Field Guide to Sharks, Rays & Chimaeras of Europe and the Mediterranean 9780691205984, 0691205981

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FIELD GUIDE TO

SHARKS, RAYS & CHIMAERAS OF

EUROPE AND THE MEDITERRANEAN

David A. Ebert and Marc Dando

Published by Princeton University Press, 41 William Street, Princeton, New Jersey 08540 In the United Kingdom: Princeton University Press, 6 Oxford Street, Woodstock, Oxfordshire OX20 1TR press.princeton.edu Princeton University Press is committed to the protection of copyright and the intellectual property our authors entrust to us. Copyright promotes the progress and integrity of knowledge. Thank you for supporting free speech and the global exchange of ideas by purchasing an authorized edition of this book. If you wish to reproduce or distribute any part of it in any form, please obtain permission. Requests for permission to reproduce material from this work should be sent to Permissions, Princeton University Press Copyright © 2021 by Princeton University Press Illustrations copyright © 2021 by Marc Dando Copyright in the photographs remains with the individual photographers. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of the publishers. British Library Cataloging-in-Publication Data is available Library of Congress Control Number 2020944541 ISBN 978-0-691-20598-4 Ebook ISBN 978-0-691-21182-4 Production and design by WILDNATUREPRESS Ltd., Plymouth, UK Printed in Italy

10 9 8 7 6 5 4 3 2 1

Contents ● Acknowledgements

6

● Introduction European Seas – biodiversity European Seas – habitats

7 8 11

● Conservation and management by Ali Hood, The Shark Trust

14

● How to use this book Topography Tooth types and tooth counts

28 30 35

● Cartilaginous fishes dentition guide

36

● Cartilaginous fishes eggcase guide

42

● Cartilaginous fishes key guide

43

● CHIMAERAS CHIMAERIFORMES Chimaera families key guide Chimaera species eggcase guide Short-nosed chimaeras Chimaeridae Short-nosed chimaera species key guide Long-nosed chimaeras Rhinochimaeridae Long-nosed chimaera species key guide

46 47 48 49 50 58 59

● SKATES AND RAYS BATOIDEA Skates and rays key guide ● Skates Rajiformes Skates key guide Softnose skates Arhynchobatidae Bathyraja species key guide Hardnose skates Rajidae Skate genera key guide Skate species eggcase guide Inshore skate species comparison Offshore skate species comparison Deepsea skate species comparison Amblyraja species key guide Dipturus species key guide Leucoraja species key guide Malacoraja species key guide Neoraja species key guide Raja species key guide Rajella species key guide ● STINGRAYS AND RELATED SPECIES MYLIOBATIFORMES Stingrays and related families key guide Stingrays Dasyatidae Stingray species key guide Butterfly rays Gymnuridae Eagle, cownose and mobulid ray species key guide Eagle rays Myliobatidae

64 66 68 71 72 73 77 78 81 84 86 88 90 94 102 108 111 114 130 139 141 142 143 151 153 156

Cownose rays Rhinopteridae Mobulid rays Mobulidae ● Electric rays Torpediniformes Torpedo rays Torpedinidae Torpedo ray species key guide ● Rhino rays Rhinopristiformes Sawfishes Pristidae Sawfish species key guide Guitarfishes Rhinobatidae Guitarfish species key guide Giant guitarfishes Glaucostegidae Comparison of shark-like rays and ray-like sharks

