analysis highlights the need and a way of involving many actors in the implementation of procedures in order to produce wellaccepted and sufficiently credible decisionmaking vulnerability and risk assessment projects in the coastal zone. However, in order for them to be useful for integrating coastal zone planning and management, these procedures should achieve the widest possible consensus. Such procedures also produce broader insight into projects and establish priorities for intervention. Truly shared management corresponds to levels of involvement with a high degree of interaction, which encourages various types of functional, interactive, and mobilizing participation. For this reason, it is essential to establish trusting relationships that are supported by dialogue and discourse between the different groups involved in the decision-making process (Johnson and

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Coastal Defenses and Engineering Works, Fig. 6 Three key dimensions for the success of the integrated coastal zone management (Source: author; adapted from Antunes do Carmo 2019)

Dagg 2003; Dalton 2006; Milligan and O’Riordan 2007; Bremer and Glavovic 2013; Ramesh et al. 2015; Dronkers and Stojanovic 2016; Antunes do Carmo 2018). This relational procedure is primarily based on three dimensions: information, integration, and interaction, as is schematically shown in Fig. 6. The process begins with the identification of the needs of the intervention, which is accomplished by defining the type and design of the project. The needs of the intervention are noted during the coastal work implementation period and continue with monitoring the structure and surrounding space. Various stakeholders are involved in all stages of the decision-making process. Decision-makers should consider stakeholders an integral part of the plan to remain informed, motivated, and active during the various phases of the definition, implementation, and monitoring of the proposed project. Contemporary Process of Decision-Making in Coastal Works The creation and maintenance of a healthy, multifunctional system requires strong collaboration between broadly skilled technicians, public and private entities, local authorities, residents, nongovernmental organizations (NGOs), interest groups, and citizens (Fig. 7). The interdependencies shown in the organizational chart outlined in Fig. 7 are also recognized by Kamphuis (2010), who states that “to integrate all social and technical requirements and to

facilitate an optimum solution, coastal managers must organize and maintain clear communication between the various actors.” Indeed, concerns in coastal areas are not limited to safety; lifestyle and physical and mental well-being have become highly valued as well. Other features of the project, such as impact, multifunctionality, attractiveness, and environmental sustainability, have also become important. The additional complexities are further aggravated by other aspects that need to be integrated into the overall design of a project, such as nonengineering and nonscience concerns (Kamphuis 2005, 2010; Cliquet et al. 2010; Ramesh et al. 2015; Marshall et al. 2017). Examples of these concerns include socioeconomic aspects and the quality of life, which encompasses, among other things, leisure, tourism, sporting practices, fishing industries, and water quality. These emerging sociological realities, as well as the voices of actors and interest groups that would like their input to be incorporated into the project design, need to be addressed. In fact, synthesizing these recent concerns has become a much more difficult task, since this new reality is based on assumptions of value, social acceptance, and sustainability (Halvorsen 2001; Ramesh et al. 2015). The interrelationships presented in Fig. 7 show the current complexity inherent to the contemporary management processes of the coastal zone. As is clear from the preceding discussion, two distinct realities stand out among the traditional

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Coastal Defenses and Engineering Works, Fig. 7 Contemporary decision-making process relating to coastal zone issues. This chart highlights the articulated position of the coastal manager, acting as a liaison and communication link between various actors. The final

solution may result after an iterative process involving the coastal manager and both the technical-scientific and socioeconomic judgments (Source: author; adapted from Antunes do Carmo 2019)

and contemporary approaches to coastal issues. On the one hand, the need to utilize more scientific and technological knowledge in addressing coastal issues is recognized (Ramesh et al. 2015; Antunes do Carmo 2018). Therefore, specialists from different disciplines enrich the structural component of the engineering design. On the other hand, the need to involve public agents, entities, stakeholders, and local communities is recognized in order to ensure that the necessary support and social component of the structural component are satisfied. These concepts synthesize the current manner of addressing coastal issues.

integrated coastal zone management, which requires the integration of a variety of disciplinary expertise from local, societal, and practical knowledge within coastal planning and decisionmaking processes (Johnson and Dagg 2003; Cliquet et al. 2010; Bremer and Glavovic 2013). The way in which these systems complement each other to facilitate the success of an intervention located in a coastal zone is shown in Fig. 8. The structural component (or resistant structure) suffers the physical effects of the processes and is fundamentally of the technical-scientific and environmental domain (PES). The socioeconomic status (SES) forms the support base of the resistant structure and is the domain of institutions, stakeholders, and citizens (Kamphuis 2012; ONU 2018). The need to involve researchers from different disciplinary areas in the conceptualization and development phases of an intervention program in the coastal zone has been recognized in several coastal interventions carried out on the

Structural Components of the Coastal System The interaction between both the physicalenvironmental and socioeconomic systems is at the interface of the well-known concept of

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Coastal Defenses and Engineering Works

Coastal Defenses and Engineering Works, Fig. 8 Typical coastal system composed of a resistant structure and its support base (Source: author)

Portuguese coast. The same has occurred regarding the need to involve public institutions, local communities, users, and citizens in general in the process of socioeconomic consultation. It was this perspective that allowed the coastal intervention carried out in Costa da Caparica, Portugal, in the first years of this century to succeed. According to Veloso-Gomes et al. (2009), the dialogues between authorities, the contractor, local communities, and stakeholders were key factors in the success of the intervention. Other coastal interventions in different parts of the world felt the same needs and benefits, with several projects being implemented on European and Australian coasts. An example of the application of this strategy is the implementation of a sand bypass system from the beach at Figueira da Foz (Fig. 1b) to the beaches south of it (the downdrift side). At present, public discussions relating to possible solutions, involving coastal engineers, coastal scientists, local and regional public institutions, port managers, the tourism sector, fishing communities, NGOs, stakeholders, and citizens, are taking place. One possible solution under discussion is the construction of a fixed bypass system, similar to that installed at the Tweed River entrance in Australia (Dyson et al. 2002).

in implementing effective management that meets current needs while taking into consideration the need to sustainably manage natural resources for generations to come. Experience has proven that hard engineering constructions have positive effects only over short periods and limited areas. Soft engineering may be more environmentally sustainable and can provide initial and long-term protection; however, sand nourishments have to be carried out regularly to maintain the coastline or control its retreat. Probably the best solution is in the middle of hard and soft engineering approaches, taking advantage of the benefits provided by both techniques. It is therefore of paramount importance to discuss the evolution of key coastal management processes and show how new approaches to coastal defense works can be combined (Hallegatte 2009). Contemporary coastal management relies on the integration and accountability of all stakeholders, including local communities, investors, technicians, specialists (from different disciplinary areas), and managers in the processes of conceptualization, decision-making, implementation, and monitoring of intervention programs in coastal zones.

Key Issues

Future Directions

Coastal areas currently attract large amounts of people. Coastal managers have a growing interest

To satisfy the needs of future generations, alternative solutions that safeguard the sustainability of

Coastal Defenses and Engineering Works

the environment, tourism, social resources, and services in coastal zones should be taken into account (Antunes do Carmo 2019). This is in line with the UN Sustainable Development Goals, especially SDG 14, which focuses on human interactions with the ocean, seas, and marine resources. A decline in the health of the seas and oceans due to pollution, overexploitation, and climate change impacts undermine the services they provide. Therefore, the implementation of SDG 14 aims at an urgent need to transform human behavior into sustainable practices and taking action to preserve coastal ecosystems and resilient seas and oceans. Ocean governance, grounded on empowered and transparent institutions, and responsible, inclusive, participatory, and representative decision-making will be essential to achieve the SDG 14. Coastal managers should aim to sensitize all stakeholders to intervention needs, hazards, and inherent risks. Managers and stakeholders should collegially discuss possible solutions and corresponding costs and participate in decisionmaking processes. The phases of implementation and monitoring should be shared in a way that allows everyone to be proud of the success of an intervention or motivated to accept and correct failure. Several factors contribute to the need for adapting management procedures, namely, global warming, the consequent rise in mean sea level, and the increased frequency and intensification of storms, especially in the second half of the current century (IPCC 2014). Therefore, it is extremely important for coastal managers to be aware that the impact of global warming will create a requirement for other forms of accommodation in coastal areas. At some point, it will no longer be possible to maintain the effectiveness of protection measures in high-risk areas. The effort to continue living in vulnerable areas will remain for some time, but there will come a time when the risk will no longer be acceptable and this effort will turn toward retreating from these areas. When that time comes, local communities will eventually accept the necessity of retreating to a safer place. The question of “How long will the location to which

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we retreated be a safer place?” will always remain. The costs involved in maintaining the effectiveness of protection measures in high-risk areas may be an additional problem. The contemporary reality is still such that relatively soft adaptation solutions allow resistance to adverse conditions; however, most forecasts point to significant changes within a few decades. High concentrations of population and services in coastal areas, increasing difficulties in finding safe and pleasant spaces, and the expected flooding of many lowlands as a result of global climate change are favorable conditions for the search and installation of accommodation alternatives. Such alternatives may consist of soft solutions, like floating houses and houseboats, but may also require intermediate solutions, such as submerged longitudinal barriers and houses on pilings. Last but not least, the following challenges are of paramount importance for coastal engineers in the future (Antunes do Carmo 2019): • Restoring natural sand supplies along shorelines by restoring sand transport pathways in coastal zones that have been impacted by human activities and implementing an integrated sediment management system into the sedimentary basins. • Encouraging seasonal uses and rehabilitation structures to be more resilient to water action and planning public spaces as multifunctional spaces. • Ensuring that future coastal engineering projects provide long-term solutions and maximize environmental enhancement. • Adopting solutions, such as conditioning below certain levels, adapted to extreme climatic conditions.

Cross-References ▶ Coastal Zone ▶ Mangroves Conservation: Relevant Task to Achieve the SDG14 ▶ Sustainable Coastal and Marine Ecotourism: Opportunities and Benefits

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Coastal Defenses and Engineering Works Guidance Note 12. Herefordshire Council, Plough Lane, Hereford HR4 0LE, United Kingdom, 11p IPCC (2014) Synthesis report summary for policymakers. In: Core Writing Team, Pachauri RK, Meyer LA (eds) Climate change 2014: synthesis report. Contribution of working groups I, II and III to the fifth assessment report of the Intergovernmental Panel on Climate Change (IPCC). IPCC, Geneva, 32 p Johnson DE, Dagg S (2003) Achieving public participation in coastal zone environmental impact assessment. J Coast Conserv 3(1):13–18. https://doi.org/10.1652/ 1400-0350(2003)009[0013:APPICZ]2.0.CO;2 Junak M (2016a) Floating homes: Netherlands. http:// www.floatinghomes.ltd.uk/netherlands.html Junak M (2016b) Floating homes: Bembridge. http://www. floatinghomes.ltd.uk/bembridge.html Kamphuis JW (2005) Costal science, engineering and management. In: Proceedings of the Canadian coastal conference 2005. Dartmouth, Nova Scotia, 9 p Kamphuis JW (2010) Introduction to coastal engineering and management. Advances series on ocean engineering – volume 30, 2nd edn. World Scientific Publishing, Singapore. ISBN-13 978-981-283-484-3, 525p Kamphuis JW (2012) Coastal engineering education and coastal models. Coastal engineering proceedings, [S.l.], no. 33, 7 p. ISSN 2156-1028. https://doi.org/10.9753/ icce.v33.management.30 Lynett PJ, Liu PL-F (2008) Modeling wave generation, evolution, and interaction with depth-integrated, dispersive wave equations. COULWAVE code manual, Cornell University, Long and intermediate wave modeling package, v. 2.0 Manno G, Anfuso G, Messina E, Williams AT, Suffo M, Liguori V (2016) Decadal evolution of coastline armouring along the Mediterranean Andalusia littoral (South of Spain). Ocean Coast Manag 124:84–99. https://doi.org/10.1016/j.ocecoaman.2016.02.007 Marshall N, Adger N, Attwood S, Brown K, Crissman C, Cvitanovic C, De Young C, Gooch M, James C, Jessen S, Johnson D, Marshall P, Park S, Wachenfeld D, Wrigley D (2017) Empirically derived guidance for social scientists to influence environmental policy. PLoS One 12(3):e0171950. https://doi.org/ 10.1371/journal.pone.0171950 Mendonça A, Fortes CJ, Capitão R, Neves MG, Antunes do Carmo JS, Moura T (2012a) Hydrodynamics around an artificial surfing reef at Leirosa, Portugal. J Waterw Port Coast Ocean Eng 138(3):226–235. https://doi.org/ 10.1061/(ASCE)WW.1943-5460.0000128 Mendonça A, Fortes CJ, Capitão R, Neves MG, Moura T, Antunes do Carmo JS (2012b) Wave hydrodynamics around a multi-functional artificial reef at Leirosa. J Coast Conserv 16:543–553. https://doi.org/10.1007/ s11852-012-0196-1 Millennium Ecosystem Assessment (2005) Ecosystems and human well-being: synthesis. Island Press, World Resources Institute, Washington, DC. ISBN 1-59726-040-1 Milligan J, O’Riordan T (2007) Governance for sustainable coastal futures. Coast Manag 35:1–11. https://doi. org/10.1080/08920750701525800

143 Neumann B, Vafeidis AT, Zimmermann J, Nicholls RJ (2015) Future coastal population growth and exposure to sea-level rise and coastal flooding – a global assessment. PLoS One 10(3):e0118571. https://doi.org/10.13 71/journal.pone.0118571 Oh YI, Shin EC (2006) Using submerged geotextile tubes in the protection of the E. Korean shore. Coast Eng 53:879–895. https://doi.org/10.1016/j.coastaleng.200 6.06.005 ONU (2018) Framework convention on climate change (UNFCCC). Adaptation. http://bigpicture.unfccc.int/ #content-the-paris-agreement Ramesh R, Chen Z, Cummins V, Day J, D’Elia C, Dennison B, Forbes DL, Glaeser B, Glaser M, Glavovic B, Kremer H, Lange M, Larsen JN, Le Tissier M, Newton A, Pelling M, Purvaja R, Wolanski E (2015) Land–Ocean interactions in the coastal zone: past, present & future. Anthropocene 12:85–98. https:// doi.org/10.1016/j.ancene.2016.01.005 Reis CS, Freitas H, Antunes do Carmo JS (2005) Leirosa sand dunes: A case study on coastal protection. In: Proceedings of the IMAM – maritime transportation and exploitation of ocean and coastal resources, Lisboa, vol. 2, 26–30 de September, 1469–1474. Taylor & Francis/BALKEMA. ISBN 0 415 39374 4, CD-Rom: 0 415 39433 3 Schipper MA, de Vries S, Ruessink G, de Zeeuw RC, Rutten J, van Gelder-Maas C, Stive MJF (2016) Initial spreading of a mega feeder nourishment: observations of the sand engine pilot project. Coast Eng 111:23–38. https://doi.org/10.1016/j.coastaleng.2015.10.011 Schmidt S, Neumann B, Waweru Y, Durussel C, Unger S, Visbeck M (2017) SDG14 conserve and sustainably use the oceans, seas and marine resources for sustainable development. In: Griggs DJ, Nilsson M, Stevance A, McCollum D (eds) A guide to SDG interactions: from science to implementation. International Council for Science (ICSU), Paris, pp 175–219. https:// doi.org/10.24948/2017.01 SDG Compass (2015) SDG 14: conserve and sustainably use the oceans, seas and marine resources for sustainable development. GRI, UN Global Compact, and WBCSD. https://sdgcompass.org/sdgs/sdg-14/ Sterr H (2008) Assessment of vulnerability and adaptation to sea-level rise for the coastal zone of Germany. J Coast Res 24(2):380–393. https://doi.org/10.2112/ 07A-0011.1 Taal MD, Löffler MAM, Vertegaal CTM, Wijsman JWM, Van der Valk L, Tonnon PK (2016) Development of sand motor. Concise report describing the first four years of the Monitoring and Evaluation Programme (MEP). Deltares, Delft, 62 p Ten Voorde M, Antunes do Carmo JS, Neves MG (2009) Designing a preliminary multifunctional artificial reef to protect the Portuguese coast. J Coast Res 25(1):69–79. https://doi.org/10.2112/07-0827.1 Veloso-Gomes F, Costa J, Rodrigues A, Taveira-Pinto F, Pais-Barbosa J, Neves L (2009) Costa da Caparica artificial sand nourishment and coastal dynamics. ICS2009 proceedings. In: J Coast Res, vol SI56, pp 678–682

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Coastal Environmental Quality ▶ Management and Monitoring of Eutrophication: Trophic State Indexes on the Río de la Plata Northern Coast

Coastal Lagoons ▶ Estuaries: Dynamics, Biodiversity, and Impacts

Coastal Management Guidelines ▶ Coastal Defenses and Engineering Works

Coastal Nutrient Supply and Global Ocean Biogeochemistry Leticia Cotrim da Cunha Programa de Pós-Graduação em Oceanografia/ FAOC, Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, Brazil Brazilian Network for Ocean Acidification (BrOA), Rio Grande, Brazil Rede Clima, Sub-Rede Oceanos, INPE, São José dos Campos, Brazil

Definitions Nutrients: These are the elements that are necessary for the growth of primary producers. Nitrogen, phosphorus, and silicon are considered as major nutrients, mainly in their inorganic forms as nitrate, nitrite, ammonium, phosphate, and silicic acid. Micronutrients: These are other elements also considered as nutrients since they are essential to the maintenance of life, despite being present in

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the ocean at trace level, that is, in concentrations in the order of nanograms per liter or less. Iron, manganese, copper, zinc, cobalt are examples of micronutrients. Nutrient: Nutrient-type distribution refers to the elements whose vertical distribution in the open ocean water column normally shows depletion at surface down to the thermocline, at variable depths depending on the latitude and season. Further down the water column, there is a more or less steady increase in concentrations at intermediate and deep waters, reflecting the presence of water masses formed in high latitudes. Within coastal areas, nutrient distribution is highly variable, as the influence from sources such as rivers, sediments, ground water, or atmospheric deposition are heterogenously distributed. Continental shelf: It is operationally defined as the ocean area comprised from the shore up to the 200 m isobath, where usually there is an abrupt change in the depth gradient. Its extension is variable alongside the continents as the shelf is considered the extension of the continents and corresponds to an area of 25,300 103 km2, or circa 7% of the total ocean area (Borges 2011). Coastal ocean: Its definition comprises the nearshore, lagoons, bays, outer estuaries, and all the inner continental shelf within the first hundred kilometers from the shore. Usually it is referred to the area that connects open ocean to the continent, and is equally influenced by oceanic, atmospheric, and terrestrial processes. The coastal ocean includes ecosystems such as coral reefs, mangroves, seagrass meadows, or mud flats. Exclusive Economic Zone (EEZ): It is the ocean area beyond each country’s territorial sea extending up to 200 nautical miles from the coast. Within the EEZ, the countries are sovereign to conduct exploration and exploitation activities and are responsible to conserve and manage biodiversity and nonliving resources along the whole water column. Eutrophication: It is the ensemble of processes resulting from the excess input of nutrients to an aquatic ecosystem. In response to an enrichment in available nutrients in the water column, primary producers growth is accelerated to rates that unbalance all trophic levels in the ecosystem,

Coastal Nutrient Supply and Global Ocean Biogeochemistry

leading, for instance, to the increase in respiration or microbial degradation of the excess organic matter, light limitation due to water column turbidity, or harmful algae-provoked toxicity to the biota.

Coastal Ocean and the Global Biogeochemical Cycles Importance of the Coastal Ocean to Global Biogeochemical Cycles The ocean covers slightly more than 70% of the Earth’s surface. This vast amount of water is responsible for climate regulation, as it exchanges heat, water, and momentum permanently with the atmosphere, distributing heat through its surface circulation (Visbeck 2018). The coastal ocean surrounds the continents and is indeed a unique and extremely heterogenous portion of the world’s ocean (Andersson and Mackenzie 2004). It is an extremely dynamic interface, where storage, transport, and exchange processes occur concomitantly, at different timescales, between land, atmosphere, and the open ocean. This “continuum” between land and the open ocean includes nearshore ecosystems such as bays, estuaries, lagoons, and the continental shelf and marginal seas (Liu et al. 2010). If we consider the whole continental shelf, normally limited by the 200 m isobath, it corresponds to more or less 7% of the total ocean surface, or 24– 29  106 km2 (Borges 2011). Continental shelves account for circa 20% to the world’s total primary production (Gattuso et al. 1998; Liu et al. 2010), which corresponds to 7–16 PgC year1 if we consider a range of 35–78 PgC year1 for the world’s ocean (Carr et al. 2006), from observational and modeled primary production estimates (Fig. 1). Cai et al. (2006) have estimated, based on a shelf-type classification, that this portion of the ocean may be responsible for up to 10% of the total ocean atmospheric CO2 sink (i.e., ~0.22 Pg C year1), while other estimates suggest that up to 50% (~1 Pg C year1) of the total ocean CO2 uptake happens within the continental shelves (Thomas et al. 2004). The uniqueness of the coastal ocean also lies in the fact that it

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corresponds to the triple interface between land, ocean, and atmosphere (Smith et al. 2003). These three compartments of the Earth System interplay as sinks and sources of water, gases, sediments, carbon, nutrients, and pollutants (Borges 2011). At present, more than 40% of the world’s population live within 200 km from the coast (Visbeck 2018). This thin stripe of land is also where most of the mega cities in the world, mainly along the coastal area or in an estuary (Visbeck 2018). If we consider the facts above, and the strong increase in human population since the 1950s, then the coastal ocean is more vulnerable to anthropogenic climate change, pollution, and deleterious eutrophication from increasing runoff of carbon, nitrogen, and phosphorus (Borges 2011). Where Do the Nutrients in the Coastal Ocean Come From?

Nutrients and carbon reach the coastal ocean through these main pathways: riverine inputs (Seitzinger et al. 2010), atmospheric deposition of natural and anthropogenic aerosols (Mackey et al. 2010), sediment resuspension processes (Giraud et al. 2008), and groundwater sources (Moore 2010). Riverine inputs of freshwater, nutrients and carbon, although not evenly spatially distributed along the continents (Fig. 2), are now recognized as key to understand the global nutrient and carbon budgets at both short (decades, as in Meybeck (1991) and Cotrim da Cunha et al. (2007)) and long (centuries) timescales (Lacroix et al. 2020). On the other hand, the human impact on fluvial systems affects directly, and on short timescale, the coastal ocean biogeochemistry by the input of nutrients (Lui and Chen 2012). Finally, over geological timescales, river fluxes of materials have an influence on seawater composition (AmiotteSuchet et al. 1993). Carbon and nutrients (N, P, and Si) enter riverine systems through natural leaching and erosion processes in the catchments that eventually drain to the coastal ocean (Smith et al. 2003). Fast increasing population since the 1950s decade has resulted in increasing amounts of carbon, nitrogen, and phosphorus from terrestrial origin, not only from natural sources (Regnier et al. 2013).

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Coastal Nutrient Supply and Global Ocean Biogeochemistry, Fig. 1 Satellite-derived seasonal surface average (2002 to 2019) ocean chlorophyll-a concentration (mg m3) from NASA’s processed Moderateresolution Imaging Spectroradiometer (MODIS) Aqua Chlorophyll 4 km Data (Center NGSF 2018). Higher chlorophyll concentrations are found along the continental shelves and at upwelling areas, according to the color scale at the bottom. Upper panel: (a) Boreal summer; Mid-upper panel: (b) Boreal autumn; Mid-lower panel: (c) Boreal winter; Lower panel: (d) Boreal spring

Nitrogen inputs to river basins, and consequently to the coastal ocean, come mainly from agricultural runoff, heavily loaded with fertilizers, and

domestic and industrial sewage (Bouwman et al. 2005). Phosphorus inputs have also increased from the use of fertilizers and dumping of raw

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Coastal Nutrient Supply and Global Ocean Biogeochemistry, Fig. 2 Annual estimates of riverine inputs of freshwater, carbon and nutrients to the global coastal ocean, computed in 0.5
resolution of latitude and longitude. (a) freshwater inputs in km year according to Korzoun et al. (1977) and Döll and Lehner (2002), represented as sized blue dots; (b) particulate organic carbon (POC) inputs in Tg C year according to Ludwig et al. (1996), represented as sized brown dots; (c) dissolved organic carbon (DOC) inputs in Tg C year according to

Ludwig et al. (1996), represented as sized pink dots; (d) dissolved inorganic nitrogen (DIN) in Tg N year, represented as sized green dots, and (e) dissolved inorganic phosphorus (DIP) inputs in Tg P year, represented as sized purple dots according to Cotrim da Cunha et al. (2007), Döll and Lehner (2002), and Smith et al. (2003); and (f) dissolved silica (dSi) inputs in Tg Si year, represented in sized yellow dots, according to Cotrim da Cunha et al. (2007), Döll and Lehner (2002), and Tréguer et al. (1995)

domestic sewage (Harrison et al. 2005b). Anthropogenic carbon inputs, especially in its organic form (particulate and dissolved), have also increased with increasing population. Organic carbon sources to rivers are mainly from agricultural runoff and wastewater inputs (Harrison et al. 2005a). Contrasting to increasing inputs of N and P caused by human activities, silicon (Si) fluxes have decreased with time because of river damming (Laruelle et al. 2009). Silicon is one of the most abundant elements in our planet and is necessary for the growth of planktonic primary producers such as diatoms, both in freshwater and

seawater, in addition to radiolarians, sponges, and other organisms (Tréguer and De La Rocha 2013). Silicon is also an important nutrient for terrestrial plants (Ittekkot et al. 2000). Studies have shown that the global silica cycle has been perturbed by the construction of river dams, resulting in a decrease in the total amount of particulate matter in general (Best 2019) and dissolved, reactive silica, reaching the coastal ocean (Laruelle et al. 2009). Dam reservoirs act as sinks of dissolved silica, as local exported production (containing frustules from freshwater diatoms) is retained in bottom sediments (Humborg et al. 2000), and,

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differently from N and P which can be introduced from human sources further downstream, there are no other significant silica sources (Humborg et al. 2000). Thus, the nutrient ratio delivered by rivers to the coastal ocean has been altered in many regions, changing the nutrient availability for coastal primary producers (Ittekkot et al. 2000). A classical example of the impacts of decreasing the silica inputs is the Nile river delta, after the construction and closure of the Aswan barrage in 1965 (Nixon 2003). The amount of river freshwater input has drastically decreased during the Nile seasonal flood, and coastal fisheries have decreased by almost 80%, especially sardine catching (Nixon 2003). Atmospheric deposition of nutrients through aerosols is also a considerable source of nutrients to the coastal and open ocean, especially in areas where riverine freshwater input is low. Areas such as the Mediterranean Sea (Bonnet et al. 2005), the southwestern Atlantic coast off Patagonia (Gaiero et al. 2004), the northeastern tropical Atlantic (Baker et al. 2013), or regions in the Pacific Ocean (Calil et al. 2011) may be directly influenced episodically or seasonally by atmospheric inputs of nitrogen, phosphorus, silica, carbon, or iron. Other micronutrients and/or pollutants may enter the surface coastal waters mainly by atmospheric inputs, such as the case of copper, cadmium, and lead in the western Mediterranean basin (Martin et al. 1989). In coastal areas, the atmospheric nutrient inputs have increased with increasing population density and extension of agricultural land, and so the amounts of nitrogen and phosphorus within aerosols (Marín et al. 2017). Despite its importance, atmospheric nutrient inputs are dependent on the solubility of the elements present in aerosol particles (Jickells et al. 2016). The solubility control on bioavailability is especially important for micro- and macronutrients such as iron, nitrogen, phosphorus, silica (Baker et al. 2013). In addition to the nutrient bioavailability in the aerosol particles, the state of the nutrient ratio in surface waters in the coastal and open ocean areas is also a controlling factor on the ecosystem response to nutrients. For instance, one may consider the stoichiometric molar ratio of 106C:16 N:1P:0.0075Fe (commonly referred to as the

Redfield ratio (Redfield 1958)). This proportionality may not often be found in coastal waters, because terrestrial runoff is commonly enriched in carbon related to other elements, or nitrogen in case of agricultural runoff. Thus, the atmospheric nutrient inputs will impact (enhance) coastal and open ocean primary production more or less depending on the local nutrient limitation (Jickells and Moore 2015). At present, ocean biogeochemistry modeling estimates suggest that atmospheric deposition of nutrients may support circa 5% of the global ocean productivity and 18% (or 1 PgC year1) of the export production (i.e., the amount of organic matter produced in the surface ocean and exported as particulate organic carbon below the thermocline (Jickells and Moore 2015)). Groundwater is also an important regional source of nutrients (macro- and micronutrients) to the coastal ocean and is an important compartment of the global hydrological cycle (Moore 2010). It is important to remind that the groundwater discharge to the coastal ocean is not similar to riverine inputs, as it is a mixture of terrestrial waters (i.e., rain or river water) and sea water that has penetrated permeable coastal sediments (Moore 2010). This mixing of sea water and terrestrial water occurs within some distance inland from the shore and is called coastal aquifers (Moore 2010) or subterranean estuaries (Libes 2009). As in the case of atmospheric inputs, groundwater may be locally more important sources of nutrients than riverine inputs, and these inputs occur only in the occurrence of aquifers close to the coastal ocean (Moore 2010). For instance, in the Atlantic Ocean, the estimated volume of submarine groundwater discharge (SDG) is comparable in volume to the riverine freshwater inputs entering the Atlantic Ocean from rivers, equivalent to 2–4 1013 m3 year1(Moore et al. 2008). Submarine groundwater discharge is not a freshwater flux, instead a mixture of terrestrial and sea water that has penetrated permeable coastal sediments. As a consequence, SDG has different chemical composition from the adjacent coastal ocean, that is, lower oxygen content, reduced metallic ions such as Fe2+ and nitrogen (mainly in its reduced form NH4+) to phosphorus (N:P) ratio higher than the Redfield ratio of 16

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(Slomp and Van Cappellen 2004), and dissolved carbon at both organic and inorganic forms (Moore 2010). Nevertheless, the proportion of nitrogen to phosphorus in SGD is controlled by the natural (e.g., soil leaching) or anthropogenic (e.g., extensive cropland area) sources of nitrogen, and the redox conditions are key to the availability of phosphorus (Slomp and Van Cappellen 2004). Because of the typical reducing condition in groundwater, some metallic ions may also be solubilized when seawater, richer in dissolved oxygen, enters these subterranean estuaries, such as uranium (Windom and Niencheski 2003). Groundwater inputs may exert a key role on inner continental shelf waters; off the subtropical southwestern Atlantic coast in Brazil massive diatom blooms may be associated to local circulation and nutrient inputs from La Plata River and Patos Lagoon and the cross-shelf mixing of iron- and nitrogen-rich SDG inputs along the shore (Piedras and Odebrecht 2012). Is the Coastal Ocean a Simple Stripe of the World’s Ocean?

As seen previously discussed, the coastal ocean, or even the entire continental shelf area, is not

Coastal Nutrient Supply and Global Ocean Biogeochemistry, Fig. 3 Coastal ocean division into marine ecoregions of the world, according to Spalding et al. (2007). (Licensed under a Creative Commons

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uniform either in width or depth, or in biogeochemical characteristics. Many attempts have been made in order to classify the coastal zone and shelf, according to different purposes, like biogeography, climate regime, freshwater input, population density, estuary types (Spalding et al. 2007; Borges 2011; Dürr et al. 2011). Understanding and documenting the coastal ocean heterogeneity is useful too to access the effects of climate change, such as the trends in increasing temperature, sea level rise, or primary productivity (Borges 2011). Spalding et al. (2007) proposed the division of the coastal ocean, including the whole continental shelf, into Marine Ecoregions, where biodiversity combined to oceanographic characteristics defined the division into realms, provinces, and ecoregions (Fig. 3). Another useful approach to study the effects of riverine inputs to ocean biogeochemistry is the classification proposed by Dürr et al. (2011), where coastal systems are classified according to their role as filter to materials delivered to the ocean: small deltas, tidal systems, lagoons, and fjords, while large river systems such as the Amazon river are considered to bypass the material filter function, and deliver dissolved and particulate matte directly to the ocean.

Attribution-Noncommercial-Share Alike 4.0 License – source http://www.marineregions.org/gazetteer.php? p¼image&pic¼64936)

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How Does the Coastal Nutrient Supply Influence the Global Ocean Biogeochemistry? In study using a global ocean biogeochemistry model, Cotrim da Cunha et al. (2007) used short timescale (up to 30 years from present) scenarios to access the impact of changes in river nutrient supply to the coastal and global ocean surface. Their results suggest that riverine inputs or organic carbon (dissolved and particulate) and N, P, Si, and Fe mainly enhance primary and export production especially off regions where upwelling and high runoff are combined, that is, eastern margins. Riverine nutrients increase coastal and open ocean primary production, and the enhanced sinking of particulate organic matter (from increasing diatom and fecal pellet production) adds to the decomposition of marine particles and thus to O2 consumption in the water column. The expansion of hypoxic coastal areas (where dissolved O2 concentration is lower than 25 mM) may increase up to 45%, corresponding to 2.6*106 km2 in a scenario where the world’s population increases to 12 billion inhabitants (year 2050, according to the UNDP (2004) projections), and the carbon, nitrogen, and phosphorus inputs by rivers increase accordingly (Smith et al. 2003). More recently, Sharples et al. (2017) estimated that circa 75% and 80% of riverine dissolved inorganic nitrogen and phosphorus, respectively, reach open ocean areas. Lacroix et al. (2020) suggested that riverine loads of nutrients lead to a strong increase in the net primary production in open ocean areas close to large nutrient inputs such as the tropical west Atlantic, Bay of Bengal and the East China Sea, thus concluding that riverine nutrients and carbon inputs to the ocean are needed to assess regional variability in ocean biogeochemistry, as well as the ocean-atmosphere CO2 exchange in longer timescales. Is the Coastal Ocean Also under Threat of Acidification?

Concerning the ocean acidification problem, how would be the expected impacts to the coastal ocean? The ocean acidification physical-chemical process is provoked by the dissolution of atmospheric CO2 in surface seawater, leading to an increase in the hydrogen ion [H+] concentration,

decreasing pH and carbonate ion [CO32] concentration (Doney et al. 2009). The main effect of decreasing seawater pH is that is decreases the saturation state of the calcium carbonate (CaCO3) minerals aragonite and calcite, affecting growth of aquatic organisms such as corals, shellfish, and many plankton organisms (Kleypas et al. 1999). The recent IPCC Special Report on Oceans and Cryosphere in a Changing Climate (SROCC) states that the oceans have already absorbed circa 30% of the total anthropogenic CO2 emissions CO2, and mean surface ocean pH has decreased by 0.017–0.027 pH units per decade since the 1980s (Bindoff et al. 2019). The coastal area is extremely heterogeneous and under influence of physical, chemical, and biological processes that lead to diel variations in primary production and respiration rates, salinity, and terrestrial inputs of nutrients and organic matter (natural and anthropogenic). This natural variability directly affects pH, which may vary in a 24-hour timescale more than the observed historical trend in open ocean waters (Waldbusser and Salisbury 2014). Combined effects of OA with other ecosystem stressors such as increasing temperature or changes in the ratios of nutrient supply may affect marine life in ways that are not yet fully understood (Boyd et al. 2014). Anthropogenic forcing affects the marine carbonate equilibrium in coastal seawater through eutrophication and changes in river runoff (Feely et al. 2018) in addition to increasing atmosferic carbon dioxide. Upwelling areas such as those associated to the eastern margins of continents (e.g., California Current, Humboldt Current, Canary Current, Benguela Current) may also have a key role in coastal ocean acidification, as these areas are under influence of high-CO2 waters and thus lower pH. Increasing anthropogenic CO2 content in these upwelled waters may magnify OA processes locally (Doney et al. 2011; Feely et al. 2018). Eutrophication in coastal areas is caused by an enhanced input of nutrients from various anthropogenic sources. When the water column light and temperature conditions are favorable, the combination with available nutrients triggers primary production (planktonic and benthic) and

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biomass increase (Justic et al. 2002). In a first moment, photosynthesis will consume nutrients and dissolved inorganic carbon in the water (as CO2), leading to an increase in surface pH and dissolved oxygen concentration. However, microbial degradation of organic matter will consume oxygen, release nutrients and CO2, and lower pH in the water column (heterotrophic respiration). This is the so-called acidification through eutrophication (Borges and Gypens 2010), which can lead the ecosystem to a state of hypoxia or anoxia. In shallow, stratified coastal waters, there is often a marked oxycline, with high pH and high oxygen concentrations in the surface, while bottom waters and sediments are hypoxic or anoxic and display low pH values, high CO2 concentrations, and consequently undersaturation in calcium carbonate (Waldbusser and Salisbury 2014; Feely et al. 2018). Changes in the concentration of dissolved ions other than nutrients within river basins may also affect pH in coastal areas. For instance, increased carbonate and bicarbonate ions from soil leaching increase the river water alkalinity (Raymond and Cole 2003). On the other hand, increasing riverine inputs with low carbonate alkalinity (i.e., low concentration of carbonate and bicarbonate ions) may affect the aragonite and calcite saturation in coastal waters (Salisbury and Jönsson 2018). Future Directions, or the Coastal Ocean in a Changing World As previously discussed, many of the mega-cities of the world are located along the coast, and the most populated areas in the world are located within the first 200 km from the coast (Visbeck 2018). How will organic-matter- and nutrient-rich effluents (domestic, industrial) further influence coastal sea-air fluxes? Common sense from observations and model studies is that increased availability of organic matter in coastal areas (estuaries and shelf waters) enhances heterotrophic respiration processes, thus producing CO2, lowering pH, and decreasing the aragonite (i.e., calcium carbonate form most common to marine organisms) saturation levels in both temperate and tropical areas (Cotovicz Jr. et al. 2015; Rheuban et al. 2019). In opposition to this scenario, eutrophication in

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certain tropical ecosystems may, despite that, trigger such an intense primary production and export of organic matter, that coastal areas act as net CO2 sinks (Cotovicz Jr. et al. 2015). As an example, the second largest bay in the tropical SW Atlantic ocean exports nutrients and organic carbon to the oligotrophic inner shelf at rates of 1.3 102 Gmoles DIN year1, 9.5 104 Gmoles DIP year1, and 0.4 102 Tmoles OC year1 (Guanabara Bay, SE Brazil (Lazzari et al. 2016)). Increasing atmospheric CO2 combined with increasing nutrient inputs from continental areas (rivers, surface runoff, atmospheric deposition) are factors that may turn the coastal ocean into permanent carbon sinks (Borges 2011; Bauer et al. 2013). The question remains on the future role of continental shelves, and the fate of the lateral carbon export to open ocean areas especially dissolved inorganic carbon – DIC – from the eutrophication-driven increase in heterotrophic respiration in the water column (Bauer et al. 2013). In addition to this, the coastal ocean is also prone to be affected by the decreasing oxygen content in seawater, documented by observations (Diaz and Rosenberg 2008). Breitburg et al. (2018) have documented more than 400 coastal ecosystems affected by hypoxia (dissolved oxygen concentrations below 60 mmol kg1) or anoxia (absence of detectable dissolved oxygen). In the same study, the authors have related deoxygenation to the regional population density and eutrophication, and according to their analysis of historical data, the trend is to double the number of hypoxic to anoxic coastal ecosystems every decade. The extent and severity of low-O2 areas affect the marine trophic chain because benthic marine life may be severely disturbed (Diaz and Rosenberg 2008). Permanent or seasonal development of low-O2 areas in estuaries since the 1970s likely lead to losses in biological diversity or decline in primary production may lead to deleterious impacts on local fisheries resources, as already shown in the latest IPCC Special Report on n the Ocean and Cryosphere in a Changing Climate (Bindoff et al. 2019). Finally, larger extents of low-O2 or anoxic areas in the oceans may alter microbial respiration thus

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leading to a change in sea-air fluxes of the other greenhouse gases N2O and CH4 (Landolfi et al. 2017). Closely linked to all these changes related to climate and increasing inputs of nutrients to the coastal ocean biogeochemistry, one has to consider socioeconomic aspects that depend directly to the responses to climate change and other manmade impacts. For instance, Muller-Karger et al. (2017) highlighted that approximately 50% of the world’s population health and economy relies on marine resources present in the EEZ, and circa 1/5 of the protein consumed in developing nations derives from fisheries (FAO 2016). Additionally, a sustainable use of the ocean resources depends on scientific knowledge on the physical, chemical, and biological aspects of our coastal and open ocean ecosystems. The United Nations’ adoption of 17 Sustainable Development Goals for 2030 (SDGs) in 2015 and the launch of the Decade of Ocean Science (2021–2030) (Lubchenco and Gaines 2019) reinforce the requirement for observations and multidisciplinary work on freshwater quality and availability, food security, addressing adaptation and mitigation for climate change, and terrestrial ecosystems.

Cross-References ▶ CO2-Induced Ocean Acidification ▶ Coastal Zone ▶ Global Ocean Governance and Acidification

Ocean

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Coastal Pollution: An Overview carbonate parameters and hide ocean acidification. Biogeochemistry 141:401–418. https://doi.org/10.1007/ s10533-018-0505-3 Seitzinger SP, Mayorga E, Bouwman AF, Kroeze C, Beusen AHW, Billen G, Van Drecht G, Dumont E, Fekete BM, Garnier J, Harrison JA (2010) Global river nutrient export: a scenario analysis of past and future trends. Global Biogeochem Cycles 24. https:// doi.org/10.1029/2009GB003587 Sharples J, Middelburg JJ, Fennel K, Jickells TD (2017) What proportion of riverine nutrients reaches the open ocean? Global Biogeochem Cycles 31:39–58. https:// doi.org/10.1002/2016GB005483 Slomp CP, Van Cappellen P (2004) Nutrient inputs tp the coastal ocean through submarine groundwater discharge: controls and potential impact. J Hydrol 295:64–86 Smith SV, Swaney DP, Talaue-McManus L, Bartley JD, Sandhei PT, McLaughlin CJ, Dupra VC, Crossland CJ, Buddemeier RW, Maxwell BA, Wulff F (2003) Humans, hydrology, and the distribution of inorganic nutrient loading to the ocean. Bioscience 53:235. https://doi.org/10.1641/0006-3568(2003)053[0235: HHATDO]2.0.CO;2 Spalding MD, Fox HE, Allen GR, Davidson N, Ferdana ZA, Finlayson M, Halpern BS, Jorge MA, Lombana A, Lourie SA, Martin KD, McManus E, Molnar J, Recchia CA, Robertson J (2007) Marine ecoregions of the world: a bioregionalization of coastal and shelf areas. Bioscience 57:573. https://doi.org/10.1641/B570707 Thomas H, Bozec Y, Elkalay K, de Baar HJW (2004) Enhanced open ocean storage of CO2 from shelf sea pumping. Science (80- ) 304:1005 Tréguer PJ, De La Rocha CL (2013) The world ocean silica cycle. Ann Rev Mar Sci 5:477–501. https://doi.org/10. 1146/annurev-marine-121211-172346 Tréguer P, Nelson DM, Van Bennekom AJ, Demaster DJ, Leynaert A, Quéguiner B (1995) The silica balance in the world ocean: a reestimate. Science (80- ) 268:375– 379. https://doi.org/10.1126/science.268.5209.375 UNPD (2004) United Nations Population Division, world population prospects: the 2002 revision, vol III, Analytical report. New York. Available at http://www.un. org/esa/population/publications/wpp2002/WPP2002_ VOL_3.pdf Visbeck M (2018) Ocean science research is key for a sustainable future. Nat Commun 9:690. https://doi. org/10.1038/s41467-018-03158-3 Waldbusser GG, Salisbury JE (2014) Ocean acidification in the coastal zone from an organism’s perspective: multiple system parameters, frequency domains, and habitats. Ann Rev Mar Sci 6:221–247. https://doi.org/ 10.1146/annurev-marine-121211-172238 Windom H, Niencheski F (2003) Biogeochemical processes in a freshwater-seawater mixing zone in permeable sediments along the coast of Southern Brazil. Mar Chem 83:121–130

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Coastal Pollution ▶ Coastal Zone and Wetland Ecosystem: Management Issues

C Coastal Pollution: An Overview Margarida Nunes and Sara Leston Center for Functional Ecology, Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Coimbra, Portugal

Definition Coastal pollution refers to the introduction of substances or any form of energy in the coastal environment, which results or is likely to result in adverse effects in the ecosystem due to changes in its physical, chemical, and/or biological characteristics (GESAMP 1980). Pollution in coastal areas is a long-standing problem caused primarily by anthropogenic activities, including industry, urbanization, agriculture, aquaculture, and tourism. Plastic debris (e.g., Bessa et al. 2018), nutrients (e.g., Islam and Tanaka 2004), metals (e.g., Qian et al. 2015), and persistent organic compounds (e.g., Nunes et al. 2011) are some of the pollutants most commonly found in these areas, derived from point and nonpoint sources (Ridolfi 2016). Ecological consequences of coastal pollution include degradation of habitats and biodiversity, and alteration of environmental functions and processes, resulting in a greater susceptibility to disturbances and in the decline of ecosystem services. Besides all these repercussions, pollution affecting coastal zones causes public health problems and important economic losses (Islam and Tanaka 2004). In this context, the safeguarding of marine and coastal ecosystems by preventing and significantly reducing

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pollution, in particular from land-based activities, is one of the targets of the United Nations Sustainable Development Goal 14 – Life below water.

Introduction Before discussing coastal pollution further, it is necessary to define coastal zones. However, this is not straightforward. Defining coastal areas is, to some extent, challenging since it is not simple to establish universal geographical boundaries for these zones (Lavalle et al. 2011). These areas include diverse ecosystems such as estuaries, coral and other biogenic reefs, sandy and rocky subtidal areas, mudflats, mangroves, saltmarshes, and eelgrass beds, among others (Cabral et al. 2019). Generally, the term coastal zone refers to the land-sea interface, with some authors referring to it as “the part of the land most affected by its proximity to the sea and that part of the ocean most affected by its proximity to the land” (Hinrichsen 1998; Burke et al. 2001). Another definition describes coastal zone as the “intertidal and subtidal areas on and above the continental shelf (to a depth of 200 m) routinely inundated by saltwater and adjacent lands” (Burke et al. 2001). As for the European Union (EU), the geographical delimitation of coastal zones sets a 10 km buffer from the coastline (established from administrative boundaries) and a 2 km buffer from aggregation of five Corine Land Cover classes. Thus, there are several descriptions for coastal zones, which are greatly dependent on the objectives underlying its definition. Whatever the description, coastal zones constitute unique ecosystems as areas of transition between major biomes and as such, are among the most productive and diverse in the world, having a high ecological and economic value (Iglesias-Campos et al. 2015). The interconnections between land and sea, such as tidal and currents’ movements, erosion and deposition, extreme weather conditions, and biological interactions, shape these areas into highly productive habitats providing species adapted to these fast changing conditions with protection, spawning,

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nursery, breeding, and feeding habitats (IglesiasCampos et al. 2015), resulting in a very high biodiversity. Thus, it is globally accepted that these areas constitute highly productive ecosystems, with inestimable value for human populations (Iglesias-Campos et al. 2015; Neumann et al. 2015). The goods and services derived from them include shoreline stabilization, water quality, biodiversity, food production (including fisheries and aquaculture), tourism and recreation, construction materials, marine transport, and extractive activities (e.g., oil). Given all these factors, it is quite understandable why historically the world’s largest populations have settled near the coastal zones (Burke et al. 2001; Creel 2003; Iglesias-Campos et al. 2015; Neumann et al. 2015; Tiquio et al. 2017), with estimates pointing to 75% of the global population living in these areas by 2025 (Riera et al. 2016). In fact, 14 out of the 17 largest cities in the world are located along the coasts, including Bangkok and Shanghai (Creel 2003). In the EU, 41% of the population lived in Europe’s coastal regions in 2011 (European Environment Agency 2015). Unfortunately, the ongoing overexploitation of such goods and services provided to human society is taking a heavy toll on coastal ecosystems. The ever-growing pressures like overexploitation of fish stocks, habitat loss, invasive species, and pollution on these areas have induced severe threats to the ecosystems’ health, leading to widespread coastal erosion, habitat destruction, biodiversity loss, contamination of soil and water resources, and poor water quality and quantity, to name a few (Lavalle et al. 2011; Iglesias-Campos et al. 2015; Riera et al. 2016). The subsequent and ongoing demand for coastal urbanization aside from land also requires freshwater availability as well as sewage systems, which inflicts damage to the coastal ecosystems (Creel 2003). For instance, with the destruction of mangroves and other coastal vegetation for urbanization, timber, or aquaculture, the capacity to buffer extreme weather events and nutrient cycling given by these species are severely impaired. Halpern et al. (2008) outlined that no marine area is unaffected by human influence and that more than 40% are strongly impacted by

Coastal Pollution: An Overview

multiple stressors, with the magnitude of anthropogenic impact higher in coastal zones compared to offshore areas. The definition of pollution formulated by the United Nations Joint Group of Experts on Marine Environmental Protection (GESAMP) is probably the most widely used and constitutes part of the protocol of several international agreements and conventions (Tomczak 1984). It reads: “Pollution means the introduction by man, directly or indirectly, of substances or energy into the marine environment (including estuaries) resulting in such deleterious effects as harm to living resources, hazards to human health, hindrance to marine activities including fishing, impairment of quality for use of sea-water, and reduction of amenities” (GESAMP 1980). Pollution is among the most significant stressors to coastal ecosystems (Islam and Tanaka 2004). From an ecological point of view, coastal pollution contributes to change or loss of biodiversity, degradation and destruction of habitats, and alteration of environmental functions and processes. As a consequence, ecosystems become more susceptible to disturbances and ecosystem services are lost. The ultimate effect of pollution on coastal resources depends on the type of pollutant, source, and intensity, with some species and ecosystems being more sensitive than others. Along with ecological consequences, the presence of pollutants in coastal areas leads to public health problems and important economic losses (Islam and Tanaka 2004). But, how do pollutants reach these areas? There are two distinct ways by which substances and energy enter the ecosystems: point sources and nonpoint or diffuse sources. Point sources are well-defined, clearly identifiable locations where the release of pollutants is usually continuous and their concentrations can be quantified (Ridolfi 2016). Examples of such are effluents from municipal and industrial wastewater treatment plants, farms, and hospital effluents, among others. The impact assessment is, therefore, more manageable in these cases. Nonpoint or diffuse sources, on the other hand, cannot be pinpointed to specific locations and generally are intermittent. In other words, pollutants originate from

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diverse activities without a specific point of discharge (Ridolfi 2016). Therefore, management of diffuse pollution is more complex and relies on the knowledge of natural and anthropogenic processes and their interconnection. As an example of this, the rainfall runoff on urban land can impact water quality by transporting oils, dust, and other urban waste to the water compartment. Agriculture is another major contributor of diffuse pollution, where pesticides, fertilizers, pharmaceuticals, nutrients, and even soil are carried into the water bodies via runoff. However, this can also be a point source in cases where waste is deliberately discharged into the water. Pollutants can be grouped according to their nature in physical, biological, and chemical stressors (Beiras 2018; Cabral et al. 2019) (Fig. 1).

Physical Pollution Temperature Temperature can act as a physical pollutant through shifts in the optimum water values, which can induce changes in the ecosystems. Climate change is unquestionably stirring things up by warming coastal waters, thus affecting circulation patterns, frequency, and intensity of coastal storms and precipitation patterns (Lu et al. 2018). One obvious consequence of thermal water pollution is the decrease in the oxygen-carrying capacity, which is inversely proportional to water temperature. So, higher temperatures will decrease the rate of dissolved oxygen in the water. Also, with higher temperatures, organic matter decomposition is accelerated, thus reducing further the concentration of oxygen available for the aquatic communities, leading in some cases to hypoxia and/or anoxia. Another consequence to changes in temperature is shifts in the communities. Organisms, such as fish, are adjusted to specific ranges of temperature, and accentuated changes can affect individuals significantly. Furthermore, chemical reactions are usually affected positively with increases in temperature, which can have a negative impact in the presence of chemical pollutants, potentiating their bioavailability to living organisms, to some extent.

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Coastal Pollution: An Overview

Coastal Pollution: An Overview, Fig. 1 Classification of main pollutants affecting coastal areas. (Source: original)

Light Light, along with temperature, can be considered a physical pollutant. Natural sources of light include the sun, moon, stars, and even bioluminescent species, in some environments. On the other hand, coastal development, offshore infrastructure, and shipping and fishing lights all contribute sources of artificial light to coastal ecosystems. Davies et al. (2014) estimated that in 2010, 22% of the world’s coastal regions (excluding Antarctica) were experiencing some degree of artificial light at night. The introduction of nighttime lighting may influence natural behaviors of organisms, restructuring ecosystems and compromising the services they provide. For instance, when the nocturnal conditions are altered due to anthropogenic lighting, benthic communities are affected through changes in their circadian rhythms changing predatory, feeding, and escape functions (Sabet et al. 2016). Differently, the absence of natural light due to high turbidity (resulting from dredging or other activities suspending particles in the water column) or eutrophication can subsequently lead to hypoxia and anoxia in the aquatic systems, due to the reduction of photosynthesis (Lillebø et al. 2005). Noise (Acoustic) Noise (acoustic) is another physical stressor polluting the coastal zones, enhanced by the large populations living in these areas, with industrialization, urbanization, shipping, and recreational

activities being major contributors to high levels of anthropogenic noise (Bittencourt et al. 2014; Sabet et al. 2016). Since sound waves diffuse very well underwater, many species use it as the primary sense to interact in their biological activities, and any disruption of this may impact them negatively (Bittencourt et al. 2014; Sabet et al. 2016). Fluctuations in the environmental conditions of the coastal communities, affecting the patterns of rest, feeding, or predatory escape (similar to the effect of light) decrease the chances of survival and reproduction (Bittencourt et al. 2014; Sabet et al. 2016). Radioactive Pollution Radioactive pollution reaches the coastal zones and marine environments primarily through discharges of contaminated water, disposal of radioactive waste originating in nuclear power plants and nuclear weapon industries, accidental spills, malfunction in equipment, and nuclear testing (Alexeev and Galtsova 2012; Posudin 2014). Elements presenting radioactivity possess very unstable nuclei and are known as radionuclides. As a result, the aquatic ecosystems are exposed to radioactive emissions, which can be divided into three types: alpha (α) particles, beta (β) particles, and gamma (U) radiation. Although radionuclides can also have a natural origin, radioactive pollutants pertain to artificial elements (Posudin 2014). Elements as strontium (90Sr) and cesium (137Cs) are among the most dangerous due to their long

Coastal Pollution: An Overview

half-life decays, 28 and 30 years, respectively (Posudin 2014). All over the decades, several accidents with devastating and lasting consequences have occurred, with Chernobyl (Ukraine, 1986) as one of the most notorious. The effects of exposure to radiation are the formation of free radicals in the organisms through the ionization of molecules with high energy resulting from radionuclides. Free radicals, in turn, react with other components causing the destruction of other structural polymers in the organism, with consequences varying from mild to severe, depending on the length and intensity of exposure (Posudin 2014). Plastics Plastics on coastal and marine ecosystems represent a problem of growing environmental concern. The planetary-scale occurrence of plastic pollution is not readily reversible and may cause currently unrecognized disruptive effects to vital Earth system processes (Jahnke et al. 2017). Since the start of the plastic industry in the 1940s, there has been a rapid and worldwide increase in plastic production, reaching almost 350 million metric tons produced per year in 2017 (PlasticsEurope 2018). The latest data suggest that in 2015, around 4900 million metric tons, i.e., 60% of all plastics ever produced to that date, were discarded and are accumulating in landfills or in the environment (Geyer et al. 2017). Littering and pellet leakage are two of the main entryways of plastics to the aquatic environment, along with runoffs from land (Burns and Boxall 2018). Plastic debris occurs on coastal areas, at the sea surface, on the seafloor, and even in Arctic sea ice (Barnes et al. 2009; Obbard et al. 2014). In fact, it has been estimated that 4.8–12.7 million metric tons of plastic waste generated in 192 coastal countries entered the ocean in 2010 (Jambeck et al. 2015). Moreover, the potential cumulative inputs of plastic in the ocean from 2010 to 2025 are predicted to be as high as 250 million metric tons (Jambeck et al. 2015). But what is plastic? According to GESAMP (2015), it can be described as a synthetic water-insoluble polymer, generally of petrochemical origin, that can be molded on heating and manipulated into various shapes designed to

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be maintained during use (Burns and Boxall 2018). Plastics can cause direct harm, with organisms in the aquatic environment getting caught in debris and ingesting pieces (Koelmans et al. 2016). The fragmentation of plastics into smaller sized particles, known as microplastics (5 mm), together with the plastics added to promote abrasion in personal care products, for instance, is enhancing the problem (Bessa et al. 2018; Burns and Boxall 2018). Accordingly, microplastics can be either primary, if intentionally produced under 5 mm, or secondary, if resulting from fragmentation of larger pieces. Microplastics can also be divided into five categories according to their origins: fragments, micro-pellets, fibers, films, and foam (Burns and Boxall 2018; Rezania et al. 2018). When ingested, microplastics can induce abrasion internally and physically alter physiological functions. Moreover, as modern plastics are a complex combination of polymers, residual monomers, and chemical additives, the consequent transfer of these substances to animal tissues increases the potential of plastics to cause harm to organisms in the aquatic ecosystems (Galloway et al. 2017). In addition, microplastics may interact with other contaminants such as metals and hydrophobic organic substances by absorbing these pollutants, contributing to their bioaccumulation (Koelmans et al. 2016).

Biological Pollution Biological pollutants refer to organisms with the potential to reduce the fitness for survival of some level of biological organization, from cell to ecosystem (Elliott 2003). Detrimental effects on the environmental quality can result from the presence of these stressors, leading to changes in the biological, chemical, and/or physical properties of the ecosystem (Olenin et al. 2011). Generally, these organisms are known as invasive alien species (sometimes referred to as exotics or nonnative invaders) whose presence in a given area results from human activities, either intentional or unintentional (Olenin et al. 2011). Changes induced can be at one or more levels: individual (internal presence of pathogens and parasites),

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population (genetic change), community (structural shift), habitat, and/or ecosystem (changes in the energy and organic matter flow) (Elliott 2003; Olenin et al. 2011). Alien species include very different organisms from viruses and bacteria to macrophytes and fish (Tricarico et al. 2016). Aquaculture, for instance, acts as a point source of biological pollution due to escapees and the release of pathogens (Buschmann et al. 2006; Arechavala-Lopez et al. 2013). According to Zenetos et al. (2012), aquaculture is the third most important pathway of introduction of marine alien species in Europe. The open design of most aquaculture systems also permits the exchange of pathogens and parasites between farmed and wild aquatic animal populations without direct contact. In addition, there is a potential risk of transmission of diseases from escapees to wild populations (Arechavala-Lopez et al. 2013). Climate change, on the other hand, can be viewed as nonpoint or diffuse source of biological pollution by inducing the migration of species to higher latitudes as a result of higher temperatures (Elliott 2003). Ecological modifications due to invasive events usually have negative impacts on the native communities and ecosystem processes, including biodiversity loss and biofouling, among others (Crespo et al. 2018).

Chemical Pollution Agrochemicals Agrochemicals refer to the array of chemical products used in agriculture, widely administered due to their high efficiency and efficacy in crop and animal productions, translated in increasing economic gains. However, agrochemicals are generally toxic and pose serious environmental risks and therefore are considered as pollutants. Agrochemicals include pesticides, fertilizers, disinfectants, salts, and even hormones, among the most widely used. Whatever is used in agriculture will find its way to the aquatic environment via leaching, precipitation runoffs, and accidental leaks from industry and storage facilities. Depending on the substance or mixture of substances, their effects may vary and even act

Coastal Pollution: An Overview

synergistically. Consequently, the presence of agrochemicals in the aquatic environment is ubiquitous, representing a health hazard to human populations and wildlife. Pesticides

Pesticides constitute a vast group of substances widely used in production fields and are classified depending on their target organisms, including herbicides (plants), insecticides (insects), fungicides (fungi), nematicides (nematodes), and even biopesticides. Herbicides, applied to control weeds and other unwanted plants, constitute over 50% of the net use of pesticides. Insecticides are the second most used category and for decades have been administered due to their high toxicity to several species of insects. However, the same toxicity affects human health with harmful consequences, and many of these substances were removed and replaced with other synthetic drugs based on natural pyrethroids, which are less toxic. Fertilizers

Fertilizers are another important group of chemical substances defined as agrochemicals. In this category, both inorganic and organic fertilizers are included. Inorganic (or mineral) refers to synthesized fertilizers that result from a manufacturing process from natural mineral deposits, whereas organic fertilizers is the term applied to manures, compost, or bonemeal resulting from animals and plants. Either way, fertilizers are applied to increase the nutrient concentrations such as nitrogen, phosphorus, and potassium to crop fields to boost the yield, representing an important economic gain. Both forms of fertilizers are applied in fields and both find their way to coastal waters. Overall, agricultural runoff is the largest source of nutrient pollution to many coastal ecosystems (Howarth 2008; Hale et al. 2015). The most serious consequence of their presence in the aquatic environment is eutrophication (Lillebø et al. 2005; Diaz et al. 2013). Eutrophication is a process that can be defined as an increasing rate of primary production and organic carbon accumulation in excess of what an ecosystem is normally adapted to processing (Lillebø et al. 2005; Smith 2009; Diaz et al.

Coastal Pollution: An Overview

2013). It usually translates in an excessive growth of algae and vegetation in coastal areas such as estuaries and lagoons, as a result of nutrient enrichment, especially nitrogen and phosphorus (Lillebø et al. 2005; Smith 2009; Diaz et al. 2013). As a consequence, the concentration of dissolved oxygen decreases, leading to situations of hypoxia in bottom waters. The association with other coastal stressors like higher water temperatures, which increase metabolic requirements and therefore oxygen consumption, worsens the problem (Lillebø et al. 2005; Smith 2009; Diaz et al. 2013). In extreme situations, high bacteria levels and even anoxia can occur, followed by formation of reduced compounds and accumulation of particulate organic matter, causing higher adverse effects on aquatic organisms, which can lead to the decline of animals living in these areas. Dead zones have spread exponentially and have serious consequences to more than 400 coastal sites throughout the world since the 1960s (Diaz et al. 2013). Without concerted efforts, coastal eutrophication is expected to increase in 20% of large marine ecosystems by 2050 (United Nations 2018). Metals Metals constitute a particular group among the chemical pollutants. Metals include metallic and metalloid elements with higher density compared to water, which are naturally occurring on earth, and some are vital in trace amounts as micronutrients for optimal growth and metabolism (Qian et al. 2015). However, when present in higher concentrations, these elements can become toxic for organisms. In the past decades, the concern with environmental contamination by metals has increased together with higher exposure. The sources of aquatic contamination include agriculture, industry, mining, smelting, water effluents, and even atmospheric and geological depositions (Tchounwou et al. 2012; Qian et al. 2015) that invariably reach the coastal zones. Once in the aquatic compartment, metals tend to accumulate in sediments, which will act as sinks for these elements and have been found to provide timeintegrated records of metal pollution (Qian et al. 2015). Several studies have focused on the issue

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reporting high sediment concentrations of elements such as aluminum (Al), iron (Fe), copper (Cu), cadmium (Cd), mercury (Hg), and lead (Pb), among the most common (Qian et al. 2015). When organisms are exposed to excessive concentrations of metals, several toxic effects can occur. Essential metals have biochemical and physiological functions in the organisms, but when in high concentrations, cellular and tissue damage can occur as a result of a stimulation of counter stress processes, such as the induction of antioxidant enzymes, physiological impairment, and extra energy consumption (Tchounwou et al. 2012; Qian et al. 2015). Other interactions induce DNA damage and conformational changes that have the potential to interfere with cell cycle modulation carcinogenesis and apoptosis (Tchounwou et al. 2012). Polycyclic Aromatic Hydrocarbons (PAHs) Polycyclic aromatic hydrocarbons (PAHs) designate a group of organic compounds containing only carbon and hydrogen fused in two or more benzene rings, with linear, cluster, or angular arrangements. These substances are nonpolar, uncharged, highly lipophilic, and persistent (Abdel-Shafy and Mansour 2016; Sun et al. 2018), resulting unintentionally from the incomplete combustion of organic materials such as coal, oil, and wood. However, PAHs are commercially used as industrial intermediaries in the production of pharmaceuticals, agrochemicals, lubricants, and electronics, among others (Abdel-Shafy and Mansour 2016; Sun et al. 2018). Depending on the source, PAHs can be divided into pyrogenic (resulting from exposure of organic substances to high temperatures under low or anoxic conditions), petrogenic (formed from crude oil maturation and similar processes), and biological (synthesized from plants and bacteria and organic matter decomposition) (AbdelShafy and Mansour 2016; Sun et al. 2018). The presence of PAHs in the coastal zones has several sources. It can result from atmospheric deposition after organic matter combustion, volcanoes, fires, vehicle exhaust, and industry, to name a few (Abdel-Shafy and Mansour 2016; Sun et al. 2018). Soils and sediments also constitute sinks

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for PAHs, which bond with particles, and even though they tend to stay bonded due to their nonpolarity, they do present some polarity; thus, they can dissolve in the pore water and find their way to the aquatic environment (Abdel-Shafy and Mansour 2016; Sun et al. 2018). The effects of these pollutants and the extent of their toxicity will depend on several factors and are more toxic to aquatic organisms. As other chemical pollutants, PAHs can be bioaccumulated due to their high lipophilicity, but biomagnification is not likely due to metabolic degradation. Depending on their concentration, toxic effects include inflammation, decreased immunity, kidney and liver damages, genotoxicity, teratogenicity, and carcinogenicity (Abdel-Shafy and Mansour 2016; Sun et al. 2018). Persistent Organic Pollutants (POPs) Persistent organic pollutants (POPs) are defined by the World Health Organization (WHO) as “chemicals of global concern due to their potential for long-range transport, persistence in the environment, ability to bioaccumulate and biomagnify in ecosystems, as well as their significant negative effects on human health and the environment.” These carbon-based chemicals remain unaltered physically and chemically in the environment for long periods of time (i.e., years) and are able to accumulate in fatty tissues in the organisms, which coupled to their persistency and toxicity, potentiate the negative effects to human and environmental health. The bioaccumulation and biomagnification of POPs through the trophic webs constitute cause for concern, as the effects they induce include reproductive disorders, carcinogenesis, and endocrine disruption, among others. The severity of the environmental presence of POPs induced the creation of an international treaty together with the United Nations Environment Programme, called the Stockholm Convention, that aims to protect human and environmental health from these chemicals. Emissions from land-based activities were considered to be the major source of POPs in the coastal areas, especially in estuaries, and higher levels of POPs usually occurred in populated, urbanized, and industrialized zones (Lu et al. 2018). Among the

Coastal Pollution: An Overview

most known POPs are the polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs). Due to their hydrophobic characteristics, these compounds strongly adsorb to suspended and bottom sediments in the aquatic environment, originating sinks as well as sources of contamination, especially for benthic organisms that will bioaccumulate these substances (Nunes et al. 2011). Through biomagnification, the upper levels of the trophic webs will present high concentrations of these chemicals (Nunes et al. 2011). Human exposure is also a serious concern as the dietary intake of aquatic organisms will expose them to contamination, with the subsequent potential negative effects. Pharmaceuticals Pharmaceuticals are known as emerging pollutants, not because they are newly discovered substances but due to the increasing focus given to environmental health together with advances in analytical methods, which allow the detection and monitoring of these contaminants, present in most cases, at very low concentrations (ng/L to mg/L). Although many may be rapidly degraded, the pharmaceuticals are continuously released into the environment and thus are described as pseudo-persistent (Leston et al. 2011; Desbiolles et al. 2018). These pollutants reach the aquatic environment from multiple sources, including pharmaceutical industry, wastewater treatment plants, domestic and hospital effluents, and veterinary runoff (e.g., farms, aquaculture) (Li et al. 2018; Desbiolles et al. 2018). Pharmaceuticals are specifically tailored to be biologically active, and after ingestion, due to incomplete absorption and metabolism, their activity can still be sufficient to cause effects in nontarget organisms in the environment (Leston et al. 2011; Kümmerer 2009). In other cases, the resulting metabolites may also induce adverse effects. Moreover, pharmaceuticals are designed to easily permeate cell barriers increasing the risks of bioaccumulation and biomagnification in aquatic organisms through the trophic web (Leston et al. 2011; Kümmerer 2009). Antibiotics are a group of pharmaceuticals to which special concern has been given due to the increase of resistant

Coastal Pollution: An Overview

strains of bacteria, in other words, bacterial resistance.

Future Directions The United Nations Sustainable Development Goal 14 (SDG 14) – Life below water – recognizes the environmental, economic, and social benefits that healthy oceans provide and that coastal marine resources and services are being destroyed by a range of pressures such as pollution, overfishing, and climate change. The expansion of protected areas for marine biodiversity, intensification of research capacity, and increase in ocean science funding remain critically important to preserving the coastal and marine ecosystems. The SDG 14 covers seven targets and three means of implementation to respond to the urgent need for transformative change toward more sustainable practices. It is worth pointing out the interdependencies among the SDG 14 targets, since some can reinforce each other, while others may have offsetting effects (Unger et al. 2017). The SDG target 14.1, the one directly related to coastal pollution, aims to prevent and significantly reduce marine pollution of all kinds, in particular from land-based activities, including marine debris and nutrient pollution. Meeting this target will support accomplishing: target 14.2, which intends to sustainably manage and protect marine and coastal ecosystems to avoid significant adverse impacts, including by strengthening their resilience, and take action for their restoration in order to achieve healthy and productive oceans; target 14.4, which is focused on effectively regulating harvesting and ending overfishing; illegal, unreported, and unregulated fishing; and destructive fishing practices and implementing sciencebased management plans, in order to restore fish stocks in the shortest time feasible, at least to levels that can produce maximum sustainable yield as determined by their biological characteristics; target 14.5, aiming to conserve at least 10% of coastal and marine areas, consistent with national and international law; and lastly, target 14.7, directed to increase the economic benefits to

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Small Island Developing States and least developed countries from the sustainable use of marine resources, including through sustainable management of fisheries, aquaculture, and tourism (Le Blanc et al. 2017). In view of the present challenges in the implementation of SDG 14 targets, a better understanding of the status and major threats to the coastal and marine ecosystems at several levels is required. Most studies focus on a regional or national scale; however, a global overview of major pollution issues caused by excess nutrients or plastics has not been conducted and is essential for a successful sustainable management of coastal zones (Lu et al. 2018). A considerable degree of collective action is required to drive change. Multi-stakeholder dialogues, international cooperation, and data sharing play an important role for understanding the complex nature of ocean science and supporting sustainable decision-making. Comprehensive monitoring is also crucial since it is the foundation of risk assessment and management. However, while real-time monitoring is essential to provide a scientific basis for the utilization and protection of coastal areas, it is challenging to implement an integrated observation system at the global level (Lu et al. 2018). This is accompanied by a lack of international harmonization of measurement methodologies, which can have implications for interpretation and comparability. Cooperation among governments and agencies can thus be more efficient if definitions, standard methods, and instrumentation for data collection are established. Implementation of target 14.1 is also hampered by the difficulty in negotiating change across the full pathway of the problem and a lack of resources and capacity for delivery in developing countries. Large gaps exist between developing and developed countries in the ability to provide comprehensive monitoring infrastructure and consistent data (Lu et al. 2018). Another challenge is related with the fact that coastal and marine pollution is often a transboundary issue that affects areas far from the source of the pollutants, which can be on land or at sea. As a result, responsibilities for cleanup operations tend be poorly established.

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In sum, a real commitment to cooperate across geographical, institutional, and sectoral boundaries, particularly for on-the-ground implementation, is needed. Nevertheless, some valuable actions are already underway such as the Agreement on Cooperation on Marine Oil Pollution Preparedness and Response in the Arctic (Arctic Council 2013) and the UN’s Clean Seas campaign (Clean Seas 2017).

Cross-References ▶ Coastal Zone ▶ Estuary ▶ Marine Microplastics: Chemical, Physical, Biological, and Social Perspectives ▶ Metal Contamination in Marine Resources ▶ Nature and Occurrence of Hydrocarbons ▶ Pharmaceuticals Contamination: Problematic and Threats for the Aquatic System

References Abdel-Shafy HI, Mansour MSM (2016) A review on polycyclic aromatic hydrocarbons: source, environmental impact, effect on human health and remediation. Egypt J Pet 25:107–123 Alexeev DK, Galtsova VV (2012) Effect of radioactive pollution on the biodiversity of marine benthic ecosystems of the Russian Arctic shelf. Pol Sci 6:183–195 Arctic Council (2013) Agreement on cooperation on marine oil preparedness and response in the Arctic. http://oaarchive.arctic-council.org/handle/11374/529. Accessed 17 Dec 2018 Arechavala-Lopez P, Sanchez-Jerez P, Bayle-Sempere JT et al (2013) Reared fish, farmed escapees and wild fish stocks – a triangle of pathogen transmission of concern to Mediterranean aquaculture management. Aquac Environ Interact 3:153–161 Barnes DKA, Galgani F, Thompson RC et al (2009) Accumulation and fragmentation of plastic debris in global environments. Philos Trans R Soc B 364:1985–1998 Beiras R (2018) Marine pollution: sources fate and effects of pollutants in coastal ecosystems. Elsevier, Amsterdam Bessa F, Barría P, Neto JM et al (2018) Occurrence of microplastics in commercial fish from a natural estuarine environment. Mar Pollut Bull 128:575–584 Bittencourt L, Carvalho RR, Lailson-Brito J et al (2014) Underwater noise pollution in a coastal tropical environment. Mar Pollut Bull 83:331–336

Coastal Pollution: An Overview Burke L, Kura Y, Kassem K et al (2001) Pilot analysis of global ecosystems – coastal ecosystems. Available via World Resources Institute. https://www.wri.org/publi cation/pilot-analysis-global-ecosystems-coastal-ecosys tems. Accessed 10 Dec 2018 Burns EE, Boxall ABA (2018) Microplastics in the aquatic environment: evidence for or against adverse impacts and major knowledge gaps. Environ Toxicol Chem 37:2776–2796 Buschmann AH, Riquelme VA, Hernández-González MC et al (2006) A review of the impacts of salmonid farming on marine coastal ecosystems in the southeast Pacific. ICES J Mar Sci 63:1338–1345 Cabral H, Fonseca V, Sousa T et al (2019) Synergistic effects of climate change and marine pollution: an overlooked interaction in coastal and estuarine areas. Int J Environ Res Public Health 16:1–17 Clean Seas (2017) Clean Seas – turn the tide on plastic. http://www.cleanseas.org/. Accessed 25 Oct 2019 Creel L (2003) Ripple effects: population and coastal regions. Available via Population Reference Bureau. Accessed 12 Nov 2018 Crespo D, Solan M, Leston S et al (2018) Ecological consequences of invasion across the freshwater–marine transition in a warming world. Ecol Evol 8:1807–1817 Davies TW, Duffy JP, Bennie J et al (2014) The nature, extent, and ecological implications of marine light pollution. Front Ecol Environ 12:347–355 Desbiolles F, Malleret L, Tiliacos C et al (2018) Occurrence and ecotoxicological assessment of pharmaceuticals: is there a risk for the Mediterranean aquatic environment? Sci Total Environ 639:1334–1348 Diaz RJ, Eriksson-Hägg H, Rosenberg R (2013) Hypoxia. In: Noone KJ, Sumaila UR, Diaz RJ (eds) Managing ocean environments in a changing climate: sustainability and economic perspectives. Elsevier, Burlington, pp 67–96 Elliott M (2003) Biological pollutants and biological pollution – an increasing cause for concern. Mar Pollut Bull 46:275–280 European Environment Agency (2015) The European environment: state and outlook 2015 – marine environment. http://www.eea.europa.eu/soer-2015/europe/ marine-and-coastal#tab-based-on-indicators. Accessed 11 Oct 2018 Galloway TS, Cole M, Lewis C (2017) Interactions of microplastic debris throughout the marine ecosystem. Nat Ecol Evol 1(5):0116 GESAMP (1980) Report of the eleventh Session. IMO/ FAO/UNESCO/WMO/WHO/IAEA/UN/UNEP Joint Group of Experts on the Scientific Aspects of Marine Pollution. Reports and Studies No. 10. http://www. gesamp.org/publications/report-of-the-11th-session. Accessed 12 Aug 2019 GESAMP (2015) Sources, fate and effects of microplastics in the marine environment: a global assessment. In: Kershaw PJ (ed). IMO/FAO/UNESCO-IOC/UNIDO/ WMO/IAEA/UN/UNEP/UNDP Joint Group of Experts on the Scientific Aspects of Marine

Coastal Pollution: An Overview Environmental Protection. Reports and Studies No. 90. http://www.gesamp.org/publications/reports-and-stud ies-no-90. Accessed 30 Jan 2019 Geyer R, Jambeck JR, Law KL (2017) Production, use, and fate of all plastics ever made. Sci Adv 3(7):e1700782 Hale RL, Grimm NB, Vorosmarty CJ et al (2015) Nitrogen and phosphorus fluxes from watersheds of the northeast US from 1930 to 2000: role of anthropogenic nutrient inputs, infrastructure, and runoff. Glob Biogeochem Cycles 29:341–356 Halpern BS, Walbridge S, Selkoe KA et al (2008) A global map of human impact on marine ecosystems. Science 319:948–952 Hinrichsen D (1998) Coastal waters of the world: trends, threats, and strategies. Island Press, Washington, DC Howarth RW (2008) Coastal nitrogen pollution: a review of sources and trends globally and regionally. Harmful Algae 8:14–20 Iglesias-Campos A, Meiner A, Bowen K et al (2015) Coastal population and land use changes in Europe: challenges for a sustainable future. In: Baztan J, Chouinard O, Jorgensen B et al (eds) Coastal zones: solutions for the 21st century. Elsevier, Amsterdam, pp 29–49 Islam MS, Tanaka M (2004) Impacts of pollution on coastal and marine ecosystems including coastal and marine fisheries and approach for management: a review and synthesis. Mar Pollut Bull 48:624–649 Jahnke A, Arp HP, Escher BI et al (2017) Reducing uncertainty and confronting ignorance about thepossible impacts of weathering plastic in the marine environment. Environ Sci Technol Lett 4:85–90 Jambeck JR, Geyer R, Wilcox C et al (2015) Plastic waste inputs from land into the ocean. Science 347:768–771 Koelmans AA, Bakir A, Allen Burton G et al (2016) Microplastic as a vector for chemicals in the aquatic environment: critical review and model-supported reinterpretation of empirical studies. Environ Sci Technol 50:3315–3326 Kümmerer K (2009) Antibiotics in the aquatic environment – a review – part I. Chemosphere 75:417–434 Lavalle C, Rocha Gomes CP, Baranzelli C (2011) Coastal zones – policy alternatives impacts on European coastal zones 2000–2050. JRC technical notes. Publications Office of the European Union, Luxembourg. http://op. europa.eu/en/publication-detail/-/publication/b57abcbd7a58-4ee3-a78f-315d6b6b0564/language-en. Accessed 23 Oct 2019 Le Blanc D, Freire C, Vierros M (2017) Mapping the linkages between oceans and other sustainable development goals: a preliminary exploration. United Nations Department of Economic and Social Affairs. DESA working paper No. 149. http://www.un.org/ development/desa/publications/working-paper/wp149. Accessed 23 Oct 2019 Leston S, Nunes M, Viegas I et al (2011) The effects of the nitrofuran furaltadone on Ulva lactuca. Chemosphere 82:1010–1016

165 Li S, Shi W, Li H et al (2018) Antibiotics in water and sediments of rivers and coastal area of Zhuhai City, Pearl River estuary, south China. Sci Total Environ 636:1009–1019 Lillebø AI, Neto JM, Martins I et al (2005) Management of a shallow temperate estuary to control eutrophication: the effect of hydro- dynamics on the system nutrient loading. Estuar Coast Shelf Sci 65:697–707 Lu Y, Yuan J, Lu X et al (2018) Major threats of pollution and climate change to global coastal ecosystems and enhanced management for sustainability. Environ Pollut 239:670–680 Neumann B, Vafeidis AT, Zimmermann J et al (2015) Future coastal population growth and exposure to sealevel rise and coastal flooding – a global assessment. PLoS One 10(3):e0118571 Nunes M, Marchand P, Vernisseau A et al (2011) PCDD/ Fs and dioxin-like PCBs in sediment and biota from the Mondego estuary (Portugal). Chemosphere 83:1345–1352 Obbard RW, Sadri S, Wong YQ et al (2014) Global warming releases microplastic legacy frozen in Arctic Sea ice. Earths Future 2:315–320 Olenin S, Elliott M, Bysveen I et al (2011) Recommendations on methods for the detection and control of biological pollution in marine coastal waters. Mar Pollut Bull 62:2598–2604 PlasticsEurope (2018) Plastics – the Facts 2018: an analysis of European plastics production, demand and waste data. http://www.plasticseurope.org/en/resources/publi cations/619-plastics-facts-2018. Accessed 22 Oct 2019 Posudin Y (2014) Methods of measuring environmental parameters. Wiley, Hoboken Qian Y, Zhang W, Yu L et al (2015) Metal pollution in coastal sediments. Curr Pollut Rep 4:203–219 Rezania S, Park J, Din MFM et al (2018) Microplastics pollution in different aquatic environments and biota: a review of recent studies. Mar Pollut Bull 133:191–208 Ridolfi KC (2016) Nonpoint source pollution In. In: Kennish MJ (ed) Encyclopedia of estuaries. Elsevier, Amsterdam, pp 456–461 Riera R, Menci C, Sanabria-Fernández JA et al (2016) Do recreational activities affect coastal biodiversity? Estuar Coast Shelf Sci 178:129–136 Sabet SS, Van Dooren D, Slabbekoorn H (2016) Son et lumière: sound and light effects on spatial distribution and swimming behavior in captive zebrafish. Environ Pollut 212:480–488 Smith VH (2009) Eutrophication. In: Likens GE (ed) Encyclopedia of inland waters. Academic, Oxford, pp 61–73 Sun R, Sun Y, Qing XL et al (2018) Polycyclic aromatic hydrocarbons in sediments and marine organisms: implications of anthropogenic effects on the coastal environment. Sci Total Environ 640–641:264–272 Tchounwou PB, Yedjou CG, Patlolla AK et al (2012) Heavy metals toxicity and the environment. In: Luch A (ed) Molecular, clinical and environmental toxicology. Experientia supplementum, vol 101. Springer, Basel, pp 133–164

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166 Tiquio MGJP, Marmier N, Francour P (2017) Management frameworks for coastal and marine pollution in the European and South East Asian regions. Ocean Coast Manag 135:65–78 Tomczak M (1984) Defining marine pollution: a comparison of definitions used by international conventions. Mar Policy 8:311–322 Tricarico E, Junqueira A, Dudgeon D (2016) Alien species in aquatic environments: a selective comparison of coastal and inland waters in tropical and temperate latitudes. Aquat Conserv 26:872–891 Unger S, Müller A, Rochette J et al (2017) Achieving the sustainable development goal for the oceans. IASS policy brief 1. http://publications.iass-potsdam.de/ pubman/item/escidoc:2041892. Accessed 24 Oct 2019 United Nations (2018) The sustainable development goals report 2018. http://www.un.org/development/desa/pub lications/the-sustainable-development-goals-report2018.html. Accessed 17 Jan 2019 Zenetos A, Gofas S, Morri C et al (2012) Alien species in the Mediterranean Sea by 2010. A contribution to the application of European Union’s Marine Strategy Framework Directive (MSFD). Part 2. Introduction trends and pathways. Mediterr Mar Sci 13(2):328–352

Coastal Processes ▶ Coastal Defenses and Engineering Works

Coastal Resources ▶ Impacts of COVID-19 Pandemic on Marine Resources and Livelihoods

Coastal Wetland ▶ Coastal Zone and Wetland Ecosystem: Management Issues

Coastal Zone ▶ Coastal Zone and Wetland Ecosystem: Management Issues

Coastal Processes

Coastal Zone and Wetland Ecosystem: Management Issues Prabal Barua1, Syed Hafizur Rahman1 and Saeid Eslamian2 1 Department of Environmental Sciences, Jahangirnagar University, Savar, Dhaka, Bangladesh 2 Department of Water Engineering, College of Agriculture, Center of Excellence in Risk Management and Natural Hazards, Isfahan University, Isfahan, Iran

Synonyms Biodiversity; Coastal pollution; Coastal wetland; Coastal zone; Coral reef

Definitions The coastal zone can be defined in various ways depending on the heart of interest and the availability of relevant data. According to the Millennium Ecosystem Assessment, 100 km from the coast as the distance door sill and 50 m as the elevator door sill, choosing whichever was closer to the sea. So, the interaction between the land and water is considered a coastal zone where the majority of the world’s populations live in the zone. About 40% of the global population inhabiting within 100 km of the coastline. This zone rapidly changing because of the active boundary between the oceans and the land. Winds and waves of the estuarine rivers across the coastal areas are equally eroding the rocks and sediment depositing regularly basis, and erosion rates and deposition noticeably from day to day in the coastal zone. On the other hand, the wetlands are fundamental for the survival of humanity (Islam et al. 2014). On the other hand, wetland can be defined as the areas where water covers the soil or is in attendance either at or near the soil surface all year or for anecdotal periods during the year, as well as during the growing season. There

Coastal Zone and Wetland Ecosystem: Management Issues

are two common types of wetlands that are recognized in the world which are coastal or tidal wetlands and inland or nontidal wetlands. Wetlands are active aquatic ecosystems established all over the world. A wetland is an area of land which is drenched with water either lastingly or seasonally (Thanh and Yabar 2015).

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of the earth’s land surface. Among the total population of Asia, 4 billion, 60% people live within 400 km of the coast. Approximately, 1.5 billion people live within 100 km of the sea. The total coastal population of Latin America and the Caribbean countries is nearly around 600 million; three-quarters of them live within 200 km of a coast (Pictures 1 and 2).

Introduction Coastal Landform Coastal environment of the worldwide nations is repeatedly changing as a result of the interactions among the ocean, winds, currents, waves, and anthropocentric variables. Sustainability of coastal ecosystems is contingent on the degree of use of the coast by the stakeholders and the external impacts that occur such as natural disasters. However, the extent of coastal use and external impacts may underwrite the impact of global warming and increase it significantly. Coastal areas supply the grave ecological services like nutrient cycling, flood control, the stability of the shoreline, beach replacement, and genetic resources. The ocean and coastal systems added 63% of the total value of the world’s ecosystem services. The increasing population is a major apprehension for the coastal areas with more than 50% of the world’s inhabitants concentrated within 60 km of the coast. The continued growth of the world population and of per capita consumption has the consequences of unsustainable exploitation of the world’s biological diversity, which worsens with the climate change, acidification of the ocean, and other anthropogenic environmental effects. The effective conservation of biodiversity is necessary for the survival of humans and the maintenance of ecosystem processes (Barua et al. 2017; Barua et al. 2020; Eslamin et al. 2020). Human populations have a stunning impact on the eminence of coastal environments in the world. A full two-thirds of the world’s population, 4 billion people lives within 400 km of a coastal area. Just over half of the world’s population around 3.2 billion people occupy a coastal strip 200 km wide (120 miles), representing only 10%

There are two major categories of coastal morphology, which are dominated by coastal erosion and other is coastal deposition process. They demonstrate distinctly different landforms, though every category might contain various features of the other. In common, erosionprone coasts are those with no or little sediment, while depositional coasts are illustrious by abundant sediment accretion over the long term. Both temporal and geographic variations may occur in each of these coastal types. Communities have always been haggard to the coastal areas for recreation, livelihood, food, and trade activities. Over the last half century, coastal population increases and increasing rate of land use changes have endangered the functions of ecosystem that are significant to maintain animal and plant communities, the suitability of safe drinking water supplies, and ability to crop the historically plentiful aquatic resources from our estuaries, bays, and the oceans surrounded by the coastal environments. Economic as well as technological development and populations growth are threatening the ecosystems in the coastal zone. The wagers riding on future management verdicts impacting the coastal zone are bulky. On the one hand, approaches of the traditional management have not been sufficient to stop environmental squalor and related losses. There is an obvious need for the social, scientific, supervisory management and policy, coastal communities to overcome traditional obstacles to assist a more integrated management approach to inform and steer the decisions in the coastal areas (Small and Nicholls 2003; Lichter et al. 2011).

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Coastal Zone and Wetland Ecosystem: Management Issues

Coastal Zone and Wetland Ecosystem: Management Issues, Picture 1 General view of a coastal area and mangrove wetland

Coastal Ecosystem Coastal zones are tremendously susceptible to the environmental degradation. The physical configuration within each of the zones is enormously significant, providing a specific environmental function for the community of organisms that exist in a zone. The weather is a major factor impacting all of the coastal zones. Storms enhanced the already powerful pounding of waves against the shore. This can modify the physical structure by breaking rocks down or redistributing sediments. Coastal wetlands: The earth has been covered mostly by coastal wetlands, counting salt marshes and mangrove swamps. Over the last century, the mangrove forests have been destroyed or revoltingly degraded. 50 million hectares are predictable to have been destroyed or revoltingly degraded. Mangrove wetlands gifted the rich home for over 2,000 species of fish, shellfish,

invertebrates, and plants all over the world. There are about 80 species of salt-tolerant trees at present inhabiting about 22,000 square km of intertidal, lagoonal, and riverine flatlands throughout the earth (Picture 3). Coral reefs: Coral reefs, the rainforests of the ocean, are being destroyed in the name of development. Of the earth’s 600,000 square km of reefs available in the tropical and semitropical oceans. Coral reefs are speculated of biological diversity, helping upwards of one million species and giving humankind a lot of profits. They help to cushion waves and protect the shorelines from the problem of erosion; they assist in the transfer of nutrients from the land to the open ocean; they provide the feeding, breeding, and nursery areas for many commercially important species of fish and shellfish and offer scientists a pharmacopeia of potential medicines. Yet, they are fast disappearing. In 1997, a global effort to assess the status of coral resources was carried out by the Reef Check,

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Coastal Zone and Wetland Ecosystem: Management Issues, Picture 2 Fishing is the main occupation for coastal communities

Coastal Zone and Wetland Ecosystem: Management Issues, Picture 3 Fishermen catching fishes around the area of coastal wetland

organized by the Hong Kong University. The study used professional and recreational divers to chart the health of 300 reefs in 30 countries.

According to the survey, less than one-third of all reefs had a healthy, living coral cover, while twothirds were seriously degraded. The Caribbean

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Functions of Wetland Ecosystem

Functions of Hydrological factors

Rentention of Flood water Recharge of surface and ground weater

Functions of Biogeochemical factors

Functions of Ecological factors

Retention of Nutrient and salinity intrusion in water and soils

Nursery and habitat inhabitants of nursing plants, biodiversity, microorganisms and animals, structural diversity and scenery

Benefits of Socio-economic perspectives

Option of flood defense, reduction of flood water storage capacity, damages of property assets

water quality improvement

Grading and fishing

Disposal of medicinal plants and genetic waste

Coastal aquaculture

Irrigation and Industrial purposes Helping for sustainable food chains

Trades and sequences

Transport of Water supply and balance of sediment fragility

Decontamination and onslaught of fish breeding

Crops silage and places of fuel settlements Tradition and cultural values Artistic values Values of religious and heritage

Safeguarding of Ecosystem Retention of Toxicants

Recreation and Eco-tourism Job employment of the poor

Coastal Zone and Wetland Ecosystem: Management Issues, Fig. 1 Different types of wetland ecosystem functions. (Islam 2010)

had the lowest rate of living coral, an average of only 22%. Southeast Asia was second, with only 30% of its coral reefs in good to excellent condition; coral reefs in good to excellent condition must have 50% or more of their area in living coral. Wetlands are dispersed unevenly throughout the various climatic regions of the earth due to the dissimilarity in climate, geology, and water sources. Wetlands occur in broadly assorted settings ranging from coastal borders, where tides and river release are the main source of water, to elevated mountain valleys where rain and snowmelt are the primary source of water. There are

three main functions of wetland ecosystem which are biogeochemical, ecological, and hydrological factors that providing purposes are giving the socioeconomic profits to the local stakeholders and communities and around the wetland ecosystem (Fig. 1).

Coastal Pollution A composite mixture of the anthropogenic pollutants poses a serious threat to the coastal environment. Sewage effluents include the domestic and industrial wastes, dredging, vessels dumping

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cargo at sea, and atmospheric deposition of airborne pollutants. Nitrogen and phosphorus are the most common limiting nutrients in coastal waters, and their availability determines the species composition and growth of plants, which in turn affects the entire ecosystem. In most developing countries, sewage is discharged untreated or only partially treated into rivers, lagoons, and coastal waters via short outfalls, with little attention to advanced planning. Human sewage (together with pathogenic organisms) and agricultural runoff (with increasing numbers of inorganic fertilizers) are particularly rich in nitrogen and phosphorous, and form the major source of pollution in coastal waters. Coral reefs grow only in clear waters with low nutrients. Nutrient pollution creates the algal blooms that cloud the water and limit the sunlight reaching the corals (Brown et al. 2013; Vikas and Dwarakish 2015). Chemicals, such as trace metals, radionuclides, and petroleum residues, become toxic environmental contaminants when discharged in excessive concentrations. Many contaminants become associated with the sediments and may remain sequestered until resuspended by waves and currents or until sediments are disturbed by dredging activities. Synthetic compounds are becoming increasingly important chemical pollutants in the sea. Among the most persistent ones are the chlorinated hydrocarbon pesticides used in agriculture (PCBs, DDT), dioxins from incinerators and paper mills, organotins (TBT) used as antifoulants, and oil dispersants that are toxic and cause the oil to sink on the benthic communities. The main concern for the toxic chemicals is long-term effects as many of them are persistent in the environment and become concentrated through the trophic chain. In exposed marine organisms, toxins can cause death, disease, reduced reproductive success, and developmental aberrations.

Integrated Coastal Zone Management Why is the management of coastal and ocean resources so difficult for sustainable conservation? Coastal areas contain many different

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jurisdictions – local, regional, and national – and involve different interests. Integrated Coastal Zone Management (ICZM) is a resource management approach following an integrative, holistic approach and an interactive planning process in addressing the complex management issues in the coastal area. This concept was born in 1992 during the Earth Summit of Rio de Janeiro. The European Commission defines ICZM as “a dynamic, multidisciplinary and iterative process to promote sustainable management of coastal zones. It covers the full cycle of information collection, planning (in its broadest sense), decision making, management, and monitoring of implementation. A well-informed science-based coastal zone management strategy embedded in an adequate social, institutional, and legal framework can prevent many future coastal problems. This is now usually called ICZM, Integrated Coastal Zone Management (Barua et al. 2017; Barua et al. 2020).

Threats to Coastal Biodiversity Coastal biodiversity is hampered because of the different human activities which could also be the ways that humans threaten marine biodiversity. This can be grouped into proximate threats and root causes; the former is driven by the latter. Concerns may differ from region to region, reflecting local situations and priorities. The main types of the human activities that damage marine organisms and ecosystems are overexploitation, physical alterations and habitat loss, pollution, the introduction of alien species, and global climate change (Picture 4). Coastal ecosystems are an important source of essential products for mankind, such as foods, medicines, raw materials, and recreational facilities. The ever-growing exploitation of coastal resources is a reflection of the population increase, the most important root cause for biodiversity loss. Tourist populations, generally concentrated in a few areas, increase the local exploitation for specific crustaceans such as lobsters, crabs, and prawns (Bakshi and Panigrahi 2015) (Picture 5).

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Coastal Zone and Wetland Ecosystem: Management Issues, Picture 4 Mangrove forest is available in the bank of estuarine river

Coastal Zone and Wetland Ecosystem: Management Issues, Picture 5 People are busy to collect prawn and fish fry from the seashore

Coastal Zone and Wetland Ecosystem: Management Issues

Many marine organisms, including corals, sponges, mollusks, echinoderms, puffer and trigger fishes, and turtles, are collected widely for curios or jewelry. The overfishing of shallow inshore populations can have serious local effects on these species and their habitat. Other overexploited marine products are stony corals for building material and mangroves for fuelwood and timber. These activities have contributed to species. Overexploitation not only reduces the specific populations and causes lower economic returns but also causes the genetic changes in the exploited populations and alters trophic relationships among species. Marine organisms are part of intricate food webs, involving multiple trophic levels at several spatial and temporal scales. The removal of species frequently leads to the losses of other species and to the changes in communities, food webs, and key species (Airoldi et al. 2008).

Wetland Ecosystem According to the life of many ecologically and economically important species, the wetlands are considered as the home for at least part of their life. For instance, commercially important fishes and shellfish, including shrimp, blue crab, oysters, salmon, trout and sea trout, rely on or are associated with wetlands. Wetlands are also critical habitat for migratory birds and waterfowl, including ducks, egrets, and geese. In fact, more than onethird of the species listed as threatened or endangered in the world live solely in wetlands, and nearly half use wetlands at some point in their lives (Brij Gopal and Chauhan 2006). Wetlands can be classified as in-stream systems, riparian systems, isolated basins, and coastal (fringe) systems (Table 1). The different types of wetlands can provide different values. Large amounts of water and inflows approximately equal outflows are main characteristics for formation of In-stream wetlands process. But the high productivity of these systems translates to enhance the aquatic food chains and the export of detrital material. This location is particularly vulnerable during

173 Coastal Zone and Wetland Ecosystem: Management Issues, Table 1 Characteristics of different types of wetland Wetland In-stream wetland Riparian wetland

Isolated wetland Coastal wetland

Enhanced values Fisheries resources, organic export Retention of sediments; wetland wildlife passage; control of flood; retention of nitrogen and phosphorus; migratory songbirds Recharge of groundwater; control of flood; waterfowl and amphibians Fisheries; offshore productivity; waterfowl; storm buffer

flooding and might be unpredictable in its ultimate stability. It has the advantage of potentially “treating” a significant portion of the water that passes that point in the stream. A riparian wetland fed primarily by a flooding stream allows the flood events of a river to deposit sediments and chemicals on a seasonal basis in the wetland. The wetland captures the flooding water and sediments and slowly releases the water back to the river after the flood passes. Riparian systems provide corridors for the animal movement along the river, and also a zone of transition between uplands and aquatic systems in the transverse direction. Coastal or fringe systems, as generally found along coastlines, are important to productivity in the offshore waters (Giri et al. 2011; Rana et al. 2009) (Picture 6).

Management of Coastal Wetland and Challenges Coastal wetlands offer a critical interface between the terrestrial and marine environments, and their significance to global sediment and nutrient budgets is much higher than their proportional surface area on earth would suggest. The coastal wetlands play an important role in supporting a wide spectrum of biodiversity characterized by the presence of water-dependent species of plants and animals along the coast, as well as maintaining many natural cycles. These diverse and complex ecosystems provide the goods and services that

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Coastal Zone and Wetland Ecosystem: Management Issues, Picture 6 Coastal wetlands are enrish of aquatic biodiversity

contribute to the nation’s economy. The ecosystem services provided by these wetlands to the communities are broadly classified as provisioning services, regulating services, supporting services, and cultural services (Berkes 2010). The coastal wetlands face various challenges due to the complex interactions among physical, biological, and anthropogenic factors. The human populations are concentrated along the coasts, which has affected and altered the coastal ecosystems worldwide (Picture 7). The anthropogenic pressures include those from industrial, agricultural, aquaculture, and urban developmental activities, which result in the discharge of wastes into waterways, overexploitation of the coastal and marine resources, and the physical alteration and destruction of

habitats. The waste disposed into the rivers and estuaries ultimately reaches the coastal waters and contributes to eutrophication and the deterioration of the water quality. Reclamation of wetlands, as well as encroachment for the various activities, has also shrunk the extent of the wetlands in many places. Furthermore, the coastal wetlands are also threatened by climate change, including the increasing temperature, sea-level rise (SLR), and other extreme events (Luyet et al. 2012). The South Asian region is rich in biological diversity, especially in the marine environmental realm. The countries recognize the importance of their coastal resources as they form the livelihood basis for a large proportion of the population. The countries undertake different modes of

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Coastal Zone and Wetland Ecosystem: Management Issues, Picture 7 Coastal erosion is the most common scenario in the coastal area

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action to prevent deterioration of the quality of coastal wetlands. Every country possesses specific legislative and policy frameworks, which address and regulate the concerned resources/ activities to minimize the threats to the environment and natural resources. Additionally, they all have given importance to the natural disasters that frequently hit the coastal regions of South Asia due to climate change (Barua et al. 2020) (Picture 8). However, a comparative regional assessment makes clear that there are voids to be filled by each country in addressing their issues relating to their coastal wetland management. Though all the South Asian countries have defined their coastal boundaries, India is the only country among the five coastal states of South Asia, which has demarcated and mapped the coastal zones for better regulatory purposes. There are many reasons that compound the resource depletion in the South Asian region need to be addressed and resolved (Kennish 2002). Community-based participatory wetland management is a way of establishing the community’s rights over the ecosystems with which they are closely associated. It also shows

the commitments and the responsibilities of the community to protect their environment. The community participation builds upon educating the community about the wetland ecosystems and about the processes and interactions happening in those ecosystems, which would lead to the development of better policies and conservation plans. It also increases the accountability of the community members and makes the plan of action framed by their planning body more acceptable and implementable. The community-oriented management of the coastal wetlands aids in tackling the problems that cannot be defined or dealt with by any other means (rights and claims, lifestyle) and creates a space for every community member to voice opinions and concerns relating to resource management. The management of common property resources is a collective action, an alternative to privatization or state regulation. Integrated natural resource management is a means to resolve the complex problems associated with natural resources on which people are highly dependent for livelihoods, especially to minimize the conflicts among the resource users. The approach would involve the interaction

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Coastal Zone and Wetland Ecosystem: Management Issues, Picture 8 Communities are dependent on tidal time for smooth movement

between the local community and the scientific community, which would facilitate the exchange of knowledge and help to pool the scientific and traditional knowledge about the ecosystem. The stakeholder interactions and sharing of knowledge would lead to more sustainable decisionmaking. However, the participatory processes, thus institutionalized, form a platform upon which negotiations and the decision-making for resource management are amicably resolved. The effectiveness of the integrated community-based ecosystem management depends on the degree to which suggestions from the community, including the indigenous people, are considered in decisionmaking (Picture 9). The community-based management of coastal wetlands involves the process of decision-making

and implementation of sustainable practices to conserve and manage the local ecosystems. The complexity of community-based management has created a shift from a general conservation strategy for a site-specific approach involving several issues to be addressed. The fundamental component of community-based natural resource management is decision-making, but that process could be influenced by the differences in perspectives, opinions, and the rights of the people hold over the natural resources that they depend upon in the area. A. However, they may not possess the adequate scientific knowledge to complement their traditional knowledge of the ecosystem to formulate the effective conservation and

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Coastal Zone and Wetland Ecosystem: Management Issues, Picture 9 Community based management for conservation of coastal wetland

management plan. Supervising the composite and interlinked coastal wetland ecosystems requires a good understanding and knowledge of each of the ecosystems. In the container of community-based coastal resource management, this if found that knowledge gap among the community people even though they have been living in the coastal area all their life. The environmental policies often highlight the uncertainties in the controversial condition that limit the decision-making aptitude to achieve best management practices. To keep away from these uncertainties, supplementary knowledge needs to be put in place during the time of decision-making to obtain the best management practices for the coastal wetland ecosystems.

Case Study In this chapter, the authors presented the case study of Bangladesh Sundarban which is

recognized as the world’s largest mangrove wetland to exemplify the problems, vulnerability of climate change and conservation approach for sustainable management approach. Wetlands are indispensable to human development progressions and in achieving the sustainable development goals that look for eliminating severe poverty and hunger and to make certain environmental sustainability. Bangladesh has approximately 70,000–80,000 km2 of wetland area (Khan et al. 1994) which include estuaries, mangrove swamps, rivers, marsh (haor), oxbow lake (baor) and beels, water storage reservoirs, fishponds, and some other lands (Islam and Gnauck 2008). Bangladesh has five categories of wetlands such as wetlands of saltwater, freshwater, palustrine, lacustrine, and man-made. At present, almost every wetland is under threat because of haphazard utilization, encroachments and retrieval, urbanization and downside from the development of the agriculture sectors and flood management actions (Gopal 1999). Bangladesh Sundarban mangrove is impacted because of high-salinity interference,

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coastal aquaculture activities, urbanization activities, and increasing the human settlement areas. The unfavorable influences of salinity intrusion on the Sundarbans ecosystems are patents in the top dying disease of Sundari (Heritiera fomes) trees, retrogression of forest categories, sluggish growth of forest, and declined productivity of forest areas. The high rate of salinity intrusion has crossed the salinity doorstep value for the Sundarban mangrove wetland and some mangrove species have been desiccated and displaced because of high salinity infiltration and intrusion in the South-Western coast of Bangladesh (Picture 10). Islam (2016) mentioned that the impact of climate change is a risk to biodiversity and natural resources of the local population in Sundarban. The major causes are absence of cross-sectoral collaboration in the wetland management and floodplain disciplines concerned with different ministries and poor decentralized dedicated

Coastal Zone and Wetland Ecosystem: Management Issues, Picture 10 General panorama of Sundarban forest of Bangladesh

authorities. Islam (2010) mentioned that 121,000 ha of the mangrove wetlands vanished over the last 100 years. The changing pattern of salinity level influenced mangrove plant and animal diversity in a different way. Nearly 45% of mangrove wetlands are cracked because of coastal aquaculture, construction, and other developmental actions in Bangladesh (Islam 2010). Rahman et al. (2012) stated that due to sealevel rise and coastal erosion problem, erosion rates in the Sundarbans Mangrove are changeable, and it is very difficult to get a conclusive result from the analysis of those points whether the erosion rate has been going faster from 1971 to 2010. The average erosion rates for the eastern and western parts of Sundarban are 14 m/year and 15 m/year, respectively, obtained from the ten selected transect lines. He also found that coastal erosion of Sundarbans forest happening mostly in many parts of the peripheral zone and the total forest loss because of coastal erosion is 233 km2 which is higher than the total acceleration of forest from sea, that is 104 km2 in the Bangladesh part during the period of investigation and the rate of coastal erosion is variable in different parts of Sundarban forest. Sundarban forest is shrinking due to the coastal erosion though it is not clear yet how much coastal erosion is linked to the global warming and sea-level rise (Fig. 2). Islam et al. (2014) mentioned that organizational assistance, proper planning and policy support, biodiversity conservation and management support, sustainable livelihood support, and indigenous assistance have made the policy and strategy framework of wetland sustainability and surrounding natural resource management for Bangladesh Sundarban. To prepare the effective planning and sustainable management of Sundarban mangrove resources, Islam et al. (2014) developed the essential model structure and strategy framework and its major factors and sub-factors required to strictly follow appropriately. The intangible model should be executed for Bangladesh Sundarban that could accomplish excellent consequences for enhanced management and could make certain sustainable livelihood strategies for inhabitants of Bangladesh Sundarban. The ecological position, community norms, religion and culture, climatic situation,

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089°10'00"E

089°20'00"E

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089°30'00"E

089°40'00"E

089°50'00"E 22°30'00"N

22°20'00"N 22°20'00"N

22°10'00"N 22°10'00"N

22°00'00"N 22°00'00"N

21°50'00"N 21°50'00"N

21°40'00"N 21°40'00"N

BAY OF BENGAL 089°10'00"E

089°20'00"E

089°30'00"E

089°40'00"E

089°50'00"E

Legend Stable Forest

Stable Other Vegetation

Forest

Water

Unchanged water

Water

Forest

Other Changes Scale 20

0

Km

Coastal Zone and Wetland Ecosystem: Management Issues, Fig. 2 Shoreline changes in the Bangladesh Sundarbans mangrove forest (Rahman et al. 2012)

and political potentialities are measured in that proposed policy framework. The finding of this case study could become an imperative guideline for effective planning and sustainable conservation

management of coastal wetlands and site conservation in Bangladesh and comparable groups of wetland sites in other regions of the earth (Eslamian et al. 2020).

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Coastal Zone, Wetland Management, and SDGs-14 Wetlands are significant to human well-being, inclusive economic development and mitigation and adaptation in response to climate change. They give water for the agriculture and human consumption for their livelihood strategies. They protect the sea shores and assist for developing the cities and settlements disaster safe and resilient in response to climate change (Picture 11). Wetland supports diverse communities of aquatic biodiversity and abundant for unique natural ecosystem. They are vital to mitigate and adapt to climate change. They provide sustainable livelihoods and are essential to human health and well-being (Picture 12). Coastal wetlands include estuaries, deltas, and tidal flats mangroves and coastal marine areas as well as coral reefs. The multiple benefits and services provided by wetlands are essential in achieving the Sustainable Development Goals (SDGs) which give numerous opportunities for the coastal and marine areas (Szaboa et al. 2015)

Coastal Zone and Wetland Ecosystem: Management Issues

through dealing with the coastal poverty, highlighting conservation and clearly recognizing the vulnerability of climate change. Marine and coastal environments are pertinent to most SDGs, but are overtly considered under SDG 14, Life below water: Proper conservation and sustainable utilization of the seas, oceans, and lastly marine resources for the sustainable economic development. SDG 14 intends to augment the conservation and sustainable management of the aquatic ecosystems and their resources while recognizing the threats like as ocean acidification and coastal pollution (Picture 13). Mangrove wetlands provide valuable ecosystem services to the coastal populations, including protection of storm, pollutant trapping, and a variety of cultural ecosystem services, which can all contribute in some form to most of the SDG 14. Most recently, mangrove wetland ecosystems have been positioned as high on the policy outline of many international administrations because of their role in sequestration and storage of carbon. Mangrove wetlands are a case of a blue carbon

Coastal Zone and Wetland Ecosystem: Management Issues, Picture 11 Tidal flood is the most common natural hazards for coastal communities

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Coastal Zone and Wetland Ecosystem: Management Issues, Picture 12 Coastal communities depend on wetland biodiversity for their livelihood

Coastal Zone and Wetland Ecosystem: Management Issues, Picture 13 Corals are important biodiversity for the coastal countries of the world

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Coastal Zone and Wetland Ecosystem: Management Issues, Picture 14 Coastal communities are demanding for sustainable embankment for their existence

ecosystem which have an ability to carbon storage at densities 3–5 times that of further tropical forests (Donato et al. 2011). Coastal environment and forest ecosystems required to overt consideration within Sustainable Development Goal 14. Mangrove wetland forests are muscularly associated with the poverty and development since they supply ecosystem facilities to potentially hundreds of millions of population. An SDG highlighted on marine and coastal and marine environment and ecosystems – the life below water – is therefore heartening. Though, SDG 14 is likely to have indirect and unintended consequences for the very ecosystems it aims to protect and the local communities that rely on them. Anticipating negative consequences requires thinking and planning at multiple scales and a multidisciplinary view of SDG 14 implementation that incorporates multiple stakeholders at different hierarchical levels. Ultimately, many SDG 14 targets require increasing local environmental justice and resource management (Picture 14). Coastal communities need to more explicitly deem coastal mangrove wetland ecosystems within SDG 14, as not doing so may explain the potential for unintended consequences on coastal wetlands.

Eventually, marine and coastal ecosystems visage challenges when forced into one SDG, so there is lofty conflict potentiality. A stronger acknowledgment of the unique challenges of the coastal zone and coastal wetland ecosystems, in particular, throughout all SDGs might increase their profile and for that reason, they could be more muscularly considered in sustainable conservation and management for development planning.

Conclusions The 17 Sustainable Development Goals (SDG) demonstrated the opportunity to reposition the significance of coastal zone and wetland management not only as the critical natural resource management, but also the necessary component of communities’ well-being, comprehensive economic growth, and climate adaptation and mitigation perspectives (Picture 15). Coastal zone and wetland management contribute to all of the 17 SDGs, moreover directly or indirectly and their conservation and management represent the comprehensive cost-effective speculation for the governments. Synergies can be

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of the plan. The community-based coastal wetland management is ideal for restoring and conserving biological diversity and ecological services offered by the ecosystems. However, that has to be done under a proper management structure and guidance by external expert partners during the planning and implementation processes. It is also important to ensure cooperation and coordination among all the stakeholders, especially the local community, which would help the process to sustain itself in the long run.

Cross-References ▶ Biodiversity ▶ Climate Change ▶ Coastal Zone Coastal Zone and Wetland Ecosystem: Management Issues, Picture 15 Coastal communities are using indigenous knoweldge for resource management

obtained through various actions on the coastal areas and wetlands obviously contributing to more than one SDG, and likewise, the various activities related to coastal ecosystem and wetland conservation and management issues supporting commitments under other different national and international strategies and conventions. The traditional knowledge and the knowledge gained through their lifestyle closely linked to the coastal ecosystems provide the community an inherent capacity to evolve an appropriate conservation approach and to be adaptive to the changes over time. The traditional knowledge and the experiences will not be enough for managing the coastal wetland resources due to the increased stress caused by natural and anthropogenic activities. Hence, the collective inputs of both traditional and scientific propositions are required to meet the issues surrounding the loss of biodiversity. The involvement of an external knowledgeable stakeholder would not only assist in the design of an effective resource management plan, but also facilitate the community in building an organized institution for the implementation and monitoring

References Airoldi LH, Balata GH, Beck WM (2008) The gray zone: relationships between habitat loss and marine diversity and their applications in conservation. J Exp Mar Biol Ecol 36(3):8–15 Bakshi AH, Panigrahi AK (2015) Studies on the impact of climate changes on biodiversity of a mangrove Forest: case Syudy of Sunderban Delta region. J Env Socio 12(1):7–14, 2015 Barua P, Rahman SH, Molla MH (2017) Sustainable adaptation in response to climate displacement problem in south-eastern coast of Bangladesh. Int J Clim Chang Strat Manag 17(2):45–65 Barua P, Rahman SH, Mitra A, Zaman S (2020) An exploration of land zoning for coral Reef Islands of Bangladesh. J Env Ecosy 4(3):20–40 Berkes F (2010) Devolution of environment and resources governance: trends and future. Environ Conserv 37(4): 489–500 Brij Gopal BH, Chauhan MH (2006) Biodiversity and its conservation in the Sundarban mangrove ecosystem. Aquat Sci 68(3):338–354 Brown CJ, Megan IS, Hugh PP, Anthony JR (2013) Interactions between global and local stressors of ecosystems determine management effectiveness in cumulative impact mapping. Div & Distri 20 (5):538–546 Donato DC, Kauffman JB, Murdiyarso DH (2011) Mangroves among the most carbon-rich forests in the tropics. Nat Geosci 4(2):293–297 Eslamian S, Okhravi S, Eslamian F (2020) Constructed wetlands: hydraulic design. Taylor and Francis, CRC Group, Boca Raton, 72 Pages

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184 Eslamian S, Singh VP, Askarai KO (2020) A feasibility study of urban green space design in the form of smart arid landscaping with rainwater harvesting. Amer J Eng & App Sci 11(1):60–75 Giri C, Ochieng E, Tieszen LL, Zhu Z, Singh A, Loveland T, Masek J, Duke N (2011) Status and distribution of mangrove forests of the world using earth observation satellite data. Glob Eco Biog 20(4):154–159 Gopal B (1999) Natural and constructed wetlands for wastewater treatement: potentials and problems. Wat Sci & Tech 40(4):27–35 Islam SN (2010) Threatened wetlands and ecologically sensitive ecosystems management in Bangladesh. Fron Ear Scie in China 4(4):438–448 Islam S (2016) Deltaic floodplains development and wetland ecosystems management in the Ganges–Brahmaputra–Meghna Rivers Delta in Bangladesh. Sust Wat Resour Mang 2(1):237–256 Islam SN, Gnauck A (2008) Mangrove wetland ecosystems in Ganges-Brahmaputra delta in Bangladesh. Front Earth Sci China 2(4):439–448 Islam SN, Karim R, Islam A, Eslamian S (2014) Wetland hydrology. In: Eslamian S (ed) Handbook of engineering hydrology, Ch. 29, Vol. 1: Fundamentals and applications. Taylor and Francis, CRC Group, Boca Raton, pp 581–605 Kennish MJ (2002) Environmental threats and environmental future of estuaries. Env Cons 29(3):78–107 Khan SM, Haq E, Huq S, Rahman AA, Rashid SMA, Ahmed H (1994) Wetlands of Bangladesh. Bangladesh Centre for Advanced Studies (BCAS) Dhaka, Bangladesh Lichter M, Vafeidis AT, Nicholls RJ, Kaiser G (2011) Exploring data-related uncertainties in analyses of land area and population in the “Low-Elevation Coastal Zone” (LECZ). J Coast Res 27(3):757–768 Luyet V, Schlaepfer R, Marc BP, Buttler A (2012) A framework to implement stakeholder participation in environmental projects. J Environ Manag 111: 213–219 Rahman HMT, Hickey GM, Sarker SK (2012) A framework for evaluating collective action and informal institutional dynamics under a resource management policy of decentralization. Ecol Econ 83(4):32–41 Rana MP, Chowdhury MSH, Sohel MSI, Akhter SH, Koike M (2009) Status and socio-economic significance of wetland in the tropics: a study from Bangladesh. iForest 2(1):172–177 Small C, Nicholls RJ (2003) A global analysis of human settlement in coastal zones. J Coast Res 19(3):584–599 Szaboa A, Mark D, Griffithsb R, Marcosc RD, Barbara MJ, Zsolt DH (2015) Methodological and conceptual limitations in exercise addiction research. Yal J Biol & Medic 88(4):303–308 Thanh HT, Yabar HM (2015) Climate change challenges for sustainable coastal wetland Management in Xuan Thuy Ramsar Site, Vietnam. Brit J Env Clim Chan 5(3): 214–230 Vikas MN, Dwarakish GS (2015) Coastal pollution: a review. Aqua Proc 4(3):381–388

Coastal Zone Management

Coastal Zone Management ▶ SDG 14 and Management

Integrated

Coastal

Zone

Coasts ▶ Ocean(S) and Human Health: Risks and Opportunities

Cold Ocean Environments ▶ Penguins: Diversity, Threats, and Role in Marine Ecosystems

Co-management and Conservation Below Water in Australia Melissa Nursey-Bray1 and Jillian Marsh2 1 Department of Geography, Environment and Population School of Social Sciences, Faculty of Arts, The University of Adelaide, Adelaide, SA, Australia 2 Victoria University, Melbourne, VC, Australia

Definition Co-management is a process that involves two or more social actors who work together to agree among themselves how to share responsibilities over a particular region. In Australia one term for such a region is “sea country” which is used to describe Indigenous estates that reflect the land, islands, and sea areas that belong to a certain group. Sea country encapsulates the knowledge about that area, that has been developed and maintained for millennia, and with which the Indigenous peoples of that country are affiliated and related. Kinship systems, sovereign ownership, governance, and resource rights are all held

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by the Indigenous groups that identify with that estate. Indigenous peoples in Australia have occupied it for at least 65,000 years which means that in some places, cultural connection to sea country can extend far out to seas (to the ancient previous coastline).

Introduction Ensuring the active development of marine and coastal management initiatives that properly acknowledge Indigenous world views, values, and knowledges is a priority (Maxwell et al. 2020, Weiss et al. 2013), and in Australia, there are many examples of such initiatives. The Indigenous peoples of Australia are culturally diverse and have inhabited Australia for between 50,000 and 100,000 years (Flood 1983). Long prior to European invasion, Indigenous Australians developed sophisticated and diverse cultural frameworks, with each group maintaining specific cultural mores and traditions for managing their land and seas, or country (the term used to denote specific Australian Indigenous cultural and geographical land and sea regions). Despite the impact of colonization, including disease, violence at the hands of colonists, dispossession from their country, and removal of their children, Indigenous Australians have actively lobbied for the right to return to, control, receive title over and manage their country. This includes water country, and bodies of water associated with sea country are differentiated from other bodies of water such as lakes, rivers, estuaries, and groundwater aquifers. All water systems sustain life and form an intimate part of everyday life and spirituality, with land and water both seen as equal (Jackson et al. 2005). In terms of legislation, the Native Title Act 1993 (Cth) applies to the coastal waters of Australia and waters over which Australia asserts sovereign rights under the Seas and Submerged Lands Act 1973. This includes recognition of the native title rights and Indigenous interests regarding sea and freshwater. Indigenous peoples across Australia share a diverse and rich experience of the coast, seas, and how to manage and maintain it over time

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(Rist et al. 2019). The sea country of Australia’s Indigenous peoples is at 13.86 million square kilometers, the world’s third largest marine jurisdiction. In the Northern Territory alone, the sea country of Indigenous groups is 5100 km long, with a further 2100 km in offshore islands, and of the coastline, over 85% of it is owned by Aboriginal “traditional owner” groups. In the Great Barrier Reef World Heritage Area, there are over 70 Indigenous groups which claim sea country in the region. Collectively, these waters are highly biodiverse and 85% of Australians live within 100 kilometers of the ocean and call it home. Economically, the regions below water directly and indirectly bring in billions of dollars to the economy every year via fisheries and tourism. The Great Barrier Reef, for example, makes a $6.4 billion contribution to the national economy and supports over 64,000 jobs. Future projections show that the economic value of marine industries is expected, by 2025, to contribute about $100 billion each year to Australia’s national economy. Estuarine zones are also critical sites for Indigenous activities and values, and despite usage for many generations prior to invasion are now one of the most severely impacted by unsustainable land uses and Western natural resource management. Management of these sites often continues to exclude Indigenous knowledge and standpoints (Kainamu-Murchie et al. 2018; Boshammer 2011). Further, these regions, already impacted by pollution, oil and gas exploration, tourism, over fishing and urbanization, are feeling the additional pressure of climate change. Impacts include ocean acidification and warming, sea level rise, and increased dangers caused by higher intensity cyclones, storms, and floods. These impacts have created environmental issues such as coral beaching, loss of kelp forests, habitat destruction, and species mortalities. In some cases, reproductive regimes are being disrupted – a classic example is that of the green turtle which uses temperature to determine the sex of hatchlings (Stubbs et al. 2020). In warmer temperatures, female turtles are favored: unsurprisingly then, with these increased temperatures, sand nests are hotter, and more female turtles are being born

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Co-management and Conservation Below Water in Australia, Fig. 1 Sea country of the Guugu Yimithirr people, along the Great Barrier Reef, traditional hunting

ground and habitat for Green Turtle and Dugongs, Cape Yorke Peninsula, Australia. (Source: Photo taken by Melissa Nursey-Bray)

(Stubbs et al. 2020). This will have significant ramifications as turtles are important cultural species for many Indigenous peoples, such as the Guugu Yimmithirr in north Queensland Australia, where hunting for turtle is an important cultural activity (see Fig. 1).

for Indigenous involvement at every level and scale of management. It also needs to recognize and incorporate claims to property rights specifically in relation to Indigenous perceptions and ancestral rights to water, and the ongoing lack of recognition of Indigenous cultural rights to water across Australia (Marshall 2014, 2017). As an ongoing process that enables sharing of power, responsibility, and goals working together in co-management can provide multiple benefits and new forms of power sharing, while being constrained at the same time by its colonial legacy (Borrini-Feyerabend et al. 2004, Stjernström et al. 2020). Other dimensions of co-management include sharing of information, flexibility, the use of both traditional and scientific knowledge, and ongoing communication between all parties (Iwasaki-Goodman 2005). Another central feature of co-management is its capacity to recognize and then incorporate Indigenous governance structures within the running of the co-management program – ensuring cultural match is an important element. With the rising pressure of climate change, co-management has also had to become adaptive – which requires a capacity to deal with external uncertainty and surprise and to support flexible and multi layered governance systems (Folke et al. 2005). In the context of life under water, while these definitions are useful, it is also important to note that water rights in Australia do not articulate specific Indigenous interests and

Co-management and Sea Country Effective and ongoing management of these challenges and values is required in order to achieve conservation goals and the balance between environment, social justice, and economic viability. Co-management is one model that, in various ways, has been trialed in Australia. In particular, it has been a model that has facilitated enduring partnerships between Indigenous and nonIndigenous peoples. These partnerships reflect the active presence of Indigenous peoples who are seeking to manage their estates as they have done for millennia, and depute their severe disruption by colonial invasion. The next section outlines the models of co-management in action that have been trialed in Australia so far. Some of these initiatives are summarized and, in exploring case studies of marine management, offer some reflections on lessons learned moving forward for life under water. In order to achieve environmental management, it is argued that conservation needs to be socially just and build in mechanisms

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that co-management of sea country remains distinct from water allocation plans, Native Title negotiations and programs like the Aboriginal Water Initiative Program in the Australian states of New South Wales and Victoria.