159 161 166 168 169 175 176 177 180 180 181 184

● SHARKS SELACHIMORPHA Shark orders key guide ● Cow and frilled sharks Hexanchiformes Cow sharks Hexanchidae Frilled sharks Chlamydoselachidae Cow and frilled shark species key guide Cow and frilled shark species dentition guide ● Bramble sharks Echinorhiniformes/Echinorhinidae ● Dogfish sharks and related species Squaliformes Dogfish sharks and related families key guide Dogfish sharks Squalidae Dogfish shark species key guide Dogfish shark similar species comparison Dogfish shark species dentition guide Gulper sharks Centrophoridae Gulper shark species key guide Gulper shark species dentition guide Lanternsharks Etmopteridae Lanternshark species key guide Lanternshark species dentition guide Deepsea spined shark species comparison Sleeper sharks Somniosidae Sleeper shark species key guide Sleeper shark species dentition guide Roughsharks Oxynotidae Roughshark species key guide and dentition guide Kitefin sharks Dalatidae Kitefin shark species dentition guide Kitefin shark species key guide ● Angelsharks Squatiniformes/Squatinidae Angelshark species key guide Angelshark species dentition guide ● Carpetsharks Orectolobiformes Nurse sharks Ginglymostomatidae Whale sharks Rhincodontidae Carpetshark species key guide

186 189 191 191 191 192 193 198 200 202 204 205 206 206 210 211 213 220 221 222 227 230 231 234 243 244 247 247 248 252 253 254 258 259 259 260

Carpetshark species dentition guide ● Mackerel sharks Lamniformes Mackerel shark families key guide Sandtiger sharks Carchariidae and Odontaspididae Goblin sharks Mitsukurinidae Sandtiger and goblin shark species dentition guide Thresher sharks Alopiidae Thresher shark species dentition guide Basking sharks Cetorhinidae Mackerel sharks Lamnidae Mackerel shark species key guide Mackerel shark species dentition guide Large shark species comparison ● Ground sharks Carcharhiniformes Ground shark families key guide Catsharks Pentanchidae and Scyliorhinidae Catshark genera key guide Catshark species eggcase guide Catshark species dentition guide Demon catshark species key guide Sawtail catshark species key guide Scyliorhinus species key guide False catsharks Pseudotriakidae Deepsea ‘catshark’ species comparison Houndsharks Triakidae Houndshark species key guide Houndshark species dentition guide Requiem sharks Carcharhinidae Requiem shark genera key guide Requiem shark species dentition guide Carcharhinus species key guide Carcharhinus species comparison Hammerhead sharks Sphyrnidae Hammerhead shark species key guide Hammerhead shark species dentition guide

260 263 264 267 267 268 273 273 276 278 279 280 285 286 288 290 292 293 294 295 302 306 309 311 312 313 314 319 320 322 325 330 345 346 347

● Vagrants

351

● Appendices Glossary Regional oceans and seas Field observations Regional shark fin guide

352 352 357 361 371

● Image credits

379

● Index

380

Acknowledgements A book like this can only come to fruition through the contributions of many individuals, either directly or indirectly. We are fortunate to work with amazingly talented and dedicated colleagues. There are far too many to name individually but we would particularly like to thank Mark Harris, FFC, Elasmobranch Studies, for his encyclopedic knowledge of all things tooth-related; Fabrizio Serena for his wide knowledge of this region; Ali Hood for shining a spot-light on shark conservation; Sarah Fowler, Cat Gordon, Rima Jabado, Peter Kyne, Matthias Stehmann, Guy Stevens and Simon Weigmann for numerous informative discussions and input. We are extremely grateful for the excellent proofing skills of John Richardson and Peter Kyne; to Julie Dando for overseeing and managing this enormous project and to Robert Kirk for his belief and enthusiasm in this book. Dave Ebert would like to thank Marsha Englebrecht and his parents, Earl and Margaret (Peggy) Ebert, for their support and encouragement. Marc Dando especially thanks his family for their understanding, forbearance and support whilst working on this project, without their help and tolerance this guide would never have happened, so thank you, Julie, Ryan, Megan, Darren, Riley and Sonny.