Sea Country Planning Sea country planning is one co-management initiative that has enabled Indigenous groups across Australia to negotiate with marine managers and other users to articulate a set of actions that acknowledge and respect Indigenous perspectives on caring for country (Austin et al. 2018). The Sea Country plans are designed to bring together the priorities and aspirations for Indigenous communities with other community groups who also wish to use and care for the oceans and coasts. Implicit in any sea country plan is a range of objectives. These objectives include to: (i) improve Indigenous participation in marine planning and management, (ii) address a range of cultural, ecological, and economic issues and enable Indigenous people to identify opportunities to derive greater social and economic benefit from the management of sea country, (iii) facilitate Indigenous participation in sea country management at appropriate geographical and cultural scales, and (iv) help others develop greater understanding of Indigenous peoples’ sea country interests and responsibilities. To date, a number of Indigenous Sea Country Plans have been written and occur in every State and Territory in Australia (Austin et al. 2018). A good example is the Bama Ngulkurrku Wawu Wawurrku Bundangka Bubungu Jalunbu (Healthy Mob, Healthy Land and Sea Plan) for the eastern Kuku Yalanji people in north Queensland. In this plan, which enshrines a range of Indigenous driven partnerships with government and other bodies to look after their country, they note: The management of Sea Country should be given back to Bama. Together, we’ll manage our Sea Country, teaching and training our children. . . Our jalun (sea) contains our part of the Great Barrier Reef, islands and a huge number of different

187 animals. Many sea Country places and animals have cultural importance. This plan shows how we will claw back our Traditional role as custodians of our jalun to keep it healthy. (Jalunji Warra 2012)

Another group – the Gunggandji, who also have country that is within the Great Barrier Reef, has developed a Sea Country Plan that is asserted as a means by which the Gunggandji can carry out their cultural responsibilities. In their plan, they state that their purpose is to: “Identify important natural and cultural values of Gunggandji land and sea country”, “to communication the vision, aspirations and proposals of Gunggandji people to manage land and sea country,” and “to develop a strategic framework for collaboration between Gunggandji people, residents of Yarrabah, government agencies and others to manage and sustainably use the natural and cultural resources of Gunggandji land and sea country” (Gunggandji PBC Corporation 2013, 3).

Indigenous Protected Areas The establishment of Indigenous Protected Areas is another powerful mode of co-management that has been instituted in Australia. An Indigenous Protected Area (IPA) is an “area of land and sea managed by Indigenous groups as protected areas for biodiversity conservation through voluntary agreements with the Australian Government.” The IPA program is part of the national reserve system, which comprises the network of formally recognized parks, reserves, and protected areas within Australia. In 2020, there were 75 dedicated IPAs spanning over 67 million hectares, and which together account for over 44 percent of the National Research System. It is managed by groups of Indigenous rangers, and in partnership with the government, who funds the IPAs. IPAs offer more than biodiversity protection, and they also offer employment for Indigenous men and women to look after them. This system enables Indigenous peoples to manage and maintain their cultural values for present and future generations (Dobbs et al. 2016). Ongoing activities may include the leading of cultural tours, protection of rock art and other sites, and maintenance of bush tucker, medicine,

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Co-management and Conservation Below Water in Australia, Fig. 2 Wuthathi sea country. (Source: Photo taken by Melissa Nursey-Bray)

and other knowledge dissemination to younger generations, among other activities. Many of the IPAs are in coastal and marine areas and provide opportunities for the protection of life under water and collectively will cover over 1.8 million hectares of sea country. For example, in the Tiwi Islands off the north of Australia, a proposed IPA will support marine turtle nesting, seabird rookeries, and migratory shorebirds and will be managed by Tiwi Island Indigenous rangers. The Wuthathi people of northern Cape York, Queensland, are currently negotiating an IPA which will cover over 800,000 sea country hectares and which contains some of the most significant Green Turtle and Dugong habitat in the Great Barrier Reef Marine Park (see Fig. 2). In the Wet Tropics region (Fig. 3), the Mamu Aboriginal Corporation co-manage over 300,000 sea country hectares, including parts of the World Heritage listed Great Barrier Reef Marine Park (Buhrich et al. 2019).

One of the first IPAs, Dhimurru Indigenous Protected Area (IPA), which covers over 920 square kilometers in the Gulf of Carpentaria and forms part of the wider lands of the Yolngu people, is an example of successful co-management in action (Table 1). In particular, work within the IPA has focused on protecting green turtle, known in the region as miyapunu. Djawa Yunupingu, a senior Yolngu landowner, states that: “The IPA helps us look after miyapunu, so they can go on breeding on our beaches and swimming in our waters. That’s important to our country and important to us too.”

Traditional Use Marine Resources Agreements Another form of co-management is the TUMRA – traditional use marine resource agreements (Dobbs et al. 2016, Nursey-Bray and Jacobson 2014). These agreements are between Indigenous

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C Co-management and Conservation Below Water in Australia, Fig. 3 The Wet Tropics region. (Source: Photo taken by Melissa Nursey-Bray)

Co-management and Conservation Below Water in Australia, Table 1 Summary of indigenous protected area system in Australia 2020 Indigenous protected areas (IPAS) Dedicated IPAs Total area Percentage of National Reserve System

2020 78 74,693, 991 hectares 46.53%

groups and the Great Barrier Reef Marine Park Agency. There are over 70 Indigenous groups that have lived along and cared for their land and sea country within and adjacent to the Great Barrier Reef. However, with colonization and the establishment of many other uses along and within the reef, including tourism, agriculture, and urbanization, the impacts of Indigenous customary activities such as hunting for turtle and dugong have had or are seen to have had an amplified and negative effect on biodiversity management. A TUMRA is a partnership between a specific Indigenous group and the Marine Park Authority and is a community-based plan for management of traditional resources. The TUMRA program seeks to walk a line between and balance environmental and cultural aspirations in relation to the use, protection, and maintenance of marine resources (Nursey-Bray 2011). Each TUMRA is accredited in legislation. In 2020, there were 9 TUMRA and 1 Indigenous Land Use Agreement (ILUA), covering eighteen traditional owner groups, which together cover 25 percent of the marine park coastline. Each plan sets mutually agreed rules for the use and harvest or special species such as turtle and dugong, as well as

a range of other management goals that relate to the use of marine resources in ways that meet both biodiversity as well as cultural management aspirations. The ILUA is called the Kuuku Ya’u People’s Indigenous Land Use Agreement and is managed in the same way as a TUMRA. This agreement, the first of its kind within the Great Barrier Reef Marine Park, recognizes Traditional Owner native title rights and interests in the management of nearly 2000 square kilometers of sea country out to the Great Barrier Reef. Other TUMRAs include the Wuthathi Agreement, the Lama Lama agreement, the Yuku-BajaMuliku agreement, the Yirrganydji agreement, the Gunggandji agreement, the Girringun agreement, the Woppaburra agreement, and the Port Curtis Coral Coast agreement. The Girringun Agreement is a good example of a sustained co-management partnership via TUMRAs. Girringun, which is a corporation representing six sea country groups (Djiru, Gulnay, Girramay, Bandjin, Warragamay, and Nywaigi), has been part of 4 TUMRAs (2005, 2008, 2010, 2019).

Co-management in Action: Indigenous Rangers Looking After Sea Country Many co-management initiatives are also actioned via Australia’s extensive Indigenous Ranger network (Zurba et al. 2012). Beginning in the early 1990s, and now largely funded partly by the government’s Working on Country Program, there are now 127 ranger groups employing just under 900 Indigenous rangers across Australia. Indigenous Ranger Programs collectively undertake environmental and cultural management on

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Indigenous land and seas and offer substantive expertise in managing Australia’s exceptional natural and cultural values. Indigenous Ranger groups not only play an active role in implementing co-management regimes such as the IPAs, ILUAs, TUMRA, and Sea Country plans just described, but they also perform key functions in terms of national enforcement and quarantine, monitoring and evaluation programs. For example, the National Aboriginal and Island Land and Sea Management Alliance (NAILSMA) coordinates ranger groups across northern Australia to implement a program called I-Tracker. I-Tracker that is short for “Indigenous Tracker” is a program designed to assist Indigenous rangers across north Australia to monitor, manage, and research their land, sea, and cultures via hand-held and smart devices. Specific and tailored I-Tracker applications have been developed by NAILSMA to enable rangers to undertake saltwater country management such as seagrass mapping and monitoring and marine turtle monitoring. The I-Tracker program is also undertaken in conjunction with scientists and researchers who ensure best practice guidelines are met. Another good example of active Ranger activity is the Kimberley Indigenous Saltwater Science Project (Austin et al. 2018). In this project, Indigenous rangers from the Kimberley region (Western Australia) undertake research and monitor activities in order to develop understanding of saltwater needs and management (Dobbs et al. 2016). Over time, six scientists have worked with Traditional Owner representatives from the Balanggarra, Wunambal Gaambera, Dambimangari, BardiJawi, Nyul Nyul, Yawuru, and Karajarri peoples. In partnership, they have created new knowledges in a series of projects that now support Indigenous Ranger groups in the Kimberley in their management of dugong, turtle, marine ecology, human use, and social values (Dobbs et al. 2016). The GhostNet program is another practical expression of co-management in action. In Australia, the Ghostnet program has worked with 31 coastal Indigenous communities to train Ranger Groups in each one to protect over 3000 km of saltwater country from ghost nets

(Stewart et al. 2013). To date, the rangers have removed over 13,000 ghost nets and saved the lives of many Green turtles (Phillips 2017). In this case, the co-management is operationalized by a fee for service arrangement, which means that rangers are properly funded for the work that needs to be done. Indigenous rangers also contribute to Australia’s biosecurity program; 65 Indigenous ranger groups actively contribute to over 10,000 kilometers via implementation of coastline biosecurity measures. In so doing, Indigenous rangers enable the government to manage the introduction of exotic pests, to undertake animal, plant, and aquatic health surveillance and a range of mapping exercises. The Australian government since 2016 has invested more than $12.5 million, working in partnership with Indigenous rangers, to create fee for service activities and a number of Indigenous biosecurity traineeships. Research collaborations are another form of co-management: the Uunguu rangers from the Wunambal Gaambera Aboriginal Corporation (Kimberley region) whose country is immense – they are the Native Title holders of almost 2.5 million hectares of land and sea and are a good case study. In partnership with the Australian Institute of Marine Science (AIMS), rangers use science and Indigenous knowledge to monitor and look after their saltwater country. For example, rangers went on a week-long survey on the AIMS vessel RV Solander, to survey coral hotspots as part of a Benthic Habitat Project. The nearshore habitats that were surveyed are also key areas for cultural harvesting, with seagrass (jala) identified by the Wunambal Gaambera people, as a primary food source for dugong (balguja) and marine turtle (mangguru), all of which feature as management targets within their Healthy Country Plan: Making sure gawi [fish], balguja, mangguru, and other sea animals have healthy places to live and feed is important to us Wunambal Gaambera people to keep our saltwater culture strong. . .Working with scientists we can combine our traditional knowledge with modern methods to get a clear picture of how things like climate and pollution affect these important places near the shore. (Neil Waina, Head Uunguu Ranger)

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Rangers were also trained how to use drop-down cameras to survey benthic (seafloor) habitats, which enabled them to develop the skills to undertake their own future monitoring and maintain responsibility for the country their ancestors have managed for many thousands of years. This type of co-management/knowledge partnership is crucial in maintain knowledge about but also in generating ideas around how to manage such regions. As one of the AIMS researchers notes: This trip helps build a regional picture of corals being common right along the Kimberley coast, abundant and diverse in some places but present in low to moderate numbers more generally. The fringing reefs and rocky ledges, even those right on the mainland coast, can support coral communities of varying complexity.

Finally, a Traditional Owner ranger group based in Bundaberg near the southern end of the Great Barrier Reef have worked in partnership with scientists in a program that, supported by the National Environmental Science Program (NESP), trained them to monitor and manage the health of mangroves on their sea country. Working with scientists and managers, the Indigenous rangers from the Gidarjil Development Corporation (GDL) trained rangers to use a Shoreline Video Assessment Methods app (S-VAM), which enables the capture of geo-referenced imagery to identify erosion, dieback, bank accretion, and infrastructure modifications like boat ramps (Tan et al. 2020).

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Again, as a co-management partnership, this program has multiple benefits for each party: in this case, the results are useful for managers and industry end users in terms of understanding how to improve water quality and for the rangers, it enables them to reconnect with sea country and build new and transferable skills.

Lessons Time is running out for many marine and coastal systems – the Great Barrier Reef a case in point (see Fig. 4). Facing the impacts of climate change, including species shift, coral bleaching and death and temperature-related changes in flowering and species reproduction, the need to work together is more important than before. The programs outlined above showcase a diverse variety of innovative co-management partnerships for life under water that serve both the interests of conservation and culture. There are a number of lessons that can be learned from the implementation of these models that may provide insight into how to build both cultural and conservation in more socially just ways. Australian Indigenous rights remain within a framework of colonial erasure that is dominated by nationalism, dispossession, and the rights of extractive industries. The Australian Government’s Indigenous Evaluation Strategy (AGPC

Co-management and Conservation Below Water in Australia, Fig. 4 The coast along the Great Barrier Reef, near Cooktown, North Queensland. (Source: Photo taken by Melissa Nursey-Bray)

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2020) articulates as its key objective the “centring of Aboriginal and Torres Strait Islander peoples, perspectives, priorities and knowledges” (AGPC pg 6) and a whole-of-government approach to having policy and program decision-making informed by “high quality and relevant evaluation evidence” (AGPC pg 7). It pledges alignment with the UNDRIP principles of centering Indigenous views and active participation in decision making and working with Indigenous peoples during the design and conduct of evaluations but makes no explicit statement about Indigenous agency regarding decision-making within policy and program reform, and it is suggested it needs to be. Non-Indigenous people can never fully appreciate Indigenous experiences, perspectives, and standpoints of Indigenous life; however, they can interrogate the centering of white privilege and their own positionalities because of this privilege and enact them within policy frames in order to make visible and enhance Indigenous agency. As such, a first step and for co-management to be most effective, there needs to be true equity and parity between Indigenous and non-Indigenous peoples, recognitions of Indigenous rights to assert their own governance (Nursey-Bray and Jacobson 2014). This must be underpinned by an acknowledgement of historical injustices, continued legacies of oppression, and a commitment to genuine reform. All parties need to reconcile in practice the tensions between statutory vs. nonstatutory management, “traditional” and “contemporary” management regimes, and the tensions between economy, culture, or environment. Indigenous demands for recognition of water sovereignty must be a core part of decolonization of water governance (Curran 2019; Marshall 2017) and directly align with Article 25 and 32 of the United Nations Declaration of Rights of Indigenous Peoples (UN General Assembly 2007). Unless there is a firm commitment to facilitate Indigenous agency within co-management, socially just conservation will continue to be a distant vision for the future rather than an immediate overarching strategy for reconciliation, reparation, and reform.

Western managers thus need to act on what can be perceived as rhetorical claims of support for Indigenous peoples – and effectively “let go” of various power and knowledge domains (Pirsoul and Armoudian 2019). For example, Indigenous rangers need to be accredited under the legislation to have/carry the same enforcement powers as nonIndigenous rangers. Co-management requires equal weight be given to Indigenous as much as Western scientific knowledge in management and creation of an equitable decision-making framework that goes beyond an advisory capacity. The conservation paradigm of nature, living, and nonliving entities must be prepared to challenge its inherent colonialism. Indigenous paradigms have long recognized the agency of all entities, including the ecological and genealogical rights and powers of water. Knowledge transfer needs to occur in a reciprocal manner across Indigenous and Western knowledge systems and ideologies, using a restorative justice and culturally responsive right based approach. Indigenous ecological knowledges should never be perceived as a threat or competitive system that simply requires absorption or erasure for facilitating a colonial status quo. Another factor that affects the ongoing capacity of Indigenous peoples to manage their country in co-operative ways is that of employment and recognition of expertise – there remains in Australia a socio-economic disparity between Indigenous and non-Indigenous peoples that needs to be addressed. This includes in assuring the equal pay scales are applied and that ongoing security of employment is assured for those Indigenous peoples who are employed to look after their country. The emotional labor that Indigenous people invest in caring for country should also be recognized and recompensed, enabling Traditional Owners to sustain and respect their ongoing obligations to the environmental ecology of which they are a part. Some additional lessons teach us to think differently about environmental management. The Indigenous notion of country is an encompassing one, and while they have, for the sake of Western comfort, created the term “sea country,” in actuality, there remains and always will be an indivisibility between land, coast, and sea in Indigenous

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life worlds. Country encompasses everything, one’s identity, one’s past, one’s responsibilities, and the world view that humans are connected to and part of, not separate from country. Hence, caring for country is about caring for everything and connects people and place in fundamental ways. Ongoing co-management partnerships need to recognize this indivisibility and not attempt to enforce the jurisdictional separation on Indigenous management that occurs in most Western legal regimes and management programs. In Australia, co-management of life under water is also about respecting and managing life on land and the undeniable connection between land and sea, now and always. Socially just conservation, characterized by three dimensions, is needed and should be: (i) ecologically sound, (ii) politically feasible, and (iii) socially just. Brechin et al. noted as early as 2003 that “we have yet to fully articulate the procedural and distributional aspects of social justice as they relate to the goal of nature protection” (Brechin et al. 2003, 251). Conservation he argues is a process of seeking an answer to a series of moral questions, yet biodiversity conservation still focuses on objectives, that is, “the what,” without comprehensively assessing the impact of or how to consider the social and political processes by which conservation initiatives are undertaken: the “how.” This reflection resonates still. Socially just conservation must recognize the importance of partnership, its distinction from ownership, and the intellectual and cultural rights of Indigenous peoples. The treatment and documentation of Indigenous knowledges and philosophies requires a moral, ethical, and practice-based commitment that validates and embraces Indigenous epistemologies or world views, values Indigenous axiologies or meaning making strategies, and appreciates the ontological positionalities of Indigenous people’s relationships with the environment. These are not the same as in the non-Indigenous colonial domain, which remains steeped in Western constructs and Euro-centric thinking. Indigenous peoples hold a vast corpus of knowledge accumulated over numbers of

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millennia and maintain relationships with their environment that is personal, intimate, complex, and ancient. Their continuity of occupation on the Australian continent means there is no relational separation for many Indigenous peoples between “traditional” and “contemporary” practices, customs, and beliefs; this is a colonial construct based on chronological linearism and an assumed imperial superiority. There is however a structural distinction between “preinvasion” and “postinvasion” involving separation from family and country, erasure of habitat and biodiversity through clearing the land for commercial land uses, and an imposed sovereign right over lands and waters that were never ceded but stolen. These ongoing relationships and experiences are the essence of what Indigeneity consists of, and they are difficult cognitively and emotionally for non-Indigenous people to imagine or contemplate. On the basis of erasure, from terra nullius (empty land) that could be claimed as sovereign to the British crown, to aqua nullius (water belonging to no one) that could also be claimed as sovereign to the Australian government, colonial invasion, colonization, missionization, and globalization have all wrought havoc on Indigenous peoples and Indigenous knowledge systems. Moving forward, co-management partnerships must be founded not only on respect but on a hope that it will access Indigenous knowledge as a privilege and not a right. This approach will then manifest into decolonized frameworks for management, including a commitment to finding ways to keep, hold and revitalize Indigenous knowledges and value the peoples who own this knowledge. Indigenous involvement in co-management is integral to ensuring both cultural and environmental diversity and survival (Major et al. 2018). Co-management is not then simply facilitating a model of collaborative environmental governance. It can enshrine truth-telling in ways that will help heal the wounds inflicted upon country and people in the past, while being a means by which people work together to help address the current global climate crisis that will impact us all, now and into the future.

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Cross-References ▶ Concepts of Marine Protected Area ▶ Marine Protected Area and Biodiversity Conservation ▶ Ocean Sustainability ▶ Traditional Fishing Community and Sustainable Development

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Community-Based Research and Participatory Approaches in Support of SDG14 turtles (Chelonia mydas) under climate change and marine heatwave scenarios. Ecol Model 431:109185 Tan YM, Dalby O, Kenick GA, Statton J, Sinclair EA, Fraser MW, Macreadie P, Gillies CL, Coleman RA, Waycott M, van Dijk K-j, Verges A, Ross JD, Campbell ML, Matheson FE, Jackson EL, Irving AD, Govers LL, Connolly RM, McLeod IM, Rasheed MA, Kirkman H, Flindt MR, Lange T, Miller AD, Sherman CDH (2020) Seagrass restoration is possible: insights and lessons from Australia and New Zealand. Frontiers in Marine Science 7(14 Aug):1–21 UN General Assembly, United Nations Declaration on the Rights of Indigenous Peoples: resolution/adopted by the General Assembly, 2 October 2007, A/RES/61/ 295. Available at: https://www.refworld.org/docid/ 471355a82.html. Accessed 30 Oct 2020 Weiss H, Hamann M, Marsh H (2013) Bridging knowledges: understanding and applying indigenous and Western scientific knowledge for marine wildlife management. Soc Nat Resour 26(3):285–302 Zurba M, Ross H, Izurieta A, Rist P, Bock E, Berkes F (2012) Building co-management as a process: problem solving through partnerships in aboriginal country, Australia. Environ Manag 49(6):1130–1142

Community-Based Research and Participatory Approaches in Support of SDG14 Maéva Gauthier Community-based Research Laboratory, Department of Geography, University of Victoria, Victoria, BC, Canada

Definitions Community-based Participatory Research (CBPR) invites research subjects to become partners to address an issue in the community and lead to action and positive change (Duran and Wallerstein 2003; Gutberlet et al. 2014; Kindon 2016a; Coughlin et al. 2017). A few variations of the CBPR approach are present in the literature, such as community-based research (CBR), Participatory Action Research (PAR), and Community-based Participatory Action Research (CBPAR). In Community-based Research (CBR), the role of the participants is not as much in-depth as CBPR; while there is still engagement and

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consultation, they are not coresearchers or coleaders on the project (Flicker et al. 2008). Participatory Action Research (PAR) is closer to CBPR as it includes the three interconnected aims of research, action, and education (Duran and Wallerstein 2003); however, PAR does not necessarily include community participation – community in the sense of common interest or geographically defined. PAR “seeks to bring together action and reflection, theory and practice, in participation with others, in the pursuit of practical solutions to issues of pressing concern to people, and more generally the flourishing of individual persons and their communities” (Argyris et al. 2008). Community-Based Participatory Action Research (CBPAR) can be perceived as the integration between CBR and PAR which aims to create social change through research and action – an approach that was developed from the global south academic world (Duran and Wallerstein 2003; Gutberlet et al. 2014; Giatti 2019). Participatory Video (PV) is a collaborative method engaging a group or community in sharing their own stories using video, to support colearning and communication, and create positive change (PV-NET 2008). Citizen science is widely used to engage participants or “citizen scientists” from the general public in gathering scientific data, to monitor species or environmental indicators, or help with data analysis (Dickinson et al. 2012). When citizens or community groups collecting data are focused on a common issue or local area, it is defined as community-based monitoring (Whitelaw et al. 2003; Conrad and Hilchey 2011).

Introduction Community-based participatory research (CBPR) and participatory methods have been used to study and address environmental change while working closely with communities during that process. Community-based research is seen as an appropriate approach to address issues of importance to a community and lead to action and social change. In the past, researchers took a more “outsider’s approach,” keeping a distance between the

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researcher and the researched. That “outsider’s approach” was questioned by Freire (1982, cited by Coughlin et al. 2017, p. 2), while proposing a more participatory and inclusive approach to doing research. CBPR represents a fundamental shift in the academic world where research is not on communities, but rather with and for communities. Some of the CBPR principles include: building capacity, combining knowledge and action to benefit everyone involved, supporting knowledge coproduction, enabling a collaborative partnership in all steps of the project, empowering the community and paying attention to social equity, using a cyclical approach that is refined along the way, and sharing results with all partners (Israel et al. 2003; Castleden et al. 2012). Levels of engagement in CBR vary depending on various factors – often community members are more involved in defining research questions, collecting data, and using results for advocacy reasons (Flicker et al. 2008). Engagement in data analysis and interpretation is less common in general, for a variety of reasons. Community members do not always have the capacity to be fully involved in research projects, and so it is recommended to offer all participants a choice to participate or not at various stages of the research (Wang et al. cited by Flicker et al. 2008). Ethics, Positionality, and Critical Reflexivity While this entry will not go into detail about ethics, it is important to mention that it is an important aspect of this research approach. CBPR tends to be an ethical approach for doing research; however, five themes have emerged to pay attention to. Those include: (1) The protection of the participants: considering transparency vs. vulnerability; (2) Conflicts between “insiders” and “outsiders”: beliefs, expectations, or assumptions may differ (3) Power differences emerging from the collaboration; (4) Validity and research integrity: participants’ capacity and levels of expertise may vary; and (5) Relational nature of CBPR and ethics review: constant evaluation and self-reflection is critical by the researcher (Wilson et al. 2018). In doing research with communities, researchers may encounter challenges that require

them to be critical of their own positionality, reflexivity, and power dynamics (Mistry and Berardi 2012; Blazek 2017). As researchers, it is really important to determine one’s positionality and be reflexive during the process (Dowling 2016; Waitt 2016). Reflexivity is the process of looking at oneself and the research topic in a critical and self-reflective way. It means examining personal circumstances, from an outsider’s point of view, and is often helped by keeping a research diary. It is hard but worthwhile. A researcher has to ask himself/herself questions, such as “What is happening? What social relations are being enacted? Are they influencing the data?” (Dowling 2016). A main initial point, explains Waitt (2016), is to recognize why a certain research topic (context) was chosen and initial preconceptions about the topic (bias). Positionality, which is also connected to reflexivity, is locating oneself in the context of the project and may include lived experiences. Positionality may change as the research evolves, so a crucial part of a positionality statement is noticing and contemplating on these transformations as the project evolves. In participatory research, it is necessary to be continuously reflexive to what is appropriate also to other partners of this process (Pain 2008). Some of the challenges of CBR or CBPR projects include funding and human resources, as these projects often require multiple steps, lots of communication, and dissemination requirements, which require long-term commitment (Tremblay et al. 2015). Indeed, Flicker et al. (2008) found that larger project financial resources were more prone to report greater levels of community member involvement. Castleden et al. (2012) also mentioned those challenges, while expanding on the academic funding or ethics license processes that sometimes seem to be counterintuitive for doing community-based research. There is still work to be done to improve relationships and trust between researchers and communities (Wilson et al. 2018). A variety of participatory methods or tools can be used to successfully engage communities on environmental topics, including photovoice, participatory video, participatory mapping, citizen science, and community-based monitoring

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(Whitelaw et al. 2003; Gutberlet et al. 2014, 2016; Tremblay et al. 2015; Cox et al. 2017). Here, we will review key themes, benefits, and challenges related to community-based approach and some of these participatory tools that can support the SDG14.

Arts-Based Approaches: Photovoice and Participatory Video (PV) Photovoice Developed in the 1990s by Wang and Burris (1994, 1997) with the “photo novella” approach, this method is considered an “empowerment education” tool that provides cameras to community members, so they can document their observations related to a certain topic. This experience is normally followed by interviews, dialogue, or the creation of captions (audio or written) to assist with the interpretation of the photos. It has been used to engage communities on projects related to health, and more recently applied to environmental projects. Photovoice can be a useful method for understanding the broader array of social and environmental changes that communities are facing (Bennett and Dearden 2013). Participatory Video The early days of the PV concept started on Fogo Island in the late 1960s (Crocker 2003, 2008), and it is now referred to as the Fogo Process. Created as a broadcast documentary project initially, it offered the opportunity for the local community to give feedback on inclusion and poverty. The National Film Board provided video equipment to these remote communities located north of Newfoundland, so they could share their voices on specific social issues. What started as a side project became way more interesting than the straightforward broadcast television tool. Through that process, they came to the realization that the filmmaking process was more powerful than the finished product, and can bring about social change. The sense of community and cooperation that came out of it was empowering. Around the same era, Freire’s (1970) concept of conscientization, encouraging critical thinking, collective action, and

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empowerment, became a strong influence in participatory action research. There are two impacts clearly emerging from the Fogo Process (Crocker 2003, 2008): 1. Channels of communication expand, within the community involved, between communities, and distant decision-makers, which give more power to the community to communicate their needs and issues. 2. The empowerment that comes from seeing your life or yourself as others see you, through the screen, has a powerful self-confidence impact. Recognized as a great tool to empower communities (Cunsolo Willox et al. 2013; Tremblay et al. 2015; Tremblay 2013), as well as youth (Haynes and Tanner 2015; Cox et al. 2019), who do not necessarily have a say in certain political decisions affecting their lives, the use of PV has the potential to give “voices to the voiceless.” However, this can be seen as an ideal concept and can look differently in practice. As Shaw (2012a, p.230) describes, “the empowerment narrative rests on the assumption that the balance of social power can change.” With the use of digital media creating new spaces for interactions and reshaping more equal relationships (High 2005), the process is perhaps more important than the knowledge itself produced in terms of creating positive change (Shaw 2012b). Benefits: Empowerment, Engagement, and Communication The process of PV can have multiple benefits such as enhanced self-confidence, knowledge and leadership skills, critical self-reflection, organizational capacity, and increase in the mobilization of community knowledge (Tremblay and Jayme 2015). Many of the participatory digital media approaches support capacity building, the coproduction of knowledge, increase awareness and education at different levels (participant, community, and policy-makers), and can contribute toward empowerment and representation (Gutberlet et al. 2016; Shaw and Robertson 1997; Shaw 2012a; Tremblay and Jayme 2015).

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The production of knowledge potentially happens at multiple stages in the PV process: through the making of the videos (discussions, brainstorms, storyboarding, and interviews) and via the video itself viewed by the participants and shared with the community (Mitchell et al. 2012). Participatory video has been considered an effective communication and dissemination tool (Crocker 2008; Shaw and Robertson 1997; Tremblay 2013; Wheeler 2012; White 2003). This reach can happen at different levels: with the audience targeted, which can be a group, a community, or policy-makers. There is the potential for PV to “open up spaces in between top-down and bottom-up where participants’ social influence can emerge if conditions are favorable” (Shaw 2012b, p.18). PV can indeed create a bridge for dialogue and integrate different and often missing voices into policy discussions, but it is hard to know how much impact this new form of knowledge will have in terms of social change impacts or changes in policy (Wheeler 2012). Issues Related to Power and Representation The PV approach is beneficial because it is causing a shift in representation and power – although it is still not completely neutral. People involved (i.e., funders, practitioners, and participants) can have different motivations and those can be conflicting (Shaw 2012a). One of the themes or issues in the PV literature concerns the issue of representation (Braden 1998, 1999; Wheeler 2012; Zoettl 2013). Representation can have two meanings: one, an “image of,” and two, “speaking on behalf of,” and both are used in the videomaking context for participatory representation (Braden 1999). PV has certainly a crucial and needed role in bringing underrepresented voices to policy spheres; however, as Cahill et al. (2007) question: “who has the ‘authority’ to represent a community’s point of view? Who should speak for whom, and in what language?”. Indeed, PV has been seen as a major tool in combining process and product to offer opportunities for marginalized communities to contribute “in both forms of self-research and ways of self-representation” (Evans and Foster 2014).

It is important to recognize that, as critiqued by Walsh (2016), PV and PAR in general rarely address the political norms about power on which they are grounded. Because of its more liberal political views, there is a tendency to put the problem on “individuals without power to emancipate themselves” within a system that is presented as equal. She argues that there is a “hopeful naivety” around the use of PV and its potential benefits. Those empowered voices end up somewhere and serve someone – PV should try to not only go beyond expressing those concerns to people in power, but also promote reflection to create new ways of experiencing the world (Walsh 2016). Gaventa and Cornwall (2008) looked at how power and knowledge are connected and how participatory research aims to change power relations by questioning the traditional ways of knowledge production. To challenge power inequities, one must use and produce knowledge to influence prevalent knowledge of the issues and power interactions which affect “the lives of the powerless,” a goal that proponents of participatory research have been advancing. Shaw (2017) has identified some important ethical questions raised with PV, particularly related to the risk of incorrect exposure, the politics related to the community response, and power relationships between project partners. Indeed, the end product does not always reflect the full picture of a story or reality. There are obstacles to empowerment in the field of participatory video. In particular, the power structures existing in a community will create an unequal access to the tool, where not all voices may be represented (Gadihoke 2003). Empowerment does not miraculously happen, and there is sometimes the problematic assumption that using PV as a tool will “give voice to the voiceless.” There are ways to tackle these challenges, such as being inclusive in the participant selections, for example, by inviting not only students but also youth who are not at school or by allowing multiple voices to be heard through the creation of different edits of the videos. Kindon (2003) advocated for the use of PV as a feminist practice and with the potential to disrupt hierarchical power relations and create spaces for change. In a follow-up of this pivotal

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paper in 2016, she raised concerns about the benefits of PV such as empowerment or feminist practice of looking, which should be moderated by more careful consideration to “the complexities of power within which the technology and its conventions are imbricated” (Kindon 2016b). Figure 11 gives an overview of the participatory video process, its benefits, and challenges or influencing factors.

Citizen Science and Community-Based Monitoring Citizen science is widely used to engage participants or “citizen scientists” from the general public in gathering scientific data, to monitor species or environmental indicators, or help with data analysis (Dickinson et al. 2012). Certainly, it can be labor intensive and expensive for environmental monitoring or sampling programs led by academics, governmental, or nongovernmental organizations to be carried out. When citizens or community groups collecting data are focused on a common issue or local area, it is defined as community-based monitoring (Whitelaw et al. 2003; Conrad and Hilchey 2011). There are real advantages to involve citizen scientists in programs to expand the geographical scale, increase the level of samples, or monitor certain species long-term. Advantages of those types of projects include the increase of the scientific capacity, social networks, and influence on

Creative Commons Credits for the diagram: “File:Video Camera 1 2 – The Noun Project.svg” by aartiraghu is marked under CC0 1.0. To view the terms, visit http:// creativecommons.org/publicdomain/zero/1.0/deed.en; “File:Cartoon Guy Being Filmed By A Camera Crew For A Marketing Video.svg” by Free Clip Art is licensed with CC BY-SA 4.0. To view a copy of this license, visit https:// creativecommons.org/licenses/by-sa/4.0; “brainstorming” is marked under CC0 1.0. To view the terms, visit https:// creativecommons.org/licenses/cc0/1.0/; “File:Cartoon Video Editing And Streaming.svg” by Free Clip Art is licensed with CC BY-SA 4.0. To view a copy of this license, visit https://creativecommons.org/licenses/by-sa/ 4.0; “File:Movie – The Noun Project.svg” by XOXO is marked under CC0 1.0. To view the terms, visit http:// creativecommons.org/publicdomain/zero/1.0/deed.en

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decision-making at the local level (Whitelaw et al. 2003). On the educational side, participants have the potential to acquire new skills related to the scientific data collection, critical thinking, and analysis, where participants can use this knowledge to create new research questions, design more studies, or develop models to answer those queries (Dickinson et al. 2012). In addition, citizen science has been recognized as a great tool to increase public awareness and science education, bridge scientific and the public facilitating more support for science, as well as environmental stewardship (Dickinson and Bonney, cited by Dickinson et al. 2012). Challenges Related to Citizen Science Programs There are some challenges related to the use of citizen science and community-based monitoring (See Table 1), although systematic reviews of citizen science projects provide recommendations and guidance to help alleviate some of the challenges. One of the critiques of citizen science and community-based monitoring is the validity and reliability of the data collected (Whitelaw et al. 2003). Careful attention to the design of the protocols is crucial to help with data accuracy (Pocock and Evans 2014), and so is the step of validating data (Gardiner et al. 2012). In an effort to help with combining data from different citizen science projects, there is a momentum toward creating data and metadata standards for the Public Participation in Science Research (PPSR) (Fraisl et al. 2020), although there is still much room for improvement in regard to data access and data-sharing standards (Turbé et al. 2020). In addition, it requires a considerable amount of time and effort to retain and recruit participants in citizen science projects, including promotion, frequent communication, and incentivizing participation through contests or certificates (Dickinson et al. 2012). Communicating results back to the citizen scientists is also a great way to maintain momentum and interest in the program (Forrest et al. 2019). To ensure the viability of a project, it is critical to have the leadership in place, a database, and a website, which all require access to long-term funding.

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Community-Based Research and Participatory Approaches in Support of SDG14, Fig. 1 Participatory video process (yellow rectangles), benefits (purple circles),

Community-Based Research and Participatory Approaches in Support of SDG14, Table 1 Review of benefits and challenges of citizen science and community-based monitoring Benefits Community engagement and network Awareness and education increase Easy or cheaper access to data for scientists Better monitoring (more data on ecosystems) Support policy-making Can help detect new events or species

Challenges Retaining participants Sustainability of funding Data reliability, validity, and quality control Data use for policymaking Access to expertise

Adapted from Conrad and Hilchey 2011

A lack of transparency related to data use, as well as tracking impacts on research and publications, are also some of the issues expressed, which can impact participants’ retainment and policy

and influencing factors or challenges (orange arrows). (Source: Creative Commons)

linkages. Turbé et al. (2020) also found that while many citizen science projects claim open access to their data, most projects only provide data summaries or maps on their websites – very few actually provide a straightforward way to download the data. Although policy impact is difficult to determine, one of the gaps in the literature regarding citizen science is how the data collected is used in environmental decisionmaking (Conrad and Hilchey 2011; Turbé et al. 2020). Determining policy connections is complicated. Turbé et al. (2020) who assessed over 500 citizen science projects in Europe indicated that project coordinators often had problems determining appropriate policy needs, reaching policy-makers, and persuading them of the significance of citizen science data. In addition, determining the uses of citizen science data is very difficult, both in science and in policy. There seems to be no direct link between the end users of the data and project coordinators and no easy way to monitor the use of citizen science data.

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This emphasizes the struggle to recognize concrete policy impact and to connect it to a particular policy sector. Some recommendations by Turbé et al. (2020) to improve the connection between citizen science and policy connections include (1) expanding the coverage of environmental policy sectors by citizen science programs; (2) increasing outreach to decisionmakers via capacity building, displaying best practices, and protocols, so that government officials are more inclined to use and trust the data collected; (3) centralizing access to citizen science resources via knowledge hubs would improve access to data and help projects to combine resources for training and assistance; (4) promoting diverse partnerships and collaboration to create innovative funding mechanisms (NGO/private sector/academic); and (5) aiming to measure citizen science impacts and track success (i.e., outcomes, numbers of participants) through project evaluation – which in turn will help future funding (Turbé et al. 2020). To link citizen science and policy requires careful attention – some improvements are needed for the data collection, data analysis tools, and validation approaches, so that the data is organized in a way to ensure high quality, comparability, and supports the link to policy (Fraisl et al. 2020). Turbé et al. (2020) called for SDGs to be thoroughly analyzed to find and encourage citizen science opportunities that can feed into policy implementation and monitoring. Citizen science contributions to the achievement of the UN Sustainable Development Goals (SDGs) have been assessed by Fraisl et al. (2020) and have shown that it has the potential to contribute to all 17 SDGs. More specifically, Fraisl et al. (2020) found that citizen science is already contributing to the SDG14 indicator 14.1.1 and could contribute to 14.3.1, 14.4.1, and 14.5.1 (See Table 2). This shows great potential for putting citizen scientists at the center of the monitoring of the SDG14, especially in data collection like time series, and strengthening rapid response to environmental hazards. With the potential for the public to inform policy, citizen science can be a vehicle to increase confidence, reliability, and

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Community-Based Research and Participatory Approaches in Support of SDG14, Table 2 Citizen science current and potential contributions to SDG14 indicators SDG14 Indicators 14.1.1 Plastic debris density, coastal eutrophication 14.3.1 Marine acidity measurements 14.4.1 Proportion of fish stocks within biologically sustainable levels 14.5.1 Coverage of protected areas in relation to marine areas

Current contribution X

Potential contribution

C X X

X

Adapted from Fraisl et al. 2020; UN 2021

eventually accountability throughout the course of the SDG monitoring (Fraisl et al. 2020). More generally, globally recognized policy frameworks, such as the Sustainable Development Goals (SDGs), should be systematically analyzed in order to identify and promote the many opportunities that citizen science can bring to policy implementation and monitoring. Citizen Science Examples in Support of SDG14 There has been an increase of citizen science projects addressing marine plastic pollution and increase in participation over the last few years, indicating that the public is becoming more aware of the issue and taking actions (Fraisl et al. 2020; Napper and Thompson 2020). There are many examples of citizen science projects related to plastics monitoring in the literature. This past year was a bit different in terms of participation due to COVID-19, although the Marine Conservation society in the UK still attracted over 2000 participants for their annual beach cleanup – as opposed to 10,000 the year before. Nevertheless, data have shown a sharp increase of personal protection equipment (i.e., masks, gloves) found on beaches, resulting in 30% of the marine debris (Marine Conservation Society 2020). Data collected annually are contributing to a worldwide report on litter levels.

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Tourists traveling to remote places, such as the Arctic, have the potential to contribute to plastic debris data collection in areas that would be normally hard to reach by citizen scientists. Bergmann et al. (2017) looked at data collected by cruise ship travelers who carried out surveys on six beaches in Svalbard. They categorized and quantified marine debris and took photos of impacts on wildlife. Over 80% of the marine litter encountered belonged to the plastics category, most of which came from fisheries. Because tourism is an important source of litter around the world (Alshawafi et al. 2017), involving tourists in citizen science is a great opportunity to bring awareness and educate them on the impacts of plastics on wildlife and on beaches (Eastman et al. 2013). Another study involving citizen scientists in a microplastics sampling program also found that the real value of the initiative was the community outreach and better awareness related to plastic pollution (Forrest et al. 2019). Monitoring microplastics (30% of the world’s coral reefs

3.

>3000 species of fish

4.

37% of the 6000 coral reef fishes in the world 52% of the reef fishes of the indo-Pacific 73,000 Km2 (or 29%) of the global coral reef area 50% of razor clams

5. 6. 7. 8.

Six out of the seven sea turtle species

References Veron (2000) Green et al. (2011) Green et al. (2011) Allen (2008) Allen (2008) Burke et al. (2012) Saeedi et al. (2016) Asaad et al. (2018)

Benefits of Conservation Intervention Marine biodiversity crisis is a serious matter but not given the importance it deserves in decisionmaking. It needs urgent attention as the stakes are too high. Oceans are in peril, and so is the life on Earth. There are reasons to believe that ocean acidification and other effects of climate change, overfishing, destructive fishing, and habitat degradation, especially the loss of marine critical habitats, are changing the oceans as never before. Loss of marine life is a matter of concern to all of mankind. Calls from the scientific community for real action for conserving and managing the marine environment in order to maintain healthy ecosystems and human well-being are getting louder (Bennet et al. 2017). In response, an international consensus was evolved through Convention on Biological Diversity (Aichi Target 11) and United Nations Sustainable Development Goal 14 for at least declaring 10% of the vast environment as the MPA by 2020. This is just one of the tools for governance of sustainable fisheries, blue carbon stocks, spatial planning, and adaptation measures. The scale of impacts is much higher than conserving just 10% of its area, but for any further expansion to be effective we need to consider if

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the society is onboard as the livelihood of millions of people is closely tied to marine resources. Bennet et al. (2017) have highlighted the societal issues needing attention in planning and implementation through a code of conduct that is socially acceptable and ecologically effective. If humans are to play the ocean stewardship role, it is essential that our actions should be based on current knowledge and experience for effective future-proofing of oceans and sustainable benefits to the future generations. Protecting biodiversity and the essential ecosystem services that it supports has become a priority for generating knowledge and capacity development for achieving the multiple SDGs. There is no dearth of topics that can be pursued, but it makes sense to identify thrust areas to be given special attention to combining knowledge that exists or likely to be gained through problem-solving innovations. The species of animals serving as seafood can no longer be regarded in isolation from other species and habitats. A sustainable seafood supply system requires ecosystem-based management of oceans. This has been amply emphasized by Mustafa and Estim (2019). Priority areas emerging from their key points pertaining to conservation and sustainable development are presented below: 1. Baseline knowledge of all the three levels of marine biodiversity (genes, species, and ecosystems) at temporal and spatial scales, and the factors that control generation of diversity 2. Digital documentation of data pertaining to marine biodiversity that can be easily updated and shared 3. Further insights into the role of marine biodiversity in marine ecosystem health and stability of planetary life support systems 4. Understanding of the factors that promote, preserve, and threaten marine biodiversity 5. Adaptation of marine species to modifications caused by changing climate, and implications of such changes for oceans and human wellbeing 6. Links between marine biodiversity and ecosystem functioning in the context of sustainable development goals

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7. Quantifying the specific marine biodiversity indicators and their use in management systems 8. Nationwide efforts toward accurate understanding of marine biodiversity tipping points and their consequences for economic sectors such as seafood security 9. Delivering economic benefits through projects designed to capitalize on sustainable use of marine biodiversity in fisheries, aquaculture, marine biotechnology, and nature tourism 10. Applying the state-of-the-art technologies including those of the Industrial Revolution 4.0 for new knowledge, real-time monitoring, and governance, especially in marine biodiversity hotspots 11. Facilitating disruptive innovations in marine biodiversity knowledge, seafood production systems, and climate change adaptations in fisheries and aquaculture

natural resources and related issues, the institutions can leverage their expertise toward investment in partnerships to achieve more impact on the society, far beyond what can be accomplished by working alone. The challenges facing marine biodiversity and fisheries are interconnected and qualitatively similar in many countries, so the partnerships can lead to exchange of knowledge and sharing of experiences that will help in overcoming the challenges and collective actions in various ways:

Linking marine biodiversity with food security through credible research aimed at seeking synergies between the two will generate benefits for ecological, social, and economic development (Cramer et al. 2017). Countries do develop policies and action plans to implement SDGs nationwide, but a fast-track progress can be achieved by localizing the efforts at institutional levels. While analyzing the positive outcomes of biodiversityfocused practices, FAO (2019b) reported that researchers in many countries continue to emphasize the need for more investigations which delays action. Many biodiversity-focused practices are relatively complex, with many interlinked issues and variables, but implementable in a knowledgebased and context-specific ecosystem. However, to be successful, the plans and actions should be based on a good understanding of the local environment (FAO 2019b). Universities that have transformed into EcoCampus and are racing for green metrics scores are in a better position for adapting the SDGs to local situations, and incorporating them in institutional programs of education, public outreach, and ways of working (Mustafa et al. 2019; Shaleh et al. 2019). By localizing the efforts for conservation of marine

Local efforts can benefit from knowledge of the marine biodiversity generated internationally since some countries have already made a significant headway in this area. In fact, as a result of sustained investment in research, several marine biodiversity databases that provide a rich source of information have already been developed and can be consulted. These include: World Register of Marine Species, Marine Regions Ocean Biogeographic Information System, Global Marine Environment Datasets, FishBase, and AlgaeBase.

1. Disseminating the evidences arising from scientific trials to inform the key features of successful methods for possible adoption or adaptation. 2. Governance mechanisms that have proved effective. 3. Data for informed decision-making. 4. Benefits of inclusive approaches. 5. Showcasing feasible solutions.

Conclusions and the Way Forward Marine biodiversity which underpins our seafood systems is declining. This is putting at risk the food security, livelihoods, health, and other aspects of human welfare. Realizing that seafood seeks to bridge the gap between food supply and demand, health of the oceans has taken the center stage as the last frontier on Earth for food production. This scenario is likely to prevail due to population growth and changing food consumption habits of people.

Coral Triangle: Marine Biodiversity and Fisheries Sustainability

Maintaining all of the biological components of the marine ecosystem at functional levels is necessary for its ability to meet additional food demand. There are many effects of biodiversity loss that are not so much tangible as seafood, and these include chemicals used in biopharmaceuticals and raw materials used in industries. Now that the blue growth is emerging as a significant sector of the global economy, sustainable ocean management should be a major factor in national policies and practices. It is necessary to undertake structured initiatives for marine ecosystem for species survival and diversity, and seafood security. There are many marine biodiversity indicators, but more research is needed on this topic for their responsiveness to pressures in a dynamic ocean ecosystem and their accuracy to reflect changes. This will enhance the confidence in the information that the indicators would generate and its use in biodiversity management policy framework. It will augur well for marine biodiversity conservation if further studies link it with the societal benefits. Focused studies on marine biodiversity-sustainable development of fisheries linkage will contribute significantly to highlighting the conservation benefits for long-term seafood security.

Cross-References ▶ Estuaries: Dynamics, Biodiversity, and Impacts ▶ Fisheries Management and Ecosystem Sustainability ▶ Higher Education and Sustainable Development of Marine Resources ▶ Marine Animals and Human Care Toward Effective Conservation of the Marine Environment ▶ Sustainable Coastal and Marine Ecotourism: Opportunities and Benefits

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Duffy JE (2003) Biodiversity loss, trophic skew and ecosystem functioning. Ecol Lett 6:680–687 EASAC (2005) A user’s guide to biodiversity indicators. European Academies’ Science Advisory Council, Brussels FAO (2003) Technical guidelines for responsible fisheries – fisheries management 2: the ecosystem approach to fisheries. Food and Agriculture Organization, Rome FAO (2018) The state of world fisheries and aquaculture: meeting the sustainable development goals. Food and Agriculture Organization, Rome FAO (2019a) 2050: a third more mouths to feed. Food and Agriculture Organization, Italy FAO (2019b) The state of the world’s biodiversity for food and agriculture. FAO commission on genetic resources for food and agriculture. Food and Agriculture Organization, Rome FOLU (2019) Growing better: ten critical transitions to transform food and land use. The Food and Land Use Coalition, Colombia Frank K, Petrie B, Choi J et al (2005) Trophic cascades in a formerly cod-dominated ecosystem. Science 308 (5728):1621–1623 Green SJ, White AT, Christie P et al (2011) Emerging marine protected area networks in the Coral Triangle: lessons and way forward. Conserv Soc 9(3):173–188 Heip C, McDonough N (2012) Marine biodiversity: a science roadmap for Europe. Marine Board Future Science Brief 1, European Marine Board, Ostend Heiskanen AS, Berg T, Uusitalo L et al (2016) Biodiversity in marine ecosystems—European developments toward robust assessments. Front Mar Sci. https://doi. org/10.3389/fmars.2016.00184 Hessen D, Kaartvedt S (2014) Top–down cascades in lakes and oceans: different perspectives but same story? J Plankton Res 36(4):914–924 HLPE (2014) Sustainable fisheries and aquaculture for food security and nutrition. Committee on World Food Security, Rome Hoagland P, Sumaila UR, Farrow S (2001) Marine protected areas. In: Steele JH, Thorpe SA, Turekian KK (eds) Encyclopedia of ocean sciences. Academic Press, London, pp 1654–1659 IUCN (1994) Guidelines for protected area management categories. World Conservation Monitoring Center, Gland/Switzerland/Cambridge Kavanagh L, Galbraith E (2018) Links between fish abundance and ocean biogeochemistry as recorded in marine sediments. PLoS ONE 13(8). https://doi.org/ 10.1371/journal.pone.0199420 Lubchenco J, Grorud-Colvert K (2015) Making waves: the science and politics of ocean protection. Science 350:382–383 Martin G, Fammler H, Veidemane K et al (2015) Development of indicators for assessing the state of marine biodiversity in the Baltic Sea within the LIFE MARMONI project. Estonian Marine Institute, University of Tartu Mäealuse 14 12618 Tallinn

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Deep Seabed Mining and Sustainable Development Goal 14 Pradeep A. Singh Ocean Governance, Institute for Advanced Sustainability Studies, Potsdam, Germany

Synonyms Activities in the Area; Deep-sea mining; Life below water; Marine minerals; Marine mining; Marine resources; Ocean minerals; Ocean mining; Ocean resources; Ocean sustainability; Offshore mining; SDGs; Seafloor mining

Definition Deep seabed mining refers to the exploration and eventual exploitation of minerals located on the seafloor at depths of 200 m and onwards. Mining interests primarily involve three different types of resources, namely, polymetallic nodules, polymetallic sulphides and cobalt-rich

ferromanganese crusts. These mineral deposits are rich in critical metals such as nickel, copper, cobalt and manganese, as well as some quantities of zinc, gold, silver and rare earth elements, among others (Hein and Koschinsky 2014; Miller et al. 2018; Koschinsky et al. 2018). Deep seabed mining can occur in areas within national jurisdiction and in areas beyond national jurisdiction (which is also known as the international seabed or “the Area”). In relation to the former, coastal states have sovereign rights over the mineral resources, whereas in the case of the latter, an international organization known as the International Seabed Authority has jurisdiction over these resources and is mandated act in the benefit of mankind as a whole (Singh and Hunter 2019; Haugan et al. 2020). The 2030 Agenda for Sustainable Development, adopted by the UN General Assembly in 2015, is a global political commitment that comprises of 17 Sustainable Development Goals and 169 associated targets, which are intended to be achieved by the end of 2030. Sustainable Development Goal 14, titled “Life below water,” specifically aims to “conserve and sustainably use the oceans, seas and marine resources for sustainable development” (United Nations 2015).

Introduction The ocean covers over 71% of the surface of the Earth and plays a crucial role in absorbing and

© Springer Nature Switzerland AG 2022 W. Leal Filho et al. (eds.), Life Below Water, Encyclopedia of the UN Sustainable Development Goals, https://doi.org/10.1007/978-3-319-98536-7

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sequestering carbon, as well as in the regulation of the global climate. Coastal communities rely on the ocean as a vital source of livelihood, while a significant portion of the global population relies on the ocean for food. Moreover, the ocean remains to be an important source for medical and pharmaceutical products, while various forms of ocean or coastal tourism continue to expand. Therefore, it is not an understatement to say that the ocean is a pivotal and indispensable contributor to human health and well-being (United Nations Educational, Scientific and Cultural Organization (UNESCO) 2012). At the same time, it is not an overstatement to say that the ocean, its marine life and intricate ecosystems are currently under unprecedented levels of threat (United Nations 2017). The adverse impacts of human activities, which take place both on land and at sea, have reached as far out to the deepest and most remote parts of the ocean, resulting in the worsening of ocean health and weakening of the important functions that it performs (RamirezLlodra et al. 2011). Simultaneously, climate change has also added to the negative impacts currently experienced by the deep ocean (Levin and Le Bris 2015). It is now clear in that while the impacts arising from harmful activities or phenomena will be felt most within a localized area, the degradation of the marine environment and its ecosystem functioning through human activities and natural variables will generally and gradually be felt all over the ocean, which should be seen as a global shared space (Golden et al. 2017). Consequentially, protecting the health and environmental status of the ocean is arguably a common concern of the global community (Harrison 2017; Rudolph et al. 2020). In this respect, the UN Convention on the Law of the Sea affirms that “the problems of ocean space are closely interrelated and need to be considered as a whole” (United Nations Convention on the Law of the Sea 1982). In 2015, the global community came together and agreed upon the 2030 Agenda for Sustainable Development, as adopted by the UN General Assembly that year. In particular, a set of 17 global goals were identified, collectively known as the Sustainable Development Goals (SDGs), which supposedly acts as a “blueprint to achieve

a better and more sustainable future for all.” Sustainable Development Goal 14 (SDG 14), entitled “Life below water,” is most pertinent to the ocean. The overarching goal of SDG 14 is to “conserve and sustainably use the oceans, seas and marine resources.” Marine resources here include both living resources (such as fish and marine mammals) and non-living resources (such as oil and gas as well as minerals). Commercial interests in extracting ocean mineral resources located on the deep seabed can be traced to the 1960s, even though the existence of these resources were first discovered about a century earlier. Generally speaking, deep seabed minerals are known to exist from average depths of 500 to 6000 m, depending on the resource type, and exist in areas within national jurisdiction (i.e., on the continental shelf of coastal states) as well as in areas beyond national jurisdiction (i.e., on the international seabed or otherwise known “the Area”). To date, there has not been any commercial scale exploitation of these minerals, both in areas within and beyond national jurisdiction. However, exploration and the development of extraction technologies have been ongoing for several decades now as the industry prepares itself for actual mining. On the one hand, proponents of the activity contend that it is necessary to turn to the ocean in order to procure the metals that are needed for the green transition, as well as that mining the seabed for these critical metals is more advantageous – from an environmental perspective, among others – than sourcing them through terrestrial mining (see e.g., Paulikas et al. 2020a). On the other hand, current scientific knowledge reveals that seabed mining would cause significant and potentially irreversible harm to the marine environment, possibly causing the extinction of species, destruction of habitats, widespread disturbances resulting from pollution (e. g., of sediment, noise and light), as well as severely impacting local marine ecosystems and impairing the vital services they provide (see e.g., Miller et al. 2018). As such, the correlation between deep seabed mining and the concept of sustainability or sustainable development is quite intriguing, and arguably, rather elusive.

Deep Seabed Mining and Sustainable Development Goal 14

This chapter sets out to examine the conduct of deep seabed mining activities in the light of the Goal 14 of the SDGs. Section “The Sustainable Development Goals (SDGs) and SDG 14” provides an overview of the SDGs with a focus on SDG 14, while section “Deep Seabed Mining” introduces the emerging deep seabed mining industry. Section “Reconciling the SDGs and SDG 14 with Deep Seabed Mining” then explores, with a view to reconcile, deep seabed mining activities in the context of the SDGs and SDG 14 in particular, followed by some concluding remarks in section “Concluding Remarks.”

The Sustainable Development Goals (SDGs) and SDG 14 In September 2015, the UN General Assembly adopted Resolution A/RES/70/1 to give effect to the 2030 Agenda for Sustainable Development. However, the basic principles of sustainable development can be traced as far back to the Stockholm Conference on Human Development in 1972, which eventually contributed to the work of the World Commission on Environment and Development (or the “Brundtland Commission”) and the “Our Common Future” report in 1987, and subsequently led to the celebrated Rio Declaration on Environment and Development in 1992. The 2030 Agenda for Sustainable Development supersedes the Millennium Development Goals, adopted in 2000 with eight goals, which had expired in 2015. The main foundation that provided momentum for the eventual adoption of the 2030 Agenda for Sustainable Development was the United Nations Conference on Sustainable Development in 2012 (or the Rio + 20 Summit), which resulted in an outcome document called “The future we want.” Subsequent to that, an Open Working Group of the General Assembly on Sustainable Development Goals was established in January 2013 with a mandate to provide a proposal on the Sustainable Development Goals (SDGs). The said Open Working Group provided its proposal in August 2014, which was later negotiated and adopted the following year in September 2015.