6

ACKNOWLEDGEMENTS

INTRODUCTION ARCTIC OCEAN

BARENTS SEA

DENMARK STRAIT White Sea

NORWEGIAN SEA

ICELAND SEA

NORTH ATLANTIC OCEAN OTHER SEA AREAS 1 Gulf of Bothnia 2 Gulf of Finland 3 Gulf of Riga 4 Kattegat 5 Skagerrak 6 Inner Seas 7 Gulf of Lion 8 Ligurian Sea 9 Gulf of Trieste 10 Myrtoan Sea 11 Thracian Sea 12 Sea of Marmara 13 Sea of Crete 14 Gulf of Antalya 15 Gulf of Iskenderum 16 Gulf of Suez 17 Gulf of Sidra 18 Gulf of Gabes 19 Strait of Sicily 20 Strait of Gibraltar

1 2 BALTIC SEA 3

5

6

4

NORTH SEA

Irish Sea Celtic Sea English Channel

Sea of Azov Bay of Biscay

BLACK SEA 9 7

8

Adriatic Sea

Balearic Sea

Tyrrhenian Sea 20 Alboran Sea

19

11 Aegean Sea

Ionian Sea

This book is intended to be a guide to all known living species of sharks and their relatives, the skates, rays and chimaeras, found in the waters of the Northeast Atlantic and Mediterranean region. Seventy-nine species of shark, fifty-eight species of skate and ray (batoids) and nine species of chimaera are found in the region. These are variously distributed from coastal nearshore waters, including estuaries, out to depths of approximately 200m, along the outer continental shelf, and beyond that, hundreds to thousands of metres down the continental slope and beyond, where many fascinating and unusual looking deepsea species occur. While some species occurring in these waters have a global distribution, others

15 14

13

MEDITERRANEAN SEA

Levantine Sea

Libyan Sea

18

Regional seas covered in this book

10

12

17

16 Red Sea

are endemic or near endemic to the Northeast Atlantic. The Mediterranean Sea also has several endemic species, as well as others that appear to have migrated from the Red Sea through the Suez Canal. Many of the species present in the Northeast Atlantic and Mediterranean region are well known, and often have a long history associated with fisheries, whereas others have only recently been documented as occurring here, including several species new to science. We hope this guide will encourage and inspire more people to take an interest in sharks and their relatives, whether as a casual observer, or more actively through research, education, fisheries management or conservation. INTRODUCTION

7

European seas – biodiversity Sharks and rays are among the most recognisable of fishes and, while most people easily recognise charismatic species such as the White Shark Carcharodon carcharias or Giant Manta Ray Mobula birostris, fewer are aware of the remarkable diversity of species that exist. Sharks come in a variety of sizes and shapes: from the Spined Pygmy Shark Squaliolous laticaudus that, with a maximum length of 22cm, you can hold in the palm of your hand; to the largest fish in the ocean, the Whale Shark Rhincodon typus, reaching 20m total length. However, only 18% of shark species have a maximum length exceeding two metres or a maximum weight exceeding 10kg. This is also true of rays and skates. Sharks and their relatives, the skates, rays and chimaeras, collectively form the Class Chondrichthyes – a distinctive fish group also referred to as ‘cartilaginous fishes’ pertaining to their simple internal skeletons. In these fishes, cartilage replaces the more complicated internal calcified bony structures found in ‘bony fishes’. Globally, there are presently 540 known species of shark, 665 species of skate and ray (known collectively as batoids and affectionately as ‘flat sharks’) and 52 species of chimaera (or ‘ghost sharks’), an overall total of 1,257 species. In comparison, the far more diverse bony fishes total about 33,000 species. The waters of the Northeast Atlantic and the Mediterranean region are home to nearly 12% of all known shark species, placing it among the world’s top 20 shark diversity hotspots, with a combined total of 146 species. In comparison, the top three global shark Class

Subclass

Cohort

Holocephali

Batoidea (batoids)

Chondrichthyes

Neoselachii Selachii (sharks)