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Resolution 70/1, titled “Transforming our world: the 2030 Agenda for Sustainable Development,” states that the “Agenda is a plan of action for people, planet and prosperity” and a commitment to “achieving sustainable development in its three dimensions – economic, social and environmental – in a balanced and integrated manner” (United Nations 2015). At its core, the 2030 Agenda comprises of 17 SDGs with 169 associated targets, “which are integrated and indivisible,” that came into effect on 1 January 2016 for a duration of 15 years (United Nations 2015). It is important to note that the 2030 Agenda and the SDGs are political aspirational and therefore not legally binding. Indeed, Resolution 70/1 clearly stipulates that Member States are given the flexibility to design their own national-level development strategies and give effect to the SDGs therein. Regional-level cooperation and engagement is also encouraged for the purpose of implementation. National and regional efforts then feed into a network of follow-up and review processes at the global level via a high-level political forum. The purpose of the high-level political forum, as stated in Resolution 70/1, is to “facilitate sharing of experiences, including successes, challenges and lessons learned, and provide political leadership, guidance and recommendations for follow-up,” to “promote system-wide coherence and coordination of sustainable development policies,” and to “ensure that the Agenda remains relevant and ambitious and should focus on the assessment of progress, achievements and challenges.” Although not legally binding, the SDGs effectively provide “a globally endorsed normative framework for development” (Nilsson et al. 2017), with sustainability at its core. SDG 14 (or Goal 14), titled “Conserve and sustainably use the oceans, seas and marine resources for sustainable development,” comprises of seven targets and three means of implementation that specifically targets the ocean. At the outset, it is important to acknowledge that SDG 14 is largely premised on the 2012 outcome document of the Rio + 20 Summit titled “The future we want,” where a resounding commitment was made “to protect, and restore, the health, productivity and resilience of oceans and marine

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ecosystems, to maintain their biodiversity, enabling their conservation and sustainable use for present and future generations, and to effectively apply an ecosystem approach and the precautionary approach in the management, in accordance with inter-national law, of activities having an impact on the marine environment, to deliver on all three dimensions of sustainable development” (United Nations 2012). Since the adoption of the SDGs, SDG 14 has received some rather significant attention from the global community. In particular, the UN General Assembly decided to convene a dedicated “High-Level United Nations Conference to Support the Implementation of Sustainable Development Goal 14” or the “Oceans Conference” to facilitate urgent action on ocean sustainability, which took place in 2017 and resulted in the adoption of Resolution A/RES/71/312 titled “Our ocean, our future: call for action.” Premised on the above, ocean conservation and responsible use of ocean resources have finally received formal recognition as being part of the wider sustainable development context (Schmidt et al. 2017). SDG 14 is said to provide “a fundamental impulse for humanity” to protect the global commons – the ocean (Rudolph et al. 2020). However, it should be noted that “SDG 14 is undoubtedly intended as a starting point rather than a final destination” (Armstrong 2020). Indeed, a recent report assessing the current progress of SDGs confirms that there is much work that is left to be done to attain the targets found in SDG 14 (United Nations 2020). At the same time, it is also equally clear that SDG 14 is linked with all of the other SDGs and that safeguarding a healthy and productive ocean requires strong support and positive implementation of all of the other SDGs as well (von Schuckmann et al. 2020). More importantly, a proper and detailed scientific understanding of the ocean is necessary in order to achieve SDG 14 and all other SDGs insofar as they relate to the ocean (Pendleton et al. 2020). In response to a proposal by the Intergovernmental Oceanographic Commission (IOC) of the United Nations Educational, Scientific and Cultural Organization (UNESCO), aptly titled “The ocean we need for the future we want,”

the UN General Assembly in Resolution A/RES/ 72/73 proclaimed the “United Nations Decade of Ocean Science for Sustainable Development” (or “the Decade”) for a 10-year period commencing on 1 January 2021. The Decade has two overarching goals, namely, “to generate the scientific knowledge and underpinning infrastructure and partnerships needed for sustainable development of the ocean” and “to provide ocean science, data and information to inform policies for a wellfunctioning ocean in support of all SDGs of the 2030 Agenda.” In addition, the Decade aspires to generate and accomplish six societal outcomes, which are as follows: “a clean ocean,” “a health and resilient ocean,” “a predicted ocean,” “a safe ocean,” “a sustainably harvested and productive ocean” and “a transparent and accessible ocean” (Ryabinin et al. 2019). The Decade has the potential to address “disciplinary understanding of ocean processes and solution-oriented research to generate new knowledge” that will inevitably help towards reduce ocean pressures, preserve and restore ocean ecosystems and ensure a healthy ocean for generations to come (Visbeck 2020). The urgent need to rely on science and to further improve the current knowledge pertaining to the ocean is particularly pertinent for the deep sea, which remains to be a poorly understood frontier that requires more targeted attention (Visbeck 2020). Indeed, the Decade presents an exceptional opportunity to increase current levels of scientific understanding that will enable the shift to a more sustainable future for the deep sea (Howell et al. 2020). This is particularly relevant given the increased interest in turning to the ocean as a source for minerals in recent times, which has created an emerging industry that is hoping to embark on a nascent activity otherwise known as deep seabed mining.

Deep Seabed Mining The deep sea generally refers to the parts of the ocean that are 200 m and more in depth. Deep seabed mining, accordingly, generally refers to the extraction of mineral deposits from the seafloor at depths greater than 200 m (Smith et al. 2020).

Deep Seabed Mining and Sustainable Development Goal 14

Although deep-sea minerals (polymetallic nodules) were first discovered in the 1860s and 1870s, commercial interests in deep seabed mining only started to receive attention after almost a century later with the publication of the book “Mineral Resources of the Sea” (Mero 1965; Thompson et al. 2018). Current interests centre on three mineral deposits, namely, polymetallic nodules, ferromanganese crusts and seafloor massive sulphides (Koschinsky et al. 2018). Polymetallic nodules form in abyssal plains at average depths of 3000–5000 m and contain manganese, iron, nickel, copper and cobalt primarily (et al. 2018; Koschinsky et al. 2018). Ferromanganese crusts form on the slopes and summits of seamounts at average depths of 800–2500 m and are notably rich in cobalt, manganese, iron, copper, nickel and platinum (Hein and Koschinsky 2014; Miller et al. 2018; Koschinsky et al. 2018). Seafloor massive sulphides are found at hydrothermal vents along oceanic ridges at average depths of 1000–4000 m and mainly comprises of copper, zinc, gold and silver (Miller et al. 2018; Koschinsky et al. 2018). Traces of rare earth elements are also found within the above deposits. All three resource types can be found in seabed areas within national jurisdiction as well as seabed areas beyond national jurisdiction, albeit in varying abundance and quality. This jurisdictional distinction is critical because having jurisdiction over the mineral resources confers certain rights as well as obligations. It is estimated that approximately 42% of known areas with seafloor massive sulphides, 54% of areas with cobalt-rich crusts and 19% of known areas of polymetallic nodules are located within seabed areas that fall under the jurisdiction of coastal states (Petersen et al. 2016). That said, more than 50% of the total seabed area are located within areas beyond national jurisdiction, i.e., the forming the “international seabed,” where the majority of known mineral deposits are to be found (Lodge 2017). Since the ocean is essentially a shared space and most of its problems are interconnected, it is necessary to consider deep seabed mining activities in both areas within and beyond national jurisdiction. In areas within national jurisdiction, the coastal state in question enjoys sovereign rights to

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explore and exploit the resources located therein. The sovereign rights of coastal states over the seabed and its resources apply up to 200 nautical miles from their baselines (provided it does not overlap with the seabed areas of one or more coastal states, in which case delimitation is necessary) and may be extended further pursuant to international law (i.e., up to 350 nautical miles and even further in exceptional cases) if certain geomorphological conditions pertaining to the continental margins are applicable (United Nations Convention on the Law of the Sea 1982, Part VI). Having jurisdiction over the seabed accords the coastal state the right to explore and exploit the mineral resources located therein if, when and how it so chooses, although exercising this right also entails certain obligations under international law, such as the general duty to protect the marine environment and to avoid, minimize and control the harmful effects that arise from such activities (Singh and Hunter 2019). The international seabed, i.e., the seabed area beyond national jurisdiction (or otherwise known as “the Area”), is subject to a unique regime as it has been declared by the UN General Assembly as the “common heritage of mankind” about half a century ago (United Nations 1970a), which was coincidentally prompted by a series of events following the 1965 publication of the earlier mentioned book Mineral Resources of the Sea (Lodge 2017). Essentially, the international seabed belongs to mankind as a whole, wherein no state can claim sovereignty or exercise sovereign rights over any part of the seabed (United Nations 1970b). Premised on that, the UN Convention on the Law of the Sea 1982 established an international organization known as the International Seabed Authority (“ISA”) to organize and control all activities relating to the exploration and exploitation of the mineral resources of the Area (United Nations Convention on the Law of the Sea 1982, Part XI). All Member States to the said Convention, which now stands at 167 states and the European Union, are automatically members of the ISA. Pursuant to the UN Convention on the Law of the Sea 1982 and a subsequent modifying instrument adopted in 1994 known as the Agreement

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Relating to the Implementation of Part XI of the Convention, the ISA has the mandate to develop rules, regulations and procedures relating to the exploration and exploitation of the mineral resources of the Area; consider and approve (or disapprove) mining applications; adopt necessary measures to ensure the effective protection of the marine environment from the harmful effects of mining activities in the Area; promote the conduct of marine scientific research in the Area; control, supervise and inspect all mining activities in the Area; and design and operationalize an appropriate mechanism for the equitable sharing of benefits arising from the conduct of such activities. Critically, mineral exploration and subsequently exploitation may only be carried out under a legally binding contract with the ISA and subject to its rules, regulations and procedures (Lodge 2017). Member States, as well as state-owned enterprises and private actors under the sponsorship of Member States, may submit applications to, and upon approval enter into contract with, the ISA in order to obtain exclusive rights over a particular site for the duration of the contract (Lodge and Verlaan 2018). As of mid-2020, the ISA has awarded 30 exploration contracts for all three deposit types in various parts of the Area, while negotiations on regulations for exploitation activities are currently ongoing at the ISA (Levin et al. 2020). To date, deep seabed mining has not taken place at a commercial scale, both in areas within or beyond national jurisdiction (Haugan et al. 2020), although the first successful full-scale and on-site test mining operation – involving seafloor massive sulphides – was reportedly conducted near Okinawa Island, Japan, in 2017 (Okamoto et al. 2018). In terms of methods of extraction, the recovery of polymetallic nodules is expected to involve a modified form of dredging with the use of a collector, while the extraction of ferromanganese crusts and seafloor massive sulphides will involve mechanical recovery through cutting or drilling (Haugan et al. 2020; Miller et al. 2018). The material recovered will likely be lifted as a slurry using a riser or basket system and transported to a surface support vessel for shipboard processing (i.e., cleaning and dewatering),

whereby waste water and sediment is expected to be returned to the water column (Cormier 2019; Haugan et al. 2020). It is then anticipated that the collected ores will be transported via barge to selected sites located on land (Heinrich et al. 2020), in order to extract the targeted metals via metallurgical processes that largely depend on the deposit type. With respect to environmental implications resulting from mining activities, current scientific knowledge anticipates that mining will cause substantial harm, in some cases irreversible, to the remote deep-sea marine environment that is both vulnerable and not accustomed (and therefore sensitive) to direct human disturbances (Halfar and Fujita 2007; Wedding et al. 2015; Boetius and Haeckel 2018; Mengerink 2018; Ashford et al. 2018; Smith et al. 2020). Such harm includes the immediate loss of biodiversity and destruction of habitats as a result of operations, not only directly as a result of the use of mining equipment but also indirectly due to the generation of sediment plumes that are capable of travelling for kilometres, as well as the impacts from the ensuing noise and light pollution that would extend far beyond the mine sites (Drazen et al. 2020; Miller et al. 2018; Christiansen et al. 2020; Popova et al. 2019; Van Dover et al. 2017). Marine ecosystems, their structures and functioning will also be impacted, which would inevitably affect and impair the vital services they provide to sustain life (e.g., fish and marine mammals) as well as in regulating the climate (Le et al. 2017; Thompson et al. 2018; Drazen et al. 2020; Orcutt et al. 2020). The reintroduction of waste water to the sea after shipboard processing would also significantly affect marine life due to sediment suspensions in the water column (Drazen et al. 2020; Christiansen et al. 2020). In some respects, the environmental degradation caused by mining activities would be irreversible on human timescales (Simon-Lledó et al. 2019), whereas currently known restoration or offsetting potentials are low in terms of effectiveness and could be extremely costly and challenging to implement in any event (Cuvelier et al. 2018; Niner et al. 2018; Van Dover et al. 2017; Levin et al. 2020; Thompson et al. 2018; Boetius and Haeckel 2018).

Deep Seabed Mining and Sustainable Development Goal 14

Although many uncertainties still persist, such as the extent and scale of the potential impacts (which is also due to the fact that there has not been any large-scale conduct of mining activities as yet), it is clear that deep seabed mining, added to the other pressures and cumulative impacts (including climate change) faced by the deep ocean, could result in overall deleterious consequences for the deep ocean if not strictly and properly managed (Cormier and Londsdale 2020; Levin et al. 2020; Mengerink 2018). The deep ocean remains to be poorly understood today (Watzel et al. 2020), and significant knowledge gaps (especially regarding functioning, connectivity and resilience) still need to be filled in order to better comprehend the intricate nature of the environment in which mining activities could take place. The possibility that a variety of species, functions and services could be lost due to seabed mining activities even “before they are discovered, understood, and valued” is very real indeed (Blue Marine Foundation 2020). On the one hand, the above evidently demonstrates that if large-scale deep seabed mining activities were to take place, the environmental consequences that would result therefrom are expected to be significant, deleterious and farreaching. On the other hand, it is known that the mineral resources in question are rich in numerous critical metals that are essential for the development of green infrastructure and technologies (Hein et al. 2013). In this respect, some have argued that it is now necessary – from the sustainability perspective – to look to the deep seabed in order to source for some of these critical metals (Sovacool et al. 2020), given that land-based reserves are gradually deteriorating in quantity and quality and compounded by the fact that supply from terrestrial sources (which is largely controlled by just a handful of countries) is limited, unreliable and susceptible to disruption (Paulikas et al. 2020a; Watzel et al. 2020; Hein et al. 2013). The narrative continues to go on to say that terrestrial mining often occurs in areas rich in biodiversity with valuable ecosystems (such as rainforests) as well as involves the construction of permanent infrastructure, which results in degradation, deforestation, changes in land use and

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displacements and, in some cases, promotes internal conflicts and the use of child or forced labour (Paulikas et al. 2020b). In addition, it has been pointed out in order to successfully implement the Paris Agreement on Climate Change as well as to meet the sustainable development ambitions and targets set under Agenda 2030 and the SDGs, mining activities must intensify, at least in the short to mid-term, including to look to opening up new sources such as the bottom of the ocean because an adequate supply of raw materials is needed to manufacture clean technologies in order to tackle climate change (Ali et al. 2017). It follows, from this line of argumentation, that sourcing for some of these critical metals from the deep ocean instead, although seemingly harmful as well, could help alleviate most of those negative concerns associated with terrestrial mining to some extent and amount to a better overall solution from a global or “big picture” perspective and thus pave the path towards sustainable development and a low carbon future. However, the connection between deep seabed mining and sustainable development has been termed as “oxymoronic” (Childs 2019), “unquestionably unsustainable” (Ecorys et al. 2020) and a “sustainability conundrum” laden with “challenges” (Levin et al. 2020), thus giving rise to a “deep-sea dilemma” (Heffernan 2019). More specifically, mining the deep ocean could cause severe destruction to marine ecosystems and lead to loss of biodiversity, which could ultimately impact humans (e.g. through the impacts on food webs or impairment of ecosystems services). Additionally, it is entirely possible that opening up a new source for these metals could be perceived as additional competition and this might end up further exacerbating terrestrial mining activities, thus leaving society with severe environmental degradation both on land and at sea. This begs the following question to be asked: how does seabed mining interact with the SDGs, in particular SDG 14?

Reconciling the SDGs and SDG 14 with Deep Seabed Mining At the outset, it is necessary to clarify that the SDGs are pertinent and applicable to the extractive sector (Pedro et al. 2017) as well as in relation

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to the use of natural resources (Blue Marine Foundation 2020). In this respect, it should be further emphasized that the UN Convention on the Law of the Sea 1982 and the provisions therein relating to the development of mineral resources make clear “that this task must be carried out in the broader context of sustainable development” (Harrison 2017). In other words, if deep seabed mining activities are to commence – whether in areas within and beyond national jurisdiction – particular attention must be paid towards ensuring the effective protection of the marine environment, especially to avoid the loss of biodiversity and ecosystem services, in order to safeguard the rights and interests of future generations to a healthy and productive ocean (Christiansen et al. 2019). Thus, even though deep seabed mining would undoubtedly inflict substantial environmental harm, and current levels of global consumption that drives the need to extract more metals, including from the ocean, are obviously unsustainable (Kim 2017), efforts ought to be made to reconcile deep seabed mining, should it take place, with the sustainable development agenda insofar as possible – even though this might prove to be challenging (Levin et al. 2020), counterintuitive or outright elusive. Nevertheless, it would appear that the current regulatory approach towards enabling deep seabed mining activities to commence, especially in the Area, is somewhat incompatible with the concept of sustainability, when considered primarily from an environmental perspective, given the urgent need to halt the further degradation of the marine environment and to improve the health of the ocean (Seas at Risk 2017; Bennett et al. 2019). Indeed, a recent report commissioned by the High Level Panel for a Sustainable Ocean Economy observed that it is “conceptually difficult to align [deep seabed mining] with the definition of a sustainable ocean economy [since the activity] raises various environmental, legal and governance challenges, as well as possible conflicts with the UN Sustainable Development Goals” (Stuchtey et al. 2020). The consideration of sustainability and future deep seabed mining activities in areas beyond national jurisdiction is complex, since the

decision on whether or not to mine and under what circumstances is to be taken at the ISA, which means overall accountability lies with the Member States altogether, since ISA decisions are not in the hands of any one government. Furthermore, the status of the Area and its mineral resources as the “common heritage of mankind” and encompassing the rights and interests of future generations, coupled with the requirement that mining activities shall be conducted “for the benefit of mankind as a whole,” makes this discourse a lot more sophisticated (Christiansen et al. 2019). It is a fair question to ask indeed if mining activities on the international seabed would actually result in a “net benefit” to mankind, especially if the environmental costs of mining are overwhelmingly high and disproportionate (Christiansen et al. 2018). The 2019–2023 Strategic Plan of the ISA emphatically states that “the mission of the ISA is to be the organization through which States Parties to the United Nations Convention on the Law of Sea organize and control activities in the Area, which is the common heritage of mankind, to promote the orderly, safe and responsible management and development of the resources of the Area for the benefit of mankind as a whole, including through the effective protection of the marine environment and contributing to agreed international objectives and principles, including the Sustainable Development Goals” (ISA 2018). The said Strategic Plan identifies SDG 14 as the most pertinent SDG for the ISA, although several others (e.g., SDGs 1, 4, 5, 8, 9, 12, 13, 16 and 17) have also been highlighted as relevant to the work of the ISA. Specifically with respect to SDG 14, the document states that the ISA will support SDG 14 “through its contribution to increasing scientific knowledge, developing research capacity, transferring marine technology and advancing a common and uniform approach, consistent with the Convention and international law, to the sustainable use of ocean resources.” The ISA Strategic Directions and High Level Action Plan for 2019–2023 further mandate the Secretariat of the ISA to promote, develop and align all relevant ISA programmes and initiatives with the SDGs, in particular SDG 14, to keep them under review

Deep Seabed Mining and Sustainable Development Goal 14

and provide regular status reports (ISA 2019a). Premised on that, the Assembly of the ISA very recently adopted the “Action plan of the International Seabed Authority in support of the United Nations Decade of Ocean Science for Sustainable Development” (ISA 2020). In its contribution to the UN General Assembly ahead of the 2020 UN Ocean Conference, the ISA affirms that it “makes relevant contributions towards the achievement of SDG Target 14.2 (‘Sustainable management and protection of marine and coastal ecosystems’), SDG Target 14.5 (‘Marine protected areas and effective management plans’), SDG Target 14.7 (‘Increase the economic benefits to small island developing states and least developed countries from the sustainable use of marine resources’) as well as SDG Target 14(a) (‘Increase scientific knowledge, develop capacity and transfer marine technology’) and SDG Target 14(c) (‘Enhance the conservation and sustainable use of oceans and their resources by implementing international law as reflected in the United Nations Convention on the Law of the Sea’)” (ISA 2019b). Prior to that, the ISA had registered the following seven voluntary commitments in support of SDG 14 in 2017 (ISA 2017): a. Enhancing the role of women in marine scientific research through capacity-building [#OceanAction15467] b. Encouraging dissemination of research results through the ISA Secretary-General Award for Deep-Sea Research Excellence [#OceanAction15796] c. Improving the assessment of essential ecological functions of the deep-sea oceans through long-term underwater oceanographic observatories in the Area [#OceanAction17746] d. Enhancing deep-sea marine biodiversity assessment through the creation of online taxonomic atlases linked to deep-sea mining activities in the Area [#OceanAction17776] e. Abyssal initiative for Blue Growth [#OceanAction16538] f. Fostering cooperation to promote the sustainable development of Africa’s deep seabed resources in support to Africa’s Blue Economy [#OceanAction16374]

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g. Mapping the Blue Economy of Africa to support decision-making, investment and governance of activities undertaken on the continental shelf and in adjacent international seabed areas [#OceanAction16494] Moving away from the international seabed, as explained earlier, states have the flexibility to determine their own national sustainable development priorities and sovereign rights over the mineral resources located within their national jurisdiction. In this connection, a handful of Pacific Island states are keen to proceed with domestic seabed mining. The Cook Islands, for example, have openly expressed that it considers the exploration and eventual exploitation of deepsea mineral resources within its national jurisdiction as part of its broader national “sustainable development aspirations,” whereas some of its neighbouring states are not entirely convinced that seabed mining should take place just yet (Evans 2020; Levin et al. 2020). Recently, a group of 14 heads of states and governments issued a timely “Call to Action” titled “Transformations for a Sustainable Ocean Economy: A Vision for Protection, Production and Prosperity,” in which the topic of deep seabed mining was addressed. In particular, the group committed to require that “sufficient knowledge and regulations are in place to ensure that any activity related to seabed mining is informed by science and ecologically sustainable” and to “ensure that all seabed mineral activities within and beyond national jurisdiction comply with robust environmental standards” (High Level Panel for a Sustainable Ocean Economy 2020). Given the importance of the topic, it would seem to be necessary for states with deep-sea resource potential to formally engage with the public and civil society through its domestic settings as well as regional settings and globally at the ISA, in order to collectively determine whether deep seabed mining would be compatible with the sustainable development aspirations that are applicable (Penjueli 2019; Levin et al. 2020). Simultaneously, more effort should be channelled towards reducing global consumption rates, improving recycling methods and product design,

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investing in innovation and the development of technologies that rely less on critical metals and strenuously promoting the global transition towards a circular economy.

Sustainable Development, for instance, which up until now primarily focuses on terrestrial mining (Sovacool et al. 2020; Ali et al. 2017; Kim 2017).

Cross-References Concluding Remarks From the above, it is evident that the compatibility of deep seabed mining, whether in areas within or beyond national jurisdiction, with the SDGs and in particular SDG 14 is a subject of debate. Moreover, while one might opine that deep seabed mining could have some potential or play a limited role in contributing towards achievement of some of the SDGs, which should arguably be treated holistically and synergistically anyway (Donoghue and Khan 2019; Kroll et al. 2019), it is quite another thing altogether to tout deep seabed mining as a sustainable activity. Additionally, attempts to harmonize or reconcile deep seabed mining with SDG 14 (i.e., the Ocean’s SDG) in particular prove to be an elusive endeavour, primarily because of the potential scale and gravity of the anticipated environmental harm that such activities could inflict upon the marine environment and the trade-offs it would force when interacting with the other SDGs. Moreover, while it is possible that deep seabed mining may be able to provide the raw material necessary for the development of clean technologies to tackle climate change, the environmental and societal costs at which these metals are procured from the deep ocean should be questioned, i.e. does the end justify the means? After all, it is possible that deep seabed mining might end up further exacerbating terrestrial mining activities, resulting in deleterious consequences occuring simultaneously on land and at sea. That said, decisions on whether or not to proceed with mining the mineral resources located in our shared ocean space need to be made collectively at the national, regional and global level through open dialogue, including a candid discussion on how the concept of sustainable development would fit in the grand scheme of things. Such discourse could take place under the auspices of the Intergovernmental Forum on Mining, Minerals, Metals and

▶ Conservation Target for Marine Biodiversity in Areas Beyond National Jurisdiction ▶ Responsible Ocean Governance: Key to the Implementation of SDG 14 ▶ Role of International Law in Effective Governance of the Marine Environment ▶ Sustainable Use of Marine Genetic Resources ▶ United Nations Agreement on Marine Biodiversity Beyond National Jurisdiction

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Deep-Sea Mining ▶ Deep Seabed Mining and Sustainable Development Goal 14

Defining and Measuring a Marine Species Population or Stock Marina Dolbeth CIIMAR – Interdisciplinary Centre of Marine and Environmental Research of the University of Porto, Matosinhos, Portugal

Synonyms Biological population

Definitions A population is a group of individuals of the same species living in a particular area at the same time

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that share a common genetic pool, allowing them to interbreed (Pielou 1974; Waples and Gaggiotti 2006). The individuals from a species’ population are self-recruiting and share similar growth and mortality rates. The former definition encompasses both an ecological and an evolutionary view since it refers to their performance in a particular living space and time, as well as to their genetic pool (Waples and Gaggiotti 2006; Rockwood 2015). The term population is also used from a statistical point of view to delimitate the number of observations from which statistical inferences will be made (Waples and Gaggiotti 2006). A stock is generally understood as a population that can be regulated taking into account its “actual or potential use” (Ricker 1975), or regulated from a management point of view (e.g., fish stock). Stocks are discrete groups of individuals sharing characteristics that influence the population and managers can use (Begg et al. 1999), such as size, the processes that determine that size (e.g., recruitment, growth, natural mortality, and nonnatural mortality), and the harvesting rate (Ranta et al. 2005; Hawkins et al. 2016). So, the identification and delimitation of a stock are essential for mankind as providing a basis for the sustainable use of biological resources, such as for fisheries and/or endangered species management.

Introduction Sustainable development goal 14 explicitly targets the sustainable use of marine resources. For a long time, humans have been using the ocean for feeding purposes, which has set the fishing activity (on fish and other seafood) as the basis of economic and social development for many countries. Unfortunately, a long history of unregulated harvesting, destructive fishing practices, and illegal fishing, also affecting bycatch resources, has led to the overexploitation of several marine resources and the unnecessary loss of several marine species (FAO 2018). Nowadays, at least one-third of the marine resources are over-exploited, beyond their natural biological limits (FAO 2018; www.fao.org). Current

fisheries statistics generally do not acknowledge unreported catches, which may turn target populations decline numbers even more dramatic (Pauly and Zeller 2016). This reality highlights the need to conserve and exploit marine resources within sustainable levels, to preserve them and ocean wildlife in general, and the human population that relies on them for food and livelihood. The basis for exploring natural resources within sustainable levels and conserving these resources is knowledge of the species population dynamics or stocks. So this entry will briefly explore the concept of a species population and a species stock, provide an overview of the classical methods usually used to study population dynamics, and enumerate the current software used in population dynamics or stock assessment.

Fundamental Properties of a Population and a Stock A population is a fundamental unit of an ecosystem, commonly defined as a group of individuals of the same species living in a particular area (Pielou 1974). However, the term population may have at least three different definitions depending on an ecological, evolutionary, or statistical context (Waples and Gaggiotti 2006). From an ecological point of view, a population is generally defined as mentioned: a group of individuals of the same species living in a particular area at the same time. However, from an evolutionary perspective, it usually refers to the individuals that share a common genetic pool and live close enough to allow reproduction among them. Finally, from a statistical approach, a population is the total number of observations from which inferences will be made, within a specified sampling area limited in space and time. A discussion on these definitions, related terms and the associated difficulties in defining what a population represents from different audiences can be found in (Waples and Gaggiotti 2006). In this work, the focus will be on the biological definition of a population, targeting essentially its ecological view, shaped by demographic aspects, but

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considering that individuals can interbreed, evolutionary view (Waples and Gaggiotti 2006). An individual is a result of the processes that regulate the energy/biomass flow and its accumulation, such as consumption, assimilation, respiration, gonad production, egestion, and finally production (Brey 2001). The production is the assimilated organic matter or energy incorporated through time (Dolbeth et al. 2012), which for an individual and regarding the energy budget, corresponds to the individual growth (Brey 2001). To study a population, that is, the group of individuals, it is relevant to consider its dynamics, encompassing the changes in population size over time and the factors responsible for those changes. From an ecological perspective, this also implies recognizing that populations have growth rates, age distributions and spatial patterns (Rockwood 2015). The processes that determine population dynamics are, on the one hand, the individual growth itself- incorporation of body mass through time (Fig. 1a, adapted from Brey 2001). On the other hand, the processes that regulate the population growth are mostly reproduction and mortality, as represented in the blue survivorship curve in Fig. 1b (abundance through time, i.e., several individuals with small size at t0, which decline over time as body size increases).

These processes are also the ones needed to evaluate production (Brey 2001; Dolbeth et al. 2012). However, in Nature, a population is rarely closed so immigration and emigration also define population growth (Rockwood 2015). A fundamental difference when evaluating or studying a population or a stock is the view of the target species as a manageable economic resource. As such, the stock is generally considered as a “management unit grouped by genetic relationship, geographic distribution, or movement patterns” (Kilduff et al. 2009), a term widely used in fisheries (e.g., fish stock, shellfish stock). However, other definitions consider a genetic or a phenotype/environmental perspective (Coyle 1998), similarly to the definition of population or sub-populations. There are other definitions for stock (Sparre and Venema 1998), highlighting that an accepted universal definition is far from consensual. For instance, the Fisheries and Resources Monitoring System (FIRMS) from FAO, defines stock as “a group of individuals in a species occupying a well-defined spatial range independent of other stocks of the same species, that can be affected by random dispersal movements and directed migrations due to seasonal or reproductive activity” (firms.fao.org, accessed in 2018).

Defining and Measuring a Marine Species Population or Stock, Fig. 1 Hypothetical representation of the processes involved in evaluating population dynamics in a closed system (without emigration or immigration) for (a) a single individual – size increase through time, with an

indication of the individual growth rate r at time t; (b) group of individuals from the same species, with an indication of the population growth rate r at time t (please see below). (Figure adapted from Brey 2001)

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The use of stock or population concepts has set differences in the terminology and view of biological resources themselves, for instance, between fishery biologists and benthic ecologists (Brey 2001). Fishery biologists generally use terms such as stock assessment, maximum sustainable yield, catch per unit effort, fishing effort (Sparre and Venema 1998; Jennings et al. 2001). Benthic ecologists generally target population abundance, structure and dynamics, interactions among populations within communities, such as position in the food web, among others (Brey 2001). Still, the essential processes that underlie obtaining the information on population or stock dynamics are the same. As such, both fishery biologists and benthic ecologists share common interests and methods to obtain information on growth, reproduction, recruitment, mortality, production, and productivity. These properties or processes are generally described with mathematical functions quantifying a group of individuals and

not the individual alone (Odum and Barrett 1971). Indeed, to study populations and use population ecology for conservation, resource management purposes, or to understand the life history of a species, it is relevant to organize the information in a simplified and predictive way. So, population ecology has evolved mainly as a mathematically driven discipline (Pastor 2008; Rockwood 2015). One of the most common applications is the use of growth models, which aim to synthesize information on population growth. Next, growth rates and the most common growth models will be briefly explained. However, due to the complexity of these rates and models, the equations and derivations will not be described in detail and readers are advised to consult, for instance, Turchin (2003), Ranta et al. (2005), Pastor (2008), Rockwood (2015). But first, a short description of some of the most used terms when defining and studying populations/stocks (Table 1) and an overview on the relevant processes that determine

Defining and Measuring a Marine Species Population or Stock, Table 1 Short definition of the important terms associated with the population and stock concept, based on Brey (2001), Rockwood (2015) and FISHBASE Term Absolute growth Absolute growth rate Abundance Assimilation Bycatch Body size or individual body mass

Carrying capacity Catch Catch-at-age

Catch-at-length Catch per unit effort (CPUE)

Closed population Consumption

Definition Change in mass/size in a time period Change in mass/size per time (e.g., grams day1) Number of individuals (see also population density) Amount of the consumed food that is used by the individual for physiological purposes Species took incidentally in a fishery The amount of living tissue of one individual, generally expressed as mass unit (e.g., grams, kilograms of wet mass, dry mass or ash-free dry mass) or energy unit (e.g., Joule, Kilojoule). Some authors refer to it as individual weight (w), but it is usually expressed with mass units The maximum number or biomass of individuals of a particular species that the environment can sustain; represented by K Usually used in fisheries to designate the total annual fish harvest, including dead discards Usually used in fisheries to designate the distribution of fish ages in the catch (can be obtained from the age composition of catches through, for instance, analysis of otoliths) Usually used in fisheries to designate the distribution of fish lengths in the catch (can be obtained from the analyses of the length composition of catches) Indirect measure of a species abundance usually used in fisheries evaluated as the total catch divided by the total amount of effort used to harvest the catch; nowadays this term is usually referred to as catch/effort Population with any immigration or emigration of individuals from outside of the population is expected; rarely occur in nature Total food ingested per unit of time (continued)

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Defining and Measuring a Marine Species Population or Stock, Table 1 (continued) Term Cohorts Density-independent growth Density-dependent growth Emigration rate Fecundity Fertility Generation time Immigration rate Individual growth Intrinsic growth rate or instantaneous growth (r) Maximum sustainable yield

Metapopulation Mortality Mortality rate Population biomass, or biomass

Population density Population dynamics

Population ecology

Primary production Production

Recruitment Reproduction

Secondary production Survivorship curve Yield

Definition Group of individuals from the same population with the same age, born at the same time The growth rate is not affected by the current population size, when unlimited resources and in absence of species interactions The growth rate depends on the actual population density, being affected by the environmental constraints Number of individuals that leave the population per time interval, and how old they are when they leave Reproductive potential under ideal circumstances, set by the genetic potential and not by the environment; expressed as a rate (e.g., offspring per time unit) The actual reproduction performance under specific environmental conditions; expressed as a rate (e.g., offspring per time unit) The time period from birth to average age of reproduction Number of individuals that join a population per time interval due to immigration Increase in size and mass of one organism with time Growth rate per individual (or per capita) per time unit (e.g., per year) in a population, estimated as the b, birth rate per individual per year, minus the d, death rate per individual per year (r ¼ b  m) Quantity of the catch which can be taken from a stock, without severely depleting or eliminating that stock, under existing environmental conditions; it assumes that removals and natural mortality are balanced by stable recruitment and growth. Also called maximum equilibrium catch, sustainable catch A population of many local populations from the same species that can exchange individuals and recolonize sites in which the species has recently become extinct Loss of individuals from the population; expressed as a rate (see below) Mean number of deaths in a population per unit time and unit area The total amount of living tissue (or mass), considering all individuals from a population being studied per a given area or volume; it is the product of body mass and density (sum of all body mass), and it is often referred to as standing stock. It is expressed as mass or energy unit per area or volume (e.g., g m2, J or kJ per m2) Number of organisms from a species expressed per unit of space (e.g., area: m2, km2; volume: L or dm3) Study of the changes in population size over time, including the factors responsible for those changes (e.g., growth, reproduction, mortality and interactions among them) Generally refers to the study of populations in time and space taking into account their density and distribution, relative to factors causing changes in the populations and influencing their fundamentals properties, that is, growth, survivorship, and reproduction Production by autotrophic organisms (see also production) Organic matter or energy incorporation in a given area per time unit; it is considered a flow, generally expressed as biomass per area and per time (e.g., grams m2 year1), but energy units are also used (e.g., kJ m2 year1) Addition of new individuals to the population Addition of new individuals in a population (see also fertility or fecundity). It may be via sexual reproduction, that is, live births, hatching of eggs, and seed production; or through asexual reproduction, that is, binary fission, budding, asexual spores, and clonal spreading of higher plants Production by heterotrophic organisms (see also production) Graphic representation of the number of individuals through time (can be age classes, for instance) Catch in mass

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population dynamics will be provided, based on the descriptions by (Brey 2001; Rockwood 2015) and FISHBASE (www.fishbase.org). Population Growth When referring to a single individual, growth is the increase in size or mass of the organism with time (Fig. 1a; Brey 2001). The simplest way to measure growth is to determine the size or mass of the individual at two different times. Absolute growth is the change in size/mass, whereas the absolute growth rate is the change in size/mass per unit of time. This “growth determination” is quite simple. However, the growth rate of an organism is generally continuous (in opposition to being pulsed) and may change during its lifetime. Therefore it is advisable to have a more accurate way to obtain information on growth (Brey 2001). A way to accomplish this is to reduce the distance between time, as much as possible, and this way, calculate growth with the differential equation (see also Geometrical representation of absolute growth rate calculation in Brey 2001). The relative growth rate is the growth relative to the initial size/mass and is also calculated with a differential equation (see below) (Brey 2001). As stated above, growth is an individual characteristic. However, for the same species, individuals from the same population and location may behave similarly, and the population growth described by average growth function parameters from an “average individual” (Fig. 1b). As mentioned earlier, four processes generally regulate population growth: reproduction, mortality, immigration, and emigration: r ¼ ðb  d Þ þ ði  eÞ where r is the growth rate; b, birth rate; d, death rate; i, immigration rate; and e, emigration rate of the population. However, several population studies have not considered immigration or emigration, because they assume that their rates are minor compared with birth and death rates (Turchin 2003). Also, the information on emigration and immigration may be extremely difficult to obtain for biological populations (Rockwood 2015). However, emigra-

tion and immigration are now being considered with recognition of the metapopulation concept: a population of local populations able to exchange individuals through dispersal, balancing extinction and colonization processes (Rockwood 2015). In line with the metapopulation concept, local populations are prone to extinction, which is balanced by emigration from other patches/ habitats. As seen above, one of the descriptors of population growth is the growth rate, which refers to the change in mass/size of the individuals per time units. The growth rate is determined by the environment, including the physical environment and the potential interactions of the population with other species in its habitat. Overall, if a population develops in an environment with “unlimited” resources, without competitors or predators, growth will be density-independent, meaning that the growth rate is not affected by the present population size (Rockwood 2015). In such conditions, fertility rates will be high and mortality rates low, and the population may grow exponentially or geometrically. Indeed, one of the first principles of population dynamics (Turchin 2001) is the exponential law of population growth by Malthus (1798), that is, “a population will grow (or decline) exponentially as long as the environment experienced by all individuals in the population remains constant.” In these types of growth, “the growth rate is determined by a fixed parameter, which is not modified by competition for resources” (Rockwood 2015). This type of growth may occur for populations with discrete or continuous generations, with no overlapping cohorts. This type of growth is expressed in the exponential growth model with the differential equation (r represented in Fig. 1b), which can be solved into the following equations: dN ¼ rN dt r¼

ln N t  ln N 0 t

N t ¼ N o ert

Defining and Measuring a Marine Species Population or Stock

Where dN∕dt is the growth of the population N for a given time t; N is the population size; r is the intrinsic growth rate of increase or instantaneous growth rate of the population (or per capita rate of increase), which, as seen above, may simply correspond to the difference between the birth rate per individual and the death rate per individual during the considered time t (assuming no emigration nor immigration). In the exponential growth model, r has a positive value, independently of the population size N. Whether the growth model becomes exponential or geometric depends on the life history of the species, continuous or discrete, and examples of such growth forms can be found in Pastor (2008) and Rockwood (2015). However, few populations can grow exponentially or geometrically (Turchin 2001), as the environment is not unlimited indefinitely, nor species lack interactions with others. Populations may face limiting resources in the environment, either as food availability, space, water or other constraints that will limit growth, particularly as the population grows. This has set for the selflimitation growth principle (Turchin 2001, 2003), stating that population growth decreases with resource depletion. In this situation, the growth rate decreases and approaches zero at the environment carrying capacity, meaning the environmental limit for growth. The growth rate will depend on the population density, referred to as densitydependent growth. This concept of the environment carrying capacity for biological populations is associated with the logistic equation, where the carrying capacity is termed with the symbol “K.” The logistic growth is usually expressed with the following differential equation, which can resolve into the following ones: h i dN KN ¼ rN dt K ra ¼ rm Nt ¼

h i KN K

K 1 þ eart

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Where dN∕dt is the growth of the population N for a given time t; N is the population size; K is the carrying capacity; ra is the actual growth rate as modified by carrying capacity; rm is the densityindependent growth rate or the r-max; and a is the constant of integration, which for t ¼ 0 becomes: a ¼ ln

  K  N0 N0

The logistic model is based on the concept of competitive interaction, meaning a “biological interaction between individuals for a resource in short supply,” conducting to interference or depletion (Rockwood 2015). Here, resources are understood as anything in the environment that influences growth, survivorship, or reproduction, and competition may be intraspecific or interspecific (Rockwood 2015). Interactions among species (e.g., interference, commensalism, amensalism, and trophic) are also important determinants of population growth. They are known to produce oscillations in growth and other processes that influence the population dynamics, such as fertility, mortality, development rates and behavioral characteristics (Turchin 2001, 2003; Rockwood 2015). In such cases, other models and descriptors of population growth have been developed, mostly based on the logistic framework. These have been described by consumer-resource oscillations or trophic oscillations models by Turchin (2001, 2003) in his attempt to formulate general laws of population dynamics and include the LotkaVolterra predation model. Turchin (2003) and Rockwood (2015) provide more information on these models and other specificities of the former descriptions (e.g., time lags, growth structured vs unstructured populations). Overall, all the former descriptions of growth, that is, exponential, logistic and trophic oscillations, are regarded as essential starting points in the history of analyzing and systematizing growth. However, they fail as general rules for biological growth because of their simplistic assumptions (Turchin 2001, 2003; Rockwood 2015). For most species, growth rates change along their life cycle, and therefore a single

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growth rate may not be adequate to represent lifetime growth (Brey 2001). As such, growth models have been developed to describe the patterns of lifetime growth (Brey 2001). Still, “no one model of population growth suits all organisms or all environments,” and as such, different growth models have been “adjusted” depending on the nature of species growth (Pastor 2008; Rockwood 2015). Examples of such models are the von Bertalanffy growth models (VBGF), from which other adapted models have been produced, such as the generalized (equation below), specialized or seasonal forms; the Schnute growth model; the Gompertz model; the Richards model; the single logistic model, among others (Brey 2001; Rockwood 2015). In fisheries science, among the most used growth models are the von Bertalanffy one and its derivatives (Pauly and Morgan 1987; Elliott and Hemingway 2002). The usual parameters in these sort of models are: the asymptotic size (in fisheries, usually length – L1), representing the size that the individuals would reach if they were to grow forever; the growth coefficient, here designated as K, representing the growth rate at which size approaches the asymptote; the hypothetical time/age at which size would have been zero, designated as t0; and the shape parameter D, another growth constant, determining the shape of the curve (more or less sigmoid). An example of the generalized von Bertalanffy equation is provided below: h i Lt ¼ L1 1  eK ðtt0 Þ Where Lt is the length at time t; L1, the asymptotic length; K, the growth constant; t0, hypothetical time for Lt ¼ 0. Acquiring Data for Growth Models The use of a growth model and the definition of the growth rate precedes the analyses of the individual and population growth based on the observation of changes in size or mass over time. For most population dynamics or stock assessment studies, most species have to be sized and aged (for species that can be aged). These size-at-age

data are then quantified with the growth models. The way to obtain information on size/mass variation with time may vary depending on the species. For species that can be aged, growth can be determined directly from size-at-age data (Jennings et al. 2001). If the species cannot be aged, then growth may be estimated using indirect methods, such as length-frequency distributions or size-increment data (Brey 2001). Indeed, the following three main data sources are currently used to estimate growth: size-frequency, size-atage, and size-increment data (Brey 2001; Rockwood 2015), explained in more detail below. Particularly for fisheries, it is frequent to have catches data as data sources, and examples of assessment methods used in fisheries can be found in Pauly and Morgan (1987), Gayanilo et al. (2005), and Chrysafi and Kuparinen (2016). Size Frequency Size-frequency analyses use the size-, usually length-, distribution analyses that include the possible life cycle of a discrete population with synchronized life history, where a cohort or cohorts can be recognized. It is necessary to have a sufficient sample size and size-frequency interval to depict growth (Fig. 2). Different statistical techniques are available to obtain information from these size-frequency distributions to evaluate growth, but also on other important population properties such as recruitment, mortality patterns, among other properties. Examples of such techniques are: 1. modal progression analyses and using a method to separate overlapping cohorts, such as the Bhattacharya method or NORMSEPprogram, which allows separating several samples into their normally distributed components (Goonetilleke and Sivasubramaniam 1987). 2. Other methods consider a direct fit of the length-frequency data, such as the ELEFAN – Electronic LEngth Frequency ANalysis, which allows deriving growth parameters of the von Bertalanffy growth function from length-frequency data (Pauly and David 1981; Gayanilo et al. 2005).

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Defining and Measuring a Marine Species Population or Stock, Fig. 2 Growth from a hypothetical invertebrate species: (a) Length-frequency distribution from successive time, with the indication of the cohorts as identified with modal class analyses (e.g., NORMSEP-program

from FISAT) and eye-adjusted growth pattern; (b) estimated cohort linear growth based on the information from length-frequency analyses (average and s.d. for each modal class), new cohorts appear in September and March

All these analyses can be applied using FAO’s website (http://www.fao.org), such as the ones provided in FISAT II – FAO-ICLARM Stock Assessment Tool (Gayanilo et al. 2005), a user-friendly Windows-based program, which allows applying and determining the growth models. Currently, there are also R packages and other software tools available for such analyses, developed mainly for fisheries yet applicable for a wide range of species. Examples of such tools are the TropFishR, which offers a traditional and an updated version of ELEFAN method (Mildenberger et al. 2017); fishmethods, providing a wide range of lengthstructured methods applied in fisheries science (Nelson 2017), among others (Table 2). Particularly for fisheries and evaluation of fish stocks, information based on catch or length-frequency data alone is considered data-poor. Such data usually require a particular set of methods (Chrysafi and Kuparinen 2016), for which several R packages have been developing (Table 2).

incrementally with age, such as scales and otoliths in fish (the most usual) or other bony structures (Elliott and Hemingway 2002; Gayanilo et al. 2005), growth rings in the bivalves’ shells, polychaetes jaws, among others (Fig. 3). More sophisticated and reliable techniques include stable isotope analyses (Brey 2001). In fishery biology, a standard method is using artificial marks or tags to provide information on growth rates and behavior (Jennings et al. 2001). This data can then be analyzed using free software, such as the ones supplied in FISAT II – FAO-ICLARM Stock Assessment Tool (Gayanilo et al. 2005) or in other R packages, as mentioned above and in Table 2. Brey (2001) also provides a user-friendly computation spreadsheet to estimate the growth rate, determine the growth models using size-atage analyses and the growth model fit to size-atage or size-increment data.

Size-at-Age Analyses Size-at-age analyses are aimed at populations with structured age, where the age of the target species is initially determined. The age can be determined using the particular growth marks that increase

Size-Increment Analyses Size-increment data is generally used when information about age or cohorts are not available, which is frequent in organisms with continuous reproduction. A size-increment data pair consists of a particular size at a time (size 1 at time t) and subsequent measurement of the size in the next

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Defining and Measuring a Marine Species Population or Stock, Table 2 Examples of the software and useful database developed and used for population Program/package FISAT II FAO-ICLARM Stock Assessment Tool

Type Windows based

Brey Virtual handbook on population dynamics

Spreadsheets Databank

TropFish Fish stock assessment methods and fisheries models DLMtool – DataLimited Methods Toolkit

R package

LBSPR – Functions to run the LengthBased Spawning Potential Ratio

R package

Fishmethods Fishery Science Methods and Models in R

R package

FishBase

Databank

R package, simulation toolkit

dynamics or stock assessment, including the ones designed specifically for fisheries analyses

Examples of available methods/functions Several methods developed mainly for the analysis of length-frequency data and related analyses, such as size-at-age, catch-at-age, selection. Examples include: Modal progression analysis: For example, Bhattacharya, NORMSEP Direct fit of length-frequency data: For example, ELEFAN I Analysis of growth increment data Growth model fit to size-at-age or size-increment data Mortality by size-converted catch curve (SCCC) Somatic production (classical methods and empirical models) Mass-to-mass-to-energy conversion factors Bhattacharya ELEFAN Cohort analysis Yield-per-recruit models Management strategy evaluation framework across different fisheries that allows to (1) identify the most effective management methods given the uncertainties associated with data-limited fisheries, (2) computing explicit management guidance based on the best available data, and (3) prioritizing future data collection programs Fishery library Different functions that can be used to (1) simulate the expected length composition, growth curve, and spawning potential ratio and yield curves using the LBSPR model and (2) fit empirical length data to provide an estimate of the spawning potential ratio Several fishery science’ methods and models from published in literature and contributions from colleagues, such as Fitting Von Bertalanffy growth equation to clustered data via bootstrapping Fitting growth curves to length- or weight-at-age data Estimating the relative abundance of fish from a trawl survey Yield-per-recruit analysis Information on population properties such as growth, maturity, reproduction, recruitment, ecology in general, among others

time unit size (size 2 at time t + 1). This sort of data should cover the whole range of body sizes present in the population, to fit a growth model (Brey 2001). Different growth models can be fitted to this type of data using Walford’s linearizing transformation of the growth function, after which the

Internet link/ references www.fao.org/ fishery Gayanilo et al. (2005)

www.thomasbrey.de/science/ virtualhandbook/ navlog/index.html Brey (2001) Mildenberger et al. (2017)

www. datalimitedtoolkit. org

Hordyk (2017)

Nelson (2017)

www.fishbase.se

von Bertalanffy or the Gompertz growth models can be applied (Brey 2001). Other examples of how to use such size-frequency data to estimate growth and a computation spreadsheet (i.e., growth model fit to size-increment data) can be found in (Brey 2001).

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Defining and Measuring a Marine Species Population or Stock, Fig. 3 Examples of growth marks usually in the determination of age: (a) otoliths of fish, exemplifying a fish with annual growth (two years old), and another juvenile with daily growth marks; (b) growth rings from the bivalve Scrobicularia plana. (Otolith photos from F. Martinho)

The Relevance of Population Ecology Studies As highlighted in the introduction, population dynamics and ecology studies are essential for conservation biologists and resource managers (Pauly 2007; Callaway et al. 2013; Rockwood 2015). Population dynamics studies are the baseline for understanding species life-history characteristics, determine productivity and the system’s carrying capacity for a particular resource (Benke and Huryn 2010; Dolbeth et al. 2012), and the maximum fishing that allows maintaining the long-term viability of populations (Jennings et al. 2001). Indeed, conservation biologists and resource managers often do not have adequate information to implement strategies for preserving biodiversity and wild living resources in general. For instance, as mentioned in the sustainable development goal 14 “fisheries contribute significantly to global food security, livelihoods and the economy. However, if not sustainably managed, fishing can damage fish habitats. [. . .] Fish stocks must maintain within biologically sustainable limits, at or above the abundance level that can produce maximum sustainable yields.” This aim has already been stated before, such as in the Law

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of the Sea of 1982 (UNCLOS 1982), Code of Conduct of the United Nations calls for responsible fisheries (FAO 1995), EU-Common Fisheries Policy (Chrysafi and Kuparinen 2016). Despite these international efforts, for several fisheries, stock depletion is still a reality (Pauly and Zeller 2016; FAO 2018). So, the scientific analysis and evaluation of fisheries based on the population dynamics or stock assessment are essential as providing the basis for sustainable exploitation of marine resources. Species with slow growth, late maturity, large body size, and low population turnover rates are generally more vulnerable to fishing than species with faster life-history characteristics (Jennings et al. 2001), and this information is only possible with population dynamics studies. Also, particular or successive events driving species mortality, such as severe climate, that may impair the viability of a population in the ecosystem is also revealed through population dynamics studies (Callaway et al. 2013). These studies, particularly those aiming to define fishing management targets, are extremely data demanding, usually needing several and different data inputs (Pauly and Zeller 2016), and with complex numerical data analyses that may be a challenging task on a regional basis (FAO 2018).

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Nevertheless, efforts have been made to improve data quality and data analyses training, following this recognition that population dynamics and stock assessment are essential steps for efficiently defining conservation and management strategies toward the sustainability of the natural resources.

Cross-References ▶ Artisanal Fisheries: Management Sustainability ▶ Fisheries Management: An Overview

and

References Begg GA, Friedland KD, Pearce JB (1999) Stock identification and its role in stock assessment and fisheries management: an overview. Fish Res 43:1–8 Benke AC, Huryn AD (2010) Benthic invertebrate production – facilitating answers to ecological riddles in freshwater ecosystems. J North Am Benthol Soc 29: 264–285 Brey T (2001) Population dynamics in benthic invertebrates. A virtual handbook. Version 01.2 Callaway R, Burdon D, Deasey A, Mazik K, Elliott M (2013) The riddle of the sands: how population dynamics explains causes of high bivalve mortality. J Appl Ecol 50:1050–1059 Chrysafi A, Kuparinen A (2016) Assessing abundance of populations with limited data: lessons learned from data-poor fisheries stock assessment. Environ Rev 24: 25–38 Coyle T (1998) Stock identification and fisheries management: the importance of using several methods in a stock identification study. In: Taking stock: defining and managing shared resources. Australian Society for Fish Biology, Pyrmont, pp 173–182 Dolbeth M, Cusson M, Sousa R, Pardal MÂ (2012) Secondary production as a tool for better understanding of aquatic ecosystems. Can J Fish Aquat Sci 69:1230– 1253 Elliott M, Hemingway K (2002) Fishes in estuaries. Blackwell Science, Malden FAO (1995) Code of Conduct for Responsible Fisheries, FAO, Rome, 41 p., ISBN 92-5-103834-5 FAO (2018) The state of world fisheries and aquaculture, meeting the sustainable development goals. Rome, ISBN: 978-92-5-130562-1 Gayanilo FCJ, Sparre P, Pauly D (2005) FAO-ICLARM Stock Assessment Tools (FiSAT II). Revised version. User’s guide. FAO, Rome Goonetilleke H, Sivasubramaniam K (1987) Separating mixtures of normal distributions: basic programs for

Bhattacharya’s method and their applications to fish population analysis. FAO, Colombo Hawkins SJ, Bohn K, Sims DW, Ribeiro P, Faria J, Presa P, Pita A, Martins GM, Neto AI, Burrows MT, Genner MJ (2016) Fisheries stocks from an ecological perspective: disentangling ecological connectivity from genetic interchange. Fish Res 179:333–341 Hordyk A (2017) Package ‘LBSPR ’: Length-Based Spawning Potential Ratio (r package), Version 0.1.2 Jennings S, Kaiser MJ, Reynolds JD (2001) Marine fisheries ecology, Blackwell Publishing, Oxford Kilduff P, Carmichael J, Latour R, Berger TL (ed) (2009) Guide to fisheries science and stock assessments. Atlantic States Marine Fisheries Commission, Washington, 66p Mildenberger TK, Taylor MH, Wolff M (2017) TropFishR: an R package for fisheries analysis with length-frequency data. Methods Ecol Evol 8:1520–1527 Nelson GA (2017) Package ‘fishmethods’: Fishery Science Methods and Models in R (r package), Version 1.10-4 Odum E, Barrett G (1971) Fundamentals of Ecology. Thomson, Brooks/Cole, Philadelphia Pastor J (2008) Mathematical ecology of populations and ecosystems. Wiley-Blackwell, Oxford Pauly D (2007) The Sea Around Us Project: documenting and communicating global fisheries impacts on marine ecosystems. Ambio 36:290–295 Pauly D, David N (1981) ELEFAN I, a BASIC program for the objective extraction of growth parameters from length-frequency data. ICLARM Contrib 32:205–211 Pauly D, Morgan GR (1987) Length-based methods in fisheries research. ICLARM conference proceedings. International Center for Living Aquatic Resources Management/Kuwait Institute for Scientific Research, Manila/Safat Pauly D, Zeller D (2016) Catch reconstructions reveal that global marine fisheries catches are higher than reported and declining. Nat Commun 7:10244:1–9 Pielou EC (1974) Population and community ecology. Principles and methods. Gordon and Breach Science Publishers, New York Ranta E, Kaitala V, Lundberg P (2005) Ecology of populations. Cambridge University Press, Cambridge Ricker WE (1975) Computation and interpretation of biological statistics of fish populations. Bulletin of the Fisheries Research Board of Canada, Bulletin 191, Ottawa Rockwood LL (2015) Introduction to population ecology, 2nd edn. Wiley-Blackwell, Chichester Sparre P, Venema CS (1998) Introduction to tropical fish stock assessment – part 1: manual, FAO fisher. FAO, Rome Turchin P (2001) Does population ecology have laws? Oikos 94:17–26 Turchin P (2003) Complex population dynamics. A theoretical/empirical synthesis. Princeton University Press, Princeton/Oxford UNCLOS (1982) - UN General Assembly, Convention on the Law of the Sea, 10 December 1982, available at:

Destructive Fishing Practices and Their Impact on the Marine Ecosystem https://www.refworld.org/docid/3dd8fd1b4.html [accessed 16 April 2017] Waples RS, Gaggiotti O (2006) What is a population? An empirical evaluation of some genetic methods for identifying the number of gene pools and their degree of connectivity. Mol Ecol 15:1419–1439

Derivatives ▶ Sustainable Use of Marine Genetic Resources

Destructive Fishing Practices and Their Impact on the Marine Ecosystem Miguel Carneiro and Rogélia Martins Department of Sea and Marine Resources, Division of Modelling and Management of Fisheries Resources, Portuguese Institute for Sea and Atmosphere, Lisbon, Portugal

Definitions The concept of destructive fishing, originated in the middle of the twentieth century, can be defined as any type of fishing technique or fishing practice that reduces the fishing stocks in an unsustainable way and destroys fish and invertebrate habitats and ecosystems, becoming unable to provide their essential functions. A more comprehensive view includes an ecosystem and precautionary approach perspective not only dealing with the target population but also with the associated or dependent species or their habitat. Thus, it is important to avoid the eliminating point when the stock’s ability to ensure an economically and ecologically sustainable exploitation for the present and future generations, particularly if its recovery is not possible within an acceptable time frame. However, most fishing gears or fishing methods are not actually destructive. Only a very limited number of them can be considered as destructive, regardless the place or season in which they are used (explosives and synthetic toxins).

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Destructive fishing practices jeopardize achieving some of the sustainable development goals defined by the United Nations, since biological resources are not used or exploited in a reasonable and/or sustainable way, compromising the goods and services provided by the ocean. In the long run, destructive fishing practices contribute significantly to decreasing fish stocks and seafood quality, endangering the development of the human society and in some cases increasing problems regarding food safety and human health.

Overfishing Overfishing occurs when the number of fish caught surpasses the natural capacity of the population to reproduce, leading to an overall degradation of the system. Thus, overfishing is a nonsustainable use of the oceans not only affecting the social and economic aspect of coastal communities depending on fishing activity but also the ecosystem. The increase in overfishing practices and the lack of sustainable management plans will reduce many fish stocks below acceptable levels, as it has been happening in the Mediterranean Sea. It is estimated that over 60% of its fish stocks are now “overfished” and at risk of being depleted. In the short run, an increase in catches may seem like a profitable practice, but in the long run, it can put ecosystems at risk and affect the life in the oceans. Overfishing may assume extreme forms of exploitation and then can be considered as destructive fishing. Overfishing affects the ecosystem by changing species composition, dominance relationships, and their natural balance. The effects of overfishing on the ecosystem can be direct or indirect. For example, the former effects can be an excessive mortality of target or nontarget species and the return to the sea of discarded species. The latter effects may modify the trophic structure by reducing or eliminating both lower and higher trophic level species, changing the size composition or the life history traits of the resource. The impacts of these effects on marine species diversity are the modification of the

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community structure, the reduction in species richness, and the risk of local extinction (FAO 2010). Marine ecosystems are generally complex systems, and any imbalances can cause harmful cascading effects, sometimes making entire habitats uninhabitable. The overfishing of a particular species generally causes the increase of its natural preys, leading to their overpopulation. The elimination of large predatory fish can have marked cascading effects on the oceanic food chain. For instance, when large predators are overfished (e. g., sharks), other predators such as tunas thrive and overpopulate, which can cause a decline of small pelagic fish, crabs, and shrimps populations. This can lead to an increased number of largebodied zooplankton, which in turn may cause the decrease in number of phytoplankton which can result in an increase of nutrient levels (e.g., nitrate). This chain effect may occur and will help the macro-algae grow on the water surface. Overfishing can also compromise the availability of fish for human consumption, which can mean a threat to world food security, especially in least developed countries. In addition to overfishing, unintended catches also occur, which constitute an important fraction of world catches that are usually discarded or even traded. Some of these unintended catches include dolphins, turtles, stingrays, and even seabirds. Moreover, for controlling overfishing, several measures have been implemented which include the adoption of new technical and management measures, as well as regional, national, and international regulatory instruments. These measures have generally led to a worldwide reduction in catches, which causes serious economic and social losses in the fishing sector. One of the main goals of the UN SDG 14 is to end overfishing; illegal, unreported, and unregulated fishing; and destructive fishing practices, which has the clear goal of restoring fish stocks while safeguarding their sustainable use.

Trawling and Dredging Trawling represents one of the most common fishing practices along the coastal oceans of the

world with an increasing trend toward the deepsea soft bottom (Pusceddu et al. 2014). Bottom trawls are fundamentally nonselective gears (UN Report A/60/189 2005). The use of bottom trawls and dredges can have an impact on species either directly (i.e., causing mortality) or indirectly (i.e., by disturbing their habitats) (MCS 2008). The main adverse impacts of bottom trawling affect the seabed and often the halieutic resources. The physical impact on the seabed currently results in the disturbance of the sediment surface by changing the grain size distribution or characteristics and its benthic organisms. In more vulnerable ecosystems, such as critical habitats (e.g., coral reefs, which afford the basic conditions to marine life such as food, shelter, and protection), the physical impact is increased, resulting the loss of marine biodiversity. The additional impact on fish resources may be a consequence of gear performance mainly due to inadequate selectivity to reduce the catch of juveniles of target species and nontarget species whether discarded (NRC 2002). After the depletion of fish stocks and destruction of the marine habitats on continental shelves and the introduction of new technologies (rock hopper trawls) in the 1980s, a rapid displacement into the deeper ocean was observed. This allowed most of the ocean floor to be available to be trawled down to a depth of 2000 m (WWF 2017; Pusceddu et al. 2014). Thus, it was reported that about 95% of the damage inflicted on deep water systems associated with seamounts results from bottom trawling (UN report A/60/189 2005). This fishing gear in the continental slopes and deep sea has wide impacts on marine ecosystems, including seafood stock impoverishment, benthos mortality, and sediment resuspension. Along the continental slopes, trawling affects the deep-sea sedimentary ecosystems, causing their degradation and infaunal depauperation. At the deep-sea soft bottom, it also affects the meiofauna abundance, biomass, and biodiversity in the surface sediments (Pusceddu et al. 2014). Dredging is a more restricted practice used all over the world in soft bottom of near shore areas of the oceans and in estuarine waters but sometimes also in deeper waters on the continental

Destructive Fishing Practices and Their Impact on the Marine Ecosystem

shelf. Most dredges typically catch molluscs and shellfish and occasionally are used for crustaceans, finfish, and echinoderms (NRC 2002). Towed dredges are a specific type of dredge gears that operate along the sea floor with an aggressive contact with the bottom. The dredge teeth dig the bottom and typically disturb the top layer (2 cm) of sediment but could penetrate up to 30 cm. Another more restricted dredging practice uses hydraulic jets in sandy muddy bottoms to dig and wash out mussels that have buried themselves in the seabed. A dredge has physical impacts to the sea floor and biological impacts on the benthic organisms, both with varying degrees of disturbance. These impacts may be influenced by several factors such as the dredge type, the width and weight, sediment type, number of dredges operating, methods of fishing, whether any form of deflector or rakes are used, etc. (FAO 2001–2018). The main physical impacts after dredging result in significant disturbance of the bottom, evidenced by the presence of furrows, elimination of natural bottom features (ripples and irregular topography), and dislodgement of shell fragments and small stones (Løkkeborg 2005). Sometimes, extensive sediment redistribution with suspended particles and reducing visibility take place. Furthermore, sediment compaction together with elimination of the bioturbation mounds or polychaete tubes may occur (Hall-Spencer et al. 1999). In addition, damage to reefs and similar structures jointly with chemical changes may also happen (FAO 2001–2018). The physical effects tend to diminish with time (FAO 2001–2018), but their longevity is determined by depth, sediment type, and natural disturbances (tidal current and its strength, wave actions, and biological activities) and may last from a few hours to more than a year (Gislason 1994). The most common direct biological impacts of dredging are the decrease in the number of species and reduced abundance for some species, which can be explained by the mechanical damage and removal of benthos by the dredge (Currie and Parry 1996). The indirect biological impacts resulting from habitat disturbance and the consequent reduction of its complexity involve

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the non-catch mortality of benthic organisms and the exposure of infaunal species making them more vulnerable to predation (FAO 2001–2018).

Beach Seining The beach seine is a particular type of gear commonly operating near shore, generally used in soft bottoms of shallow waters either in inland or sea water. These shallow waters close to the shore are often spawning or nursery grounds for many fish species. Fishing with small meshed nets causes a negative impact to fish populations, which is potentially even more negative in these areas. Beach seining in such areas also disturbs the breeding activities and frequently leads to the capture of juveniles. Often, the use of small meshed nets leads to a large percentage of bycatch/discards composed by undersized specimens, nonmarketable specimens, and nontarget species. On the other hand, beach-seine netting does not have a significant detrimental effect on the benthic flora and invertebrate fauna (Lamberth et al. 1995). The negative and cumulative impacts of this type of gear have led several countries to regulate/restrict by law the use of beach seine.

Bottom Set Fishing Equipment (Longlines, Gillnets, Pots, and Traps) All set fishing gears can provoke physical damages when they are deployed and hauled due to the anchors and weights or by the fishing gear itself, with particular impact in sensitive habitats. Nevertheless, these three gear groups have distinct impacts in the fishing grounds and in the water column. In addition to the abovementioned impacts, these fishing practices are known to have significant interactions with other nontarget species. For instance, longlines often catch seabirds mainly during the launching operations, as well as other marine species such as turtles, sharks, whales, and seabirds during the fishing period. Surface gillnets are also responsible for catching seabirds and turtles.

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Similar to the two previous groups of fishing gears, pots and traps have additional impacts during launching and hauling; however, according to Freiwald et al. (2004), the damage is probably much lower than with the other two types of fishing gears due to their operation and size specificities.

Muro-Ami Netting and Coral “Bashing” Muro-ami fishing or “reef hunting” is a specific and dangerous netting fishing practice mainly used in Southeast Asia which was introduced by the Japanese. In this practice, a combination of weighted nets and plastic streamers with pounding devices is used. Those weights are lifted and dropped repeatedly along the reef in order to scare the fish into the gaping net. These weights break and destroy the live coral, which has led to extensive coral reef deterioration and stock depletion. This highly destructive fishing method was banned in the 1980s, but it is still being used in some Southeast Asian places (McClellan 2008).

Spearfishing Spearfishing is an ancestral worldwide fishing technique initially used in rivers, lakes, and near shore and lately has become a common practice in the open sea. In tropical island nations, spearfishing is very important because people rely on this activity for food and income (Frisch et al. 2012). Spearfishing is one of the most common forms of fishing on coral reefs. It is highly selective, in terms of species, size, and season (Dalzell 1996), and thus has minimal direct impact on nontarget species (Frisch et al. 2008), with no bycatch. However, like other forms of fishing, it can have rapid and substantial negative effects on target fish populations (Frisch et al. 2012). Some spearfishing practices can sometimes be perverse, cruel, and unsustainable. For instance, spearfishing at night, with or without scuba (self-contained underwater breathing apparatus) diving, is especially negative

because some target species have lower activity and are concentrated at particular sites (e.g., parrotfish sleep in crevices or holes). In some cases, spearfishing activities are often concentrated in specific places or season, heavily targeting local adult fish populations, which can lead to regional or local extinction of adult fish and threatening the sustainability of the fish populations. All spearfishers make contact with corals (Giglio et al. 2018) which have a negative impact because human touching, even slight careless tourist behavior or mechanical damage, can harm them, leading to coral death.

Poisoning The use of ictiotoxic substances (e.g., roots and/or leaf extracts) for fishing goes back to ancient times and is still used in several indigenous communities in a sustainable way. Later on, during the industrial development, several chemicals started to be used in a pernicious way in fishing activities. The utilization of poisons (e.g., sodium cyanide, likely originating from the Philippines in the 1950s, Fig. 1) in some regions was widespread to supply the international aquarium trade and live reef fish for the restaurants, respectively, in the 1960s and 1980s. In this technique, fish is indiscriminately killed or stunned, which makes them easily collected by divers or fishermen using nets or seines. This practice is performed both in fresh and marine waters, being quite relevant in coral reefs and coastal lagoon fisheries. Poisons have also a large impact on the other organisms of the ecosystem, particularly the coral reef-building organisms, leading them to death and becoming whitened and empty structures.

Ghost Fishing Ghost fishing occurs when fishing gear is lost, dumped, or abandoned in the marine environment (WWF 2017) and there is no intention of profiting from the catches. This is often referred to as ALDFG (abandoned, lost, discarded fishing

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Destructive Fishing Practices and Their Impact on the Marine Ecosystem, Fig. 1 Cyanide fishing. Fisherman spraying a coral with sodium cyanide. (Source: Benjamin Sauerborn)

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gear), a collective term used for fishing gear that has been abandoned, lost, or otherwise discarded or also as “derelict fishing gear” in literature. The most frequent gears responsible for ghost fishing are gillnets, longlines, pots, and traps. However, one can find many other devices for catching marine organisms (e.g., trawling and purse seine large nets), which generally sink into the seabed, thus becoming ocean litter that is still trapping marine creatures. Those nondegradable fishing gears can continue to catch for different periods of time depending on their type. Dead organisms caught or entangled in these devices attract other species, particularly scavengers, which can also be caught in the same ghost gear, becoming new attractors and potentially killing other marine life. Whales, dolphins, sharks, turtles, fish, and invertebrates are also often caught in these snagged or drifted gears. However, the effect of ghost fishing on the depletion of commercial fish stocks and other noncommercial animals is still unknown, but it is likely to have a large impact. There is also increasing evidence that ghost gear contributes to the problem of marine plastics (MSC 2021). It is estimated that at least 640,000 t of fishing gear is lost each year and that fishing gear makes up 10% of all marine debris (FAO 2009) and is still increasing. A variety of measures have been proposed to minimize ghost fishing which are summarized in Table 1, which include preventative, mitigating, and curative measures regarding the reduction of ALDFG.

Destructive Fishing Practices and Their Impact on the Marine Ecosystem, Table 1 Measures to reduce ALDFG. (Adapted from Macfadyen et al. (2009)) Preventative measures Gear marking to indicate ownership Traceability Spatial management Onshore collection/disposal Reduction of fishing effort through limitations on gear Mitigating measures Funding innovative solutions Developing and introducing environmentally friendly fishing technology Ecolabelling/Certification schemes Curative measures Locating lost gear Reporting lost gear Recovering lost gear Recycling gear

Blast Fishing Blast fishing is an old practice still used in a number of countries or islands around the world, being a popular method across east Africa and Asia (Fig. 2). In this highly destructive fishing practice, the explosives (often home-made from an ammonium nitrate and kerosene mixture) are set off under water, and fish are stunned or killed by shock waves that rupture their swimming bladder. Afterward, the fish float to the surface where they are generally collected by scoops. It is an inefficient method of fishing where the majority of killed fish sink to the ocean floor and only a

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Destructive Fishing Practices and Their Impact on the Marine Ecosystem

Destructive Fishing Practices and Their Impact on the Marine Ecosystem, Fig. 2 Blast fishing. (Source: Benjamin Sauerborn)

small part floats to the top for collection. This fishing technique usually occurs over coral reefs, killing marine organisms indiscriminately, and is particularly harmful to coral’s calcium carbonate skeletons. This destruction prevents the natural functioning of these ecosystems. Unfortunately, this practice is still economically profitable (e.g., McClellan (2008) indicates an economic efficiency ratio of about 1:18) thus justifying the risk of its utilization. However, anti-blast fishing laws have been implemented in many countries, although with different results both in their application and in the effective reduction of this fishing practice. In shallow waters, the blast fishing impacts lead to the loss of substrate topographic complexity and habitat cover. In the case of coral reefs, they are mechanically damaged causing a decline of their recruitment and ability to regrow, leading ultimately to local extinction of some species. The recovery of coral communities may take decades or even a century before they will be back to normal. These changes may lead to the substitution of former hard coral communities by soft corals and macro-algae and consequently affecting the biotic (e.g., maintenance of biodiversity) and biogeochemical (e.g., nitrogen fixation or CO2/Ca budged control) (Moberg and Folke 1999) reef functions. Blast fishing also leads to a decline in fish biodiversity and

richness, with consequent reduction of future catches that will affect the food security and the livelihoods of fishing communities. The use of explosives is also dangerous for the users themselves due to manufacturing or manipulation errors, leading to a frequent premature explosion of these devices, causing serious injuries or even death. In Table 2 potential adverse impacts and their impact intensity on the marine ecosystems and/or fish populations by the different types of destructive fishing practices or techniques are summarized. All of the abovementioned techniques or practices can be considered destructive, and among them, muro-ami netting and coral “bashing,” poisoning, and blast fishing have the greatest impact in the marine ecosystems and/or fish populations. However, blast fishing is by far the most destructive. The social, economic, and ecological impacts of the destructive fishing activities on sustainability are shown in Fig. 3.

Ways to Prevent Destructive Fishing Destructive fishing practices are a global concern, which is reflected in several international and regional instruments, management, and technical and socioeconomic measures that tackle these

Destructive Fishing Practices and Their Impact on the Marine Ecosystem

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Destructive Fishing Practices and Their Impact on the Marine Ecosystem, Table 2 Types of destructive fishing practices or techniques and impacts on the marine ecosystems and/or fish populations

Increasing impact

Type low

medium

Potential adverse impacts high

Collapse or depletion of fish stocks; reduction of spawning aggregations; intensive fishing over vulnerable habitats, including spawning and nursery areas; By-catch and discarded species. Damage of deep-sea ecosystem and vulnerable marine ecosystems (abundance, biomass, and biodiversity); impoverishment of seafood stock, benthic habitats and communities; increase of benthos mortality; sediment resuspension. Mechanical damage particularly in sensitive habitats; killing of larger animals such as seabirds, turtles, sharks and whales; ghost fishing Mechanical damage particularly in sensitive habitats; ghost fishing. Extensive coral reef deterioration or destruction.

Overfishing

Trawling and dredging

Bottom set long-lines Bottom set gillnets Muro-ami netting &

Coral “bashing” Mechanical damage particularly in sensitive habitats; ghost fishing Reef species heavily targeted and regional or local extinction of adult fish populations when completely removed. Killing or stunning, indiscriminately, the fish, also other organisms from the ecosystem, including the coral reef-building organisms. Continuous catching of fish, dolphins, whales, turtles, and other creatures; marine litter. Complete destruction of the underwater environment.

Pots and traps Spear fishing

Poisoning Ghost fishing Blast fishing

Jeopardizing of food security and well-being of populations Destruction of habitats

Growth inhibition of new corals

Collapse or depletion of fish stocks & economic extinction Destructive fishing

Loss of biodiversity

Loss of fishery jobs & profits

Loss of human lives

Loss of coastal protection & tourism Destructive Fishing Practices and Their Impact on the Marine Ecosystem, Fig. 3 Overall effects of destructive fishing on the economic, social, and ecological sustainability

practices. In Table 3, an overview of these instruments and measures for approaching the overfishing and destructive practices is presented.

Unsustainable fishing has been identified as the most pervasive of all local threats particularly to coral reefs (Burke et al. 2011). According to these

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Destructive Fishing Practices and Their Impact on the Marine Ecosystem

Destructive Fishing Practices and Their Impact on the Marine Ecosystem, Table 3 A summary of the measures for mitigating the impacts of overfishing and International and regional instruments

Management measures

Technical measures

Socio-economic

destructive fishing on marine biodiversity and habitats. (Adapted from FAO 2010)

Measures United Nations Convention on the Law of the Sea United Nations Fish Stocks Agreement FAO Code of Conduct for Responsible Fisheries Ecosystem Approach to Fisheries Convention on International Trade in Endangered Species (CITES) IUCN Red List of Endangered Threatened Species Strengthening of Regional Fisheries Management Organizations (RFMOs) Global Plan of Action for the Protection of the Marine Environment Regional Seas and Associated Action Plans The International Convention for the Prevention of Pollution from Ships (MARPOL) Coordinated science advice Flag States control on fishing activities Port States control on fishing activities Coastal State responsibility Fishery development policy Reduction of overcapacity Marine protected areas (MPAs) Rotating harvest Discard reduction Improved monitoring, control, and surveillance (MCS) Environmental Impact Assessment (EIA) and Environmental Risk Assessment (ERA) Zoning Protecting vulnerable and critical habitat Protecting vulnerable species Banning destructive gear Eliminating dumping at sea More selective gear More selective operation Reduce discard mortality Gear substitution Gear modification Gear retrieval programs Marking of fishing gear Using biodegradable material Access and user rights Education in marine conservation Consumer action, ecolabelling, and other market-related measures Sustainable livelihoods Improve governance

authors, over 55% of the world’s reefs are threatened by overfishing and/or destructive fishing. In fact, many of the world’s most remote coral reefs are heavily fished. Basically, the main impacts of overfishing and destructive fishing are: (i) Direct overexploitation of fish, invertebrates, and algae for food and the aquarium trade (ii) Removal of a species or group of species impacting multiple trophic levels

(iii) Bycatch and mortality of nontarget species (iv) Changes from coral to algal dominance due to reduction in herbivores (v) Physical impacts to reef environments associated with fishing techniques, fishing gear, and anchoring of fishing vessels (NOAA 2011) The main management strategies to address overfishing and destructive fishing have been

Destructive Fishing Practices and Their Impact on the Marine Ecosystem

identified and include the establishment of notake areas within marine protected areas (MPAs), seasonal closures to protect breeding sites, restrictions on the number of people allowed to fish, types of fishing gear used, and the quantities or sizes of fish that can be harvested (RRN 2021). Fisheries play an important role in both poverty prevention and reduction (ISU 2012). Indeed, almost three billion people (40% of the world’s population) live within 100 km of the coast (Agardy and Alder 2005), and global coastal populations are expected to double by 2025 (Creel 2003). Having in mind this continuous increase in populations along coastlines, it is important to reduce destructive fishing and ensure the sustainability of the oceans and their ecological systems. Under a context of the UN sustainable development goals (SDG), particularly SDG 14 (conserve and sustainable use of oceans, seas, and marine resources for sustainable development), the challenges facing the future of fisheries in the oceans, seas, and coastal areas and its governance mechanisms include its sustainability and the drastic reduction on human activity, focusing on the sustainable management and protection of ecosystems, the increase of the protected areas (e.g., marine protected areas and marine reserves), and reduction in ocean acidification. Safeguarding the natural function of the marine ecosystem is a priority under the UN SDG, allowing for a sustainable exploration of natural resources without compromising its functioning in the long term.

Cross-References ▶ Artisanal Fishing Gears and Sustainable Development

References Agardy T, Alder J (2005) Coastal systems. In: Hassan R, Scholes R, Ash N (eds) Ecosystems and human wellbeing: current state and trends, vol 1. Millennium Ecosystem Assessment Board, Washington, DC, pp 513– 549. https://www.millenniumassessment.org/docu ments/document.288.aspx.pdf

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Burke L, Reytar K, Spalding M, Perry A (2011) Reefs at risk revisited. World Resources Institute (WRI), Washington, DC, 114 p Creel L (2003) Ripple effects: population and coastal regions. Population Reference Bureau, Washington, DC. https://www.prb.org/wp-content/uploads/2003/ 09/RippleEffects_Eng.pdf. Accessed 4 Jan 2021 Currie DR, Parry GD (1996) Effects of scallop dredging on a soft sediment community: a large-scale experimental study. Mar Ecol Prog Ser 134:131–150. https://www. int-res.com/articles/meps/134/m134p131.pdf. Accessed 4 Jan 2021 Dalzell P (1996) Catch rates, selectivity and yields of reef fishing. In: Polunin NVC, Roberts CM (eds) Reef fisheries. Chapman and Hall, London, pp 161–192 FAO (2001–2018) Fishing gear types. Towed dredges. Technology fact sheets. In: FAO Fisheries and Aquaculture Department [online]. Rome. Updated 13 September 2001. [Cited 29 June 2018]. http://www.fao. org/fishery FAO (2009) Ghost nets hurting marine environment. http:// www.fao.org/news/story/en/item/19353/icode/. Accessed 28 Dec 2020 FAO/UNEP (2010) Expert meeting on impacts of destructive fishing practices, unsustainable fishing, and illegal, unreported and unregulated (IUU) fishing on marine biodiversity and habitats. Rome, 23–25 September 2009. FAO fisheries and aquaculture report. No. 932. Rome, 32 p Freiwald A, Fosså JH, Grehan A, Koslow T, Roberts JM (2004) Cold water coral reefs: out of sight-no longer out of mind. UNEP-WCMC, Cambridge, UK, 88 p Frisch AJ, Baker R, Hobbs JA, Nankervis L (2008) A quantitative comparison of recreational spearfishing and linefishing on the great barrier reef: implications for management of multi-sector coral reef fisheries. Coral Reefs 27(1):85–95. https://doi.org/10.1007/ s00338-007-0293-z Frisch AJ, Cole AJ, Hobbs J-PA, Rizzari JR, Munkres KP (2012) Effects of spearfishing on reef fish populations in a multi-use conservation area. PLoS One 7(12): e51938. https://doi.org/10.1371/journal.pone.0051938 Giglio VJ, Luiz OJ, Barbosa MC, Ferreira CEL (2018) Behaviour of recreational spearfishers and its impacts on corals. Aquat Conserv: Mar Freshwat Ecosyst 28: 167–174. https://doi.org/10.1002/aqc.2797 Gislason H (1994) Ecosystem effects of fishing activities in the North Sea. Mar Pollut Bull 29:520–527. https://doi. org/10.1016/0025-326X(94)90680-7 Hall-Spencer JM, Froglia C, Atkinson RJA, Moore PG (1999) The impact of Rapido trawling for scallops, Pecten jacobaeus (L.), on the benthos of the Gulf of Venice. ICES J Mar Sci 56(1):111–124. https://doi.org/ 10.1006/jmsc.1998.0424 ISU (2012) Towards global sustainable fisheries: the opportunity for transition. The Prince’s Charities’ International Sustainability Unit, London, UK, p 49. https:// greengrowthknowledge.org/sites/default/files/down loads/resource/Towards_global_sustainable_fisheries_ Prince%27s%20Charities.pdf. Accessed 28 Dec 2020

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304 Lamberth SJ, Bennett BA, Clark BM, Janssens PM (1995) The impact of beach-seine netting on the benthic flora and fauna of False Bay, South Africa. S Afr J Mar Sci 15(1):115–122. https:// doi .org/10.2989/ 02577619509504838 Løkkeborg S (2005) Impacts of trawling and scallop dredging on benthic habitats and communities. FAO fisheries technical paper no. 472. FAO, Rome, p 58 Macfadyen G, Huntington T, Cappell R (2009) Abandoned, lost or otherwise discarded fishing gear. UNEP regional seas reports and studies no 185. FAO fisheries and aquaculture technical paper no. 523. UNEP/FAO, Rome, p 115 McClellan K (2008) Coral degradation through destructive fishing practices. In: Cleveland CJ (ed) Encyclopedia of earth, Washington, DC. http://www.eoearth.org/ article/Coral_degradation_through_destructive_fish ing_practices. Accessed 30 June 2018 MCS (2008) Bottom towed fishing gear: position statement and background paper. Marine Conservation Society p 9. https://www.mcsuk.org/downloads/fisheries/MCS% 20policy%20&%20position%20papers/MCS%20bot tom%20towed%20fishing%20gear%20position% 20statement%20and%20background%20(November %202008).pdf. Accessed 29 June 2018 Moberg F, Folke C (1999) Ecological goods and services of coral reef ecosystems. Ecol Econ 29(2):215–233. https://doi.org/10.1016/S0921-8009(99)00009-9 MSC (2021) Preventing lost and abandoned fishing gear (ghost fishing). https://www.msc.org/what-we-aredoing/preventing-lost-gear-and-ghost-fishing. Accessed 4 Jan 2021 NOAA (2011) Impacts from land-based sources of pollution. U.S. National Oceanic and Atmospheric Administration. https://coralreef.noaa.gov/issues/lbsp.html. Accessed 4 Jan 2021 NRC (2002) Effects of trawling and dredging on seafloor habitat 18–29. Committee on ecosystem effects of fishing: phase 1 – effects of bottom trawling on seafloor habitats. National Research Council National Academy Press, Washington, DC, 126 p. https://doi.org/10. 17226/10323 Pusceddu A et al (2014) Chronic and intensive bottom trawling impairs deep-sea biodiversity and ecosystem functioning. Proc Natl Acad Sci 111(24):8861–8866. https://doi.org/10.1073/pnas.1405454111 RRN (2021) Reef resilience network. Overfishing and destructive fishing threats. https://reefresilience.org/ coral-reef-fisheries-module/coral-reef-fisheries/over fishing/. Accessed 4 Jan 2021 United Nations Report of the Secretary-General A/60/189 (2005) Sustainable fisheries, including through the 1995 Agreement for the Implementation of the Provisions of the United Nations Convention on the Law of the Sea of 10 December 1982 relating to the Conservation and Management of Straddling Fish Stocks and Highly Migratory Fish Stocks, and related instruments, 49 p WWF (2017) World Wide Fund for Nature http://wwf. panda.org/our_work/oceans/problems/destructive_fish ing/. Accessed 29 June 2018

Diatoms and Their Ecological Importance

Diatoms and Their Ecological Importance João Serôdio1 and Johann Lavaud2 1 Department of Biology and CESAM – Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal 2 UMR 6539 LEMAR, Institut Européen de la Mer, Plouzané, France

Definition Diatoms are unicellular or colonial photoautotrophic microalgae, eukaryotic organisms classified as protists of the group of the Bacillariophyta. They are characterized by the unique feature of possessing a cell wall made of silica. Diatoms form an extremely diverse and evolutionarily successful group. They are found in all marine and freshwater habitats and in moist terrestrial habitats, being the most diverse group of algae, the number of species being estimated to reach between 100,000 (Mann and Vanormelingen 2013) and 200,000 (Armbrust 2009). Diatoms have an enormous ecological importance, contributing to 20–25% of the Earth’s global primary production (Field et al. 1998; Sarthou et al. 2005). Their photosynthetic activity accounts for 40% of the marine primary production, being comparable to the total amount fixed by all the terrestrial rain forest combined (Armbrust 2009). However, their critical role in the functioning and biodiversity of oceanic and coastal zones, while representing a major carbon sink and supporting important marine food webs, is threatened by ongoing climate change, namely, by ocean acidification and eutrophication. Introduction Diatoms are unicellular or colonial photoautotrophic microalgae. Diatom cells vary between a wide range of sizes, from 5 mm to above 1 mm in diameter or length (Sabater 2009). They are most commonly found as single cells but can form colonies, living in suspension in the water column or attached to substrata. Diatoms are

Diatoms and Their Ecological Importance

found in all marine and freshwater habitats and in moist terrestrial habitats, covering extreme environments like sea ice (Arrigo 2014) or deep marine sediments well below the photic zone of the ocean (Cahoon et al. 1994). Diatoms are a major constituent of the phytoplankton in oceanic and coastal waters, where they often dominate over other groups of microalgae or cyanobacteria (Armbrust 2009). They are typically the dominant group in the microphytobenthos, the highly productive biofilm-forming communities of microalgae and cyanobacteria that colonize intertidal flats or shallow subtidal sediments (Underwood and Kromkamp 1999). Their ubiquity in virtually all marine habitats (Mock and Medlin 2012) and ability to strive in extreme habitats, such as polar systems (Lyon and Mock 2014) or under prolonged darkness (Frankenbach et al. 2019; Kennedy et al. 2019), is believed to be based on their unique physiological and metabolic features (Wilhelm et al. 2006; Gruber and Kroth 2017). The Siliceous Cell Wall The most distinctive feature of diatoms is the presence of a silicified cell wall (“frustule”) made of two identical pieces (“valves”), which gave origin to the name of the group (from the Greek word “diatomos,” meaning “cut in half”). The two pieces overlap each other like the parts of a Petri dish, with a larger one (“epitheca”) partially enclosing a smaller one (“hypotheca”). Because the valves do not increase in size after being formed, cell division implies the formation of new, smaller valves within the ones of the parental cell, causing a gradual reduction in cell size over several generations (De Tommasi et al. 2017). Original cell size is restored through sexual reproduction, by the production of diploid zygotes called auxospores (Davidovich et al. 2015). The siliceous cell wall has been thought to be a major factor explaining the adaptive success of diatom, as it confers multiple advantages, such as the following (Pickett-Heaps 2003): (i) although rigid and impermeable, it is transparent and porous, allowing light penetration and the diffusion of carbon and nutrients, thus permitting photosynthesis; (ii) silica is an abundant element, that is available from sand and suspended silt, and

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only in oligotrophic waters limits diatom growth; (iii) the uptake and precipitation of silica is efficient, being energetically cheaper than and equivalent organic wall. Diatom cell walls are rich in complex and intricated ornamentation that result from the deposition of siliceous material in regular patterns. Due to its enormous intricacy and diversity, the morphology of the frustule has been the basis for traditional diatom taxonomy and classification since the first microscopy observations (Round et al. 1990). The advent of scanning electron microscopy, revealing with finer detail the ornamentation of the cell wall, caused an increase in the number of diatom taxa, as compared to the previously described on the basis of light microscopy observations (Round et al. 1990). However, phenotypical changes in the frustule morphology may occur as responses to varying environmental conditions, affecting their taxonomical value. Recent approaches based on molecular sequence data are contributing to improved phylogeneticbased taxonomical classifications (Sims et al. 2006). Diversity and Evolution Diatoms are an extremely diverse and evolutionarily successful group. They appeared between 190 and 250 million years ago, depending if the estimates are based on the fossil record or on molecular clocks (Benoiston et al. 2017). Diatoms are the most diverse group of algae, the number of existent species being estimated to reach above 100,000 (Mann and Vanormelingen 2013) and even up to 200,000 (Armbrust 2009). Diatoms are eukaryotic organisms, classified as protists of the group of the Bacillariophyta. Despite long and intensive research, the phylogeny and classification of the group is still under debate (Yu et al. 2018). Diatoms have evolved through two successive endosymbiotic events from which originate both their secondary plastid (Dorrell and Bowler 2017) and chimeric genome harboring a unique mix of bacterial, algal, and animal-like features (Tirichine et al. 2017). The diatom plastid is thought to derive from red algae, originally suggested by the conservation of chlorophyll c and a plastid four membrane-bound ultrastructure,

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and later supported by plastid gene trees (Dorrell and Bowler 2017). There are two main groups of diatoms, the centrics and the pennates, which differ markedly regarding key cytological, biological, and ecological aspects, that include cell wall symmetry, chloroplast number and morphology, sexual reproduction, and motility (Pickett-Heaps 2003). The most obvious difference between the two groups is cell wall symmetry. Many centric cells show radially symmetrical valves, with radially organized patterns in valve ornamentation (Fig. 1a, b). Pennate species, while showing a large variety of forms and ornamentation complexity, typically show a well-defined main axis conferring a clearly non-radial symmetry (Fig. 1c, d). Another major morphological difference regards

chloroplasts, with the centrics having a large number of small chloroplasts and the pennates often possessing one or two large chloroplasts per cell (Fig. 1b, d). Centric diatoms are typically planktonic, often dominating the phytoplankton, especially in turbulent, nutrient-rich marine waters (Malviya et al. 2016). Pennate diatoms are predominantly benthic, dominating the microphytobenthos, the biofilm-forming communities that colonize intertidal and well-lit subtidal sediments (Underwood and Kromkamp 1999), and sea-ice habitats (Poulin et al. 2011). These differences in habitat preference between centrics and pennates seem to be associated with the evolution of directed motility in the presently larger group of pennate diatoms, the raphid pennates, enabled by the development of

Diatoms and Their Ecological Importance, Fig. 1 (a,c) Scanning electron micrographs of frustules of a centric (Thalassiosira angulata; a) and a pennate diatom (Navicula phyllepta; c ). (b, d) Optical microscopy photographs of a centric (Coscinodiscus granii; b ) and a pennate diatom (Nitzchia sigma; d ), showing the differences in

chloroplast number and size. (a, courtesy of James M. Ehrman, Digital Microscopy Facility, Mount Allison University. b , courtesy of NCC - Benoit Tesson, Université de Nantes. d , courtesy of NCC-Pierre Gaudin, Université de Nantes)

Diatoms and Their Ecological Importance

the “raphe,” a longitudinal thin and long slit through the surface of the valve (Nakov et al. 2018). However, not all pennates possess a raphe, for which reason the pennates are further separated between the araphids (without raphe) and the raphids (with raphe). Motility in Pennate Diatoms The raphe and associated cell motility are relatively recent traits in diatom evolution, having appeared during the Palaeocene, ca. 30 million years ago (Armbrust 2009). Their appearance is hypothesized to have conferred an adaptive advantage to colonize new niches including the sedimentary microenvironment, due to an improved efficiency in fast responding to environmental gradients (light, nutrients) and exploiting habitat heterogeneity (Cohn et al. 2015; Nakov et al. 2018). The evolution of motility is thought to be a primary driver of diatom diversification, explaining the rapid and large expansion of raphid pennate species, which are currently the most numerous group of diatoms (Kooistra et al. 2007). The most common form of motility in pennate diatoms is known as “gliding,” consisting in directed cell movement, typically along the direction parallel to the longitudinal axis of the cell, and when the cell is in close contact with hard surfaces (Edgar and Pickett-Heaps 1984). Directed motility, for example, toward a stimulus, is achieved by varying the time between the reversal of direction, causing forward progression when the movement in the direction of the stimulus lasts longer than away from it (Cohn et al. 2004; Apoya-Horton et al. 2006). Diatom gliding is a complex process, involving the extrusion of adhesive, mucilaginous extracellular polymeric substances (EPS) through the raphe. According to the widely accepted model proposed by Edgar and Pickett-Heaps (Consalvey et al. 2004; Molino and Wetherbee 2008), diatom gliding is based on an actin-myosin mechanism, resulting in the transient attachment of the cell to the substratum while moving. Actin filaments run the length of the raphe in the cytoplasm immediately adjacent to the cell membrane and allows the cell to attach and to glide over of the substratum (Poulsen et al. 1999).

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Ecology Diatoms have an enormous ecological importance. Through their photosynthetic activity, the group contributes to a massive 20–25% of the Earth’s global primary production, carbon fixation, and oxygen release into the atmosphere (Field et al. 1998; Sarthou et al. 2005). The amount of carbon fixed by diatoms’ photosynthesis per year represents 40% of total marine primary production, being equivalent to the total amount fixed by all the terrestrial rain forest combined (Armbrust 2009). Diatom productivity is thus a key source of carbon for marine, coastal, and estuarine trophic webs, supporting a range of animal populations, from small crustacean to commercially valuable fishes, seabirds, and marine mammals (Benoiston et al. 2017). Because of the heavy siliceous frustule, planktonic diatoms tend to sink through the water column, carrying organic carbon to the deep zones of the ocean. There, it is used as food for deep-sea organisms, remineralized back to CO2, fueling the ocean’s carbon pump, or converted to carbonates and incorporated in deep sediments (Tréguer et al. 2018). The vertical migration of large centric diatoms along the water column represents a form of “nutrient mining,” through which substantial amounts of nutrients are transported upwards across the nutricline, replenishing the otherwise nutrient-depleted photic layer and contributing to new production (Singler and Villareal 2005). Vertical migration also causes that the photosynthetically fixed carbon near the ocean surface is transported downward and respired at sub-photic layers. These processes have a large impact on the vertical fluxes of nitrogen (and other nutrients like phosphorous) and have been estimated to contribute to more than one quarter of the ocean surface nitrate pool (Singler and Villareal 2005). The vertical migration of centric diatoms is widespread and has major biogeochemical consequences, calling for the reassessment of the role of motility in marine phytoplankton and of the predicted implications of global warming on changes in phytoplankton diversity (Villareal et al. 2014). Diatoms also strongly influence the carbon cycling in benthic sedimentary habitats. Diatom

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gliding causes the excretion from the raphe of large amounts of carbon-rich mucilage formed by extracellular polymeric substances (EPS) (Pickett-Heaps 2003) which represent a major source of organic carbon fueling the growth of heterotrophic bacteria and their remineralization activity (Bohórquez et al. 2017). A similar high excretion of EPS has been reported for sea-ice diatoms (Underwood et al. 2013). The critical role of diatoms in the global carbon cycle makes them major players, as well as sentinels of environmental disturbances, in the context of global change scenarios (Raven 2017). Due to their abundance in planktonic and benthic habitats and to the strict dependence of silicic acid for forming their cell walls, diatoms are main drivers of the silicate cycle at the global scale (Tréguer and De La Rocha 2013). In the ocean, diatoms are a major sink of silica, ultimately causing the accumulation on the sea floor of massive deposits of cell walls from dead cells, called “diatomaceous earth” or “diatomite.” On the other hand, the availability of dissolved silicic acid is often a limiting factor of diatom growth, determining the productivity and species composition of phytoplankton communities (Tréguer and De La Rocha 2013). On estuarine tidal flats and subtidal sediments, diatom-dominated microphytobenthic biofilms also strongly affect the fluxes of silica across the sediment-water interface, influencing the silica concentrations in the water column (Ní Longphuirt et al. 2009; Bondoc et al. 2016a; Welsby et al. 2016). Reasons for Success Several factors seem to contribute to the success of diatoms, including specific subcellular light energy distribution and allocation patterns of carbon into macromolecules (Dorrell and Bowler 2017; Wagner et al. 2017). In comparison with other photoautotrophs, diatoms appear as particularly efficient in coping with high and/or fluctuating solar light intensities (Ruban et al. 2004; Wilhelm et al. 2006), which are a major cause of photoinhibition, the light-induced damage to the photosynthetic apparatus, in many situations a main limitation of microalgae productivity (Raven 2011). This ability has been attributed to the efficient operation of energy-dissipation

Diatoms and Their Ecological Importance

photoprotective processes of diatoms, allowing withstanding the high light levels and rapid fluctuations in light exposure occurring in the turbulent upper layers of the ocean’s photic zone (Lavaud and Goss 2014). Diatoms are known to be highly efficient for thermal dissipation of excess absorbed energy (Buck et al. 2019). One of the main mechanisms underlying this capacity for thermal dissipation is the so-called xanthophyll cycle, a biochemical process consisting in the reversible conversion of photosynthetic pigment under high light conditions (Goss and Lepetit 2015). Unlike land plants, in diatoms and other microalgae group, the xanthophyll cycle involves the conversion of the pigment diadinoxanthin into the energy-dissipating form diatoxanthin (Lavaud et al. 2002). Cell motility also plays a role in enhancing productivity, by allowing cells to actively exploit spatial heterogeneities in the resource distribution. Planktonic centric species can regulate their buoyancy and move vertically in the water column, between the surficial nutrient-poor photic zone and the nutrient-rich deeper layers (Villareal et al. 1999). This capacity to move vertically in the water column has been thought to represent an adaptation to living in stratified waters, typical of warm, oligotrophic regions (Kemp and Villareal 2013). Vertical migration confers these cells the capability for obtaining nutrients from sub-euphotic layers and for photosynthetizing in well-lit conditions and for avoiding direct competition with much more abundant, non-migratory smaller phytoplankton, overcoming the disadvantages of their larger size (Villareal et al. 2014). In the benthos, directed vertical migration by pennate diatoms appears to have an even more important significance in terms of exploiting environmental heterogeneity. Directed motility allows benthic diatoms to respond behaviorally to a wide array of abiotic and biotic factors and cues, such as visible light (intensity and spectrum) (Cohn et al. 1999), ultraviolet radiation (Waring et al. 2007), gravity (Frankenbach et al. 2014), temperature (Cohn et al. 2003), salinity (Sauer et al. 2002), desiccation (Coelho et al. 2009), pH (Cohn and Disparti 1994), chemical gradients (Bondoc et al. 2016a), or pheromones (Bondoc

Diatoms and Their Ecological Importance

et al. 2016b). Responses to intensity and spectral composition of light are among the most important for diatoms, as they not only directly determine photosynthetic rates and growth, but also photodamage and possibly cell death (Serôdio et al. 2006). The motility response of pennate diatoms to changes in light intensity is characterized by the avoidance of both darkness and low light and of very high light intensities and the preference of intermediate irradiance levels (Serôdio et al. 2006). Furthermore, due to the comparable scales of spatial variability of resources like light or nutrients, the diatom cell size, and the distances covered through gliding, motile diatoms are able to rapidly move toward regions with more favorable light, carbon, or nutrient conditions within the sedimentary microhabitat (Cohn et al. 2015; Bondoc et al. 2016a) or to avoid unfavorable conditions such as photoinhibitory irradiances (Serôdio et al. 2006), or predators (Kingston 1999). Vertical movement by raphid diatoms is partially endogenously controlled, exhibiting a self-sustained rhythm synchronized with environmental day-night and tidal cycles (Consalvey et al. 2004). This allows the cells to anticipate environmental periodicity, such as main periodic events including sunrise or sunset, and tidal ebb, or flood (Coelho et al. 2011). Diatoms also have the ability to survive for prolonged periods in continuous darkness, often while buried in anoxic sediments, and to regain photosynthetic activity and carbon fixation upon exposure to favorable surface conditions (Wasmund 1989; Frankenbach et al. 2019). Survival in darkness or while buried has been documented for deep sea sediments (Wasmund 1989; Cahoon et al. 1994) and Antarctic sediments (Wulff et al. 2008). This is enabled by the capacity to live heterotrophically, based on organic energy sources (Lewin 1953; Tuchman et al. 2006), or by the formation of morphological unchanged resting cells (Jewson et al. 2006) or spores (Sugie and Kuma 2008). Facultative heterotrophy of diatoms seems more common among pennate, benthic forms (Lewin and Hellebust 1970; Rivkin and Putt 1987); it was shown to also occur in centric diatoms (Kamp et al., 2013; White 1974). A similar ability to survive the winter polar night prolonged darkness and rapid

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reactivation of photosynthetic activity has been reported in polar diatoms (Kvernvik et al. 2018; Kennedy et al. 2019). Applications Diatoms have been used for a variety of applications. The inert nature and long-lasting durability of the diatom silica wall makes it possible to use the deposits of frustules from dead cells (known as diatomite) for industrial and commercial purposes or for geological and paleontological analysis of aquatic sediment (Miettinen 2018). More recently, diatoms have been proposed as valuable sources of bioactive compounds (Lopez et al. 2005) as well of lipids and biofuels, due to their high lipid content, as an alternative to plants or green algae (Ramachandra et al. 2009; Hess et al. 2018). The ability to build complex three-dimensional frustules with light-interacting properties has raised considerable interest in the fields of nanotechnology and nanophotonics (Ellegaard et al. 2016; Ragni et al. 2017). Addressing SDG14 Since its earliest forms, Sustainable Development Goal 14 (conserve and sustainably use the oceans, seas, and marine resources for sustainable development) has identified the minimization of ocean acidification due to climate change and of nutrient pollution and eutrophication as key targets (targets 14.1 and 14.3, respectively). Diatoms display a critical role in the functioning and biodiversity of oceanic and coastal zones. Their photosynthetic activity represents a major carbon sink, and their productivity supports important marine food webs around the globe. However, to what extent, these processes will be impacted by climate change, ocean acidification, and eutrophication or, on the other hand, may contribute to ameliorate the expected negative impacts (e.g., rising atmospheric CO2) clearly requires more study. Efforts should thus be directed toward understanding the impacts of ocean acidification and eutrophication, among other processes, on diatom biology and ecology, in line with specifically DSG14 target 14.A (increase scientific knowledge, develop research capacity and transfer marine technology).

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Cross-References ▶ Photoinhibition: Fundamentals and Implications for Primary Productivity ▶ Role of Microphytobenthos in the Functioning of Estuarine and Coastal Ecosystems Acknowledgments Thanks are due to FCT/MCTES for the financial support to CESAM (UIDP/50017/2020 +UIDB/50017/2020), through national funds.

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Digital Sequence Information ▶ Sustainable Use of Marine Genetic Resources

Diversity ▶ Marine Protected Area and Biodiversity Conservation

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Ecological and Economic Importance of Benthic Communities Daniel Crespo1,2,3 and Miguel Ângelo Pardal2 1 MARE – Marine and Environmental Sciences Centre, ESTM, Polytechnic of Leiria, Peniche, Portugal 2 CFE, Centre for Functional Ecology – Science for People and the Planet, Department of Life Sciences, University of Coimbra, Coimbra, Portugal 3 CIIMAR – Interdisciplinary Centre of Marine and Environmental Research of the University of Porto, Matosinhos, Portugal

Synonyms Benthic communities; Benthonic communities; Bottom communities

Definitions Benthos is the full biological community that live within or associated with the bottom of any aquatic system (Sigman and Hain 2012). The term benthos was coined from the Greek by Haeckel in 1891 (Haeckel 1891). The layer which is occupied by benthos is known as the benthic zone and includes as substrate soft sedimentary or rocky bottoms. It is a widely

embracing concept, encompassing such distinct habitats as tidal pools along the foreshore, the continental shelf, and the abyssal depths. Benthic communities can be very distinct, shifting along gradients of latitude, depth, water temperature, and salinity. Also, the nature of the substrate and the interactions with the biotic and abiotic components of the water column are fundamental to define the composition of benthic communities. The benthos communities can be classified accordingly to their size (micro-, meio-, macroand megabenthos), to their energetic roles (phytobenthos or zoobenthos) or to the relative position to the substrate-water interface (infauna, epibenthos, hyperbenthos). Among benthic fauna, several feeding typologies may be found such as filter- and deposit-filtering, predation, and grazing. Some ecological processes sustaining marine trophic chains occur among the benthos, such as the primary production due to microphytobenthos, macrophyte plants and algal beds, or the decomposition of pelagic organic matter. Several valued species belong to the benthic communities, which increases anthropogenic pressures on these biotic components.

Introduction The benthic communities are fundamental to the overall structure of aquatic ecosystems because they perform several ecological processes that are exclusive. These processes occur at different

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size scales, from micro to macro level. These communities intervene in the chemical balance, in the oxygenation and pH, in the organic matter load and, in some cases, in the salinity, not only of the substrate but also of the water column. Changes affecting the bottom communities propagate their effects into the remaining aquatic ecosystem due to strong benthic-pelagic coupling. Also, the benthic communities are able to alter the physical structure of their environment due to strong bioengineering abilities and the presence of habitat-forming species (Lemieux and Cusson 2014). They represent a highly diverse biota, with estimations up to more than one million different species (Gage 2001). Regardless their vital importance, those communities differ along geographic and environmental gradients where they are found (Levin et al. 2000; Pinet 2003). Therefore, to understand the variety of ecological processes in which they are involved, it is fundamental to understand what they have in common and what makes them distinct. The gradients governing the bottom communities’ assemblages can be latitude and depth as geographic gradients, and, for example, water temperature, salinity, bottom water energy, or turbidity, as environmental gradients (Levin et al. 2000). These communities, under different natural or human-induced stressors, differ not only in the identity of their members but also in the relative and absolute population densities and ultimately in the quality and amount of ecological processes in which they are involved (Pratt et al. 2014; Zeppilli et al. 2015). The benthic communities have been used as indicators for ecological quality status within aquatic systems (Chapman and McDonald 2005; Borja et al. 2011; Zeppilli et al. 2015). These organisms are valuable indicators of the effects of environmental changes due to their sessile or reduced mobility nature, therefore unable to migrate in order to escape from the stressors. Also, several species respond differentially to different anthropogenic pressures. For instance, meiofaunal communities respond to several environmental changes (Zeppilli et al. 2015). Seagrass prairies are often described as indicators of good environmental quality, providing support not only

to benthos but also to the other levels in the aquatic ecosystem (Short et al. 2017). The dominance of benthic communities by some groups of polychaetes annelids, such as Capitella sp., is often a signal of pollutant contaminations (Grémare et al. 1989). Additionally, recent techniques are offering a more profound insight on the metabolic processes taking place in the benthic communities, being potentially useful and efficient proxies for environmental quality assessment (Arévalo et al. 2013). The particular nature of the bottom of the aquatic systems forced the benthos to evolve with specific adaptations in order to cope with the environmental features they had to face, because they are usually sessile or with reduced mobility and, therefore, unable to flee in the presence of those adverse pressures. The benthic organisms of intertidal systems had adapted to tolerate and survive to high ranges in temperature (and in salinity, in the case of transitional systems); these organisms also feature mechanisms to face desiccation, tidal currents, wave action, and sediment instability (Elliott and Whitfield 2011). Organisms that live on rocky shores show additional properties that allow them to attach to the solid substrate. Benthic primary producers as plants, sessile algae, and bottom-dwelling diatoms depend on light to grow and therefore can only survive in shallow zones, within the photic zone. In the open ocean, environmental variables are more stable. Nevertheless, organisms must face high pressures and highly energetic profound bottom currents. The infaunal component of the benthos evolved to body shapes offering less resistance to movement within soft substrates, with cylindrical- or round-shaped bodies, while some of the epibenthic organisms evolved toward flat-shaped bodies, in order to withstand the resistance of tidal and wave currents and pressure. This article will attempt to distinguish among the different groups and levels of the benthic communities, their threats, and also the ecological processes they are involved in. The ecological and economical relevance of some benthic communities, as well as their role in the functioning of aquatic ecosystems, remains a source of interest

Ecological and Economic Importance of Benthic Communities

among researchers and managers. A sustainable use of the ocean and other aquatic systems, as preconized by the 2030 Agenda for Sustainable Development, particularly the Sustainable Development Goal (SDG) 14 (United Nations 2015), depends on the integrated functioning of all of its components. The benthic compartment must be regarded as a fundamental piece in the proper functioning of such systems.

Classification In order not only to understand the ecological relevance of benthic communities but also to better manage the resources which they represent, it is necessary to recognize how these are compartmentalized. It is possible to frame benthic species within guilds defined by their physical characteristics, their energetic role in the ecosystem or their relationship with the bottom floor. Size Size is perhaps the main trait used to classify benthos. Although apparently arbitrary, this broad classification is partly derived from research or management plans, mostly because monitoring programs imply particular sampling technics for different sizes (Kröncke et al. 2000; Rice et al. 2010) and which are based in the retention of organisms on sieves with different mesh sizes. During their life cycle, several species may be included in different size categories, which increase the complexity in the standardization of this classification. Microbenthos refers to the smallest living organisms living in association with the bottom of aquatic systems, defined as smaller than 0.1 mm, and includes bacteria, diatoms, ciliates, fungi, and protozoans. This is the group less studied (Azovsky et al. 2013), due to the size which is below the detection capacity of the human eye, and inherent difficulties in the identification of the microbiological community. Nevertheless there are recent significant advances in the molecular technology used in the identification of those groups (Crespo et al. 2017). Despite being less scrutinized, they represent a significant amount of

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the benthos biomass (variable according to the substrate type, e.g., as much as 120 mg.cm
2 in the Yellow Sea, Meng et al. 2011) and are responsible for the highest percentage of ecological processes that occur in subaquatic floors (as much as 67% in a temperate estuary, Lillebø et al. 1999). This fraction of the benthos is responsible for fundamental functions such as the final stage of decomposing and nutrient recycling. Some classifications define meiobenthos (also called meiofauna, Zeppilli et al. 2015) as the benthic organisms that fit within 0.1 and 0.5 mm, while others expand the definition to fit sizes between 0.02 and 1 mm (Coull and Chandler 2001; Zeppilli et al. 2015). Regardless the adopted classification, this group includes a diversified assemblage, including unicellular protists and multicellular metazoans, small polychaetes and oligochaetes, nematodes, turbellarians, foraminiferans, and small crustaceans (copepods, ostracodes, cumaceans): it represents the benthic group with the higher diversity (Zeppilli et al. 2015). It can reach abundances as high as 6–12 million individuals m
2 in estuarine muddy soft sediments (Coull and Chandler 2001). Although larger than microbenthic organisms, the study of meiobenthos implies the use of powerful magnification equipment. Like microbenthos, meiobenthos intervene in the recycling of detritus, but they can be predators and are predated by larger benthic organisms. This group represents an important link in the benthic ecology, as its members are known to interact with the microbenthos communities, with positive feedback on their functioning, by performing bioturbation on the aquatic bottom sediments (Zeppilli et al. 2015). The best-studied group of the benthos is macrobenthos (or macrofauna). It includes invertebrates that are larger than 0.5 mm (or 1 mm, depending on the classification) and are the most commonly observed group of animals that live associated with aquatic bottoms. Also, in shallow waters, plants are included in this group and represent a significant amount of benthos biomass (Gage 2001). Macrobenthos gathers distinct groups of invertebrate species, such as bivalves and gastropods, several groups of crustaceans,

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polychaete and oligochaete annelids, anthozoans, echinoderms, sponges, and ascidians (Gage 2001). Several of these animals, especially bivalves or crustaceans, can reach considerable sizes as large as 300 or 400 mm. Density and composition of macrobenthos communities depend on the position on the depth gradient, as well as their dominant life traits (Levin et al. 2000). Most macrobenthos members are suspension- and deposit-feeders, with several species showing flexible feeding behaviors. Nevertheless, carnivores and herbivores are also present within this group (Gage 2001). Vertebrates, such as demersal fishes, can also be included under the macrobenthos definition. Nevertheless, these are usually divided into benthic or bentho-pelagic, respectively, if they are permanently associated with the bottom or not. The concept of megabenthos is less clear than the smaller classes, but it can be considered as the larger subclass within macrobenthos than can be sampled with a beam trawl (Long et al. 1995). This includes, among other, larger decapods, molluscan, ascidian, corals, echinoida, ophiura, and benthic vertebrates, which are highly sensitive to trawling pressure, with hardly reversible consequences (Williams et al. 2010). Macrobenthic communities have been widely used as indicator of environmental quality (Warwick et al. 1987; Gage 2001; Borja et al. 2011) due to reduced motility and relative ease to sample and identify. The effects of pollutants, eutrophication, or other anthropogenic stressors have been analyzed by looking upon changes in the composition and abundance of the communities. Nevertheless, during the last two decades, attention is being paid to the maintenance of functions and ecologic processes that occur within this ecosystem compartment (Solan et al. 2006). Energy Source Another fundamental classification among benthos is related with their energetic position. Primary producers within the benthos are called phytobenthos. The members of this group are able to sequester inorganic carbon and turn it into organic compounds using light energy, by means of photosynthesis, releasing oxygen as a

by-product. These organic compounds are stored within the primary producers and used in the heterotrophic metabolism, routing energy and carbon throughout the remainder of the food webs (Wilkinson 2001). This group is particularly important for the functioning in shallower waters, where the benthic layer is still within the photic zone. Globally, the most abundant group of phytobenthos is algae. Nevertheless, in shallower areas of coastal aquatic systems or in terrestrial water bodies, seagrasses and other macrophytes are important primary producers and ecosystem engineers on subtidal and intertidal areas, where they often form meadows (Short et al. 2017). Some of these habitats (such as saltmarshes/mangroves) are among the most productive in the world, providing shelter, food, and nurseries grounds for several species. Photosynthetic diatoms and bacteria are also included in phytobenthos, the so-called microphytobenthos. Hydrothermal vents, on the deep sea, are completely aphotic areas. Nevertheless, they present biological communities that receive not only the energy input from above but simultaneously depend on chemoautotrophic microbes, which harvest energy by oxidizing hydrogen sulphide, abundant in the vicinities of these hydrothermal vents. These communities were discovered in 1977 and represented a breakthrough because prior to this discovery the scientific community believed that the only source of primary production was photosynthesis (Arp 2001). On the other hand, consumers are included in the zoobenthos. These harvest their energy not only on phytobenthos but also in the plankton and decaying organic matter from the water column above. All benthic animals fall into this category. Zoobenthos can be further divided into categories according to their feeding categories, as suspension and deposit-feeders, carnivores, and herbivores. Nevertheless, more detailed categorization is limited because these guilds often overlap and this fauna can show feeding-behavior flexibility (Gage 2001). The energetic classification is often combined with size categories. Therefore, we may find: microphytobenthos, which includes all the photosynthetic microorganisms (photosynthetic

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diatoms, cyanobacteria, flagellates, and green algae) living in the surface of aquatic sediments; meiophytobenthos and macrophytobenthos, which includes algae and seagrasses. The consumers are also divided accordingly to their sizes: microzoobenthos, meiozoobenthos, and macrozoobenthos. Position Relative to the Surface There is another important distinction among the benthos: organisms can be classified accordingly to their position relatively to the sediment-water interface. The relevance of this classification reflects the organisms’ ability to interact with the sediment and their general feeding guilds. The sediment-water interface represents one of the most abrupt discontinuities in the nature, with sharp transitions on the oxygen and nutrients availability, water accessibility, or, the most obvious, from a highly fluid environment into a disaggregated solid matrix. Nevertheless, some organisms are able to cross this transition and capitalize it, for instance, living inside the sediment and feeding on the surface, or, inversely, living on the surface and feeding on the buried fauna, therefore transferring energy and matter from one compartment to the other. Endobenthos (also known as infauna or endofauna) are the organisms that live buried the sediments (Gage 2001). The organisms included in this group have evolved to cope with the particular conditions that occur inside the sediment. The compactness increases with sediment depth, reducing the water availability and dissolved oxygen. Also, these species have to face the abrasion by sediment particles (Pinet 2003). Several of these animals are tube builders, others live in the particle interstices, and are usually dominated by bivalves and polychaetes (Reiss et al. 2010). These animals are highly intervenient in the remobilization of particles and fluids (bioturbation, see below). Epibenthos (or epifauna) are the organisms that live associated with the surface of the substrate, either on solid or soft bottoms. This group of species has to deal with water movements, such as tidal currents and waves. They could be attached to the substrate by byssal threads, holdfasts, muscular

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feet, or suction cups, or they could be motile. They feed on detritus or they could be predators. They also, at least in the shorelines, must face the risk of desiccation during low tides. The epibenthic communities are usually more diversified than endobenthic communities. Nevertheless, it is estimated that they occupy only 10% of the total benthic zone (Gage 2001). Besides bivalves and gastropods, they include several taxa among crustaceans, echinodermata, anemones, corals, porifera, nemertea, and polychaeta (Reiss et al. 2010; Williams et al. 2010; Kędra et al. 2017). This group has less potential for sediment remobilization than endobenthos; nevertheless their impact must not be neglected, at least in the first centimeter of the sediment. Hyperbenthos usually refers to organisms that swim and live in close relation with the bottom, but not necessarily in permanent contact with it. They are usually fish; nevertheless cephalopods and crustaceans are also included. Both epibenthos and hyperbenthos are highly susceptible to trawl fisheries pressure and similar perturbations of the aquatic floor (Williams et al. 2010).

Patterns of Benthos Distribution The benthic assemblages are influenced by gradients that can be geographic or environmental/ physical. These include, for example, latitude, depth or distance to the shoreline as geographic drivers, and water temperature, salinity, bottom water energy, or turbidity as physical stressors. These are responsible for identifiable small- and large-scale patterns in the composition of the benthic communities. Zonation in Rocky Shores The littoral zones of midlatitudes, especially along the rocky shorelines, are characterized by a marked zonation, also known as vertical zonation, and each of this parallel bands are defined by distinct communities of epibenthic organisms. These bands are controlled by the exposition to air and the tolerance of organisms to desiccation (Pinet 2003). The band closest to the beach, the

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littoral fringe (Raffaelli and Hawkins 1996) is marked by the presence of blue-green algae and Littorina sp. gastropods: this band is exposed to the air most of the time because it is only completed submerged during spring high tides and relay mostly on the splash or spray due to the wave action. This is followed downward by a band of barnacles (Cirripedia) and mussels (such as Mytilus sp.), which is immersed on every tidal cycle, during high tide and is known as eulittoral (Raffaelli and Hawkins 1996). The next band is markedly dominated by seaweeds such as Laminaria sp. and red algae and is called sublittoral fringe (Raffaelli and Hawkins 1996). This last band has short emersion periods, mostly during spring low tides. These communities’ composition and the degree of the variation are determined by the interaction of several factors, such as emersion times, slope of the rocky shore, light exposure and latitude as abiotic drivers, and competition or predation and the species ability to explore micro-niches as biotic drivers (Chappuis et al. 2014). Large-Scale Patterns There are clear large-scale patterns in the structure of benthic communities that could be detected. Epibenthic communities, estimated to cover roughly 10% of the total area, seems more affected by the latitudinal gradient than endobenthos (Gage 2001). Diversity and abundance of the epibenthos reaches its higher values in the tropics while reducing toward the poles. Endobenthos is apparently less affected because at higher depths, where these communities are found, the temperature is more homogenous (Gage 2001). Depth, sediment, and hydrodynamic energy rule the general patterns in the benthic communities’ composition. Nevertheless, these drivers are often disturbed by the presence of seamounts or islands, and, therefore, the effects of local structures on the benthic composition must not be disregarded, as communities are able to explore micro-niches with distinct assemblages within reduced geographic areas. Examples such as the vertical zonation described above must be framed within these larger-scale patterns.