8

INTRODUCTION

diversity hotspots are the regional waters of Australia (329 species), India (227 species) and Japan (212 species). Of the 146 European species, 137 occur in the Northeast Atlantic and just 86 in the Mediterranean. Seventy-seven species occur in both. The number is higher in the Northeast Atlantic because many deepwater species that live there in depths below 500m are missing from the Mediterranean, probably because the narrow, relatively shallow (300m) Strait of Gibraltar creates a barrier to their movement. There are about 23–25 Northeast Atlantic endemics (species that are found nowhere else in the world). The Mediterranean species list includes four sharks and five batoids that are not recorded in the Northeast Atlantic. These are mostly coastal warm water species. Two batoids are endemic to the Mediterranean, and three species have entered the Mediterranean from the Indian Ocean and Red Sea, through the Suez Canal. Their entry to the Mediterranean from the Red Sea is known as ‘Lessepsian migration’ (so named after Ferdinand de Lesseps, the engineer in charge of constructing the Suez Canal during the 1860s). The known diversity of sharks and their relatives (hereafter collectively referred to as sharks) has increased exponentially over the past 19 years, with nearly 300 new species described between 2000–2018. This is over 20% of all shark species that have been described and named to date. However, in the 50 previous years between 19501999, only 330 species were described. The majority of recent discoveries have come from the Indo–Australian region, followed by southern Africa and the western

Order Chimaeriformes

page 46

Rajiformes

page 68

Myliobatiformes

page 139

Torpediniformes

page 166

Rhinopristiformes

page 175

Hexanchiformes

page 191

Echinorhiniformes

page 198

Squaliformes

page 200

Pristiophoriformes

not in this region

Squatiniformes

page 252

Heterodontiformes

not in this region

Orectolobiformes

page 258

Lamniformes

page 273

Carcharhiniformes

page 286

Table 1. The Class Chondrichthyes is divided into two major groups: the chimaeras, comprising the subclass Holocephali; and the sharks, skates and rays, forming the subclass Neoselachii. While the chimaeras all belong to a single order (Chimaeriformes), the sharks, skates and rays are separated into 13 orders: nine orders of shark-like fishes (cohort Selachii), and four of ray-like fishes (cohort Batoidea).

2

4

9

Chimaeriformes (chimaeras)

Species

Chimaeriformes (chimaeras)

Cohort/order

Family

Genera

Cohort/order

Mediterranean Species

Northeast Atlantic

Genera

The modern taxonomic classification system for all organisms was designed by Carolus Linnaeus (1707–1778), a Swedish botanist, physician and zoologist. Linnaeus formalised the system for naming organisms, with each assigned a binomial (two-part) scientific name, usually based on Latin or Greek. The binomial scientific name consists of the genus (generic) and species (specific) name, both of which are written in italics. Therefore, when identifying or recording an organism, the binomial scientific name is given preference over its common name, which may vary from region to region. The taxonomic system is hierarchal, with kingdom being the broadest or highest level of classification, followed in descending sequence by phylum, class, subclass, cohort, order, family, genus and species. In this book, the class Chondrichthyes is the highest taxonomic classification referred to, see Table 1. The ordinal classification is relatively even between the Northeast Atlantic and Mediterranean, with 12 and 11 orders, respectively. The only order found in the Northeast Atlantic, but absent in the Mediterranean is the Orectolobiformes (carpet sharks). However, with each descending taxonomic level the difference between the two regions increases, see Table 2. All the families in this book occur in the Northeast Atlantic. However, there are five families that are not represented in the Mediterranean, the Chlamydoselachidae (frilled sharks), Ginglymostomatidae (nurse sharks),

Table 2. Chondrichthyes diversity in the Northeast Atlantic and the Mediterranean regions, the greatest diversity being visible in the sharks.

Family

North Pacific. Although the majority of Northeast Atlantic and Mediterranean species were described in the 20th century, six new species have been named during the past 20 years, five were named from specimens collected in the region, while a sixth was described outside the region, but subsequently found to occur here. Sharks are one of the most successful groups of fishes, having penetrated most of the world’s marine ecosystems, from tropical to high latitude waters over continental and insular shelves, out into the open ocean and the deepsea (>200m). Their success is not limited to marine ecosystems; in some regions certain shark and ray species either inhabit, or seasonally visit, estuarine and freshwater river ecosystems. The diversity of known species is greatest in tropical marine ecosystems, followed by the deepsea and temperate ecosystems, with oceanic and freshwater ecosystems having the lowest diversity. The majority of species (~55%) occur on continental shelves from the intertidal zone, including bays and estuaries, along coastal nearshore areas and out to about 200m depth. The diversity of these shelf species is greater in the tropics and lower in temperate seas. The remainder (~45%) are considered deepsea species. Species diversity in oceanic and freshwater habitats is comparatively low, making up only approximately 3% and 2%, respectively.