Functions and Ecological Services: The Ecological and Economic Importance of Benthic Communities The United Nations’ 2030 Agenda for Sustainable Development states that its goals can only be achieved if the use and management of natural resources are included in a broader view where its three dimensions – economic, social, and environmental – are integrated in a balanced manner (United Nations 2015). This resolution includes 17 Sustainable Development Goals and the SDG 14 has a particular focus on oceans, seas, and marine resources and aims to their conservation and sustainability. The benthic compartment includes several valued resources and provides fundamental services that are under threat unless caution is taken. Also, the interconnectivity between marine systems implies that the inadequate use of resources of any of the compartments propagates its effects to the remaining ones, therefore impairing the implementation of the SDG 14 (United Nations 2015). The benthic communities represent a fundamental biological component of aquatic systems. The maximum depth of aerobic organisms inside the sediment is defined by the redox discontinuity layer (bellow which anoxic sediments are found), which is often located just a few centimeters below the surface, and therefore, when compared with the water column above, the available volume for organisms is much reduced. Nevertheless, the processes occurring within the benthic compartment are responsible for some of the most important ecosystem functions provided by aquatic systems (Solan et al. 2006). Ecological Relevance The benthos plays fundamental roles in the overall balance within aquatic systems: these communities are essential in the decomposition and recycling of decaying matter (Fig. 1). The combined activity of filter feeders in both macro- and meiobenthos and the final stage of decomposition by microbenthos allow the reentry of nutrients into the food web. For example, coral reefs intervene in fixation of nitrogen in nitrogen-limited waters (Cardini et al. 2016). Also related with

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Biological compartment

Environment Water column

Pelagic community

Benthic community Zoobenthos

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Macro Meio Micro Phytobenthos Macro Meio Micro Sediment

Nutrients and organic matter

Food

Ecological and Economic Importance of Benthic Communities, Fig. 1 Energy and matter transferences on aquatic systems. The interconnectivity among compartments is based on the movement of nutrients and

decaying organic matter, as well as on direct consumption (predation or herbivory) across trophic levels and environments

nitrogen fixation, microbenthos is stimulated by the interaction with macrobenthos (Stief 2013), releasing biologically available nitrogen (in the form of NH4) to the pelagic compartment (Christensen et al. 2000). The presence of macrophytes in shallow waters, in the photic zone, contributes not only for the overall primary production and sequestration of carbon dioxide but also stabilizes unconsolidated sediments when facing currents, reducing erosion, and, as bioengineers, they provide shelter and microhabitats for several species to flourish. Other bioengineers such as corals or bivalves contribute to the diversification of habitats among the benthos, with improvements in the abundance and diversity of biological communities (Lemieux and Cusson 2014). The aquatic systems are compartmentalized; nevertheless the components are not isolated:

this is the underlying idea of benthic-pelagic coupling concept (Fig. 1): there are strong links between the processes that occur in the benthos compartment and the above pelagic system. The benthic zone can have high primary and secondary production rates (Cusson and Bourget 2005), fuelling the remaining aquatic system. The organic matter and nutrients recycling affects not only benthos but also the pelagic compartment. The filtration activity among benthos affects the overall water quality. Therefore, events affecting benthos propagate through the trophic web, affecting aquatic ecosystems as a whole. There is an ecological process occurring among benthos that sustains several ecosystem functions, which is bioturbation. This was defined as all transport processes carried out by animals that directly or indirectly affect sediment matrices (Kristensen et al. 2012). The intensity of

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bioturbation depends not only on the abundance but also on the composition of benthic communities and affects the balance of pH, nutrients, salinity and oxygenation of both sediments and water column, as well as the rate of decomposition and benthic metabolism. Economic Value Beside the importance of the ecological functions, which support many ecosystem services such as nutrient recycling, primary and secondary production, water quality maintenance, or erosion prevention, there are direct values associated with benthos communities. Ecosystem services, which are the benefits offered by natural systems to human populations, are extremely complex to estimate (Costanza et al. 2014). Nevertheless, several of those services cannot be replaced by human endeavor. The loss of those services and functions will have severe consequences on the overall human well-being, with significant costs related with the mitigation/adaptation to those circumstances. The use of benthic communities as proxy for environmental quality instead of more costly surveys can be also included as an important economic asset (Warwick et al. 1987; Gage 2001). More direct and discernible goods are also provided by benthos. Benthic communities are usually explored for valued species, such as bivalves, lobsters, shrimps, or benthic fishes, for human consumption. Also, polychaetes are often used as bait in recreational fisheries. The health status of the benthic compartment will affect the trophic web, with repercussions, for example, among demersal fisheries.

Threats to Benthic Biodiversity Usually sessile or with reduced motility, benthic organisms are unable to escape in the presence of unfavorable conditions. Therefore, environmental changes are highly impacting on these communities, with extinction events becoming more frequent and impairing the overall ecosystem function within aquatic systems, especially on larger species (Payne et al. 2016).

Benthic species are highly susceptible to the mechanical perturbation of sediments, such as raking, trawl fisheries, dredging, or construction of structures in the sea (Williams et al. 2010): the effects of those activities are even more deleterious in habitats that are based in large biogenic structures such as coral reefs, or bivalve and seagrass beds (Dernie et al. 2003). Fishing is, actually, one of the most relevant stressors on benthic communities (Payne et al. 2016). Changes in water quality due to the increase of pollutants or toxins have significant impacts in filter-feeder organisms, with consequences that propagate throughout the trophic web. Nutrient enrichment/eutrophication often affect benthic diversity, especially in coastal, shallow waters where the consequences of micro- and macroalgal blooms are notorious (Lopes et al. 2000; Rabalais et al. 2009). Ocean acidification is described to affect benthic species that create biogenic carbonate structures, such as molluscan shells or corals (Caldeira and Wickett 2003; Zeppilli et al. 2015) as well as affecting the species interactions (Gaylord et al. 2015). Global warming and thermal pollution, similarly to ocean acidification, are responsible for modified species interactions (Gaylord et al. 2015). Nevertheless, these have physiological consequences on benthic species, especially in coastal areas where abrupt shifts in the thermal conditions are less buffered, originating catastrophic events (Coma et al. 2009). Invasive species are known to have deleterious effects among the invaded communities. Also, biological invasions are often human-mediated: therefore, the effects of biological invasions appears to be more relevant in coastal waters, where the bulk of the activities responsible for the introduction of non-native species take place (Ruiz et al. 1997; Zeppilli et al. 2015). Aquaculture represents an additional stress to benthic communities, especially near the coast, where this activity enhances some of the aforementioned threats. Is it often associated to the introduction of non-native economically valued species that, in some cases, are able to escape confinement and act as invaders. Also, aquaculture is responsible for the artificial nutrient-enrichment of sediments and water, with the risk of eutrophication hazards due to the

Ecological and Economic Importance of Benthic Communities

wastes (Zeppilli et al. 2015). Additionally, the industry of aquaculture depends on the use of pharmaceutical products to ensure productivity, which are released into the environment along with waste water and deposits, with consequences for the benthic and other aquatic communities (Leston et al. 2013).

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Cross-References ▶ Metal Contamination in Marine Resources ▶ Metazoan Meiofauna: Benthic Assemblages for Sustainable Marine and Estuarine Ecosystems ▶ Role of Microphytobenthos in the Functioning of Estuarine and Coastal Ecosystems ▶ Saltmarshes: Ecology, Opportunities, and Challenges

Knowledge Gaps Despite a profound general knowledge of some of the benthic communities around the globe, there are much more to investigate and to focus on. Several communities have been well scrutinized on their members, their ecology, and threats they face. Nevertheless, the largest part of these studies addresses nearshore areas, or coastal systems. There are vast sections in the deep ocean that remains under profoundly unknown: this means that there is potentially an almost infinite work to do in terms of taxonomy and ecology. There is still work to do on the complexity of trophic webs in marine sediments, especially among the smaller size classes, due to the difficulty in the manipulation and visualization of the individuals. Noise pollution is not a recent concern among marine ecologists, but the idea that benthic communities may be affect by noise is only now starting to receive the proper attention. The question on how the benthic communities are affected by the anthropogenic pressures and how this affects the remaining aquatic systems has received an important awareness increase in recent years. Nevertheless, the number of possible scenarios is far from being all tested. The predictive power of models will benefit from a more thoroughly assessment on the communities’ response to those anthropogenic stressors, allowing better management of these resources for the near future. Recognizing the importance of these ecological compartments to the overall functioning of ecosystems must be enhanced, which is only possible by increasing the knowledge of the benthic communities.

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Ecology of Marine Fish Larvae Sigman DM, Hain MP (2012) The biological productivity of the ocean. Nat Educ 3:1–16 Solan M, Raffaelli D, Paterson DM et al (2006) Marine biodiversity and ecosystem function: empirical approaches and future research needs. Mar Ecol Prog Ser 311:175–178 Stief P (2013) Stimulation of microbial nitrogen cycling in aquatic ecosystems by benthic macrofauna: mechanisms and environmental implications. Biogeosciences 10:7829–7846. https://doi.org/10.5194/bg-10-78292013 United Nations (2015) Transforming our world: the 2030 Agenda for Sustainable Development. A/RES/70/1 Warwick RM, Pearson TH, Ruswahyuni (1987) Detection of pollution effects on marine macrobenthos: further evaluation of the species abundance/biomass method. Mar Biol 95:193–200. https://doi.org/10.1007/ BF00409005 Wilkinson M (2001) Phytobenthos. In: Steele J, Thorpe SA, Tukerian KK (eds) Encyclopedia of ocean sciences. Academic Press – Elsevier, Oxford, pp 2172–2179 Williams A, Schlacher TA, Rowden AA et al (2010) Seamount megabenthic assemblages fail to recover from trawling impacts. Mar Ecol 31:183–199. https://doi. org/10.1111/j.1439-0485.2010.00385.x Zeppilli D, Sarrazin J, Leduc D et al (2015) Is the meiofauna a good indicator for climate change and anthropogenic impacts? Mar Biodivers 45:505–535. https://doi.org/10.1007/s12526-015-0359-z

Ecological Indicators ▶ Metazoan Meiofauna: Benthic Assemblages for Sustainable Marine and Estuarine Ecosystems

Ecology of Marine Fish Larvae Ana Lígia Primo Centre for Functional Ecology – Science for People and the Planet, Department of Life Sciences, University of Coimbra, Coimbra, Portugal

Synonyms Fish early life stages; Fish egg; Ichthyoplankton; Transitional forms

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Definitions Fish larvae are early life stages of fish and, together with fish eggs, comprise the ichthyoplankton fraction of plankton (Fig. 1). Due to their null or limited swimming ability, they are included within the meroplankton, the organisms that only spend part of their life cycle within the plankton. This stage usually lasts from a couple of weeks to a few months (Russell 1976; Victor 1986). The larval stage of fish includes stages from hatching until juvenile and can show distinct shapes according to their adaptation to habitats. Marine fish larvae are mainly pelagic and found in the upper layers (from 200 m depth to the surface) of the water column and their presence reflects nearby spawning areas. From an initial batch of millions of eggs, only a limited number of larvae survive. They can be dispersed to unfavorable areas and die of starvation or be predated before reaching the juvenile stage. Fish larval abundance and survival rate can be closely related to adult population size and spawning stock biomass, thus ichthyoplankton surveys are often a component of fisheries management.

Introduction The general terminology of planktonic development of fishes includes the “egg stage” and the “larval stage.” The “egg stage” encircles from spawning to hatching. Eggs are usually small (until 1.5 mm in diameter), transparent, and practically spherical; they are composed by an outer porous membrane, the chorion, perivitelline space, and yolk. The state of development at hatch varies from species to species, water temperature, size of the egg, and the amount of yolk. Longer development will result in more advanced larvae at the hatch (Blaxter 1969; Moser 1984). A transitional stage of “yolk-sac larvae” if often recognized. At this point larvae present a yolk sac on the anterior ventral side of the body, which ensures larvae nutrition until the development of the functional mouth. The presence and position of oil globules can be of diagnostic value in this stage, as well as the shape and size of the

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Ecology of Marine Fish Larvae

Ecology of Marine Fish Larvae, Fig. 1 Ichthyoplankton (fish eggs and larvae) sample

yolk sac itself and the position of the anus. Also, the occurrence of black melanophores and other colored pigmentation on the body, primordial fin, yolk sac and/or oil globe can be a further help in identification. Generally, these larvae hatch with unpigmented eyes and the body is fringed with a marginal primordial fin, which present no fin rays. Several species are able to delay the hatch until the yolk sac is absorbed, as occurs with salmonids, which larvae transform directly in juvenile (Kendall Jr et al. 1984; Fuinmann 2002). During the “larval stage” the fish gradually assumes the adult characters. The flexion of the notochord and the hypochordal development are the most fundamental events on the development, allowing larvae to improve locomotive ability and feeding techniques. Thus, this stage is often subdivided into preflexion, flexion, and postflexion. The ossification and development of the fin rays starts also during this phase. Usually, body shape and size, pigmentation patterns, presence of spines, number of rays and vertebrae, and gut length and shape are useful diagnostic features for family/genus/species (Kendall Jr et al. 1984; Moser 1984; Fuinmann 2002). Before the juvenile stage, a transitional stage called “transformation stage” can also be recognized. Morphologically the transformation stage is characterized by getting juvenile-adult body form and characters. This stage can be abrupt or prolonged and, in several species, is accompanied by a change from habits (pelagic/demersal) and/or habitat, since migration to a “nursery” ground also

occurs during or just before this stage. Changes that occur during this stage include pigment pattern, body shape, fin migration (e.g., in clupeids and engraulids), photophore formation, loss of elongate fin rays and head spines (e.g., in epinepheline serranids and holocentrids), eye migration (pleuronectiforms), and scale formation; this process is often named metamorphosis. The metamorphosis marks the end of the larval stage, after which, the fish has full organ development and will attain juvenile body proportion (Kendall Jr et al. 1984; Fuinmann 2002).

Diet Composition of Marine Fish Larvae In 1914, Hjort’s Critical Period Hypothesis recognized that larvae can survive for only a brief period without food after their supply of yolk and oil globules is gone and that the natural abundances of their food vary greatly in space and time (Hjort 1914). Ideally, marine fish larvae consume more than 50% of their body weight, but some species of the warm seas, like tunas and anchovies, need to consume more than 100%. The main prey for larval fish is zooplankton between 50–100 mm width since the maximum prey size that can be ingested is limited by their mouth size. Copepod nauplii is the most common prey for small fish larvae; however, they also feed on a variety of small planktonic organisms as phytoplankton and protozoans (Houde 2001); exception to the copepods preys include appendicularians,

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other larval fish (including cannibalism), and mollusk larvae. Larvae tend to be more euryphagous during the earliest stages due to the existence of a greater variety of organisms of the proper size. As they grow larvae specialize in preys that are more nutritionally advantageous. Yet some species seem to survive by just eating large amounts of small preys, their growth is compromised (Hunter 1981). Most feeding occurs at daylight but for fish larvae light intensity threshold to feed is equivalent to dusk/dawn. They are visual predators and need to be in proximity to their preys. For early larvae, the detection and capture of prey is highly dependent on encounter opportunities but as swimming capacity improves, the larvae actively search for food and the maximum reaction distance increases (Blaxter 1986). As a result, initially, the ability of the fish larvae to survive starvation is very low, increasing as they grow with the development of sensory organs and swimming capacity. Fish larvae diet composition studies have traditionally relied on stomach content analysis, focusing in the animal’s diet over the last few hours. Stable isotope analysis (SIA) has gained popularity as a less time consuming and complementary technique. SIA is based on the bioaccumulation of heavier isotopes along the food web, nitrogen (δ15N) and carbon (δ13C) being commonly used for estimating, respectively, the consumer trophic level and carbon sources. It reflects species diet over the previous weeks/months being a useful tool for gaining additional insight into feeding relationships and changes therein (Michener and Kaufman 2007). The amount and the quality of prey ingested will be fundamental for a successful larval development and survival. Larvae in better condition are presumably less likely to die of starvation or predation, since nutritional standing and energy storage act as buffers against environmental variability. The RNA:DNA ratio has been widely used as nutritional condition indicator of fish larvae. This ratio reflects variations in protein synthesis rates and organisms in good condition tend to have higher ratios than do those in poor condition and have been used to predict reliable survival probabilities.

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Fish Early Life Stages Mortality Mortality rates of marine fish in pelagic ecosystems are strongly size-dependent. Natural mortality rates of fish are maximum during early life stages, decreasing from larvae to juvenile and stabilizing after maturity. Mortality estimates for marine fish larvae can be equivalent to 21.3% day
1 so, from a cohort of one million larvae under average mortality conditions and larval stage duration, only 180 individuals are expected to survive the larval stage (99.9%). For freshwater species, mortality is usually lower (14.8%) due to their bigger average size and lower predation pressure. Long-lived fishes have lower natural mortality rates that short-lived species and the knowledge of the population mortality rates’ is fundamental to study impacts of man-induced mortality, like fishing. Although sources of early life mortality can act independently (e.g., episodic events), most interact in complex ways making it difficult to estimate mortality rates with accuracy and precision. General catch-curves (abundances vs ages) in early life are usually known but can seldom be assessed with confidence. Successful estimation of mortality rates increase in environments where dispersal losses are minor or can be accounted by sampling the entire system (e.g., embayments, estuaries) (Houde 2002). Feeding conditions are intrinsically linked with fish larvae growth, mortality, and survival which can cause major changes in the recruitment levels. Larvae that experience superior feeding conditions, by association with areas/times of enhanced food abundance, exhibit faster growth, and higher survival increasing recruitment success, the socalled “growth-mortality” hypothesis (Anderson 1988; Hare and Cowen 1997). The paradigm can be explained by three different factors: size (body size), time (stage duration), and growth rate (per se rate). The size-based concept has been labeled as “bigger-is-better” hypothesis and suggests that larger larvae are less vulnerable to predation (Miller et al. 1988). The “stage duration” hypothesis postulates that faster growth reduces the high mortality larval period (Houde 1987). Finally, faster-growing larvae are less vulnerable to predation thus growth rates have direct impacts on

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mortality, independently of both size-selective mortality and stage duration, the so called “growth-selective predation” hypothesis. Summarizing, the main causes of early life mortality include the following: Starvation and nutritional conditions: The Critical Period Hjort’s Hypothesis arose from laboratory observations of massive deaths right after the yolk-sac absorption (Hjort 1914). Temporal and spatial match between larval hatching and their planktonic prey are fundamental to several recruitment variability hypotheses with strong proven evidence (see below). Starvation and nutrition-related mortalities will selectively remove poorly nourished larvae which are highly vulnerable to predation (Leggett and Deblois 1994; Houde 2002, 2008a, b). Predation: Organisms that prey on larval fishes include juvenile and adult fishes (cannibalism), jellyfishes (ctenophores and medusa), and chaetognaths. Eggs and larvae are usually predated by active pursuit, ambush, or filtering and their susceptibility to predation is domeshaped in relation to size. Once the larvae grow and start to improve their skills to detect predators and swimming abilities they are less vulnerable to be predated (Houde 2008a; Leggett and Deblois 1994). Transport, retention, and dispersal: Due to their size and reduced movement capacity, fish larvae are strongly exposed to water movements. Often, their survival depends on their dispersion and transportation to favorable environments, as well as, retention mechanisms within. Atypical transport or poor retention will lead to high mortality (see below) (Houde 2002, 2008a).

Assessing Fish Larvae Age and Growth Patterns The growth of fish influence population dynamics by affecting survival and even fecundity. The greater weight increase (i.e., growth) occurs during the larval phase, denoting that important recruitment regulation occurs via growth variability at this stage (Jones 2002). Fish that grow faster are more

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likely to survive because they reach larger size sooner, increasing swimming ability, food capture, and escape from predators – “growth-mortality” hypothesis (Anderson 1988; Hare and Cowen 1997). Thus, a population of faster growing individuals will experience a lower cumulative mortality than a slower growing one. Initially, size differences were used as a proxy for age and fisheries scientists aged group of fish by length-frequency analysis. Later, the discovery of annuli in hard parts like otolith, scales, fin rays, and spines had a significant impact, allowing to age individual adult fish. However, the most important discovery in measuring survival in larval fishes was the development of the daily age techniques in the 1970s. Then, scientists found that, in addition to annual marks, otoliths have daily ring marks, enabling to age fishes before completing 1 year of age. Since then, the daily pattern of otolith marks had been validated for several larvae and juvenile species. Since calcification occurs only after complete metamorphosis, the use of fin rays and spines for aging larvae is not possible, thus otolith microstructure prevails (Campana and Neilson 1985; Jones 2002). Scientists use age to assess growth rates, survival, and hatch dates. Age is determined by counting daily rings (light plus a dark band) beginning from hatch/yolk absorption marks till the otolith edge. Hatch date can then be calculated by subtracting the age to the date of capture. Also, growth rates can be determined by measuring the width of the bands (Campana and Neilson 1985). Combined with length and weight, fish age can provide information on stock composition, age at maturity, life span, mortality, and production. Spawning locations, transport, and migrations to nursery grounds can also be inferred analyzing otolith microstructure and microchemistry, as well as transition phases in the early life. Growth during the larval period can be influenced by external factors as food, temperature, and salinity and by endogenous factors like genetics and maternal contribution (Houde 2001). Temperature is a key factor affecting larvae growth directly but also indirectly by influencing the amount of food needed by larvae, as well as its availability. Generally, growth rates are slower at

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colder temperatures, maximum at intermediate temperatures, and drop with above optimal temperatures. Cumulative effects of endogenous and exogenous factors increase variability in larval size as they age. This growth depensation phenomenon is important to survival since larvae mortality is strongly size-dependent (Jones 2002; Sogard 1997). As larvae growth, the body increases both length and weight. Differences in body proportions have wide use in adult fishes to identify subpopulations of a species. When the ratio of body depth and length remains the same along the fish growth, it is referred as isometric. When growth of one body part in faster/slower than other, growth is referred as allometric. For adults, fish biomass is often determined in function of its length, however for larvae this relation is not so straightforward since larvae present different development patterns and experience lower/ higher body changes. However, the relationship between body size and otolith size is one of the most useful to study larval ecology. Otolith metrics can be used to reconstruct larvae growth history, as growth rates. With this information, scientists can determine size-selective mortality or the effects of environmental condition on growth, among others (Jones 2002).

Fish Larvae Abundance and Recruitment Variability Abundances of fish populations can differ over time from five-to-ten-fold orders of magnitude and recruitment variability plays an important role in these fluctuations. Recruitment can be defined as the number of fish surviving to enter the fishery or to some life history stage such as settlement or maturity. Deficient knowledge about recruitment variability has been recognized as the main gap in fisheries science. This is because it is a complex process affected by the offspring abundance and density-independent and dependent processes occurred afterward. Substantial advances have been made in understanding recruitment variability due to the development of new technologies, analytical tools, and models.

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Some of these include: otolith aging and chemical analysis, molecular genetic approaches, acoustic and video tools, and statistical and time series analysis (Houde 2008a). It is well known that recruitment success is related to mortality during early life stages, as eggs, yolk-sac larvae, larvae, and juveniles. Throughout the years, several hypotheses have been proposed to explain larval survival and recruitment success. The Critical Period Hjort’s Hypothesis reports that more than 90% of the mortality occurs soon after larvae absorb their yolk and initiate exogenous feeding (Hjort 1914). Accordingly, larvae survival would be limited by the levels of available prey emphasizing larval nutrition and starvation as key factors on the recruitment variability. However, several studies soon showed that this was insufficient to explain recruitment variability and other recruitment hypotheses arose. As an extension of Hjort’s, the “Match-Mismatch” hypothesis (Cushing 1974) states that a match in timing of fish spawning and larval production with the spring zooplankton bloom, i.e., larval prey, is critical for larvae survival. A mismatch between predator/prey abundance will result in year-class failure. The matchmismatch dynamics has strong evidence in high latitude seas being the main mechanism supporting cod recruitment in Norwegian Arctic and in the North Sea (Ellertsen et al. 1989; Beaugrand et al. 2003). Others hypothesis go beyond the food-mediated mechanisms and link larval survival with the surrounding environment. The “Stable Ocean” hypothesis (Lasker 1978) highlights the importance of calm periods in upwelling ecosystems that increase aggregation of fish larvae and prey, as occurs with northern anchovy (Engraulis mordax) (Peterman and Bradford 1987). Also, the “Optimum Environmental Window” proposes that recruitment in upwelling ecosystems is domeshaped being most successful under moderate wind stress (Cury and Roy 1989). Sardine and anchovy recruitments in Ekman-type upwelling areas support this hypothesis. Furthermore, Iles and Sinclair (1982) hypothesized that physical retention of early-life stages is critical in the recruitment process (“Larval Retention/Membership-

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Vagrancy”), as in the case of the Atlantic herring (Clupea harengus) where spawning apparently is keyed to physical features associated with retention instead of plankton productivity. Larval fish distribution, abundance, and survival is controlled by both biotic and abiotic factors. Biotic factors can include: adult spawning condition, behavior and abundance; environmental optima and tolerances; presence of suitable food and potential predators; and larval behavior. On the other hand, physical factors include temperature, salinity, vertical and horizontal gradients in water density, turbidity, and water current speeds and directions. Hence, processes emphasized in each hypothesis may work simultaneously or sequentially to determine recruitment (Houde 2008a).

Ichthyoplankton Surveys and Assemblages Since the year-class strengths and population dynamics are regulated during early life stages, research into the patterns of early development and survival will improve understanding and predictability of recruitment. For that fish larvae need to be sampled in their natural habitat. Ichthyoplankton is generally collected by research vessels towing with fine mesh nets. Neuston nets are used for sampling just below the surface. MOCNESS and Tucker nets use Ecology of Marine Fish Larvae, Fig. 2 Ichthyoplankton net (WP3) collecting samples

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multiple nets that open and close at different depths to access vertical distribution. Ring and bongo nets are attached to circular frames (one or two, respectively) and can be towed horizontally at different depths, vertically or obliquely. Fish eggs are collected using a specific net, the CalVET/PAIROVET, that was first designed by The California Cooperative Oceanic Fisheries Investigations (CalCOFI) to estimate anchovy and similar species egg production in the 1980– 1985 period. Besides towing, samples can also be collected by light traps, a method widely used at coral-reefs or by plankton pumps, like the Continuous Underway Fish Egg Sampler (CUFES). After sampling, organisms are retained in the cod end of the net, collected and placed in preservative fluid prior to analysis (Fig. 2). An ichthyoplankton assemblage is a group of species whose eggs and larvae are collected in the same area and at the same time. Assemblages have no strict limits on the spatial or temporal scale. But it is acceptable to speak of the assemblage in a single season and/or region. Main difference with the other branches of ecology is that ichthyoplankton assemblages are transient since it is restricted to a specific period of fish life cycle. Often, juvenile and adult phases of the species present in an ichthyoplankton assemblage do not interact (Miller 2002). With the purpose of identifying ichthyoplankton assemblage, the distribution of eggs and

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larvae must be compared between locations and/ or time. Often, assemblages can be distinguished simply by the presence and absence of species but the majority includes abundance data. An overlap in space and time indicate that species share the same assemblage. This can be the starting point to explore, not only species relationships, but also their relationship with the surrounding environment. Nowadays, more advanced tools are available and studies explore patterns in structure, duration, and extent of the assemblages with clusters and ordination analysis. The formation, maintenance, and disruption of the larval fish assemblages are regulated by physical and biological processes (Boehlert and Mundy 1993). Physical processes are responsible for most large spatial differences between assemblages. In the inability of water masses with different densities to mix, due to the absence of energy sources like wind and tides, they become distinct (Miller 2002). Studies have identified distinct ichthyoplankton assemblages between oceanic and shelf, or between near-shore and estuarine, with differences in the water masses as the proposed mechanisms responsible for the assemblage formation (Cowen et al. 1993). To belong to the same ichthyoplankton assemblage, species must have similar spawning behavior of adults, which is seasonal for most of the species or with synchronous single events (Boehlert and Mundy 1993). Fishes must spawn in the right place and time to maximize survival. So, the location of release reflects favorable hydrography for survival, while time match with adequate abundances of the larva’s principal food resources (Houde 2008a, b). Processes affecting maintenance of the assemblage are more likely to operate at a smaller scale. These include upwelling, that due to the high advection (consistent and prolonged) ensures that the assemblage maintain its integrity, or gyres, eddies, and convergent fronts that concentrate passive particles. On the other side, the principal biological processes supporting maintenance of assemblages are those that promote larval growth and survival like feeding success or behavior (responses to common environment, foraging, swimming) (Miller 2002).

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The dynamic nature and typical distribution of fish larvae represents a challenge to identify ichthyoplankton assemblages. It requires intensive sampling efforts and the characterization of infrequent events. New techniques can offer hope for the future but it seems fundamental to increase the knowledge of multiple assemblages, since comparative studies provide responses to different constraints.

Fish Larvae Transport, Aggregation, and Retention Mechanisms A successful transport and retention of fish eggs and larvae ensures that a sufficient amount of offspring survives and remains in the geographic areas of their populations. Marine abrupt topographies, like shelf breaks, seamounts, and canyons, generate physical processes that increase larvae aggregation, retention, and/or dispersion (e.g., gyres, upwelling, currents fronts). These areas are often spawning areas of fish with pelagic eggs and larvae and are characterized by high productivity (Genin 2004; Mann and Lazier 2006). Fronts are boundaries and discontinuities at the sea in which circulation patterns promote particle aggregation, retention, and facilitation of predator–prey interactions. They can be permanent, predicted or variable and act at many spatial scales. At the macroscale, the Eastern Boundary Currents are responsible for the major upwelling systems along the west coasts of continents and represent one of the most productive areas responsible for the recruitment of several of the most exploited fisheries resources. At the meso-scale, gyres and eddies have proven to present the ideal conditions for larval growth of several fish species around the world. Examples of small-scale frontal features are tides, river-plume, estuarine turbidity maxima, and vertical stratification (Houde 2008a; Mann and Lazier 2006). Larval distribution patterns may reflect larval behaviors interacting with circulation features acting locally. Despite their planktonic nature, fish larvae perform vertical migrations that can range over tens of meters and this ability changes along their ontogenetic development. This allows larvae to take advantage of currents to transport to or

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retain in favorable areas, escape from predators, follow their food distribution, and avoid poor water conditions (Houde 2001). The mechanism how fish larvae vertical movements affect their entrance/retention in estuarine systems is well documented. By means of “selective tidal stream transport” larvae coordinate vertical migrations with tides and currents to ensure transport and retention into nursery areas (Epifanio and Garvine 2001). This mechanism is also important for continental shelf nursery areas affected by upwelling events. During these events, the offshore transport at the surface and the onshore transport of deeper living larvae are favored while upwelling relaxation favors larval retention and concentration in coastal waters. The larvae diel vertical movements act as a retention mechanism during upwelling – during night larvae at surface are transported to offshore but, by adjusting their depth, during day they return to nearshore (Farrell et al. 1991; dos Santos et al. 2008). Likewise, coral reef fish larvae are capable of adjusting their depth when in the presence of vertical stratified water column, thus avoiding advective loss and promoting selfrecruitment (Paris and Cowen 2004). Transport and connectivity between habitats has been a major focus in the past decade, however larval dispersion is hard to study, due to their size. Physical modeling, chemical tracking, and genetic approaches have represented a fundamental progress to understand fish larval and population dynamics. This knowledge represents an important contribution to the management of fisheries resources, design of marine reserves, and prediction of climate-change effects.

Applications to Fisheries Management A major goal of scientists and fishery managers is to forecast recruitment, being often referred to as “the Holy Grail of fisheries science.” In this way, knowledge of the abundances and variability in earliest life stages represent a fundamental role. Ichthyoplankton surveys, data analysis, and modeling will increase our understanding of the processes that control and regulate recruitment, thus contributing to a successful forecasting.

Ecology of Marine Fish Larvae

Ichthyoplankton surveys have been conducted worldwide and have been used to examine species spatial and temporal distributions, community structure, trophic links, age and growth, and relationships with environmental conditions. Before 1900, ichthyoplankton surveys focused mainly on sampling eggs and larvae, and on experimental rearing and release at sea. From 1900 to 1950, most studies were conducted by the International Council for the Exploration of the Sea (ICES) at the North Sea with focus on fish stock fluctuations, increasing significantly the state of knowledge for that region. About the same time, similar research began at the Northwest Atlantic, Mediterranean Sea, and a little bit around the world. Later, larvae of many oceanic fishes were described based on collections of the worldwide Dana expeditions. Some of these studies continued till now and these long-term surveys represent important contributions to the knowledge of the ichthyoplankton communities and fisheries resources of the studied areas (Houde 2008a, b). Ichthyoplankton research has allowed the development of a detailed knowledge of the life history cycles of commercially, recreationally, and ecologically important fish stocks. Temporal and spatial distribution of fish larvae and eggs can identify species spawning period and location as well as nursery areas and their environmental characterization, highlighting also the importance of the connectivity between spawning and nursery grounds on the species recruitment. Insights gained from ichthyoplankton surveys have been used to develop individual-based models (IBMs) coupled with hydrodynamic models, allowing to test through experimental simulation, various hypotheses concerning transport, physical and biological parameters (Houde 2001; van der Lingen and Huggett 2003). A major application of ichthyoplankton research is the estimation of spawning stock biomass (SSB) by mean of the daily egg production method (DEPM), allowing the prediction of future species recruitment success. These results have also been used to calibrate relative estimates of fish biomass made using other methods (e.g., hydroacoustic). Lately, larval fishes have also been studied as indicator of potential ocean changes allowing researchers to predict

Ecology of Marine Fish Larvae

the impact of climate variability on fish stocks (van Damme et al. 2009; van der Lingen and Huggett 2003). Studies such as these, in conjunction with continued research about trophic interactions, mortality, growth, and environmental connectivity, could bring us closer to solving the recruitment problem, thus it is fundamental to increase the knowledge about the relations between environment, SSB (Standing Stock Biomass), ichthyoplankton production, juvenile survival, and recruitment. All these examples demonstrate that ichthyoplankton surveys have made a substantial contribution toward identifying key mechanisms impacting recruitment success and hence management of fish stocks.

Marine Fish Larvae Importance on SGD14 The Sustainable Development Goal 14 of the United Nations Agenda for 2030 focuses on the conservation and sustainable use of oceans, seas, and marine resources. Since it is strongly related to recruitment and spawning stocks biomass, the information provided by marine fish larvae ecology can be incorporated into single-species and ecosystem-based models to regulate commercially and ecologically important stocks or/and to predict the spawning success of species. Thus, marine fish larvae knowledge contributes to implement science-based management plans, regulating harvesting and overfishing in order to restore fish stocks and contribute to a more sustainable use of oceans. Furthermore, studies on ichthyoplankton distribution and larvae dispersion/retention patterns are of critical importance to the establishment of marine protected areas, often fundamental to sustainably manage and protect marine and coastal ecosystems and achieve healthy and productive oceans, the key component of SGD14.

Cross-References ▶ Concepts of Marine Protected Area ▶ Estuary

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▶ Fisheries Management: An Overview ▶ Nursery Areas for Marine Fish

References Anderson JT (1988) A review of size dependant survival during pre-recruit stages of fishes in relation to recruitment. J Northwest Atl Fish Sci 8:55–66 Beaugrand G, Brander KM, Lindley JA, Souissi S, Reid PC (2003) Plankton effect on cod recruitment in the North Sea. Nature 426:661–664 Blaxter JHS (1969) Experimental rearing of pilchard larvae, Sardina pilchardus. J Mar Biol Ass UK 49:557–575 Blaxter JHS (1986) Development of sense organs and behavior of teleost larvae with special reference to feeding and predator avoidance. Trans Am Fish Soc 115:98–114 Boehlert GW, Mundy BC (1993) Ichthyoplankton assemblages at seamounts and oceanic islands. Bull Mar Sci 53:336–361 Campana SE, Neilson JD (1985) Microstructure of fish otoliths. Can J Fish Aquat Sci 42:1014–1032 Cowen RK, Hare JA, Fahay MP (1993) Beyond hydrography: can physical processes explain larval fish assemblages within the Middle Atlantic Bight? Bull Mar Sci 53:567–587 Cury P, Roy C (1989) Optimal environmental window and pelagic fish recruitment success in upwelling areas. Can J Fish Aquat Sci 46:670–680 Cushing DH (1974) The natural regulation of fish populations. Pp. 399-412. In: Harden Jones FR (ed) Sea fisheries research. Wiley, New York dos Santos A, Santos AMP, Conway DVP, Bartilotti C, Lourenço P, Queiroga H (2008) Diel vertical migration of decapod larvae in the Portuguese coastal upwelling ecosystem: implications for offshore transport. Mar Ecol Prog Ser 359:171–183 Ellertsen B, Fossum P, Solemdal P, Sundby S (1989) Relation between temperature and survival of eggs and firstfeeding larvae of Northeast Arctic cod (Gadus morhua L.). Rapports et Proces-Verbaux des Reunions Conseil International pour l’Exploration de la Mer 191:209–219 Epifanio CE, Garvine RW (2001) Larval transport on the Atlantic continental shelf of North America: a review. Estuar Coast Shelf Sci 52:51–77 Farrel TM, Bracher D, Roughgarden J (1991) Cross-shelf transport causes recruitment to intertidal populations in Central California. Limnol Oceanogr 36:279–288 Fuinmann LA (2002) Special considerations of fish eggs and larvae. In: Fuiman LA, Werner RG (eds) Fishery science. The unique contributions of early life stages. Blackwell Science Ltd., Oxford, pp 1–32 Genin A (2004) Bio-physical coupling in the formation of zooplankton and fish aggregations over abrupt topographies. J Mar Syst 50:3–20 Hare JA, Cowen RK (1997) Size, growth, development, and survival of the planktonic larvae of Pomatomus

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332 saltatrix (Pisces: Pomatomidae). Ecology 78: 2415–2431 Hjort J (1914) Fluctuations in the great fisheries of northern Europe viewed in the light of biological research. Rapport et Proces-Verbaux des Reunions Conseil International pour l’Exploration del la Mer 20:1–228 Houde ED (1987) Fish early life dynamics and recruitment variability. Am Fis Soc Symp 2:17–29 Houde ED (2001) Fish larvae. In: Steele R, Thorpe SA, Tukekian KK (eds) Encyclopedia of ocean sciences. Academic Press, London, pp 381–391 Houde ED (2002) Mortality. In: Fuiman LA, Werner RG (eds) Fishery science. The unique contributions of early life stages. Blackwell Scence Ltd., Oxford, pp 64–87 Houde ED (2008a) Recruitment variability. In: Jakobsen T et al (eds) Fish reproductive biology and its implications for assessment and management. Wiley-Blackwell, Oxford, pp 98–187 Houde ED (2008b) Emerging from Hjort’s shadow. J Northw Atl Fish Sci 41:53–70 Hunter JR (1981) Feeding ecology and predation of marine fish larvae. In: Lasker R (ed) Marine fish larvae. Morphology, ecology and relation to fisheries. University of Washington Press, Seattle, pp 34–77 Iles TD, Sinclair M (1982) Atlantic herring: stock discreteness and abundance. Science 215:627–633 Jones C (2002) Age and growth. In: Fuiman LA, Werner RG (eds) Fishery science. The unique contributions of early life stages. Blackwell Science Ltd., Oxford, pp 33–63 Kendall Jr AW, Ahlstrom EH, Moser HG (1984) Early life history stages of fishes and their characters. American Society of Ichthyologists and Herpetologists, Special publication 1. (eds HG Moser, WJ Richards, DM Cohen et al.), Allen Press, Lawrence, KS, pp 11–25 Lasker R (1978) The relation between oceanographic conditions, and larval anchovy food in the California current: identification of factors contributing to recruitment failure. Rapport et Proces-Verbaux des Reunions Conseil International pour l’Exploration de la Mer 173:212–230 Leggett WC, Deblois E (1994) Recruitment in marine fishes: is it regulated by starvation and predation in the egg and larval stages? Neth J Sea Res 32: 119–134 Mann, K.H. and Lazier, J.R.N. (2006) Dynamics of marine ecosystems. Biological-physical interactions in the oceans., Blackwell Science, Oxford. 496 pp Michener RH, Kaufman L (2007) Stable isotope ratios as tracers in marine food webs: an update. In: Michener R, Lajtha K (eds) Stable isotopes in ecology and environmental science. Blackwell Publishing, Oxford, pp 238–282 Miller TJ (2002) Assemblages, communities, and species interactions. In: Fuiman LA, Werner RG (eds) Fishery science. The unique contributions of early life stages. Blackwell Science Ltd., Oxford, pp 183–205 Miller TJ, Crowder LB, Rice JA, Marschall EA (1988) Larval size and recruitment mechanisms in fishes:

Ecosystem Governance toward a conceptual framework. Can J Fish Aquat Sci 45:1657–1670 Moser HG (1984) Ontogeny and systematics of fishes. American Society of Ichthyologists and Herpetologists ed., Special publication Number 1 Paris CB, Cowen RK (2004) Direct evidence of a biophysical retention mechanism for coral reef fish larvae. Limnol. Oceanography 49:1964–1979 Peterman RM, Bradford MJ (1987) Wind speed and mortality rate of a marine fish, the northern anchovy (Engraulis mordax). Science 235:354–356 Russell FS (1976) The eggs and planktonic stages of British marine fishes. Academic, London. 539 pp Sogard SM (1997) Size-selective mortality in the juvenile stage of teleost fishes: a review. Bull Mar Sci 60:1129–1157 van Damme CJG, Bolle LJ, Fox CJ, Fossum P, Kraus G, Munk P, Rohlf N, Witthames PR, Dickey-Collas M (2009) A reanalysis of North Sea plaice spawningstock biomass using the annual egg production method. ICES J Mar Sci 66:1999–2011 van der Lingen C, Huggett J (2003) The role of ichthyoplankton surveys in recruitment research and management of South African anchovy and sardine. In: Browman HI, Skiftesvik AB (eds) The big fish bang. Proceedings of the 26th annual larval fish conference. Institute of Marine Research, Bergen, pp 303–343 Victor BC (1986) Duration of the planktonic larval stage of one hundred species of Pacific and Atlantic wrasses (family Labridae). Mar Biol 90:317–326

Ecosystem Governance ▶ Environmental Governance in Context of the Marine Ecosystem: Considerations for Sustainability

Ecosystem Health ▶ Management and Monitoring of Eutrophication: Trophic State Indexes on the Río de la Plata Northern Coast

Effective Marine Conservation ▶ Effective Marine Conservation in the Global South: Key Considerations for Sustainability

Effective Marine Conservation in the Global South: Key Considerations for Sustainability

Effective Marine Conservation in the Global South: Key Considerations for Sustainability Henry Bikwibili Tantoh Department of Environmental Science, College of Agriculture and Environmental Science, University of South Africa, Pretoria, South Africa Department of Geography, Faculty of Arts, University of Bamenda, Bamenda, Cameroon

Synonyms Effective marine conservation; Marine conservation/Marine resource conservation; Marine Protected Areas (MPSs); Sustainability; Sustainable marine conservation

Definitions Marine conservation or marine resource conservation refers to the protection of marine ecosystems through the planning and management of its resources. It suggests that conservation must be simultaneously informed by the natural histories of marine organisms with the hierarchy of scalerelated relationships and ecosystem processes (Carleton Ray 2014). Marine conservation is also the contractual arrangements between formal and informal institution aimed at achieving oceans and coastal conservation targets (Lundquist and Granek 2005). This entails deliberately refraining from certain destructive actions and voluntarily transfers certain responsibilities to the appropriate and legal controllers for socioeconomic and environmental outcomes. Marine Protected Areas (MPAs) are naturebased solutions for mitigating pressures to marine biodiversity. According to the International Union for Conservation of Nature (IUCN), MPAs are defined as: “any area of inter-tidal or sub-tidal terrain, together with its overlying water and associated flora, fauna, historical, or cultural features, which has been reserved by law or other effective

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means to protect part or all of the enclosed environment” (Kelleher and Kenchington 1992). MPAs are aimed at preserving and promoting marine life and have the tendency to produce better conservation and management outcomes (Smith et al. 2020) which is possible through collaborative or participative management between national governments, municipal authorities, nongovernmental organizations (NGOs), community-based organizations (CBOs) among others. Sustainability has several viewpoints and how it can be achieved. It entails the ability or the process for “something” to be sustained. It seeks to protect the natural environment, human, and ecological health while driving innovation without compromising common practices and lifestyles. The concept of sustainability is generally comprised of three pillars: social, economic, and environmental also known informally as people, profits, and planet (Grant 2020). Sustainable marine conservation refers to the processes and actions through which society manage common practices to prevent the depletion of oceans and marine resources and retain the ecological balance for the future. Effective marine conservation is similar to sustainable marine conservation and is referred to as an approach for maintaining future marine resources and managing the ways marine resources are exploited to sustain social and economic growth for present and future generations.

Introduction Life on earth would be problematic without seas and oceans. Humanity has shaped and continues to reshape the environment at times in ways that cannot be reversed. Oceans, for example, occupy about 71% of the earth’s surface and represents 99% of the living space on the planet by volume (IPCC 2007; Feist and Levin 2016). Oceans and marine ecosystems are one of the bases through which the global system is driven and makes the planet inhabitable for the society. For example, oceans buffer about 30% of carbon-dioxide (CO2) generated by humans and provide about three billion people with coastal and marine

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biodiversity for their livelihoods and wellbeing and a market value of about US $3 trillion per year which is about 5% of global Gross Domestic Product (GDP) (IPCC 2007; Feist and Levin 2016). However, despite the decreases of CO2 and the provision of goods and services to millions of people, the pressure and destruction of marine biodiversity continue to increase (Roberts et al. 2017). Furthermore, increasing population, rising urbanization, improved standards of living, changes in consumption patterns, economic growth and industrial development, improvement and extension of agricultural activities have greatly impacted oceans and marine resources (Bruno et al. 2018). Large-scale pollution of the ocean and its resources has contributed to the depletion of marine biodiversity. Feist and Levin (2016), for example, highlighted that increasing development, rising population, and settlement on coastlines have resulted in their development with associated impacts on marine biodiversity. It is argued that human-induced impacts on the coastlines have aggravated the modification of marine biodiversity with about 40% of the ocean, for example, affected by pollution from diverse sources (Patil et al. 2016). Extra inclusive actions are required to improve the resilience of marine ecosystems and protect their wildlife and capacity to provide vital marine ecosystem goods and services to the increasing global population. Several studies have documented that the impact of climate change has become an additional stressor on oceans and marine resources with projected impacts to be more severe in the twenty-first century (IPCC 2007; Roberts et al. 2017; Bruno et al. 2018). Species mostly limited to marine reserves, for example, are particularly sensitive to human-induced climate change due to their genetic diversities and limited numbers (Peters 1985). The human-induced stressors on oceans and marine ecosystems have been extensively established to cause several adverse alterations in biodiversity (Bruno et al. 2018), comprising: deficit of marine biodiversity, reduced species, destruction of marine habitats, and deficits of environmental functions, resulting in extra pressures. Furthermore, climate change has the possibility to intensely shape and reshape

ocean dynamics, upsetting the structure and function of the marine environment and biodiversity (Harley et al. 2006; Roberts et al. 2017). Some of the physical changes happening and expected to happen on oceans and marine ecosystems due to the effects of climate change include fluctuations in ocean current patterns and ocean temperature changes, acidification and deoxygenation of oceans, variations in storm intensity, and sea-level rise (Bruno et al. 2018). Recent evidence suggests that global warming has significant impacts on ecosystems and populations within marine and terrestrial reserves (Bruno et al. 2018). Attempts to conserve and manage marine biodiversity against climate change will necessitate advances to the prevailing projecting framework (Harley et al. 2006). In view of mitigating the effects of climate change and other human-induced impacts on marine ecosystems, international organizations, nongovernmental organizations (NGOs), national governments, and community-based organizations (CBOs) have identified Marine Protected Areas (MPAs) as a primary and nature-based management process to effectively conserve marine resources (Pendred et al. 2016; Jantke et al. 2018; Smith et al. 2020). It is argued that well-situated and managed MPAs prevent pressures on biodiversity and produce resilient conservation outcomes (Pendred et al. 2016). One of the targets of the United Nations Sustainable Development Goals 14 (UN SGSs 14) specifically obligates the safeguarding of “at least 10% of coastal and marine areas” by 2020 (United Nations 2016). The SDG 14 also aims to significantly prevent and reduce marine pollution of all kinds, in particular from land-based activities, including marine debris and nutrient pollution by 2025, increase the economic benefits from the sustainable use of marine resources, including through sustainable management of fisheries, aquaculture, and tourism to Small Island developing States and Least Developed Countries by 2030, and enhance the conservation and sustainable use of oceans, seas, and marine resource to ascertain “the future we want” (Bruno et al. 2018; Ren et al. 2020). However, despite the benefits of marine ecosystems and several efforts by marine conservation practitioners, scholars, and governments in conserving oceans and marine

Effective Marine Conservation in the Global South: Key Considerations for Sustainability

biodiversity, results have been limited as benefits are contingent on the implementation of effective and efficient of conservation strategies. In the case of Madagascar and Angola in the Global South, for example, the management of MPAs is not proportionate with the mission of their specific maritime domain (Weigel et al. 2011). This is because each MPA is unique and requires different management and performance indicators specific to the socio-economic and environmental features of the MPA and adjacent communities (Himes 2005). Noteworthy is that appropriate management and performance indicators comprise the involvement and engagement of all resource-driven stakeholders (national governments, NGOs, CBOs, etc.) in decision-making (Tantoh et al. 2019; Tantoh and Mckay 2021). This constitutes the practice of interacting with those directly or indirectly influenced by the overall benefit of the management. The effective management of MPAs usually depends on how the stakeholders perceive it. Their requirements, expectations, perceptions, personal agendas, and concerns will influence the management, shape what success looks like, and affect the outcomes that can be achieved (Ricart 2020). Successful engagement depends on understanding who to engage with, the reasons for engagement, and the strategies applied. When all the stakeholders are involved and engaged, positive outcomes are guaranteed. However, MPAs have been inadequately planned (Agardy et al. 2011). Although much has been written on MPAs and marine ecosystem conservation and management (Agardy et al. 2011; Jantke et al. 2018), concerns about the effectiveness of MPAs continue to grow resulting in the necessity for investigating sustainable conservative management techniques, particularly in the Global South.

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huge volumes of biomass due to its density, which is 80 times as dense as air (Kenchington 2003). The ocean, for example, is a comprehensive environment and occupies three-quarters of the earth and is a source of food, energy, and water that sustains humanity. It is argued that oceans and marine ecosystems are the most varied ecosystems that contribute to essential global cycles and regulate the climate (Bruno et al. 2018; Smith et al. 2020). Human-induced carbon emissions result in severe perturbations ranging from rising sea levels, increasing storm intensity, deoxygenation, and acidification (Henson et al. 2017), causing the modification of the physiognomy of organisms. This will permit them to withstand several possible threats from opposing qualities. For example, changing oxygen concentration and increasing temperatures in MPAs facilitates deoxygenation which affects the geochemical and physiological processes of species production (Breitburg et al. 2018). In the same lens, mean sea-surface temperatures within MPAs are estimated to increase by 0.035  C per year and further warm 2.8  C by 2100 (Bruno et al. 2018). This will further deoxygenate oceans and increase the metabolism of fish and other invertebrates. The irregularity of the ocean and seabed determines the availability of particular species either permanently or for life-threatening life cycle stages (Kenchington 2003). Since they are heavily exploited, like many other biological systems, some emanating self-adjusting, organization, and adaptation are apparent. Marine environments are, therefore, crucial in achieving essential socioeconomic and environmental goods and benefits which have not been adequately acknowledged and managed.

Oceans and Marine Ecosystem Services The Nature of Marine Environment Oceans and marine ecosystems are the most diverse ecosystem and they play a fundamental role in sustaining life on earth. Oceans and marine ecosystems can be typified by their composition, functions, and dynamics. They support and enable

Environmental Goods and Services For many coastal inhabitants, oceans and marine ecosystems are considered sacred and provide a wide range of seafood. Even with the limited technology for hunting and expedition, for example, many coastal communities prospered due to the continuous supply of seafood. Marine

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ecosystems have been a source of capital accumulation for those ready to take the necessary risks of exploiting the seas and oceans. This has resulted at times in overfishing with the introduction of sophisticated technology. The abuse of marine ecosystems is unfortunately only realized when they are damaged. Furthermore, coastal and marine tourism is a huge industry that supports regional and global economies. This is particularly true due to the fast-growing eco-tourism which has resulted in conservation efforts towards threatened natural environments (Ren et al. 2020). Many tourism experts believe that this increase is due to people becoming more knowledgeable about ecosystem values and benefits. For example, marine habitats such as coral reefs and salt marshes provide natural coastal defenses and nursery grounds for fisheries as well as diverse ecosystems. Oceans and marine ecosystems are also favorable for larval dispersal that replenishes fish populations. Many industrial processes rely on oceans and marine ecosystems for resources such as gas, oil, and marine aggregates apart from reaping food from the oceans and seas. Furthermore, oceans and seas provide huge potential for clean energy technologies, such as tidal and offshore wind farms (Plymouth Marine Sciences Partnership 2006). Regulating Processes Oceans and marine ecosystems moderate the intensity of climate change by means of absorbing part of greenhouse gases and excess heat resulting from human-induced activities. Furthermore, wind-driven surface currents in the North Atlantic head poleward from the equator and eventually sinks at high altitude into the ocean basins causing widespread mixing across ocean basins, and this reduces the alterations between them, making the ocean a global system. Oceans are heat sinks and help in delaying the full effects of climate change. For example, oceans are the largest reservoir of carbon with 40,000 Gt C (Plymouth Marine Sciences Partnership 2006). Although about 15.2% (20.46 million km2) of the land base was protected by 2020, the importance of these more newly added protected areas as carbon sinks and stores has not yet been quantified (UNEP-WCMC et al.

2020). It is possible that the uneven distribution of large tracts of protected areas and carbon-rich ecosystems such as the Amazon Basin, Congo Basin, and the Boreal Tundra areas is one of the causes (Dinerstein et al. 2019). However, some restoration activities that support carbon sequestration such as revegetation, re-establishing historical hydrology, raising soil surface levels with dredged material, increasing sediment supply by removing dykes and dams (Howard et al. 2017) are practiced in some regions to regulate the effects of climate change. Cultural Values and Aesthetics Human interaction with the ocean and marine environments has greatly shaped the growth of cultures, religion, spiritual, and aesthetic features. Examples of goods with cultural values obtained from marine ecosystems include corals, pearls, and tortoiseshells. Pearls, for example, have been used for jewellery in many societies and the competition from the Gulf States, in particular, has unfortunately resulted in a steady trade decline on the one hand and on the other, overexploitation of marine organisms (Carter 2005). Furthermore, appropriate pieces of either life or dead corals are used to decorate aquariums. The substantial demand for coral skeletons for decorative purposes necessitates regulation. Countries such as Nigeria are raising public awareness and enforcing activities against illegal domestic trade of wildlife products (United Nations 2016). However, the effects of human-induced activities on the quality and quantity of fish caught are challenged by many cultures (Kenchington 2003). For example, the catches of the best years are considered normal despite advances in marine science, whereas poor catches are first explained by bad luck. The seas and oceans also serve as a source of recreational activities such as sporting events-swimming, sea bathing, and fishing. Coastal environments have been accepted as spaces for summer retreats and holiday resorts and are becoming a global culture. These holiday resorts in coastal zones are also fast becoming retirement homes with almost permanent occupancy generating huge quantities of wastes with adverse impacts on marine ecosystems

Effective Marine Conservation in the Global South: Key Considerations for Sustainability

(Kenchington 2003). This, together with issues of access, overexploitation (natural resources), ownership and climate change emphasize the intent of managing marine environments.

The Management of Oceans and Marine Protected Areas

Effective Marine Conservation in the Global South: Key Considerations for Sustainability, Table 1 Highlights protected areas according to IUCN categories Categories I II III

The unsustainable exploitation of natural resources and habitat degradation, particularly in countries of the Global South, stems primarily from increasing population, overexploitation, extension, and intensification of agriculture. This has been further deepened by inadequate funding and political instabilities. However, the legal design and establishment of protected areas have resulted in the definition and adoption of new management strategies by formal and informal national and international organizations. The International Union for Conservation of Nature (IUCN), for example, adopted a universal declaration for the creation of a representative system of MPAs in 1998 which aims at: . . .the protection, restoration and effective use of the marine resources through the creation of a global, representative system of marine protected areas following the principles of the World Conservation Strategy of human activities that affect the marine environment.

This declaration enhances concerns about the use and management of MPAs. It further situates MPAs as one of the fundamental features of management for effective use, understanding, and satisfaction as well as biodiversity preservation. Subsequent, increases in population numbers and human-dominated seas and marine ecosystems have triggered the conservation of biodiversity and in some cases, protected areas were instituted to resist human-induced impacts (Feist and Levin 2016). The global human-induced effects on oceans and marine ecosystems have, therefore, heightened the need for conservation. Furthermore, development practitioners, international aid organizations, scholars, NGOs, and CBOs have identified nature-based approaches such as MPAs to conserve and preserve sensitive ecosystems (Jantke et al. 2018; Smith et al. 2020).

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IV

V

VI

Designation Strict nature reserve National park Natural monument Habitat/Species management area Protected landscape/ Seascape Managed resource protected area

Objective of MPA Science or wilderness protection Ecosystem protection and recreation Conservation of specific natural features Conservation through managed intervention Landscape/seascape conservation and recreation Sustainable use of natural ecosystems

Source: IUCN (1994)

Studies show that MPAs are conventional management measures to conserve oceans and marine biodiversity. There is evidence of increased marine biodiversity, biomass, and the volume of some exploited species in MPAs (Lester et al. 2009). The evolution of the design and establishment of MPAs have, thus, resulted in the combination of several techniques and approaches to enhance and manage protected areas (see Table 1). Several national and international aid organizations have advocated MPAs as vehicles for addressing long-term conservation and management of marine resources (National Research Council 2001; Pendred et al. 2016). This is because of the essential benefits they provide to humanity. Furthermore, MPAs align to the UN SDGs No 14 which aims to “Conserve and sustainably use the oceans, seas and marine resources for sustainable development.” Along these lines, the International Union for Conservation of Nature (IUCN) has divided protected areas into six subgroups by based on their objectives. These subgroups are globally recognized by international aid organizations, NGOs, and national governments as essential elements in biodiversity management. Two comprehensive approaches are, however, used for marine

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ecosystem and biodiversity management processes: large area ecosystem-scale management of natural resources (uses impacts to make sure they are effective) and site scale management (strictly protected areas such as reserves and national parks). Based on the IUCN subcategories, this relates to category VI with core areas of category I and/or II management areas (IUCN 1994). Generally, category VI provides a framework through which uses are permitted provided that they are managed on a basis of objectives that address noticeable sustainability outcomes (Kenchington 2003). For example, the inclusion of category I or II addresses protection of representative areas of marine biodiversity and of sites critical for breeding, feeding, or migration of rare, endangered, or economically significant species. Furthermore, categories II, III, IV, and V have the potential in managing recreation and tourism to preserve the resources. They can also contribute to the important responsibilities such as educating visitors about the importance and value as well as the beauty of marine ecosystems. These MPAs have the potential to produce stronger conservation outcomes especially when all the stakeholders are involved. However, the paradox between conservation-focused and productiondominated environments is outdated (Kueffer and Kaiser-Bunbury 2014). Preferably, effective ocean-use practices would view oceans and MPAs as opportunities for preservation and conservation. Different management approaches have been used by national governments to manage natural resources and MPAs. Centralized, Top-Down Management Most governments in developing countries have managed their natural resources (land, water, wildlife) from a centralized, top-down management system (Tantoh and Simatele 2017). Decisions regarding the management of these resources are taken at the central ministerial departments and applied nationally. Given that natural resources are the foundation of rural livelihoods, access and tenure are frequently governed by power struggles that lead to the exclusion of those who depend on the resources for their livelihoods and wellbeing (Tantoh and Simatele 2018).

Prohibitive formal and informal systems of natural resources management (NRM) mostly expressed by centralized, top-down approaches have resulted in bureaucracy, immeasurable inadequacies and are time-consuming. These top-down management approaches to NRM which were practiced during colonization, however, continued even after the independence of most states (Mengang 1998). Different ministries such as the Ministry of Livestock, Fisheries and Animal Husbandry, the Ministry of Environment and Forestry among others were, thus, created after independence to continue with the colonial legacy. Recent developments in governance have heightened the need for institutional restructuring, encouraging local resource users and CBOs to take leading roles in the management of natural resources (Donkor et al. 2017; Tantoh 2018). Collaborative or Participative Management Community involvement in the management of natural resources has been identified as one of the ways for the effective management of CommonPool Resources (grazing land, water, etc.) (Tantoh and Simatele 2017). This management approach promotes standards of participation of individuals, resource users, and CBOs in matters that concern them. Experience shows that involving and engaging all the stakeholders in every stage (initiation, implementation, management, etc.) of a development project is necessary for sustainable outcomes (Tantoh 2018; Nemutamvuni et al. 2020). When all the stakeholders participate in the different stages of a project, it builds their trust and self-esteem which is necessary for sustainability (Njoh 2003; Musavengane et al. 2019). Some national governments, however, maintain management prerogatives, especially that of last resort. This brings to the fore new power relations to be arranged in an enabling environment among all the stakeholders and until all the stakeholders are fully represented and participate in decisionmaking processes, uncertainty will dominate. Thus, clarifying the roles of all the stakeholders is crucial for realizing user-participation, improving communication, and equal expectations of stakeholder groups for sustainable outcomes (Lundquist and Granek 2005; Tantoh and

Effective Marine Conservation in the Global South: Key Considerations for Sustainability

Simatele 2018; Nemutamvuni et al. 2020). Increased interest in the involvement of different stakeholders with different needs and interests in the management of the marine ecosystems should be encouraged. The importance of collaborative/ co-management (Musavengane et al. 2019), participative (Njoh 2003; Tantoh and Simatele 2018), and community-based management (Tantoh et al. 2019) approaches in the effective management of natural resources has been documented. The involvement of local communities in the management of endemic marine habitats in the Comoros Island in the West Indian Ocean with 80% control, for example, empowered them to monitor sea turtle nesting beaches, uninhabited islets, reef health, fisheries, guide eco-tourists, and educate visitors (Granek and Brown 2005). The sustainability of MPAs should moreover encompass different disciplines (social, economic, political, environmental). This would be facilitated by an integrated system (human and biophysical) and this will provide novel practical views of conservation.

Problems Encountered in Marine Conservation and the Management of Marine Protected Areas Inadequate Enforcement and Instabilities Insufficient implementation of management plans, inadequate surveillance, and the absence of public support have been identified as some of the major factors affecting the proper management of several MPAs (Jones 2002). Furthermore, the inability of the government to adequately enforce national laws has compromised the management of MPAs. This can lead to a collapse in monitoring and implementation set-ups. Instabilities in most countries in the Global South such a Nigeria, Cameroon, Mozambique, Angola, the Comoros Island among others further impede global ocean and marine ecosystem management goals (Granek and Brown 2005). Increasing disagreements in conservation efforts, marine habitat degradation, and species declines necessitate for a novel conservation approach.

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Insufficient Scientific Information and Top-Down Management Tendencies A common problem in conservation design particularly, in the Global South is the lack of information about many marine ecosystems, such that examining appropriate MPAs is mostly based on unreliable information (Lundquist and Granek 2005). Since decision-making in most countries in the Global South is top-down in nature, obtaining permission of the necessary resources such as maps of ecosystems and baseline information is time consuming coupled with high costs. Furthermore, a processoriented approach through which science informs the selection of sites and stakeholders about relevant ecological sites is often opposed by proponents of a consensus-based approach. Thus, scientific knowledge should be combined with local knowledge to determine different options for the location of MPAs (Jones 2002).

Enabling and Promoting Effective, Resilient, and Inclusive Blue Economies Healthy oceans and marine ecosystems are crucial for sustainable outcomes both for the planet and its inhabitants. Effectively managing the oceans and marine ecosystems will facilitate the achievement of the SDG 14. Presently, the effects of climate change, coastal development among others have endangered marine biodiversity, livelihoods, and wellbeing, jeopardizing the ability for risk reduction (Donkor et al. 2019). Enabling effective socio-economic and environmental benefits of marine ecosystems within their planetary confines is imperative. This will be possible through inclusive participation of all stakeholders, managing and monitoring oceans, and marine ecosystems for the future, a systemic approach and inclusion of knowledge. Inclusive Participations of Stakeholders Oceans and marine ecosystems can be difficult to manage because of the trans territorial nature of species and activities demonstrated by an overlap between diverse activities and territories. Thus, engaging with the national, regional, and local partners will enhance decision-making, enable

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conditions and capacities to develop, and implement effective management of oceans and marine ecosystem. This will entail an inclusive blue economy strategy, policies, and solutions that moderate human-induced impacts and sustain comprehensive use of marine and coastal ecosystems and their services. Studies have shown that involving and engaging all the stakeholders in marine conservation strategies, from the initiation, development, execution, management, and monitoring phases, is crucial for the success of marine conservation projects (Leslie 2005; Lundquist and Granek 2005). When local resources users, especially those in close proximity, are involved in the establishment, design, planning, and management, it gives them a sense of proprietorship and tenure which is necessary for effective management (Njoh 2003; Musavengane et al. 2019; Tantoh et al. 2019). Even though the degree and extent of stakeholder involvement differ between cases, integrating diverse interest groups should be recognized as a necessary component of successful conservation planning. Stakeholder involvement further instills a sense of commitment among the parties (Granek and Brown 2005). For example, the involvement of local community-based institutions in the Comoros Islands and Papua New Guinea promoted longterm interests and improved the capacities of the individuals formally and informally in managing conservation activities. The participation of CBOs in the resources management resulted in both approvals of and support with implementing the regulations of MPAs (Granek and Brown 2005). Managing, Monitoring, and Evaluation for the Future It is essential to institute the culture of monitoring and evaluation during the life-cycle of a project. Constant monitoring and evaluation comprise continual appraisal to gauge attainment of socioeconomic and environmental objectives. Monitoring and evaluation are essential for assessing the level of effectiveness of conservation measures. This will determine the adaptation strategies to be used to mitigate the human-induced effects on oceans and marine ecosystems. Monitoring and evaluation contribute to enhancing conservation processes by indicating short-medium and long-

term successes. In the case of marine habitats, for example, the recovery time differs between the different species. Thus, identifying the recovery time for the different species would help the stakeholders predict likely recovery times (McClanahan 2000). However, insufficient postexecution institutional support for monitoring and evaluation undermines the capacity to effectively define the goals of the protected areas to be realized (Lundquist and Granek 2005). Periodic monitoring and evaluation of MPAs also informs the stakeholders on ecological impacts of the different management preferences and to assess if the MPAs meet their targets. An important aspect of appraising conservation planning strategies is identifying exact conservation performance targets and appropriate monitoring to address the targets (Leslie 2005). Systemic Approach and Inclusion of Available Knowledge Taking into consideration the context of the surrounding environment or a holistic approach is essential for the effective management of human and natural systems (Bosch et al. 2007). A system approach to effective ocean and marine ecosystem management implies giving emphasis to the interactions between the different elements, rather than examining them separately (Fig. 1). A system approach also means taking into consideration the situation that surrounds the specific system studied (Tantoh and McKay 2021). Effectively managing MPAs can be a simple problem as well as a complex one, referred to as a “mess” (Ackoff 1978). This is a situation which most people agree is somehow unsatisfactory because of a clique of mostly interrelated poorly defined problem with a limited agreement concerning what is to be done to improve the situation. In such circumstances, coordinated actions from diverse groups of stakeholders will lead to significant and lasting improvements to the situation. Marine ecologists, conservationists, and scholars might think they know the problem just to find out that others (local resource users, agroforestry, farmers, development practitioners, etc.) appreciate the situation differently. For example, some may see MPAs as a solution to the indiscriminate exploitation and solutions to protect the marine ecosystem, but the fisherman who

Effective Marine Conservation in the Global South: Key Considerations for Sustainability

Complexity Unconnected Knowledge Divergent Views Changing circumstances

Stakeholder involvement & engagement + System thinking + Adaptive management

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Co-learning Common understanding Knowledge integration

Towards achieving effective management of Marine Protected Areas

Knowledge building

Effective Marine Conservation in the Global South: Key Considerations for Sustainability, Fig. 1 Conceptual diagram summarizing the effective management of Marine Protected. (Adapted from Bosch et al. 2007)

depends on fish for livelihoods sees it otherwise if they have no say in the design and decision-making process. While traditional knowledge is important, scientific investigations have also provided a significant amount of evidence-based data. Thus, local knowledge should be complemented with scientific knowledge for a comprehensive and effective appraisal of MPAs. However, the privation of available data about biodiversity, the structure of the habitat, and other ecosystem indicators that determine the location of protected areas is one of the major difficulties in the design, planning, and endorsement of MPAs. Most effective MPAs instituted to this date have, therefore, combined appropriate and available scientific data and local knowledge (Fig. 1). To appreciate and safeguard ocean and marine biodiversity, improve the impacts of ocean variation, and change on the people, strategies to comprehend and forecast uncertainty and complexity of the changes should be developed. This entails a combination of scientific and local knowledge to comprehend human ingenuities and vulnerabilities through behaviors, values, and beliefs. When local science is not comprehensive, however, careful planning can even so result in success. Subjective information provided by local stakeholders can be valued in many cases where methodically conceived investigations are absent and may help overcome possible doubts and complexities in detecting MPAs.

ecosystems to maintain these vital processes is, however, endangered in several ways by direct impacts of increased CO2 levels on the one hand and on the other the indirect impacts of climate change. These effects have inevitably influenced the sustainability of various ecosystems. It is, therefore, crucial to protect oceans and marine ecosystem through improved ocean conservation for sustainability. The SDG 14 has outlined several targets required to strengthen and promote nature-based solutions to effectively conserve and sufficiently use the oceans, seas, and marine resources for sustainable development. A major weakness of marine conservation projects has been the failure to accurately define the problem, resulting in the inability to effectively address objectives leading to perceived failures or loss of support from certain stakeholders. However, the oceans, seas, and MPAs can be effectively managed if there is inclusive participation of all the stakeholders, periodic monitoring, and evaluation for the future and a systemic approach that combines scientific and local knowledge in the management. It is imperative to highlight that the combination of both scientific and local knowledge, long-term monitoring, and evaluation strategies that appraise the achievement at the different levels (social-economic, scientific, and local knowledge systems) are important instruments in the process. When these different knowledge streams are complemented with political information at the different phases, sustainability is assured.

Conclusion

Cross-References

Oceans and marine ecosystems are a life-giving force considering the fact that portable water, weather, climate, food, and oxygen are driven by the sea. The ability of oceans and marine

▶ Adaptation to Sea-Level Rise and Sustainable Development Goals ▶ Coastal Zone and Wetland Ecosystem: Management Issues

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▶ Community-Based Research and Participatory Approaches in Support of SDG14 ▶ Concepts of Marine Protected Area ▶ Conserving Coastal and Marine Areas for Sustainable Development: Opportunities and Constraints ▶ Coral Triangle: Marine Biodiversity and Fisheries Sustainability ▶ Environmental Governance in Context of the Marine Ecosystem: Considerations for Sustainability ▶ Fisheries Management and Ecosystem Sustainability ▶ Global Ocean Governance and Ocean Acidification ▶ Higher Education and Sustainable Development of Marine Resources ▶ Management and Monitoring of Eutrophication: Trophic State Indexes on the Río de la Plata Northern Coast ▶ Mangroves Conservation: Relevant Task to Achieve the SDG14 ▶ Marine Animals and Human Care Toward Effective Conservation of the Marine Environment ▶ Marine Ecosystems ▶ Marine Ecosystems: Types, Their Importance, and Main Impacts ▶ Marine Modelling: Contributions, Advantages, and Areas of Application of Numerical Tools ▶ Marine Protected Area and Biodiversity Conservation ▶ Maritime Spatial Planning and Sustainable Development ▶ Ocean-Related Effects of Climate Change on Society ▶ Plastic Pollution in Aquatic Ecosystems: From Research to Public Awareness ▶ Promoting Coastal and Ocean Governance Through Ecosystem-Based Management ▶ Responsible Ocean Governance: Key to the Implementation of SDG 14 ▶ Sustainable Coastal and Marine Ecotourism: Opportunities and Benefits ▶ Wetland Ecosystems and Marine Sustainability

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Elevated pCO2 ▶ CO2-Induced Ocean Acidification

Environmental Governance ▶ Environmental Governance in Context of the Marine Ecosystem: Considerations for Sustainability

Environmental Governance in Context of the Marine Ecosystem: Considerations for Sustainability Khomotso Semenya1 and Felix Kwabena Donkor2 1 College of Agriculture and Environmental Sciences (CAES), University of South Africa (UNISA), Florida, South Africa 2 College of Agriculture and Environmental Sciences (CAES), University of South Africa (UNISA), UNISA Science Campus, Johannesburg, South Africa

Synonyms Anthropogenic factors; Ecosystem governance; Environmental governance; Human factors; Human impacts; Natural resources governance; Sustainability; Sustainable development

Definition Sustainability refers to the harnessing of nature within its capacity for renewal and essentially harmonising human-environmental interactions (Haque 2017). In general, it has burgeoned from describing biological systems to explore the successful co-existence between the biosphere and human civilisations in the twenty-first century premised on the cardinal pillars of economy,

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environment and society. In addition, environmental governance encompasses a suite of regulations, practices, policies and institutions that control human-environment interactions (Haque 2017). The notion of environmental governance largely draws on political ecology and environmental policy promoting sustainability/sustainable development as the principal imperative in the management of human actions (Underdal 2010). This approach integrates the political, social and economic elements in systemic governance around government, business and civil society (Mascia and Mills 2018). It provides a framework that promotes coherence amongst policies, institutions, procedures, tools and information enabling diverse stakeholders build consensus, facilitate decision-making, enhance conflict management and reinforce accountability mechanisms (Ioppolo et al. 2013). Moreover, the term anthropogenic factors designate or relate with the influence of human activity including on the environment or ecosystem (Bampton 1999). First traced to Russian geologist Alexey Pavlov, it was adopted into English by British ecologist Arthur Tansley regarding the impact of human activities on climax plant communities, whilst the atmospheric scientist Paul Crutzen pioneered the notion of the Anthropocene in the mid-1970s (Crutzen and Stoermer 2000).

Introduction A Decade of Action to Deliver the Global Goals The United Nations (UN) reports indicate that although there has been evidence of progress in several dimensions of the SDGs, in general there is still a lot of work in achieving the SDGs (Donkor 2020). This is because the needed pace of activity to realise the goals is not yet at the requisite speed or scale required. The year 2020 ushered in a decade of ambitious activity to realise the sustainable development goals (SDGS) by 2030 (UNDESA 2020). The so-called Decade of Action is a global rally of efforts to accelerate sustainable measures and requisite interventions to the entirety of the global community’s pressing challenges – this includes issues which stretch

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from poverty and gender (Sarrasanti et al. 2020) to climate change (Semenya and Machate 2020), inequality and closing the finance gap. The United Nations has encouraged all sectors of society to rally their resources towards the Decade of Action in three core dimensions: global action to achieve effective leadership, improved resources and smarter solutions for realising the Sustainable Development Goals; local action centred on the requisite transitions in the policies, budgetary allocations, institutional and regulatory systems of governments, cities and local authorities; and people action, comprising those by the youth, civil society, the media, the private sector, unions, academia and other stakeholders, to foster an unrelenting drive advancing for the essential transformations across the globe (UNDESA 2020). This is more so as climate-induced extreme events and natural disasters have been on the ascendancy across the globe and in many cases reverse developmental gains and cause untold havoc to individuals, communities and related livelihoods. In addition, the COVID-19 pandemic and its consequences on all dimensions of the 17 SDGs has demonstrated that what commenced as a health crisis has rapidly developed into a human and socio-economic disaster (Donkor and Mearns 2020a). It is argued that even as evidence shows that the crisis is impeding progress in the attainment of the SDGs, it also lays emphasis on the point that their realisation is all the more pressing and needed (Sarrasanti et al. 2020). It is imperative that all the advances and successes regarding the SDGs are safeguarded as much as possible. A transformative recovery from COVID-19 is very urgent and by all indications has to be advanced, one that deals with the underlying issues of the crisis, limits the threats from future potential disasters and redoubles the concerted execution activities (Donkor 2020) to realise the 2030 Agenda and SDGs within the period and timeline of the Decade of Action. In general, there have been great efforts to rally people across the globe to become active and support the global goals. Countries, establishments, groups and people from all parts of the globe need to work together to deal with the current and future challenges from diverse areas, for an improved

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common future for humanity (Donkor and Mearns 2020b). In order to motivate, gather and disseminate information (Donkor et al. 2017) about novel projects being undertaken to advance the SDGs across the globe, several United Nations bodies such as the UN DESA have created user-friendly virtual platforms such as “SDG Accelerations Actions” database that is hosting several hundreds of events by governments and stakeholders amongst others (UNDESA 2020). This includes projects and measures towards novel housing plans and human settlement development to address housing inequality and affordable decent housing for slum dwellers and curb the outbreak of the coronavirus epidemic in Egypt. The University of South Africa introduces policies for the rollout postgraduate degree and course in Sustainable Development from 2022, in line with the 2030 and 2063 Agendas, and coupled with the objective of awarding degrees to qualified graduates by 2023. The UNDP Colombia helps the state government to enhance ecosystem management and biodiversity conservation of about 60,000–80,000 hectares of productive lands in the Amazon region, profiting the livelihoods of 4000 people by 2024 (UNDESA 2020). The project of the SDG Decade of Action is traced to the 2019 SDG summit where world leaders recognise there is only 10 years in realising the Sustainable Development Goals, advocated for a Decade of Action and delivering on the commitment for sustainable development (#ForPeopleForPlanet). This triggered pledges to marshal funding, improve country-level execution and reinforce institutions to realise the goals by the proposed deadline of 2030 whilst leaving no one behind in the process (UNDESA 2020). This has led to several SDG Decade of Actiondriven projects in climate, WASH (water, sanitation and hygiene) and the ocean, amongst others. Thus, the Ocean Decade presents a joint framework to promote ocean science towards supporting countries realise the 2030 Agenda for Sustainable Development. The Ocean Decade represents a “once in a lifetime” opportunity to develop novel partnerships across the sciencepolicy interface to reinforce the management of the world’s oceans and coasts for the benefit of humanity. The Ocean Decade will enhance the

international collaboration needed for developing the scientific research and innovative technologies that can link ocean science with societal needs. Furthermore, within the framework of the broader SDG Decade of Action, several civil society leaders and groups have equally advocated for a “super year of activism” to fast-track advancement on the Sustainable Development Goals, calling on all world leaders to intensify measures towards addressing the plight of global populace furthest behind, promote local measures and innovation, enhance data frameworks and institutional structures, ensure harmony in the interaction people and the environment and provide increased funding for sustainable development (UNDESA 2020). Reports from the United Nations indicate that more individuals across the globe are enjoying an improvement in their lifestyles in comparison to about a decade past. This is evidenced in the reports indicating increasing numbers of the global populace are now accessing improved healthcare, better working conditions and educational opportunities than ever before in history (UNDESA 2020). However, evidence suggests that global inequities and climatic variability (Ebhuoma et al. 2020a) are compromising and in some cases reversing such critical developmental gains (Donkor and Mazumder 2020). This has increased calls for increasing investments in inclusive and sustainable economic systems to ensure greater opportunities for shared prosperity (UNDESA 2020). Therefore, a common denominator in the narrative of the 2020–2030 decade is the requirement for measures to address increasing poverty and empowerment of women and girls and tackle the ever-threatening climate emergency (UNDESA 2020). Moreover, the political, technological and financial response measures and solutions (Ebhuoma et al. 2020b) are not beyond reach. However, more enhanced demonstration of leadership and accelerated, unparalleled transformations are required to achieve alignment between such crucial levers of change with sustainable development imperatives (Tantoh et al. 2019; UNDESA 2020). In addition, a core theme in the sustainable development goals is the imperative of intra- and inter-generational equity to ensure that development in the present generation is inclusive as well as does not

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compromise the capacity of future generations to attain meaningful development. One area where this issue has become urgent in the final Decade of Action in delivering the SDGs is with regard to the management of the marine resources of the planet (Claudet et al. 2020). This article therefore looks at some of the critical issues affecting governance of the marine environment and implications for sustainability. Given the grave challenges facing the planet’s marine environment including the existential threat of small island nations, the importance of this topic cannot be overemphasised (Claudet et al. 2020). These are further detailed in the foregoing account. Marine Education and Research for Reinforcing Sustainability in the Decade of Action Fortner and Wildman (1980) describe marine education encompasses the entirety of formal and informal education experiences that affect information about the interrelationship of the worldwide sea with the overall global systems and the mutual influence of both entities. The sea, or the world ocean, refers to the continuous body of saline aquatic system covering circa 71% of the Earth’s landmass (361,132,000 km2 [139,434,000 sq mi]), representing an overall volume of about 1,332,000,000 km3 [320,000,000 cu mi] (WHOI 2012). The massive water system regulates the climatic system of the planet and is critical to processes such as the water cycle, carbon cycle and nitrogen cycle. Generally, the term sea refers to smaller, partially landlocked segments of the ocean and some larger, completely landlocked massive water bodies (NOAA 2020). This includes about 50 water formations across the globe with diverse geographical locations, expanses and ecological systems that are classified as seas. Historically, the Seven Seas concept has been in reference to water bodies along trade routes, regional water bodies or exotic and far-away water bodies (NOAA). From Greek literature which the term is traced to, Seven Seas referred to the Aegean, Adriatic, Mediterranean, Black, Red and Caspian seas, including the “Persian Gulf.” However, Medieval European works, pointed to the North Sea, Baltic, Atlantic, Mediterranean, Black, Red and Arabian seas. In contemporary times, the

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Seven Seas comprise the Arctic, North Atlantic, South Atlantic, North Pacific, South Pacific, Indian and Southern Oceans (NOAA 2020). Although the terms ocean and sea are often used interchangeably, in geographical contexts, oceans are bigger than seas, whilst seas are often situated where the land and ocean meet. Moreover, the oceans are largely classified in terms of geography as the Atlantic, Pacific, Indian, Arctic and Southern (Antarctic) Oceans (NOAA 2020). The hydrosphere unites the entire freshwater and saltwater systems. The significant levels of salinity or salt content and global circulation differentiate marine ecosystems from other aquatic ecosystems. There are other physical factors that shape the profile of marine ecosystems that include geology, temperature, tides, light availability and geography. The importance of improving the education and research of this critical global resource is gaining currency. Consequently, some posit that marine education is a comparatively new academic field but comes with great potential to enrich conventional educational curricula as well as societies across the globe. The observations by Fortner and Wildman (1980) are corroborated by recent accounts that indicate that there are serious differences in the capacities of nations and institutions across the globe to successfully conduct marine scientific research (UNESCO 2020) which is counterproductive to the goals of SDGs. Nevertheless, Santos et al. (2017) are of the view that environmental education (EE) is a unique opportunity to facilitate coastal and marine literacy in the society from an interdisciplinary perspective for the advancement of the coastal sciences. One plausible approach to addressing this challenge is to enhance the scientific knowledge base by empowering core stakeholders (Stacey et al. 2019) with the requisite capacities and capabilities particularly small island developing states and the least developed countries (UNESCO 2020). In effect, the domain of ocean science, underpinned by sound capacity development, is critical to multidisciplinary understanding of the complicated challenges of the coastal zone, thus facilitating SDG 14 as well as other SDGs. In line with such goals, the United Nations declared a Decade of Ocean Science for Sustainable Development

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(2021–2030) to create a shared resource that enables the effective harnessing of ocean science such that it facilitates country-level actions towards the attainment of the 2030 Agenda for Sustainable Development (Claudet et al. 2020). The Decade is touted to offer a uniquely “once in a lifetime” opportunity to form a new foundation, across the science-policy interface, to reinforce the systems governing our oceans and coasts for the benefit of humanity. Moreover, a core theme in the sustainable development goals is the co-production of knowledge to inform sustainable development policy and the forging of vital partnerships to drive sustainable development. This makes the case for improved public awareness, education and research related to the marine environment imperative (Chen et al. 2020). The more people are made aware or educated about the environment, the more they appreciate it as a resource and become proactive stakeholders in its management. However, it is argued that ocean science represents a minute 0.04% and 4% of overall research and development funding globally (UNESCO 2020). Mobilising the requisite collaborations and improving investments in important themes is imperative (Claudet et al. 2020). Such actions will enhance the prevailing collaborations and create fresh alliances and technological approaches to develop the worldwide scientific abilities needed to engender tailored information for addressing the dynamic needs of ocean and coastal zone management and a burgeoning blue economy (Stacey et al. 2019; Chen et al. 2020). In order to realise the aims of this project, it is important to enhance international collaboration to help engender the requisite scientific research and novel technological approaches that tailors ocean science with the pressing socio-economic demands of society (Claudet et al. 2020). This will come with benefits in the translation and interpretation of coastal challenges for the public and facilitate professional research. Moreover, reliable information made accessible to the public and ocean community on diverse coastal matters will go a long way in maintaining or improving the quality of shoreline resources. This also necessitates greater policy coherence with overarching global imperatives and United Nations

interventions towards conserving the ocean and its materials, including the Aichi Biodiversity goals, the SAMOA Pathway, the United Nations Convention for the Law of the Sea and the Sendai Framework for Disaster Risk Reduction. In essence, there is great need for interaction with diverse stakeholders to produce novel ideas, response measures, partnerships and applications (Claudet et al. 2020). The Decade of Action is a rallying cry to all relevant stakeholders’ scientists, governments, academics, policy makers, business, industry and civil society to answer the call of humanity. This involves common global thinking, forging strategic alliances, effective knowledge dissemination and charting a sustainability pathway where humanity and the oceans support each other such that future generations are provided with the opportunity of living and thriving in a sustainable world. This includes addressing the existential threat to the survival of island nations, communities, households, livelihoods and natural habitats. Island Nations and Climate Action Island nations are experiencing exacerbated climate change impacts more than other human societies, due to their low-lying, ocean-inclined frontiers, comparatively small land masses and being exposed to extreme weather conditions and climate variability and change (Gilman et al. 2014). As sea levels steadily increase, island communities and cultures are being endangered (Gilman et al. 2014). There are small and low islands with populations that are lacking satisfactory resources accessible to preserve the island and its related human and natural resources (Gilman et al. 2014). Given the aggravated threats to human health, livelihoods and physical environments in which people reside, the pressure to abandon the island communities is in most cases mediated by the lack of opportunity in accessing the requisite resources and material (Reddy 2019) necessary for successful relocation. A core problem with climate change in the context of island nations is the phenomenon of sea level rise. Records from NOAA and NASA, for example, indicate that there has been an annual increase in threatening sea levels at the degree of 3.41 mm annually. This is directly attributed to the increase

Environmental Governance in Context of the Marine Ecosystem: Considerations for Sustainability

in water as it becomes warmer and the phenomenon whereby polar ice caps continue to steadily melt (Patel 2006). Such serious challenges are being driven by global warming as an outcome of climate change. The steady but increasingly clear evidence of sea level rising is particularly frightening in the context of low-lying island nations given the reality that seas are invading on the already scarce habitable land and imperilling existing cultures with the threat of being submerging ever urgent (Rudiak-Gould 2012). Coupled with this threat, there is evidence that reef islands are changing their shapes and being displaced from original positions due to the influence of moving sediments (Rudiak-Gould 2012). The challenge of sea level rise coupled with negative anthropogenic impacts and transformation due to human development has painted a grim future for island nations as they are struggling when it comes to effectively adapting or mitigating the increasing threats of rising sea levels and are thus seriously endangered. There are also several secondary impacts of climate change and sea-level increase especially regarding island nations. It is argued that the palpable effects of climate change and climate variability (Donkor et al. 2019) are such that some island nations will experience steady rises in air and ocean surface temperatures, heightened incidences of extreme weather events and heavy precipitation in the summer months and a limited level of precipitation in the winter months (Ford 2013). Such a development involves different changes to the often tiny, varied and remote island ecosystems and biospheres (Gilman et al. 2014) available within several of these island nations. Furthermore, increases in sea level with respect to island nations lead to heightened threats of loss of coastal arable land because of the environment being degraded coupled with the problem of salinification (Ford 2013). In an area where land is limited and arable soil even more scarce as in the case of island nations, when the already scarce available soil in such areas become saline, it becomes very challenging to grow important subsistence crops. This comes with severe implications for the agricultural (Donkor and Mearns 2018) and commercial industrial sectors in the majority of island nations. Furthermore, the

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artisanal fishing industry is gravely impacted by steadily increasing ocean temperatures and worsening ocean acidification. With the phenomenon of ocean temperatures increasing and whilst the pH of oceans reduces, several florae, fauna and other marine species are likely to be lost or change their habits and range (Gilman et al. 2014). In addition to this, the steady supply or availability of water and local ecosystems, including mangroves, is under the palpable threat of global warming. The tourism industry as well will be exceptionally endangered by rising incidences of extreme weather events including events like hurricanes and droughts (Donkor and Mearns 2020d). One plausible response measure is to enhance the resilience of coastal habitats. Reinforcing Efforts Towards Conservation of Coastal Habitats Coastal flood hazards represent some of the most expensive natural disasters facing coastal areas with the devastation attributed to Hurricanes Katrina (2005) and Sandy (2012) regarded as amongst the most expensive ever in human history highlighting this point (Kochnower et al. 2015). The hazard mitigation opportunities afforded by natural coastal habitats have in the past been overlooked. Thus, coastal hazard mitigation policy has largely been premised on building hardened, or grey, infrastructure (Kochnower et al. 2015). However, in recent times, there has been significant traction towards the usage of habitats, or natural infrastructure (NI), buoyed by growing positive environmental, engineering and economic findings. Evidence indicates that dunes, wetlands, oyster reefs, coral reefs and mangroves have great potential in mitigating erosion and floods as they serve as buffer against destructive wave energy (Donkor and Mearns 2020c) and absorb and store water from high tides and storm surges. Therefore, environmental advocates and pressure groups are increasingly advocating for integrating habitat restoration and protection or natural infrastructure within the measures towards building the resilience of communities, governments and businesses (Kochnower et al. 2015). In the Decade of Action, natural infrastructure (NI) is described as natural areas, or an amalgamation of natural areas and hardened constructions, that

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equally offer the identical suite of services that grey infrastructure affords such as marshes and bulkheads together reducing erosion attributed to waves (Kochnower et al. 2015). Furthermore, coastal habitats are highly productive areas comprising expanses both aligning and in close proximity with marine shorelines. These serve critical ecosystem functions that help address the effects of climate change (Macura et al. 2019). This includes providing buffers against the impacts of floods and storms, as well as supplying a suite of essential services such as sites for feeding, nursery, spawning, migration for several species and managing agricultural runoff (Reddy 2019). The preservation of such habitats is essential for the protection of shorelines, providing food and shelter for marine life and mitigating climate change impacts. Some of the habitats include mangroves, seagrass meadows, salt marshes and coral reefs. Mangrove roots protect coastal shorelines against storm surges, tidal waves and currents, as well as serve as nurseries and provide refuge for vulnerable fish from predators (Reddy 2019). Moreover, seagrass meadows are crucial habitats of largely submerged aquatic flora providing nursery grounds for several fish and wildlife species, as well as protecting water quality. They mitigate the effects of severe weather, limit erosion and limit impacts of climate variability on coastal communities. Furthermore, salt marshes capture rainwater and limit flooding, thereby acting as natural infrastructure safeguarding coastal communities and carbon sinks. In addition, coral reefs provide refuge to several species, acting as breeding and feeding grounds for a number of marine species, as well as safeguard coastlines in the event of dangerous storms and flooding (Reddy 2019). In all, vegetated coastal ecosystems are critical to coastal defence, sequestration of carbon and facilitating coastal defence infrastructure. There are also other tangible and intangible factors impinging on the sustenance of marine areas which equally deserve further attention. As the Millennium Ecosystem Assessment (2006) notes, there are essential cultural and amenity services that are traced to coastal and marine habitats which will need attention in the Decade

of Action for delivering the SDGs. Cultural services include activities like touristic and recreational activities, aesthetic and spiritual values, traditional knowledge (Ebhuoma et al. 2020a) and educational (Donkor et al. 2017) and research (Donkor et al. 2018) values. Touristic and recreational values are essential cultural services afforded by the coastal and marine ecosystems even though the biological and functional integrity of these biomes is being compromised at unprecedented levels (UNEP 2006). The naturebased tourism sector will have to be assisted to redouble its efforts at safeguarding the biodiversity (such as landscapes and seascapes) which underpins a thriving sector including the invaluable recreational and scenic values (UNEP 2006). These natural amenities are of crucial importance to human being and afford substantial socioeconomic benefits (Ebhuoma et al. 2020a). Poor enforcement of building and construction codes can aggravate ecosystem degradation and damage, thus resulting in the loss of cultural diversity. In this regard, the sustainable tourism development needs to be backed with strict adherence to building and land use codes in fragile environments such as the marine and marine coastal habitats to forestall substantial and frequently irreparable damage. The cultural and spiritual values that are ascribed to marine resources will deserve greater attention as efforts to ensure co-ownership of biodiversity conservation gains traction. This ties in with the concept of traditional ecological knowledge (TEK). TEK denotes the bio-cultural heritage that indigenous and other traditional communities have developed about their environment which supports their communities and maintains their cultural identity. Material benefits from TEK which are widely appreciated include ethnobotany products (medical herbs) and unique traditional foods. TEK is woven into the dynamics of island environments and the inhabitants as demonstrated in their traditional folklore, norms and customs with benefits for conservation. Studies indicate TEK contributes to sustainable conservation such as the preservation of reefs from the negative effects of commercial and recreational fishing as well as safeguarding the sustainable development of the intertidal zone in

Environmental Governance in Context of the Marine Ecosystem: Considerations for Sustainability

Kiribati and Micronesia amongst others (UNEP 2006). In general, the effective conservation of coastal areas involves managing competing interests and conflicts amongst core stakeholders.

Troubled Waters: Creating an Enabling Atmosphere for International Cooperation to Facilitate Marine Conservation It is noteworthy that no meaningful development or successful conservation of marine resources can be achieved in an unstable or hostile condition. In the final Decade of Action, protracted maritime boundary disputes with implications for maritime laws need attention to maintain the conducive atmosphere for global cooperation in the management of critical marine resources (Hasan et al. 2019). The disputes about maritime boundaries are increasingly commonplace and often revolve around the demarcation of the various maritime areas between or amongst states. Furthermore, maritime boundary contestations often take place or are centred on commercial, economic and security interests (Newman 2015). When such disputes persist or remain unresolved beyond reasonable time frames, they are then classified as a protracted maritime dispute. This includes the lack of traction in resolving maritime boundary contestations resulting politically deadlocked negotiations regarding China and Japan in the East China Sea and also Greece and Turkey in the Aegean Sea (Yiallourides 2019). This comes in the face of decades of diplomatic resolution measures to amicably settle conflicting respective maritime and territorial claims. This not withstanding, there have been multiple marine skirmishes and incidents which have triggered diplomatic countermeasures, military standoffs and sometimes occasional exchanging of fire (Yiallourides 2019). Protracted maritime conflicts compromise the political harmony and rather exacerbate discord in international relations. They also disrupt sustainable development of marine areas and come with significant socio-economic and environmental implications. In this regard, the expeditious

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resolution of maritime conflicts and other contestations is crucial for harmony in the coexistence and cooperation of coastal states. Maritime territorial disputes are an alarming problem all across the globe. The challenges introduced by climate change have increased competition of scarce natural resources. Furthermore, as the global economy increasingly becomes in need of ocean-based resources touted as the Blue Economy, countries are going to great extents to secure marine resources. This is evidenced in the record escalation in interventions globally to explore and exploit marine-based mineral as well as food resources (Newman 2015). Although the Law of the Sea Convention serves (Song and Tønnesson 2013) as a reference framework providing guidelines for addressing maritime disputes, conflicting interpretations and often a lack of consensus building exacerbate the incidences of conflicts amongst marine communities and other core stakeholders. In most instances, the failure to achieve an amicable settlement on resolution has truncated or led to a suspension of several bilateral or multilateral agreements. Negotiation represents the most amicable channels for settling all forms of bilateral or multilateral conflicts with maritime boundary delimitation contestations inclusive. In the final Decade of Action for delivering the SDGs, concerted efforts towards enhanced negotiation amongst disputing parties in maritime conflicts deserve great attention. Moreover, there are a number of merits for pursuing negotiations. Disputing parties are at liberty to dictate the terms of the negotiation taking note of their unique circumstances under no compulsion (Aceris Law 2015). The parties are also at liberty to accept or reject the final verdict of negotiation processes and can renege on their cooperation at any stage of the entire process. In essence, maritime boundary disputes, without being effectively resolved in a collaborative and timely approach, tend to jeopardise both the short-term and longstanding execution of maritime policies and strategies. United Nations members states and core stakeholders need to therefore give priority to boundary dispute settlement in order for effective maritime socioeconomic development to be realised. The

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ENVIRONMENTAL RESOURCES Environmental Governance in Context of the Marine Ecosystem: Considerations for Sustainability, Fig. 1 Critical levers in ocean governance for the final Decade of Action and post-COVID era

substantial threats to maritime security attributed to maritime contestations makes it urgent to explore all amicable yet effective responses and mechanisms that can be adopted in the successful resolution of disputes. The dynamic interaction between the various themes of this article is illustrated in Fig. 1. From Fig. 1, it surmised that climate change (through its effects such as higher temperatures, drought, fluctuations in seasons and rainfall patterns) has consequences for the sustainable management of natural resources such as the ocean (Fig. 1). When these resources are managed sustainably, it helps in managing climate change. Similarly, environmental challenges, such as plastic wastes, marine pollution and poor management practices, tend to exacerbate

the impact of climate change (Fig. 1) and the sustainable management of ocean resources. As the world initiates more interventions to recover from the impacts of the coronavirus crisis and facilitate sustainability in the final Decade of Action, the importance of effective ocean governance is more urgent. Some levers that can facilitate this include marine education and research (research and development), addressing the impact of climate change on island nations, enhancing the conservation of coastal habitats and reinforcing international cooperation the management of marine resources. Given the mutually reinforcing nature of the SDGs, the progress made will complement other SDGs and help in leaving no one behind in the process.

Environmental Governance in Context of the Marine Ecosystem: Considerations for Sustainability

Conclusion Collaborative approaches to socioenvironmental challenges will equip society and core stakeholders with an integrated and interdisciplinary perspective, with the capacity to enhance inclusive marine management decision processes and empower social actors including the ocean community. The United Nations declaration of a Decade of Ocean Science for Sustainable Development (2021–2030) provides a “once in a lifetime” opportunity to form novel structures across the science-policy interface, to reinforce the management of the world’s aquatic systems (especially the oceans and coasts) for the sake of humanity. The Decade is a unique time to develop common information systems, guided by reliable science-based data from all core stakeholders of the ocean community. This includes bottom-up and top-down mutual learning amongst researcher and stakeholder communities, facilitating effective crosssector communication, across stakeholder communities. The Decade serves as a participative and transformative framework for scientists, policy makers, managers and service users to collaborate in ensuring that ocean science offers enhanced benefits for the ocean ecosystem as well as the entire society. These actions and related interventions are critical to effectively addressing potential man-made and natural hazards threatening the marine environment and improving the quality of life in various marine locales. Ultimately, they will amongst others engender the science we need for the ocean we want.

Cross-References ▶ Adaptation to Sea-Level Rise and Sustainable Development Goals ▶ Effective Marine Conservation in the Global South: Key Considerations for Sustainability ▶ Fisheries Management and Ecosystem Sustainability ▶ Global Ocean Governance and Ocean Acidification

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▶ Higher Education and Sustainable Development of Marine Resources ▶ Marine Ecosystems: Types, Their Importance, and Main Impacts ▶ Marine Protected Area and Biodiversity Conservation ▶ Maritime Spatial Planning and Sustainable Development ▶ Measuring Success: Indicators and Targets for SDG 14 ▶ Ocean(S) and Human Health: Risks and Opportunities ▶ Ocean-Related Effects of Climate Change on Society ▶ Ocean-Related Impacts of Climate Change on Economy ▶ Promoting Coastal and Ocean Governance Through Ecosystem-Based Management ▶ Resilient Oceans: Policies and Practices to Protect Marine Ecosystems ▶ Sustainable Coastal and Marine Ecotourism: Opportunities and Benefits

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Environmental Threats to Cetaceans ▶ Cetacean Threats

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Epipelon ▶ Role of Microphytobenthos in the Functioning of Estuarine and Coastal Ecosystems

Epipsammon ▶ Role of Microphytobenthos in the Functioning of Estuarine and Coastal Ecosystems

Estuaries: Dynamics, Biodiversity, and Impacts Patrícia G. Cardoso Group of Endocrine Disruptors and Emergent Contaminants, Centre of Marine and Environmental Research (CIIMAR/CIMAR), University of Porto, Matosinhos, Portugal

Synonyms Brackish waters; Coastal lagoons; Transitional waters; Water basins

▶ Role of International Law in Effective Governance of the Marine Environment

Definition

Environmental Resources

An estuary can be defined as a semi-enclosed coastal body of water where freshwater masses from land are in straight connection with the open sea. This creates a heterogeneous environment that can be divided into different sectors, according to Fairbridge (1980): (1) a more marine one with higher influence of the sea; (2) an

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intermediate sector characterized by brackish waters and very resilient species, subject to strong tidal influence; and (3) a more freshwater sector, but still with some saline influence.

Estuarine Ecosystem Types of Estuaries Based on Water Dynamics/ Balance An estuary is considered a dynamic system where there is a free linking with open sea through which the seawater enters according to the tides and mixes with the freshwater draining from land. Depending on the degree of dilution, volume of freshwater, tidal amplitude range, and evaporation, the estuaries can be classified into three distinct types (McLusky and Elliott 2004): Positive estuary, the degree of evaporation in the surface is lower than the volume of freshwater. So, outgoing freshwater floats over the saline water and it mixes gradually and vertically from the bottom to the top. This type is typical of temperate systems. Negative (or inverse) estuary, the degree of evaporation in the surface is higher than the volume of freshwater, so the salinity on the top tends to be higher and the freshwater sinks. It is typical of tropical environments. Neutral estuary, the degree of evaporation equals the volume of freshwater and in this case occurs a static salinity regime. This type of estuary is quite rare. Types of Estuaries Based on Geological Origin Besides the water circulation, the topography of estuaries is continually changing, and according to this characteristic, following different types of estuaries (McLusky and Elliott 2004, Kowalewska-Kalkowska and Marks 2015) can be defined: Fjords, associated with high-latitude areas where glaciation has been responsible for the shape of the valleys. They are characterized by elongated deep channels with steep sides and linked to the sea by shallow entrance sills. They are typical of Norway, Sweden, Alaska, British Columbia, and New Zealand.

Estuaries: Dynamics, Biodiversity, and Impacts

Coastal plain estuaries are typically very shallow, funnel shaped, several kilometers wide, and filled with sediment which leads to the occurrence of saltmarshes and mudflats. In this type of estuary, the stretch of the freshwater river above the upper limit of intrusion of sea-derived salt is under tidal influence. Some examples are: Chesapeake Bay, Charleston Harbor, Delaware Bay (USA), Severn, Dee, Humber, Thames (UK). Rias are also formed through rise in sea level, but contrarily to plain estuaries, they are deep and narrow channels with a strong marine influence. Examples are estuaries of Cornwall (UK) and Brittany (France). Bar-built estuaries are another type of drowned river valleys in which the deposition of sediment has continued with the sea level rise, thus correspond to shallow estuaries and separated from the sea by sand spits or barrier islands. Some examples are the Ythan (Scotland), Barnegat Bay (New Jersey), southern Portugal (e.g., Albufeira), northern Mexico, most estuaries in North Carolina (Florida coast). Complex estuaries are drowned river valleys of complex origin, generally a combination of glaciation, river erosion, and sea level rise. Also, the estuaries created by tectonic activity are considered in this category. As examples, Scottish Firths: Moray, Solway, Tay, Forth, and Dornoch. San Francisco Bay is an example of tectonic activity. Embayments correspond to large natural areas formed between rocky promontories that fill with soft sediments. Some examples are the Morecambe Bay, Carmathen Bay (UK). Types of Estuaries Based on Salinity Vertical Structure and Mixing Processes Regarding the vertical stratification and the extent of lateral homogeneity, the estuaries can be classified according to Valle-Levinson (2010) as: Salt wedge or highly stratified, dominated by the river discharge, the freshwater less dense water flows over the seawater (denser), forming a sharp horizontal layer between them (pycnocline). Some examples are: Mississippi River (USA), Ebro River (Spain), Vellar (India). Strongly stratified estuaries (or fjord type), similar to the previous one, but due to the presence

Estuaries: Dynamics, Biodiversity, and Impacts

of a sill in the mouth of the river the inflow of seawater is lower. Partially stratified estuaries, dominated by tidal inflow and a weak to moderate river discharge. Are characterized by a weak pycnocline from surface to bottom. In this type of estuary there is a continuous mixing between the two water layers (e.g., Thames, Humber, Forth (UK), Elbe (Germany), Chesapeake Bay (USA)). Well-mixed (homogeneous) estuaries, characterized by strong tidal inflow and weak river discharges and mean salinity profiles are almost uniform and the flows are unidirectional with depth (e.g., Delaware (USA), Mondovi-Zuari (India)). Types of Estuaries Based on Tidal Range According to tidal range (i.e., vertical distance between the high water level and the low water level), the estuaries can be classified as follows (McLusky and Elliott 2004): Microtidal, if tidal range is lower than 2 m; it has limited intertidal areas (e.g., Portland estuary (UK), Cancun Bay (Mexico), Mississippi (USA)). Mesotidal, tidal range of 2–4 m, characterized by considerable intertidal areas, usually covered by typical vegetation, such as Spartina sp. Some examples are Clyde, Ythan, Tay (Scotland); Southampton, Orwell (UK); Mondego (Portugal). Macrotidal, tidal range of 4–6 m. Hypertidal, tidal range is higher than 6 m. In both macrotidal and hypertidal estuaries, the

Estuaries: Dynamics, Biodiversity, and Impacts, Fig. 1 Schematic representation of the tidal cycle with indication of spring and neap tides, according to the position of the Sun and Moon over the Earth. (Credits: Patrícia G Cardoso)

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existence of bare mudflats without large plants is more typical.

Estuarine Dynamics Tides Estuaries are very dynamic environments with a free connection with the sea and a great influence on the tides. These are basically created by the gravitational forces of the Moon and Sun on the Earth, being the effect of the Moon upon the Earth twice of that of Sun due to its proximity to the Earth. When the moon (during full moon and new moon) and Sun are aligned with the Earth, the gravitational force that they exert on the Earth is much higher than when they are not aligned, so in the first case are originated the spring tides, which occur twice a month, while in the latter are originated the neap tides (during quarter phases), occurring in the remaining weeks (Fig. 1). Regarding the daily tidal regime, in general, most areas around the globe are characterized by two high tides and two low tides. If the two tides a day have similar height, this pattern is called semidaily or semidiurnal tide. But if they have different heights, it is called a mixed semidiurnal tide. However, in some areas of the Earth, like in the Gulf of Mexico, there is only one tide a day. This is called a diurnal tide. All these variations are due to the fact that the presence of large continents on the surface of the Earth can block the passage of

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the tide as the Earth rotates. This way the tides establish complex patterns in each ocean basin and originates these discrepancies around the globe (Daborn and Redden 2018, https:// oceanservice.noaa.gov/education/tutorial_tides/ tides07_cycles.html). Sediments and Nutrients Another important factor that is responsible for the dynamic changes of the estuaries is the sediments’ nature, which can be more sandy, muddy or rocky, depending on the origin of the estuaries. Most of them have a large input of sediment load and tend to be characterized by fine sedimentary deposits or muds. Those sediments can come from the river or sea, but independently of the origin, the deposition of those sediments is controlled by the currents, particle size, and water dynamics. Ultimately, the stability of the substrate and the nature of it will determine the type of flora and fauna that will colonize those areas (McLusky and Elliott 2004). Along with the sediments being carried into the estuaries are also carried loads of soluble and particulate materials derived from the catchment area of the estuary. These loads may be derived from both leaching and runoff from the land or atmospheric deposition and in most cases have anthropogenic sources. Estuaries are generally rich in nutrients, especially nitrogen and phosphorus, which have an important role in the primary production of those areas. Historically, the nutrients loads have increased following the population growth in their catchments and the consequent release of wastes and the increasing use of fertilizers in agriculture. However, this increment in the nutrients load is not directly proportional to the primary production, since sometimes the high turbidity of the systems does not allow the plants’ growth.

Estuaries: Dynamics, Biodiversity, and Impacts

which is relevant for the primary production and entire life in those areas. Despite the great variability in the physicochemical characteristics (i.e., temperature, oxygen, salinity) that the organisms are subject to, estuaries are perfect areas for the development of certain species which are particularly different from those of the river or the sea. Since the tides are one of the main drivers of the life in estuaries, the organisms that live in these environments can be classified into (1) oligohaline, if they tolerate salinities lower than 0.5, despite some can support salinities up to 5; (2) true estuarine, if they live in the central part of the estuaries but could also live in the sea, they are most common in salinities of 5–18; (3) euryhaline marine, constitute the majority of the organisms that live in estuaries supporting a large range of salinities; and (4) stenohaline marine, live close to the mouth in a complete marine environment. In addition, the estuarine environment can be divided into two areas depending on the influence of the tides: (1) intertidal areas, are markedly dependent on the tides, since the substrate can be alternately covered or exposed as the tide rises or falls. These are very stressful areas which are constantly subject to changes in their physicochemical parameters (i.e., temperature, oxygen, pH), desiccation, etc., and are inhabited by a low diversity of species; (2) subtidal areas, are always covered by water, so constitute more stable environments and are inhabited by a higher diversity of species. In both intertidal and subtidal areas, there are typical organisms that live in the water column and are called pelagic organisms. These can be divided into planktonic, if they have limited swimming abilities, or nektonic, if they have free swimming abilities (e.g., fishes). The organisms that live in close connection to the bottom are the benthonic organisms. Other important groups of organisms that inhabit the estuaries are the birds and shorebirds.

Biodiversity of Life in Estuaries Estuaries are some of the most productive habitats on Earth, since they are shallow systems where the light penetrates till the bottom and can accumulate important nutrients in their surroundings

Estuarine Food Web The estuarine food web is mainly dependent on two basic pillars: the energy that reaches those systems through the sunlight and also the organic matter input into the estuary (McLusky and Elliott

Estuaries: Dynamics, Biodiversity, and Impacts

2004). Within the system, the primary producers will use those inputs as the basis for the production of living material which will be consumed directly by primary consumers which are in turn consumed by secondary consumers. Primary Producers In the estuarine ecosystem can be found distinct primary producers, depending mainly on the light, temperature, and nutrients (especially nitrogen and phosphorus). In the upper intertidal area, it is common to find the saltmarsh plants (e.g., Spartina sp., Scirpus sp., Phragmites sp., Juncus sp., etc.) which do the transition between the terrestrial and aquatic ecosystems in temperate systems. These saltmarshes are highly productive ecosystems (100–1000 g C m
2 year
1) (McLusky and Elliott 2004). They have a significant impact exporting a relevant amount of particulate organic matter, providing a rich food supply for the detritivores (i.e., detritus feeders). This environment is considered an important habitat for animals like fishes and shrimps and a breeding site for birds. In the tropics, the corresponding habitats are the mangroves whose presence correlates with warmer waters. Like the saltmarshes, they contribute to the estuarine ecosystem through the strong input of plant litter which can be used directly or in its degraded forms by many species. In other parts of the intertidal zone can be found a variety of seagrasses, such as the Zostera (Z. noltei developing in intertidal zones and Z. marina occurring in subtidal areas), Ruppia and Potamogeton in temperate systems, while Cymodocea, Posidonia, and Thallasia are some examples of seagrasses that occur in more tropical areas. These seagrass meadows are always very rich in terms of species diversity and very productive areas (up to 1000 g C m
2 year
1), being considered as well as saltmarshes and mangroves and as excellent nursery areas for many species of fishes and invertebrates (Jackson et al. 2001). In terms of macroalgae, a few species are typical of estuarine environments, such as the green Ulva sp., the red Gracilaria, and the brown Fucus. These algae can grow on the surface of the mudflats or attached to small rocky outcrops, like Fucus. Macroalgae can contribute up

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to ≈ 30% of total primary production and its highest biomass and production are associated with lower hydrodynamics and higher nutrient supply (McLusky and Elliott 2004). On the top layer of the mudflats can also be found important populations of diatoms and other microalgae that constitute the microphytobenthos. These microalgae can be present the entire year and have a significant role in the estuarine ecosystem contributing to a net production of 30–300 g C m
2 year
1 (McLusky and Elliott 2004). They are the main ones responsible for the oxygenation of the sediment surface through the photosynthesis and can play a relevant role in the sediments versus overlying water nutrients exchange. The presence of higher microphytobenthos biofilm is positively related to the hydrodynamics of the estuary, so lower hydrodynamics favor the development of microphytobenthos biofilm. In the water column, the existence of other types of primary producers like the phytoplankton (i.e., diatoms and dinoflagellates) can be considered. However, its contribution to the entire production of the estuarine ecosystem is much lower than the saltmarshes and seagrasses. But, for many species of consumers, phytoplankton is a much richer food source than the detritus coming from plants degradation. Primary Consumers: Herbivores and Detritivores As described previously, estuaries are very rich in detritus which constitute the main food resource for the primary consumers. This food supply is available the entire year being more enriched during spring/summer when the higher temperatures accelerate the biological production. Most of these primary consumers can be found on the bottom of the estuary and can be divided into four main groups: the benthic deposit feeders, the benthic suspension feeders, the grazers, and the herbivores. The deposit feeders can be divided into two categories: the surface deposit feeders and the sub-surface deposit feeders (Gaston 1987). In the first one are included the species that live on the surface of the sediment or have a direct contact

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with the surface, such as some molluscs like the bivalves Macoma baltica and Scrobicularia plana and the gastropod Peringea ulvae, which are common species of European estuaries. In addition, the amphipod crustaceans, such as the Corophium volutator or the Ampithoe valida and Melita palmata, are some of the typical estuarine amphipod species. As sub-surface deposit feeders are those organisms that live deeply buried in the sediment with little contact with the surface. They are the annelids (i.e., polychaetes and oligochaetes) that live inside the burrows that they build. The polychaetes are the most diverse group of benthic organisms that live in the estuaries, with different shapes, characteristics, and life cycles. Some examples are the ragworm Hediste diversicolor, one of the dominant polychaete species in European estuaries. In America, the clamworm Alitta succinea is probably the most abundant one. The oligochaetes are much smaller than the polychaetes and are less studied, however they are quite abundant and resistant to low oxygen conditions (McLusky and Elliott 2004). The benthic suspension feeders are those organisms that filter the organic matter in suspension, so they have an important role as cleaners of the water column contributing to a better quality of the estuaries. Some examples of suspension feeders are the mussels Mytilus edulis, the oysters Crassostrea sp. among others, such as the cockles Cerastoderma edule. In general, there are edible species with a great ecological and economic value that can be limited by the food supply, because of the hydrodynamics of the systems. Higher hydrodynamic systems favor the biomass of these organisms. The grazers correspond to those organisms, such as some gastropods that feed on the surface of the sediment or plants removing the microphytobenthos biofilm (i.e microalgae) existent, while herbivores feed directly on the plants, like gastropods (e.g., Littorina littorea) and sea urchins that feed on green macroalgae Ulva sp. Most of the species do not feed directly on the plants but prefer the plants detritus or the microphytobenthos biofilm deposited over the leaves of seagrasses, for example.

Estuaries: Dynamics, Biodiversity, and Impacts

On the other hand, in the water column should be considered the existence of the zooplankton, whose total biomass is much smaller than the one of the benthic community, however with great importance for the entire estuarine ecosystem. Secondary Consumers The secondary consumers or predators are diverse and include different groups of organisms, from the benthos, fishes to the birds. As best representative benthic predator species are the crab Carcinus maenas, the shrimp Crangon crangon, and some polychaetes like the Hediste diversicolor (both deposit feeder and also predator) or the cat-worm Nephtys hombergi. All of these are potent carnivores that have a great predatory impact on the estuarine primary consumers, despite in most cases are considered omnivorous species, being able to feed on plant detritus and other planktonic organisms. Regarding the fish community, it can be very abundant and diverse. However, it has a great seasonal influence, since many species use the estuaries to breed and use them as nursery areas where the fish grow and then return to the sea (i.e., marine species, such as cod, herring, haddock, plaice, gray mullet); others use the estuaries as a route between the river and the sea (i.e., diadromous species, like salmon, eel, trout) and few species are really estuarine ones, spending their entire lives in the estuary (i.e., estuarine residents, such as flounder, eelpout) (Elliott and Dewailly 1995). So, the estuarine ecosystem can offer different types of environments (i.e., more saline or more freshwater) that allow the great diversity of fish populations. On another level are the birds, such as the waders, gulls, and wildfowls which are more conspicuous and use the estuaries, especially as migratory routes for feeding and resting. Distinct bird species use different areas of the estuaries, mainly to feed. For example, eider ducks feed in the shallow water during low tide while the diving ducks and mergansers feed at high tide, diving to catch their preys. Other species like the redshank, shelduck, and knots feed on the infaunal invertebrates in the intertidal areas (McLusky and Elliott 2004).

Estuaries: Dynamics, Biodiversity, and Impacts

Both predators and preys have different strategies to be successful. For example, the knot that usually feeds on the gastropod Peringea ulvae waits for the tidal rise for the re-emergence of the gastropod to feed on, it while the bivalve Macoma, during the period when predators are more absent, remains closer to the surface of the sediment while during more pressure periods it lives deeper in the mud. So, all these trophic levels are interconnected and the flow of energy coming from the land or sea, in the form of nutrients and detritus, will return to the origins through the migrating fish, birds, and nutrients.

Anthropogenic Impacts The estuarine ecosystems are some of the most impacted systems worldwide. As a consequence of the population and economic growth and fixation of a great part of the worldwide population near the coastal areas (more than four billion people, according to Kennish et al. 2008), the anthropogenic impacts on the estuarine areas have increased considerably in the last decades. Estuaries are some of the most productive areas on Earth and this has also attracted more people to explore this resource, intensively. Thus, several major anthropogenic stressors can be identified on the estuarine ecosystems, such as nutrients enrichment (eutrophication), habitat loss and alterations, chemical contamination, climate change, overexploitation of resources, and invasive species. Nutrients Enrichment In many estuaries worldwide, the excessive anthropogenic nutrient loadings, like nitrogen and phosphorous, used particularly as fertilizers in the agriculture, associated with long residence times and low water dynamics as caused severe eutrophication problems with severe impacts on ecological processes in marine coastal ecosystems (Raffaelli et al. 1998; Philippart et al. 2007; Kennish and de Jonge 2011). Besides the agriculture sources, those nutrients can derive from municipal and industrial wastewaters, storm

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water runoff, malfunctioning septic systems, and atmospheric deposition (Kennish 2016). Eutrophication generally leads to an increase of primary production (i.e., phytoplankton and/ or fast growing macroalgae), reduction of dissolved oxygen levels, loss of seagrass habitat, and modifications in the biotic communities, namely the macrobenthic community structure, abundance, and biodiversity (Dolbeth et al. 2007; Philippart et al. 2007; Cardoso et al. 2008, 2010). More recently, the recognition of the importance of the ecosystem functions and services provided by the estuaries to society has led to several programs to restore and protect estuaries. A successful case was the Mondego estuary (Portugal) in which the implementation of mitigation measures, in the late 1990s, to reduce nutrients concentration and improve the water quality, as well as the seagrass Zostera noltii bed had a good response of the system. A clear decline of the dissolved inorganic nitrogen and a gradual recovery of the Z. noltii were observed. Also, the macrobenthic assemblages responded positively to the recovery process (Cardoso et al. 2010). The positive results observed for the Mondego estuary are in agreement with the sustainable development goal (SDG) 14 for the United Nations, contributing to the sustainable management and protection of marine and coastal ecosystems in order to achieve healthy and productive oceans. Habitat Loss The development of big demographic clusters near coastal areas is effectively responsible for a substantial estuarine habitat loss and modifications. Physical alteration as a result of continuous dredging of navigable channels, leading to water column turbidity and sediment erosion, as well as the coastal construction associated with the development of aquaculture infrastructures are the main causes of habitat degradation and loss of seagrasses with serious implications for the biotic communities. For example, in the Ria Formosa lagoon (south of Portugal), the construction of clam aquaculture areas, one of the most important economic activities of the region, has triggered the

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destruction of large intertidal beds of Z. noltii (Duarte et al. 2004). On the other hand, coastal construction such as impoundment dikes, dams for flood control, and water control embankments are responsible for the modifications in the hydrology of wetland systems. As a consequence, tidal flooding, water flow, and drainage are often altered which cause modifications in the saltmarshes (i.e., reduction of sediment loading and hastening marsh submergence) (Kennish 2001). The construction of other shoreline structures, like piers, marinas, stormwalls, and other protective structures, has also implications in the function of sensitive and dynamic systems like the estuaries. Chemical Contamination Coastal ecosystems, like estuaries, are subject to severe impacts due to the anthropogenic pressure. The more urbanized the estuaries are, the higher impacts they are subjected to. Major sources of contaminants are the agricultural and urban runoff, industrial discharges, groundwater inputs, riverine inflow, and also the sewage treatment plants (STP). The latter can be a strong problem to these habitats, since STPs are not totally efficient in removing several contaminants like persistent organic pollutants, such as pesticides and polycyclic aromatic hydrocarbons (PAHs), pharmaceutical compounds, and metals. Most of these contaminants are hydrophobic and tend to accumulate in aquatic organisms (Fent 2015). Some of the most relevant contaminants found in the estuaries are trace metals, persistent organic pollutants (POPs) such as organohalogenated compounds (e.g., PCBs, PCDDs, PCDFs), polycyclic aromatic hydrocarbons (PAHs), and pesticides; also, the less studied pharmaceutical compounds and personal care products. The presence of contaminants in the aquatic ecosystems is a worldwide problem, with particular attention to the sediments which act as a source of hydrophobic and dangerous compounds (Ribeiro et al. 2016). Most of these compounds, from metals to pharmaceuticals, are considered endocrine disruptors not only causing disruptive effects in the aquatic

Estuaries: Dynamics, Biodiversity, and Impacts

life (e.g., reduction of reproductive success, hatching success, and embryos survival) but also inducing negative impacts on human health, for example, increase of cancer incidence (Rocha and Rocha 2015). For example, one of the metals with higher impact on aquatic environment is mercury (Hg). While in the developed countries there has been an effort to reduce the Hg levels from industrial plants, in developing countries the rapid industrialization is responsible for the increment of Hg atmospheric burden by 1.5% per year (Rice et al. 2014). Hg is a well-studied element, and many surveys revealed its negative impact on aquatic life, namely on macrobenthic community structure and functioning (i.e., dominance of smaller size species) (Mucha et al. 2005; Matos et al. 2016), on zooplankton species diversity (Cardoso et al. 2013), and on reproductive success by altering gametogenesis and gonadal development in parents or reducing hatching success of eggs and survival of embryos, altering sex ratio of offspring (Tan et al. 2009 and references therein). Regarding the POPs, like the PAHs and pesticides, they are ubiquitous in the aquatic systems and their effects are well studied. Both groups of compounds tend to cause endocrine disruption, carcinogenesis, and mutagenicity (Köhler and Triebskorn 2013; Kennish 2016). Concerning the endocrine disrupting pharmaceuticals, they can have a natural (e.g., phytoestrogens) or synthetic (e.g., bisphenol A, progestins) origin. The most common groups represented in aquatic bodies are steroid hormones (e.g., estrogens, progestogens/progestins, androgens and glucocorticoids, phytoestrogens and veterinary growth hormones), personal care products (disinfectants, conservation agents, fragrances, UV screens), and a broad range of nonsteroidal pharmaceuticals (e.g., analgesics/ anti-inflammatories, antibiotics, cardiovascular pharmaceuticals, anti-depressants, anti-epileptic and dermatological drugs) (Li 2014, Ebele et al. 2017). Much more attention has been given to these compounds in the last years, since they are continuously released into the environment. Based on previous studies, their presence in the environment, even at trace concentrations (range

Estuaries: Dynamics, Biodiversity, and Impacts

of ng L
1), can cause negative effects at different levels, from feeding rates (Gaworecki and Klaine 2008) to reproduction of aquatic species (Runnalls et al. 2013; Cardoso et al. 2017). So, a bigger effort has been implemented in order to increase the knowledge about the fate and effects of emergent compounds and consequently prevent and propose measures to reduce marine pollution of all kinds achieving one of the targets of goal 14 life below water: conserve and sustainably use the oceans, seas and marine resources. Climate Change In the last century, we have assisted to an increase of intensity and frequency of extreme weather events (e.g., droughts, floods, heat waves) besides the unequivocal global warming and ocean acidification. As a consequence of global warming, and especially in biogeographic transition areas, substantial modifications in species geographic distribution, namely the expansion of warm water species, range northward. This can be observed for the macroalgae community (Lima et al. 2007) but also for the fish assemblages, in which landings of species of temperate waters tend to decrease while species of subtropical and tropical waters tend to increase (Gamito et al. 2016). These global changes may lead to the extinction of some species with a lower thermal limit and the colonization by species previously absent in certain areas (Cheung et al. 2009). In addition, the effects of climate change and extreme weather events on aquatic species have been documented worldwide for different groups of organisms, from coral reefs (Kemp et al. 2011, Gilmour et al. 2013), kelp forests (Wernberg et al. 2016) to invertebrates (Garrabou et al. 2009; Grilo et al. 2011). Another problem associated with climate change is the sea-level rise and coastal flooding that will affect coastal wetlands, making them more vulnerable as well as their biotic communities (Kennish et al. 2008). Overexploitation of Resources Estuaries are considered some of the most productive ecosystems on Earth, providing food, shelter, and nursery areas for many species of commercial

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interest and as a consequence their natural resources are generally overexploited. Among them, shellfish are greatly harvested by humans (Crespo et al. 2010), including shrimps, crabs, oysters, cockles, and mussels. Also, bait catching by sport fishermen has negative consequences for the intertidal seagrass beds and associated fauna, since the most traditional methods for direct capture include digging and raking, which causes serious disturbance of the sediment. In addition to the shellfish resources, also the vertebrates’ fisheries are an important resource. Many commercial species, for example, salmon, sea trout, and eels, that use the estuaries as a route, are usually exploited. Some examples of large estuarine areas that are usually exploited in terms of fisheries are the Nigerian, Indian, and Amazon estuaries (McLusky and Elliott 2004). However, the overharvesting of fisheries can have multiple impacts on the ecosystem, such as (1) the possible extinction of species, for example, what happened to the adults of cockle Cerastoderma edule in the Mondego estuary in 2005, that almost disappeared due to the excessive catching (Crespo et al. 2010); (2) the habitat modification due to trawling with negative effects on the flora and fauna, as well as water quality (i.e., resuspension of sediment, increase of turbidity); (3) bycatch effects on other species; (4) threat to target populations’ viability, maturity, and success due to removal of spawning stocks and the consequent implications on estuaries nursery functions (McLusky and Elliott 2004). So, one of the short-term targets of the sustainable development goal (SDG) 14 is to effectively regulate harvesting and end overfishing; illegal, unreported, and unregulated fishing; and destructive fishing practices, and implement science-based management plans, in order to restore fish stocks. In addition to the natural resources exploitation, another concern for the estuarine systems is the increasing development of aquaculture systems, not only for shellfish (i.e., maricultures, especially for bivalves, i.e., oysters, cockles, and mussels) but mainly for fish production. Actually, approximately 50% of the seafood consumed worldwide derives from aquaculture, being the developing countries (e.g., China (60%), India

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(6.5%), Indonesia (5%), Vietnam (5%)), those that contribute most (Chuah et al. 2016). Despite fish farming can compensate for the overfishing of natural stocks, an intensive aquaculture can cause several problems for the environment, namely (1) the destruction of natural habitat (e. g., salt ponds) affecting the related species (e.g., waders using salt ponds for feeding during the migration routes); (2). the coastal pollution with constant releases of excessive amounts of nutrients, organic matter, and feces which can contribute to the environmental quality degradation; and (3) the release of chemicals (e.g., antibiotics) to the environment contributing to the emergence of multiple antibiotic-resistant bacteria (Cabello et al. 2016, Chen et al. 2018). Invasive Species In the last decades, the colonization by non-native species in estuarine ecosystems has become a worldwide problem, which can trigger relevant ecological and economic impacts. Estuaries are particularly susceptible areas for invasions because of their nature (subject to freshwater and marine inputs) and particular physicochemical conditions; the proximity to population agglomerates can be the main vector of non-native species introduction through fisheries, aquaculture, and ballast water from shipping (Crespo et al. 2015). From the macroalgae to vertebrates, the number of invasive species has been growing because of the reasons mentioned as well as the climate change and its consequent shifts on species distribution regimes. This pattern is expected to increase in near future (Cardoso et al. 2019) due to population growth, higher commercial trade and shipping, changes in land-use and hydrology, and global climate change. The presence of nonnative species can be very harmful for the native ones since in most cases they have competitive advantage, and in the absence of their natural predators and competitors they are able to dominate community. Such distribution of non-native species will have significant impact on trophic interactions and estuarine ecosystems’ biodiversity (Butchart et al. 2010). Generally, invasions are associated with an ecological threat, however, in some particular cases, the co-occurrence of

Estuaries: Dynamics, Biodiversity, and Impacts

invasive filter feeders can have positive effects on the water quality, diminishing the bioturbation of water column with benefits for the ecosystem (Queirós et al. 2011). Yet, in the majority of cases the negative effects are higher than the positive ones, leading to economic losses, health issues, and disturbances in ecosystems structure and function (Hicks et al. 2011).

Final Remarks Estuaries are quite complex ecosystems, characterized by multiple interests and uses and where a large number of distinct actors act together. The human well-being and economic viability of these areas depend not only on the natural resources, biodiversity, landscape, and cultural heritage, but also on infrastructures, tools, human education, skills, knowledge, and culture (Constanza et al. 2014; Lillebø et al. 2017). For a sustainable ecosystem, human well-being and nature should be in an equilibrium and for that a holistic approach involving all the components of the estuarine ecosystem should be implemented. Therefore, management of these areas involves a range of institutions and administrative units and should have the support of scientific knowledge associated with the participation of all the stakeholders involved in the system. According to McLusky and Elliott (2004), a cost-effective and sustainable management depends on the following tenets: be economically viable, be environmentally sustainable, legally permissible, technologically feasible, socially desirable, and administratively achievable. So, only through the interlinking of participants, the estuaries can be successfully managed and the sustainability perpetuated.

Cross-References ▶ Biological Invasions as a Threat to Global Sustainability ▶ Coastal Pollution ▶ Pharmaceuticals Contamination: Problematic and Threats for the Aquatic System

Estuaries: Dynamics, Biodiversity, and Impacts

▶ Role of Microphytobenthos in the Functioning of Estuarine and Coastal Ecosystems ▶ Saltmarshes: Ecology, Opportunities, and Challenges ▶ Seabirds

References Butchart SHM, Walpole M et al (2010) Global biodiversity: indicators of recent declines. Science 328:1164– 1168 Cabello FC, Godfrey HP, Buschmann DHJ (2016) Aquaculture as yet another environmental gateway to the development and globalisation of antimicrobial resistance. Lancet Infect Dis 16:127–133 Cardoso PG, Raffaelli D, Lillebø AI, Verdelhos T, Pardal MA (2008) The impact of extreme flooding events and anthropogenic stressors on the macrobenthic communities’ dynamics. Estuar Coastal Shelf Sci 76: 553–565 Cardoso PG, Leston S, Grilo TF, Bordalo MD, Crespo D, Raffaelli D, Pardal MA (2010) Implications of nutrient decline in the seagrass ecosystem success. Mar Pollut Bull 60:601–608 Cardoso PG, Marques SC, D’Ambrosio M, Pereira E, Duarte AC, Azeiteiro UM, Pardal MA (2013) Changes in zooplankton communities along a mercury contamination gradient in a coastal lagoon (Ria de Aveiro, Portugal). Mar Pollu Bull 76:170–177 Cardoso PG, Rodrigues D, Madureira TV, Oliveira N, Rocha MJ, Rocha E (2017) Warming modulates the effects of the endocrine disruptor progestin levonorgestrel on the zebrafish fitness, ovary maturation kinetics and reproduction success. Environ Pollut 229:300–311 Cardoso PG, Dolbeth M, Sousa R, Relvas P, Santos R, Silva A, Quintino V (2019) The Portuguese coast (chapter 7). In: Shepard C (ed) World Seas: An Environmental Evaluation. Academic Press, London. https://doi.org/10.1016/B978-0-12-805068-2.00009-7 Chen B, Lin L, Fang L, Yang Y, Chen E, Yuan K, Zou S, Wang X, Luan T (2018) Complex pollution of antibiotic resistance genes due to beta-lactam and aminoglycoside use in aquaculture farming. Water Res 134:200–208 Cheung WWL, Lam VWY, Sarmiento JL, Kearney K, Watson R, Pauly D (2009) Projecting global marine biodiversity impacts under climate change scenarios. Fish Fish 10:235–251 Chuah LO, Effarizah ME, Goni AM, Rusul G (2016) Antibiotic application and emergence of multiple antibiotic resistance (MAR) in global catfish aquaculture. Curr Environ Health Rep 3:118–127 Constanza R, de Groot R, Sutton P, van der Ploeg S, Anderson SJ, Kubiszewski I, Farber S, Turner RK (2014) Changes in the global value of ecosystem services. Glob Environ Chang 26:152–158

365 Crespo D, Verdelhos T, Dolbeth M, Pardal MA (2010) Effects of the over harvesting on an edible cockle (Cerastoderma edule Linaeus, 1758) population on a southern European estuary. Fresenius Environ Bull 19: 2801–2811 Crespo D, Dolbeth M, Leston S, Sousa R, Pardal MA (2015) Distribution of Corbicula fluminea (Müller, 1774) in the invaded range: a geographic approach with notes on species traits variability. Biol Invasions 17:2087–2101 Daborn GR, Redden AM (2018) Estuaries. In: Finlayson CM (ed) The wetland book. Springer, pp 37–53 Dolbeth M, Cardoso PG, Ferreira SM, Verdelhos T, Raffaelli D, Pardal MA (2007) Anthropogenic and natural disturbance effects on a macrobenthic estuarine community over a 10-year period. Mar Pollut Bull 54: 576–585 Duarte CM, Marbà N, Santos R (2004) What may cause loss of seagrasses? In: Borum J, Duarte CM, KrauseJensen D, Greve TM (eds) European seagrasses: an introduction to monitoring and management. EU project Monitoring and Managing of European Seagrasses (M&MS), EVK3-CT-2000-00044, pp 24–32. http:// www.seagrasses.org Ebele AJ, Abdallah MAE, Harrad S (2017) Pharmaceuticals and personal care products (PPCPs) in the freshwater aquatic environment. Emerging Contaminants 3: 1–16 Elliott M, Dewailly F (1995) Structure and components of European estuarine fish assemblages. Neth J Aquatic Ecol 29:397–417 Fairbridge R (1980) The estuary: its definition and geodynamic cycle. In: Olausson E, Cato I (eds) Chemistry and geochemistry of estuaries. Wiley, New York, pp 1–35 Fent K (2015) Progestins as endocrine disrupters in aquatic ecosystems: concentrations, effects and risk assessment. Environ Int 84:115–130 Gamito R, Pita C, Teixeira C, Costa MJ, Cabral HN (2016) Trends in landings and vulnerability to climate change in different fleet components in the Portuguese coast. Fish Res 181:93–101 Garrabou J, Coma R, Bensoussan N, et al (2009) Mass mortality in Northwestern Mediterranean rocky benthic communities: effects of the 2003 heatwave. Glob Change Biol 15:1090–1103 Gaston GR (1987) Benthic polychaeta of the middle Atlantic bight: feeding and distribution. Mar Ecol Prog Ser 36:251–262 Gaworecki KM, Klaine SJ (2008) Behavioral and biochemical responses of hybrid striped bass during and after fluoxetine exposure. Aquat Toxicol 88:207–213 Gilmour JP, Smith LD, Heyward AJ, Baird AH, Pratchett MS (2013) Recovery of an isolated coral reef system following severe disturbance. Science 340:69–71 Grilo TF, Cardoso PG, Dolbeth M, Bordalo MD, Pardal MA (2011) Effects of extreme climate events on the macrobenthic communities’ structure and functioning of a temperate estuary. Mar Pollut Bull 62:303–311

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366 Hicks N, Bulling MT, Solan M, Raffaelli D, White PCL, Paterson DM (2011) Impact of biodiversity-climate futures on primary production and metabolism in a model benthic estuarine system. BMC Ecol 11(7) Jackson EL, Rowden AA, Attrill MJ, Bossey SJ, Jones MB (2001) The importance of seagrass beds as a habitat for fishery species. In: Gibson RN, Gibson RN (eds) Oceanography and marine biology, an annual review, vol 39. CRC Press, Boca Raton Kemp DW, Oakley CA, Thronhill DJ, Newcomb LA, Schmidt GW, Fitt WK (2011) Catastrophic mortality on inshore coral reefs of the Florida keys due to severe lowtemperature stress. Glob Chang Biol 17:3468–3477 Kennish MJ (2001) Coastal salt marsh systems in the U.S.: a review of anthropogenic impacts. J Coastal Res 17:731–748 Kennish MJ (2016) Anthropogenic impacts in encyclopedia of estuaries. Springer, Dordrecht. https://doi.org/10. 1007/978-94-017-8801-4 Kennish MJ, de Jonge VN (2011) Chemical introductions to the systems: diffuse and nonpoint source pollution from chemicals (nutrients: eutrophication). In: Kennish MJ, Elliott M (eds) Treatise on estuarine and coastal science, Vol. 8, human-induced problems (uses and abuses). Elsevier. Treatise on Estuarine and Coastal Science, Oxford, pp 113–148 Kennish MJ, Livingston RJ, Raffaelli D, Reise K (2008) Environmental future of estuaries. In: Polunin N (ed), Aquatic ecosystems: trends and global prospects. Cambridge: Cambridge University Press, p. 188–208 Köhler HR, Triebskorn R (2013) Wildlife ecotoxicology of pesticides: can we track effects to the population level and beyond? Science 341(6147):759–765 Kowalewska-Kalkowska H, Marks R (2015) Estuary, estuarine hydrodynamics. In: Encyclopedia of marine geosciences. Springer Science and Business Media, Dordrecht. https://doi.org/10.1007/978-94-007-66440_164-1 Li WC (2014) Occurrence, sources and fate of pharmaceuticals in aquatic environment and soil. Environ Pollut 187:193–201 Lillebø AI, Stålnacke P, Gooch GD, Krysanova V, Bielecka M (2017) Pan-European management of coastal lagoons: a science-policy-stakeholder interface perspective. Estuar Coast Shelf Sci 198:648–656 Lima FP, Ribeiro PA, Queiroz N, Howkins SJ, Santos AM (2007) Do distributional shifts of northern and southern species of algae match the warming pattern? Glob Chang Biol 13:2592–2604 Matos P, Sousa E, Pardal MA, Pereira E, Cardoso PG (2016) Structural and functional responses of microbenthic communities to mercury contamination. Water Air Soil Poll 227(41) McLusky DS, Elliott M (2004) The estuarine ecosystem: ecology, threats and management, 3rd edn. Oxford University Press, New York Mucha AP, Vasconcelos MTSD, Bordalo AA (2005) Spatial and seasonal variations of the macrobenthic community and metal contamination in the Douro estuary (Portugal). Mar Environ Res 60:531–550

Estuary Philippart CMJ, Beukema JJ, Cadée GC, Dekker R, Goedhart PW, van Iperen JM, Leopold MF, Herman PMJ (2007) Impacts of nutrient reduction on coastal communities. Ecosystems 10:95–118 Queirós AM, Hiddink JG, Johnson G, Cabral HN, Kaiser MJ (2011) Context dependence of marine ecosystem engineer invasion impacts on benthic ecosystem functioning. Biol Invasions 13:1059–1075 Raffaelli D, Raven JA, Poole LJ (1998) Ecological impact of green macroalgal blooms. Oceanogr Mar Biol 36: 97–125 Ribeiro C, Ribeiro AR, Tiritan ME (2016) Occurrence of persistent organic pollutants in sediments and biota from Portugal versus European incidence: a critical overview. J Environ Science Health Part B 51:143–153 Rice KM, Walker EM Jr, Wu M, Gillette C, Blough ER (2014) Environmental mercury and its toxic effects. J Prev Med Public Health 47:74–83 Rocha MJ, Rocha E (2015) Estrogenic compounds in estuarine and coastal water environments of the Iberian Western Atlantic Coast and selected locations worldwide - relevancy, trends and challenges in view of the EU water framework directive. In: Andreazza AN (ed) Toxicology studies – cells, drugs and environment. InTech, pp 154–193 Runnalls TJ, Beresford N, Losty E, Scott AP, Sumpter JP (2013) Several synthetic progestins with different potencies adversely affect reproduction of fish. Environ Sci Technol 47(4):2077–2084 Tan SW, Meiller JC, Mahaffey KR (2009) The endocrine effects of mercury in humans and wildlife. Crit Rev Toxicol 39(3):228–269 Valle-Levinson A (2010) Definition and classification of estuaries. In: Valle-Levinson A (ed) Contemporary issues in estuarine physics. Cambridge University Press, New York, pp 1–11 Wernberg T, Bennett S, Babcock RC, de Bettignies T (2016) Climate-driven regime shift of a temperate marine ecosystem. Science 353:169–172

Estuary ▶ Management and Monitoring of Eutrophication: Trophic State Indexes on the Río de la Plata Northern Coast

Exotic Species ▶ Biological Invasions as a Threat to Global Sustainability

Exploration and Production of Petroleum

Exploration and Production of Petroleum Rui Pena dos Reis1 and Nuno Pimentel2 1 Geosciences Centre, Coimbra University, Coimbra, Portugal 2 Instituto Dom Luiz, Lisbon University, Lisbon, Portugal

Definitions The petroleum is a fossil fuel that supplied most of the energy that supported the Second Industrial Revolution, from the beginning of the twentieth century. The need for energy triggered the fast evolution of the process since middle nineteenth century (Bjørlykke 2015), when the commercial extraction of oil began (In roman times, oil was already produced for several purposes, but in different conditions), established several major steps converging to the oil extraction: exploration, development, production, and abandonment (Mcnamara 2015). The following pages display a general description of the referred steps, mainly based on current technological and scientific flow chart.

Introduction In this memoir, we will consider the word petroleum in the broad sense, including liquid and gaseous hydrocarbons, usually known as crude oil and natural gas. Oil and natural gas play a major role in the global picture of economic development. Despite recent efforts in order to decrease the use of fossil energy, it is unlikely that this energy ceases to have a central position in the global energy supply, in the three or four coming decades. Oil and gas resources and related activities represent between 4.6% and 6.5% of the estimated 100 trillion USD of the total global economy (Investopedia 2018). The supply of these natural resources is crucial for the daily life of humankind all around the world, primarily as energy source

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and also as raw material for many industrial and domestic applications. In the developing part of the Earth, fossil energy is still a survival condition for a very large population, in what concerns the food and heat productions. Keeping reserves statistics updated is therefore vital for our civilization in the foreseeable future. 1. According to IEA (World Energy Outlook 2017) “. . .oil demand continues to grow to 2040, albeit at a steadily decreasing pace. The United States account for 80% of the increase in global oil supply to 2025. Natural gas use rises by 45% to 2040; with more limited room to expand in the power sector, industrial demand becomes the largest area for growth.” Eighty percentage of the projected growth in gas demand takes place in developing economies, led by China, India, and other countries in Asia (IEA 2019). 2. More than two trillion USD a year of investment in new energy supply is required until 2040, with a growing global energy demand above 25%. Despite all economic and technologic efforts made by human society, it is previewed that by 2040, oil, gas, and coal will share more than 75% of global energy supply. In this framework, oil consumption will increase in coming decades, due to a strong demand from sectors other than individual cars, enough to keep oil demand on a rising trajectory towards 105 mmb/d, by 2040. The petrochemical industry, which is the largest segment for sustainable growth, is closely followed by rising consumption for trucks, aviation, and shipping (IEA 2017). But meeting this growth in the near term means that conventional oil projects need to double from their current low levels. If we consider a Sustainable Development scenario, the goals are much more high and a significant technological jump is needed, both for replacing fossil energy demand and also for stabilizing CO2 emissions worldwide. These emissions are blamed to be the major cause of the steady rising of global temperature since the mid-nineteenth century, but many argue that this hypothesis is yet to be proved.

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A relevant data for considering environmental security is the fact that currently the offshore production corresponds to 30% of total. The deep-sea production is more challenging in technology and environmental safety, and, as most undiscovered hydrocarbons are in deep and ultra-deep waters, future production projects will be more financial and technologic demanding. Nevertheless, a lot of research and development work should be prepared in order to improve the efficiency rate of the production in a reservoir, that in average is well below 50%. This progress would allow to improve the production without increasing the environmental risks.

Oil Reserves Forecast According to the Society of Petroleum Engineers (SPE-PRMS 2007), “Reserves are those quantities of petroleum anticipated to be commercially recoverable by application of development projects to known accumulations from a given date forward under defined conditions.” These estimated reserves are affected already by the recovery factor which is the relation between the recoverable hydrocarbons and the OHIP (original hydrocarbons in place). Oil volumes are only partially recovered and produced from the reservoir, an average recovery factor of 30% is an acceptable industry norm. New innovative extraction technologies may increase the recovery factor to more than 50% hence the actual producing values (highs and lows) vary. They depend in largely on oil viscosity, permeability, and reservoir pressure. All reserve estimates involve some degree of uncertainty. The uncertainty depends chiefly on the amount of reliable geologic and engineering data available at the time of valuation and upon the interpretation of reservoir data. In natural state, hydrocarbons occupy the voids that exist in solid rocks. These voids, called pores, are small, generally tens of micron in size for conventional oil reservoirs and half a micron for unconventional oil reservoirs. A larger part of the oil and gas extraction is made from conventional reservoirs; these are

Exploration and Production of Petroleum

made of compact porous rocks that receive migrated hydrocarbons from deeper source rocks after a process of thermogenic maturation or biogenic decay of the organic remains inside these source rocks. More recently, a growing proportion of hydrocarbon (namely natural gas) extraction is based on unconventional reservoirs. This is proving to be significant scientific advance that is practiced now in the USA and Canada: it consists on an efficient technique of hydraulic fracturing stimulation that is applied to recover significant gas reserves that are trapped in thick layers of shale in those countries. Nevertheless, this hydrocarbon extraction process has some environmental inconvenient and is being criticized and got a growing social opposition. Hydrocarbons are lighter than water and migrate upwards either hydro-dynamically or through fractures into the conventional reservoir rocks where geometrically isolated and sealed traps, allows for its retaining and accumulation. Possible hydrocarbon accumulations are mapped by geologists, and eventually, a drilling campaign would be launched to explore these areas. Searching for oil in the subsurface is a trial procedure to find it far away from human eyes through best use of human intelligence. A petroleum “play” is defined and pursued before a specific “prospect” could be mapped and evaluated. The “play” and “prospect” concepts are used by the explorationist as a geologic argument to justify drilling for an undiscovered, potentially commercial, petroleum accumulations. A “play” is an association of favorable elements and situations which may lead to an oil and/or gas accumulation, whereas a “prospect” is a specific map of a potential accumulation. A play includes one or more geologically related prospects, and a prospect is a potential target that must be evaluated through drilling to determine if there are volumes that can justify a commercial extraction (e.g., Magoon and Dow 1994; Wiki AAPG 2018). From the initial definition of “plays” and “prospects” to the final extraction and commercial production, a long procedure must be followed;

Exploration and Production of Petroleum

these include the initial “exploration” stage, the decision to advance to the drilling of the potential prospect, the development of the eventual finding, the commercial extraction and production of oil and/or gas, and finally the field exhaustion and abandonment.

Exploration In the exploration assessment, there is a strong need for a detailed analysis of what is known as a petroleum system. The petroleum system is a unifying concept that encompasses all of the elements and processes of petroleum geology; these include: (a) the essential rocks (source, reservoir, seal, and overburden) and processes (trap formation, generation-migrationaccumulation) and all genetically related petroleum that might have originated from one pod of active source rock and occurs in shows, seeps, or accumulations also called hydrocarbon system (AAPG Wiki). A thick and rich source rock subjected to a thermal maturation; the effective migration into a porous and sealed reservoir and a correct timing of the different events are, among others, strong conditions for a significant discovery. The decision to drill is taken after completion of an exploration project where geology and geophysics have a major role. The assessment is based in geology, seismic, gravimetric, and magnetic data and also, in environmental risks and economic parameters, will end on the drill or drop decision (JX Nippon Exploration and Production (2018); The Norwegian Petroleum Directorate (NPD). Drilling The deepest well drilled for petroleum in the world was the Bertha Rogers No. 1 to a depth of 31,441 ft (9583 m) in Oklahoma in the year of 1974. Since reservoirs are found in a wide variety of geographical and geological settings, the wells are very different from each other, and must be drilled considering the location, the purpose, and the depth of the target prospect.

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A well that is drilled for the purpose of discovering a new oil or gas reservoir is called a wildcat or exploratory well. In case of a discovery, it will be called the discovery well. Wells drilled to improve the knowledge on the position and extent of a field are called development wells. Wells drilled between producing wells in an established field to increase the production rate are called infill wells (Hyne 2012). The drilling operation uses complex equipment namely a drilling rig which is an assembly of components, from which the most important is the drill string. This component is actually a combination of various smaller devices and includes the drill bit at the end, the main tool used to dig into the earth. The drilling rig may be either a land rig or an offshore rig. Since rig rental for onshore drilling costs account for a quarter of the total well cost (or more), the drilling for a specific well must be chosen carefully. Land rigs range from small, basic rigs, to large rigs designed for specific objectives or environments. Offshore rigs on the other hand may be fixed or mobile rigs (Fig. 1). Fixed rigs are further categorized as: jack-up rigs (jack-up rigs are used in shallow waters up to 350 ft), mobile offshore rigs are semisubmersible rigs (this type of rig is used in moderately deep water up to 3500 ft), and drills-hips (this rig can be used in water up to 10,000 ft deep). During the process of drilling, a chemical mixture called as drilling fluid or mud is circulated through the drill string into the hole to stabilize the hole, prevent formation fluids from flowing into the wellbore, to cool the drilling bit and lubricate the drilling pipes being used having great effects on the efficiency of the drilling process. Eventually, a drilling project for appraisal wells will be decided and it will then be possible to assess and meet the required economic criteria of the project. If the results recommend further work, the field is developed and then subsequently put in production. According to the Norwegian Petroleum Directorate (NPD), an appraisal well is defined as an exploration well drilled to establish the extent and size of a petroleum deposit that has already been discovered by a wildcat well.

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Exploration and Production of Petroleum

Exploration and Production of Petroleum, Fig. 1 The types of offshore drilling rigs including landrig and seabed drill. Possible water depth for offshore

drilling is increasing from drilling barge to drillship. cf. Sang Joon Pak and Hyun-Sub Kim (2016)

Development

facilities, and therefore require the building and maintenance of long-term customer in-take relationships. For extra-heavy oil developments such as oil sand projects, the cost includes build-up of facilities to convert the yield from low-grade heavy oil to high-grade light oil. The reservoir modelling and the development project must therefore allow for the optimization of the field development scenario (number, type, and location of wells, level production). A large part of the essential data gathering depends upon the execution of the development wells after the discovery. In the USA, according to WTRG (Fig. 2), the rate of success of these wells increased from 77% to about 90%, between 1974 and 2012. Development wells are made to produce hydrocarbons after they have been discovered by successful exploration and estimated trough the execution of the appraisal wells. In the oil and gas industry, a large part of the investment goes toward well drilling costs. Wells may be very different in geographic location (onshore, offshore), state, country, well class (oil, gas, dry), and type (exploratory, development). Therefore, the costs may vary on a wide range and different factors affect all of their associated costs (Fig. 3). During the last two decades (Fig. 4), there have been significant deep offshore (more than 1000 m water depth; Fig. 4) technological advances in exploration, development, and production. In many fields (e.g., Brazil pre-salt reservoirs in the

When a discovery is confirmed by exploration drilling, then an evaluation of volumes and well productivity becomes a priority. After well production, testing experts perform numerical simulation models of the reservoir together with petrophysical properties determinations of the collected samples, in order to estimate the initial volume of oil and gas in the reservoir and also to simulate the reservoir fluid flow behavior. A plan for a field development must include the number of wells to be drilled, the procedures and technology to recover the hydrocarbons in place, the recovery techniques to be used for the extraction of the reservoir fluids and the installations and infrastructure plan for production, and environmental protection systems. Many development plans deal with offshore discoveries and therefore must consider all the conditions related with tides, currents, winds, and seasonal storm regime. Following the JX Nippon Exploration and Production definition (http://www.nex.jx-group.co. jp/english/project/index.html): “Development includes the design and construction of oil and gas processing systems, pipelines, storage, and offloading facilities, and the drilling of production wells.” When developing a large gas field, the site is also assessed for liquefied natural gas (LNG) development. LNG projects require construction of large-scale liquefied plant and exporting

Exploration and Production of Petroleum

Oil & Gas Development Wells Success Rate 95%

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Exploration and Production of Petroleum, Fig. 2 Oil and gas development wells success rate from 1974 until 2012. cf Energy Information Administration (DOE, WTRG, Economics)

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Sources: Energy Information Admin. (DOE), WTRG Economics

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Exploration and Production of Petroleum, Fig. 3 Average drilling and completion costs per meter of exploratory and development oil and gas wells. (mod. Maciej et al. 2014)

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Exploration and Production of Petroleum

Exploration and Production of Petroleum, Fig. 4 Evolution of the operational deep in offshore wells. (Modified from the Economist Mar 6th, 2010)

(UDW) ultra-deep offshore realm), these very deep wells were drilled. According to “Plumbing the depths” in The Economist, (2010), the “Tupi field, 240 km off the coast of Rio de Janeiro, the discovery, beneath 2,000 meters of water, 3,000 meters of sand and rocks, and a 2,000-metre layer of salt, was touted at the time as potentially the largest offshore find ever made.” Producing deep offshore fields remains particularly complex and expensive and still represents, today, a great technological challenge.

Production This important phase in the quest for hydrocarbons depends on several agreements and contracts either with the landowners or with the concession’s authorities in most parts of the world. In some countries, like the USA and part of Canada, the contract is between the landowner and the company. In the majority of the countries in the world, there is a need for contracts that can be a concession agreement, a production-sharing contract, a tax and royalties’ contract, a service contract, or a production contract (Hyne 2012). These

contracts often include a commitment over developing acreage and point for relinquishment and abandonment. A contract can involve a specific concession, an area of land and/or ocean bottom to be explored during a specific time called the contract time. A production-sharing contract is common today. The multinational company is granted a concession to explore during a specific contract time, during which, the company is responsible for the entire cost of exploration and drilling. If commercial amounts of oil or gas are not found by the end of the contract time, the contract becomes invalid and the company loses all the costs of exploration and drilling. If commercial amounts of gas or oil are found, an agreed-upon share of the gross oil and gas production, called cost oil, goes to the company to sell and recover the costs of exploration, drilling, and production. After costs have been recovered, the remaining oil, called profit oil, is split by an agreed formula between the multinational company and the host government or company (Hyne 2012). The hydrocarbon production must consider the two main types of reservoirs: conventional and unconventional (Fig. 5).

Exploration and Production of Petroleum Exploration and Production of Petroleum, Fig. 5 Difference between conventional and unconventional basin centered gas accumulations. (Crain 2018)

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Conventional hydrocarbons may be extracted typically for a time period varying between 15 and 30 years and sometimes with an extension up to 50 years or more for “giant fields.” In average conditions, a reservoir production goes through four different phases. During the first phase which corresponds to the primary recovery, the hydrocarbons (oil in particular) flow naturally under the base of the oil rig. The natural underground pressure in the oil well pushes the oil up to the surface. This stage allows ~5% to ~15% of the oil in the reservoir to be extracted. A second phase of levelling during which the production is constant and regular. Then the production tends to decrease gradually and to maintain an adequate level, it is necessary to stimulate the reservoir pressure. The natural flow of crude oil will diminish over time. Consequently, a secondary recovery is needed. Then, the reservoir pressure must be increased in order to keep the natural oil flow constant. This is accomplished by injecting water or natural gas into the well, which drives the crude oil to the base where the oil can be pumped. This stage allows ~35% to ~45% of the oil in the reservoir to be extracted. A third phase of fluid injection may be necessary to extract more 5–15% of the crude oil. Finally, the production declines progressively until the reservoir gets depleted.

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There are currently many ongoing projects, both academic and preindustrial, assessing the possibility to reuse depleted reservoirs as long duration CO2 sink. Unconventional hydrocarbons (mainly shale gas and tight gas) are intensively produced mainly in North America. The volume of the reserves on this subcontinent, together with a strong technological advance on horizontal drilling and hydraulic stimulation of the reservoir rocks that have a very tight micro porosity justify that in 2012, the USA and Canada produced 275 million m3 of natural gas, accounting for 40% of natural gas world production. “Unlike conventional natural gas, which is found in permeable rocks through which the gas can easily flow, and from which it can be easily extracted, gas trapped in shale is extracted by hydraulic fracturing. Both shale gas and conventional gas are natural gas, consisting mainly of methane” (Erbach 2014). The extraction process is based on horizontal drilling of the reservoir rocks and the hydraulic fracturing (also known as “fracking”). This last process, used typically at a depth of 1500–3000 m, provokes the fragmentation of the reservoir rock and is followed by the injection of a mixture of water, sand, and chemicals at high pressure, allowing the mobility of the trapped natural gas. These processes have a strong opposition

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of large number of people, particularly in Europe. In many countries, this extraction method is forbidden (e.g., France, Germany, Scotland, and Ireland). Once extracted, oil and gas must be sent to a refinery for processing. Pipelines transport most of the world’s oil from well to refinery. Oil tankers also play an important role in distribution. West Texas Intermediate (WTI), also known as Texas light sweet, is a grade of crude oil used as a benchmark in oil pricing. This grade is described as light because of its relatively low density, and sweet because of its low sulfur content. The European market follows the Brent market price, usually a bit higher than WTI.

Field Abandonment The last phase in upstream life cycle is abandonment. When the hydrocarbons production rate becomes non-economical, the reservoir is abandoned. Before abandoning the field, the oil companies must (IFP School 2018): Dismantle facilities such as platforms – Special vessel to remove offshore platform should be request and enter in action. Surface facilities must be removed until few meters below seabed or left on the seabed as an artificial reef after free hydrocarbon condition reached. Put the well in a safe state – Well must be permanently closed and sealed, so no more hydrocarbons can escape to the surface. Preserve the field’s residual hydrocarbon reserves. Clean, depollute, and rehabilitate the site – The site must be restored to as close as its original condition.

Future Perspectives The HC extraction is a multiphase and complex process, and has been improved along many decades. Nevertheless, there are two main topics where new developments are coming up in the next future: the deep-sea floor production and

Exploration and Production of Petroleum

pipping tools, avoiding weather-related accidents and ensuring a safer the production process. Significant progresses are also expected about all the procedures, in order to prevent accidents and leaks, both in oceanic and terrestrial operations. There are new developing efforts in order to reduce risks in oil transport from deep sea wells, namely through the possible use of salt caverns as an intermediate step for shipping. The hydrocarbon exploration and related research have also contributed to reveal most offshore natural oil leaking, that are responsible for a very significant number of contamination underwater and coastal places. Onshore research has also shown many natural hazardous places for human health (leaking of methane, toluene, etc.) through spontaneous emanations of hydrocarbons. It is very likely that the hydrocarbons continue to have a major role in the future. Not as a source of energy but as a mainly provider of heavy molecules necessary for a large amount of industrial purposes.

Cross-References ▶ Coastal Pollution: An Overview ▶ Nature and Occurrence of Hydrocarbons

References Bjørlykke K (2015) Introduction to petroleum geology. In: Bjørlykke K (ed) Petroleum geoscience. Springer, Berlin/Heidelberg Crain ER (2018) Crain’s petrophysical handbook. www. spec2000.net. Accessed 10 June 2018 Erbach G (2014) Unconventional gas and oil in North America. European Parliamentary Research Service (EPRS). https://epthinktank.eu//?s¼Unconventional+ Gas+And+Oil+In+North+America. Accessed 12 June 2018 Hyne NJ (2012) Nontechnical guide to petroleum geology, exploration, drilling, and production 699 p. PennWell Publishing Corporation. ISBN13: 9781593702694 IEA (World Energy Outlook (2017) http://www.iea.org/ weo2017/#section-3. Accessed 12 June 2018 IEA (World Energy Outlook (2017) http://www.iea.org/ weo2019/#section-3. Accessed 26 July 2019

Exploration and Production of Petroleum IEA (2019) https://www.iea.org/reports/world-energy-out look-2020 IFP School (2018) http://www.ifp-school.com. Accessed 9 June 2018 Investopedia (2018) https://www.investopedia.com/ask/ answers/030915/what-percentage-global-economycomprised-oil-gas-drilling-sector.asp. Accessed 9 June 2018 JX Nippon Exploration and Production definition (2018) http://www.nex.jx-group.co.jp/english/project/ index.html. Accessed 6 June 2018 Maciej ZL, Anderson BJ, Augustine BC, Capuano LE, Beckers KF, Livesay B, Tester JW (2014) Cost analysis of oil, gas, and geothermal well drilling. J Pet Sci Eng 118:1–14 Magoon LB, Dow WG (1994) The petroleum system. In: Magoon LB, Dow WG (eds) The petroleum system– from source to trap: AAPG Memoir, vol 60, pp 3–24 Mcnamara A (2015) Petroleum exploration and production. The Canadian Encyclopedia, Historica Canada.

375 https://www.thecanadianencyclopedia.ca/en/article/ petroleum-exploration-and-production. Accessed 18 Feb 2021 Pak SJ, Kim H-S (2016) A case report on the sea-trial of the seabed drill system and its technical trend econ. Environ Geol 49(6):479–490 Risanto PA (2017) https://pt.slideshare.net/PuputAryanto/ introduction-to-oil-and-gas-industry-upstreammidstream-downstream. Accessed 8 June 2018 Society of Petroleum Engineers (SPE), American Association of Petroleum Geologists (AAPG), World Petroleum Council (WPC), Society of Petroleum Evaluation Engineers (SPEE) (2007) Petroleum Resources Management System SPE-PRMS, 47 p The Economist (2010) Plumbing the depths. https://www. economist.com/node/15582301. Accessed 9 June 2018 The Norwegian Petroleum Directorate (NPD). http://www. npd.no/en. Accessed 5 June 2018 WIKI.AAPG (2018) http://wiki.aapg.org/main_page. Accessed 4 June 2018

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Field Caging Transplants of Fish for Assessment and Monitoring in Aquatic Toxicology Hugo C. Vieira1, Sizenando Nogueira de Abreu1 and Fernando Morgado2 1 Centre for Environmental and Marine Studies (CESAM), Department of Biology, University of Aveiro, Aveiro, Portugal 2 The Centre for Environmental and Marine Studies (CESAM) and Department of Biology, University of Aveiro, Aveiro, Portugal

Definitions Mercury toxicity is a widespread environmental and health problem around the world (WHO 2017). Mercury is considered as one of the top ten chemicals or groups of chemicals of major public health concern (OJEU 2005, 2006; WHO 2017). Mercury is a natural element that occurs in various forms, elemental (or metallic) and inorganic (to which people may be exposed through their occupation) and organic (e.g., methylmercury, to which people may be exposed through their diet), which is found in air, water, and soil. These forms of mercury differ in their degree of toxicity and in their effects on the nervous, digestive, and immune systems and on lungs, kidneys, skin, and eyes. The Global Mercury Assessment 2018 is the

fourth such assessment undertaken by the United Nations Environment Programme (UN Environment), following earlier reports in 2002, 2008, and 2013. The Global Mercury Assessment 2018 is the second assessment produced by UN Environment in collaboration with the Arctic Monitoring and Assessment Programme (AMAP) recognizing its high policy relevance for policymakers (United Nations Environment 2018). Field cages are cages developed to integrate true ambient conditions over the chemical exposure of organisms in the field. The techniques of fish caging can be relatively easily harmonized and even standardized to increase the reliability, repeatability, and comparability of different studies. Caging experiments can serve as the first-tier field validation of toxic mechanisms found in laboratory experiments (Oikari 2006). Fish transplants are transplantation experiments in the field used in aquatic toxicology to identify responses to contaminant exposure and determine the effects of contamination in aquatic environments This method involves the transfer of organisms from a reference to a contaminated area (Bougas et al. 2016). Bioaccumulation is typically defined as the accumulation and enrichment of contaminants in organisms, relative to that in the environment. Bioaccumulation is the net result of all uptake and loss processes, such as respiratory and dietary uptake, and loss by egestion, passive diffusion, metabolism, transfer to offspring, and growth and

© Springer Nature Switzerland AG 2022 W. Leal Filho et al. (eds.), Life Below Water, Encyclopedia of the UN Sustainable Development Goals, https://doi.org/10.1007/978-3-319-98536-7

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toxicity of one contaminant can manifest after bioaccumulation occurs (Wang 2016). Bed resuspended particle are particles that can be temporarily resuspended through regular (e.g., tidal) and sporadic events (e.g., storms) and can play an important role in the metal distribution in aquatic ecosystems (Turner and Millward 2002).

Introduction The human population depends on marine and coastal biodiversity for their subsistence; however, this biodiversity is being threatened by marine pollution reaching alarming levels. Estuaries are among the most productive and valuable ecosystems in the world (Chapman and Wang 2001; Kennish 2002) providing a unique habitat and recreational and professional fishing areas (Benoit et al. 1998) and have been for long preferential sites for the human settlement and the development of their activities (Nunes et al. 2008). As a consequence, anthropogenic contamination has been increasing in the last decades in these ecosystems (Kennish 1991), and some coastal systems receive direct discharges of mercury into waterways or legacy mercury from contaminated sites. Acting as preferred sedimentation zones, estuarine ecosystems are subject to a high presence of contaminants which may adversely affect these ecosystems and are subject to control by international environmental laws (Ridgway and Shimmield 2002). Oceans health is one of the top priority problems of the present and near future that needs to be addressed, since the oceans are the main source of living marine resources used as food for humans and, at the same time, are the most significantly impacted environments by anthropogenic factors (Zoller 2006). As a result of domestic, industrial, and agricultural human activities, marine and estuarine pollution has a direct impact on human life through chemicals, toxins, and other harmful microparticles (Zoller and Hushan 2001), in that way, recreational fishermen sometimes eat large amounts of fish caught only in very limited areas, meaning that all fish consumed can come only from highly contaminated areas (Fair et al. 2018).

Controlling these sources should provide considerable benefits to local consumers. Beneficial control strategies for these coastal waters include curbing direct discharges and mitigating legacy mercury from heavily contaminated sites. Mercury poses substantial threats to human health, while local and national policies have been effective in mitigating local and regional contamination; mercury transcends political borders and moves with air and water. Addressing the transboundary and multimedia nature of mercury pollution will require global action (Lambert et al. 2012). Thus, it is very important to know the existing contamination levels and their distribution, as a starting point for the development of norms and attitudes, aiming to minimize the aggressions and impacts of an estuarine contamination (Ridgway and Shimmield 2002). The adoption of strategic plans for coastal pollution outlined the future direction toward sustainable use of the fishery resources and contributed to strengthening sustainable fisheries development. The European Commission issued a Community Strategy Concerning Mercury (E.C. 2005), which was subject to review in 2010 (BIO Intelligence Service 2010; E.C. 2010). Since its launch, the EU has made significant progress in addressing the global challenges posed by mercury. The strategy addresses the bulk of the aspects presented by the mercury cycle and identifies 20 priority actions to be taken both within the EU and on a global basis. Of particular importance is a ban on mercury exports which came into effect in 2011 (E.C. 1102/2008) and new rules on the safe storage of mercury. The Global Mercury Assessment 2018 is the fourth such assessment undertaken by the United Nations Environment Programme (UN Environment), following earlier reports in 2002, 2008, and 2013. The Global Mercury Assessment 2018 is the second assessment produced by UN Environment in collaboration with the Arctic Monitoring and Assessment Programme (AMAP) recognizing its high policy relevance for policymakers (United Nations Environment 2018). These strategies are in the framework of the Water Framework Directive set out in Directive 2008/105/EC, which requires biota monitoring against environmental quality standards, including prescribed levels for mercury and

Field Caging Transplants of Fish for Assessment and Monitoring in Aquatic Toxicology

other priority substances. In order to assess longterm trends, the environmental quality standards directive requires a monitoring plan for concentrations of mercury and other substances that tend to accumulate in sediment and/or biota and the measures required to reach good ecological status. The environmental quality standards are set for prey tissue (wet weight), with member states being able to choose whether the most appropriate indicator is fish, mollusks, crustaceans, or another biota. To evaluate the effectiveness of mercury control strategies, mercury should be broadly monitored in the atmosphere, water, and sediments of coastal waters and oceans, and these measurements should be linked to food web monitoring in the same locations. Monitoring aquatic toxicology constitutes a fundamental and essential tool for risk assessment in aquatic ecosystems and water resource management (Altenburger et al. 1996), widely used in the world in recent 30 years to support the rapid development of industrialization and agriculture (Ren et al. 2017). A wide diversity of scientific, practical, and management factors may influence and may restrict how field research is carried out. Knowledge and understanding of these conditions have led to the development of new monitoring, analysis, and assessment technologies based on biological and chemical methods. Fish caging is a technique used in aquatic toxicology to monitor and evaluate exposure to chemicals and the effects of chemical contamination on aquatic habitats. For many purposes the advantages of transplant fish caging outweigh the alternative methodologies of impact studies of xenobiotics (Burton et al. 2005). The exposure chambers are primarily designed to accommodate a variety of organisms and to test different compartments (i.e., water column, sediment, pore water, overlying water) in whatever type of aquatic ecosystem (i.e., marine or freshwater). Typically, they are constructed from common materials, including wire cages, mesh bags, plastic pipes, or bottles. Their design seeks to provide organisms with access to the compartment studied and allows water condition (and sediments when considered) fluxes to be controlled by site conditions. However, probably the most important consideration in conducting such tests is taking into account the

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technique-related artifacts which can significantly influence test outcome (e.g., reduced water flow and exchange, fouling, reduced dissolved oxygen, vandalism) and the difficulties in establishing adequate controls (e.g., choice of reference sites or references on site; plasticity of organisms in relation to environmental factors) to accurately interpret organism responses (i.e., bioaccumulation, effects) (Smink and Klaine 2013). Transplanting caged fishes in the immediate vicinity of discharges ensures maximum exposure. If bioavailable chemicals are present in the effluent, they will be accumulated within the tissues, and if the concentrations are sufficiently high to be deleterious, the effect of the exposure can be quantified. The transplant methodology described herein can be used to identify the following: (1) site-specific differences; (2) short-term and long-term trends; (3) temporal and spatial variability; (4) source identification; and (5) exposure-dose-response relationships. The concept of transplant studies with cages was largely used with bivalves and began in the 1980s and 1990s (Levings and McDaniel 1976; Wu and Levings 1980; Herve 1991; Herve et al. 1996). Bivalves are commonly used as biological indicators of exposure because of their ability to concentrate and integrate chemicals from water and sediment in their tissues (Metcalfe and Charlton 1990; Phillips and Rainbow 1993) and the utility of caged bivalve transplants in monitoring (De Kock and Kramer 1994). Field bioassays with caged bivalves combine the advantages of experimental control from standard laboratory bioassays with the environmental realism from traditional field monitoring. Recently, caged bivalve monitoring methods using field bioassays with caged bivalves have been refined to facilitate synoptic bioaccumulation and growth (Parker et al. 1991; Salazar and Salazar 1995). Reciprocal transplantation experiments have also been recently commonly applied in geobotany to study the local adaptation of plants to their habitat (Ross 2009; Scheepens et al. 2010), the effects of the adaptation capacity of plant pathogens and invasive species, or plant performance along environmental gradients (Link et al. 2003; Bischoff et al. 2006; Lipson 2007). In microbial ecology, field transplantation experiments have been often performed to assess responses of specific microbial

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functional groups and microbially mediated processes (Bottomley et al. 2004; Boyle et al. 2006) to changes in vegetation and microclimate (Hart and Perry 1999). Currently, there are only few studies that have used the reciprocal transplantation approach to investigate relationships of total microbial communities to different factors, such as vegetation (Balser and Firestone 2005; Hannam et al. 2007; Lazzaro et al. 2011), soil properties (Miglia et al. 2007; Lazzaro et al. 2011), and temperature (Waldrop and Firestone 2006; Vanhala et al. 2011), or also to test ecological theories (Bell 2010). Rapid adaptation to contaminant-induced stress and the potential mechanisms of detoxification can be also identified using this approach. Presently, transplantation experiments in the field are used in aquatic toxicology for investigating the response to contamination in different aquatic species such as daphnia (Daphnia magna) (Rivetti et al. 2015), mussel (Mytilus spp.) (Lacroix et al. 2014), barbel (Barbus graellsii) (Quirós et al. 2007), rainbow trout (Oncorhynchus mykiss), Atlantic salmon (Salmo salar) (Roberts et al. 2005), and yellow perch (Perca flavescens) (Bougas et al. 2016). Reciprocal transplant experiments are ideal tests of local adaptation yet rarely used for higher vertebrates because of the mobility and potential invasiveness of non-native organisms. An important advantage of transplant caging is its ability to integrate true ambient conditions over the chemical exposure. In fact, from the point of environmental toxicology, the simulation of natural background variables in the laboratory is the most difficult task to implement. Hence, caging experiments can serve as the first-tier field validation of toxic mechanisms found in laboratory experiments. Revealing causal links increases the weight of evidence that fish have been exposed to suspected key contaminants (Oikari 2006). At the same time, there are several disadvantages in the use of caged fish for environmental impact assessment, such as not suitable for all species, limited ecological relevance at the population level, limited exposure time due to nutritional reasons, vandalism, laborious and costly (compared to laboratory study), ambient conditions may hamper field working, and not standardized this far – each species

needs own know-how. For caging, the fish species of interest can and must be chosen among those available from hatcheries logistically close enough to the research site (maximum a few hundreds of kilometers but preferably less). The following cultured species have some popularity: rainbow trout (Oncorrhynchus mykiss), brown trout (Salmo trutta; Salmo trutta lacustris), coho salmon (Oncorhynchus kisutch), coregonid whitefish (Coregonus lavaretus s.l.), carp (Cyprinus carpio), goldfish (Carassius auratus), European eel (Anquilla anguilla), cod (Gadus morhua), chub (Leuciscus cephalus), sea bass (Dicentrarchus labrax), Nile tilapia (Oreochromis niloticus), sharptooth catfish (Clarias gariepinus), and guppy (Poecilia reticulata). Eel, carp, and goldfish are often considered as so-called hardy species for being able to tolerate relatively high handling stress. However, some trials using European eel have revealed failures (Oikari 2006). Also, a large number of local fish species may be caught from uncontaminated natural habitat by a non-damaging fishing technique for later caging. Flounder (Platichthys flesus), roach (Rutilus rutilus), fathead minnow (Pimephales promelas), pearl dace (Semotilus margarita), finescale dace (S. semotilus), white sucker (Catostomus commersonii), shortfin eel (Anguilla australis), chub (L. cephalus), Atlantic tomcod (Microgadus tomcod), three-spined stickleback (Gasterosteus aculeatus), mosquitofish (Gambusia holbrooki), and speckled sanddab (Citharichthys stigmaeus) are among these species (Oikari 2006). There are also species which appear not to be suitable for caging studies regardless of the conditions offered to them. Such species are, e.g., European perch (Perca fluviatilis), pikeperch (Stizostedion lucioperca), Baltic herring (Clupea harengus), and Northern pike (Esox lucius). Characteristics like a solitary type of living, cannibalism, or high tendency to lose scales as a result of even minimal handling may exclude their use. Finally, there are species which for some unknown reason experience substantial stress even under best circumstances known to the researchers. On the other hand, if a species has been domesticated (e.g., perch and vendace) instead of being caught as an indigenous species, its suitability for caging probably improves as well (Oikari 2006).

Field Caging Transplants of Fish for Assessment and Monitoring in Aquatic Toxicology

In order to evaluate the effectiveness of mercury control strategies, mercury should be broadly monitored in the atmosphere, water, and sediments of coastal waters and oceans, and these measurements should be linked to food web monitoring in the same locations. Efforts to decrease human exposure to mercury traditionally rely on advisories that inform people about the need to limit their consumption of certain fish species. The mercury levels in certain types of fish (e.g., bluefin tuna, swordfish) have become so high that some governments advise against consumption or have introduced import bans. The European Commission issued a Community Strategy Concerning Mercury (E.C. 2006), which was subject to review in 2010 (BIO Intelligence Service 2010). Since its launch, the EU has made significant progress in addressing the global challenges posed by mercury. The strategy addresses the bulk of the aspects presented by the mercury cycle and identifies 20 priority actions to be taken both within the EU and on a global basis. Particularly important is a ban on mercury exports which came into effect in 2011 (E.C. 2008) and new rules on the safe storage of mercury. Strategies were developed in order to reduce emissions from the chlor-alkali industry throughout new alternative and emerging production technologies (Chlistunoff et al. 2006; Brinkmann et al. 2014). As part of the process, a new mercury regulation, (EU) 2017/852, repealing regulation (EC) no. 1102/2008, was adopted in May 2017, amending and complementing these strategies. In a more global action, the 2030 Agenda for Sustainable Development, adopted by all United Nations Member States in 2015, provides a shared blueprint for peace and prosperity for people and the planet, now and into the future. Specifically, the “Goal 14. Conserve and sustainably use the oceans, seas and marine resources for sustainable development” has as targets by 2025, to prevent and significantly reduce marine pollution of all kinds, in particular from land-based activities, including marine debris and nutrient pollution, and by 2020, sustainably manage and protect marine and coastal ecosystems to avoid significant adverse impacts, including by strengthening their resilience and taking action for their

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restoration in order to achieve healthy and productive oceans. The global aim is to enhance the conservation and sustainable use of oceans and their resources by implementing international law as reflected in UNCLOS, which provides the legal framework for the conservation and sustainable use of oceans and their resources, as recalled in paragraph 158 of The Future We Want. The aims of this entry are in line with the EU’s Community Strategy Concerning Mercury. Global action and international cooperation will bring further health and environment benefits within the EU; it is seen as the best and the most cost-effective opportunity available to realize this goal for the EU while also substantially reducing mercury’s harmful impacts at a global level. Field Caging Transplants to Study Mercury Bioaccumulation Influence of Storm Events and Bed Resuspended Particles

Mercury is one of the contaminants commonly found in many estuarine systems, being classified as a pollutant of primary importance because of its high degree of toxicity, persistence, and bioaccumulative properties (Mishra et al. 2005; Vieira et al. 2013). The persistence of mercury in aquatic environments, its toxic characteristics, and the possibility of bioaccumulation along trophic chains give great importance to studies that contribute to understanding the complex phenomena that regulate the transfer of this contaminant into the environment (Bloom 1992; Amiard-Triquet et al. 1993; Mason et al. 1994; Mason et al. 1995; Langford and Ferner 1999; Faganeli et al. 2003). A progressive increase in mercury concentration in aquatic organisms, even at remote locations, has been recorded globally as a result of multiple anthropogenic sources and their discharge to ecosystems (Pacyna and Pacyna 2001). The contamination of aquatic systems by mercury in its various forms is a major concern in conservation ecology and public health. Climate change, extreme events, and human-induced change are significantly affecting the global distribution of the world’s mercury and interfering with its transport with increased risks of impacts on

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ecosystems and human health. An important current issue is thus to understand to what extent the mercury cycle in the future can be changed in relation to ongoing climate change that is occurring on both regional and global scales (Sunderland et al. 2012). The forecasts imply that most of the parameters that determine the global mercury cycle today will be changed (Krabbenhoft and Sunderland 2013; Obrist et al. 2018). Global warming and climate change will tend to increase the temperature of surface sediments and the period of sun exposure affecting methylation processes, Hg volatilization, organic complexation of other metals, and consequently increasing transfer rates to biota (Pack et al. 2014). Rising sea levels may also redefine the tidal hydrodynamic factors favoring the process of resuspension of contaminated particles from sediment bed to the water column and eventually to adjacent coastal areas (Turner and Millward 2002). Fishes are commonly used as bioindicators of the environmental conditions since they occupy a wide range of trophic levels, establishing a direct link with human populations in the aquatic food chains. Aquatic organisms may uptake mercury through different routes including water, sediment, and food which progressively incorporate in organisms. Mercury bioaccumulation implies an increase of the element concentration inside the organism comparatively to the surrounding medium, and the process is the result of both direct intake (mainly by gills) and assimilation (food uptake and ingestion) followed by retention and storage in a tissue or organ. Generally, heavy metal concentrations in bottom sediments and in suspended particulate matter (SPM) are well correlated in the aquatic ecosystems (Lawson and Mason 2001; Nguyen et al. 2005). Bottom sediments are temporarily resuspended because of the regular (tidal) and sporadic (wind- or river flowinduced) variations (Turner and Millward 2002), and these resuspended particles (bed resuspended particles or BrSP) are among the likely source of Hg in estuarine ecosystems (Hurley et al. 1998). Under these circumstances, natural events (such as tidal movement and storms) can play an important role in the metal distribution in aquatic ecosystems, since they promote the remobilization of

sediment-associated contaminants (Lawson and Mason 2001; Eggleton and Thomas 2004). Therefore, considering that these contaminants are available to aquatic organisms via food ingestion (particulate associate) (Eggleton and Thomas 2004) and that Hg tends to be linked to particles (Cossa et al. 1994), organisms living in direct contact with the contaminated sediments are more exposed to Hg contamination (Nunes et al. 2008) leading to greater accumulation of Hg in the tissues of these organisms (Abreu et al. 2000). Ria de Aveiro is a coastal lagoon (47 km2 of maximum surface area) permanently connected to the sea through a single artificial entrance, located in northern region of Portugal. For more than four decades, Ria de Aveiro received an effluent rich in Hg from a chlor-alkali plant located in an industrial chemical complex near Estarreja. This effluent was discharged through a branch (Estarreja Channel) of the lagoon (Abreu et al. 2000; Ramalhosa et al. 2001) inducing an environmental contamination gradient inside the lagoon (Válega et al. 2008; Cardoso et al. 2013). The environmental contamination gradient along Estarreja Channel (Fig. 1) was validated by a preliminary study (t0) conducted in order to assess the stored Hg in sediment, and it was possible to verify a significant decrease (p < 0.05) in concentration of Hg as one moves away from the source of contamination. This environmental mercury contamination gradient in Ria de Aveiro was described in other studies (Coelho et al. 2005; Nunes et al. 2008). Field fish caging transplants were developed as an assessment and monitoring technique in aquatic toxicology, applied to mercury bioaccumulation studies. A series of control and transplant studies were conducted to determine both the temporal and spatial pattern of mercury uptake in the pelagic food web. For the experiments, 120 field cages were manufactured using adapted 330 ml plastic water bottles. Bottles were cut at the bottom and at the top of the caps, and those parts were replaced for nets with meshes of 1 mm. Field cages allowed the water flow carrying BrSP that provided food and shelter to the caged fishes. Cages also had a floater and weight tied to them, so that they were kept near the bottom of the

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Field Caging Transplants of Fish for Assessment and Monitoring in Aquatic Toxicology, Fig. 1 Estarreja channel, Ria de Aveiro. (Photo credit: Hugo Vieira)

Field Caging Transplants of Fish for Assessment and Monitoring in Aquatic Toxicology, Fig. 2 Schematic representation of Pomatochistus microps transplantation cages

channel but avoiding their burying in the sediment (Fig. 2). The species Pomatoschistus microps (Krøyer 1838) (Fig. 3), belonging to Gobiidae, a family of

teleost fishes, is distributed in estuarine ecosystems in tropical and temperate zones. This species has a wide geographic distribution, longevity of 1 to 2 years, and position of intermediate predator in

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Field Caging Transplants of Fish for Assessment and Monitoring in Aquatic Toxicology

Field Caging Transplants of Fish for Assessment and Monitoring in Aquatic Toxicology, Fig. 3 Pomatoschistus microps (Krøyer, 1838). (Photo credit: Hugo Vieira)

the food chain, connecting the microbenthos with larger fish and seabirds (Vieira et al. 2008). Pomatoschistus microps occurs abundantly throughout the year, from areas considered less polluted by contaminated sites (Quintaneiro et al. 2008). Due to their ecological characteristics, this species is considered relevant to studies of environmental toxicology (Monteiro et al. 2007). The aim was to evaluate Hg bioaccumulation using fish Pomatoschistus microps from a reference site, transplanted to locations within a gradient of mercury contamination, and understand the influence of BrSP and the influence of storm events in this bioaccumulation process. Fish length-weight relationship, which describes mathematically the correlation between length and weight, is useful for converting length observations into weight estimates to provide some measure of biomass (Bolger and Connolly 1989; Harrison 2001). Length-weight relationships of Pomatoschistus microps captured in the reference site (Vagueira) showed a positive correlation with

a correlation coefficient r2 ¼ 0.89. No significant differences were found in the length and weight of fish specimens used in the experiment and in the control (p > 0.05). The environmental contamination gradient along Estarreja Channel (contaminated site) was validated by a preliminary study (t0) conducted in order to assess the stored mercury in sediment, and it was possible to verify a significant decrease (p < 0.05) in concentration of Hg as one moves away from the source of contamination (Table 1). This environmental mercury contamination gradient in Ria de Aveiro was described earlier by Coelho et al. (2005) and Nunes et al. (2008). BrSP that entered the field cages at Estarreja Channel during the preliminary study (t0) were analyzed for each sampling site considering the particle size. As expected, the fraction between 2 mm and 63 mm (total) presented lower concentration than the fraction