1

2

2

9

18 35

Batoidea (batoids) Batoidea (batoids)

11 23 53

Selachii (sharks)

Selachii (sharks)

19 27 49

24 41 75 Totals

37 68 137

Totals

29 47 86

EUROPEAN SEAS – BIODIVERSITY

9

Table 3. Global biodiversity of chondrichthyans by order, family, genera, and species.

Order Chimaeriformes Chimaeras

Rajiformes Skates

Myliobatiformes Devilrays, eaglerays and stingrays

Torpediniformes Torpedo, electric rays and numbfishes

Rhinopristiformes Sawfish, guitarfish and wedgefish

Hexanchiformes Cow and frilled sharks

Echinorhiniformes Bramble sharks

Squaliformes Dogfish sharks

Pristiophoriformes Sawsharks

Squatiniformes Angelsharks

Heterodontiformes Bullhead sharks

Orectolobiformes Carpet sharks

Lamniformes Mackerel sharks

Carcharhiniformes Ground sharks

Families

% of all chondrichthyan familes

Genera

% of all chondrichthyan genera

Species

% of all chondrichthyan species

3

4.5

6

2.8

52

4.1

4

6.1

38

17.6

295

23.4

12

18.2

38

17.6

237

18.8

5

7.6

14

6.5

68

5.4

5

7.6

13

6.0

65

5.1

2

3.0

4

1.8

7

0.5

1

1.5

1

0.5

2

0.1

6

9.1

22

10.2

140

11.1

1

1.5

2

0.9

10

0.8

1

1.5

1

0.5

22

1.7

1

1.5

1

0.5

9

0.7

7

10.6

13

6.0

45

3.6

8

12.1

10

4.6

15

1.2

10

15.1

52

24.2

294

23.3

Rhincodontidae (whale sharks), Mitsukurinidae (goblin sharks) and Pseudotriakidae (false catsharks). In the batoids, two families are absent from the Mediterranean: the Arhychobatidae (softnose skates) and Pristidae (sawsharks). However, the Mediterranean is home to the genus Himantura, a genus not found in the Northeast Atlantic. There are also several vagrant species, including two shark species: the Crocodile Shark Pseudocarcharhias

10

INTRODUCTION

kamoharai and Night Shark Carcharhinus signatus. More recently, in 2015, a Sicklefin Chimaera Neoharriotta pinnata was discovered in the southern Bay of Biscay, extending its previous known range from Northwest Africa. Changes in oceanographic conditions, especially due to warming water temperatures, likely explains recent vagrant records of normally warm temperate to tropical species, while deepsea species may have been overlooked until recently.

European seas – habitats Sharks, skates, rays and chimaeras can be found in a wide variety of different marine habitats. Some spend their whole life on the seabed (benthic species), whilst others cruise the high seas and never touch bottom (pelagic species). Many, including most chimaeras, lurk near the seabed where they hunt for bottom-living fish and invertebrates (bentho–pelagic species). Whether the seabed is rock, coral, sand, mud, or a mixture, there will be species living there, each adapted to its particular preferred habitat. As well as these habitat and way of life considerations, sharks, skates, rays and chimaeras can be split into three ecological groupings, based on where they live in relation to continental landmasses and the seabed. Those species found from coastal nearshore waters to a depth of about 200m are referred to as continental shelf inhabitants.

Species inhabiting depths below 200m, and living on or near to the seafloor, are considered continental slope or deepsea species. Those species mostly living far off the bottom in the upper few hundred metres of the water column, and primarily away from continental landmasses, are referred to as oceanic species. This latter small group includes some species found around offshore islands and insular slopes, but not considered to be associated with continental landmasses. Species are further differentiated biogeographically according to the temperature of their home water, which might be tropical, temperate or polar. So, for example, a species living in the warm coastal waters off Italy would be a warm temperate continental shelf inhabitant, whereas those spending all of their time far out in the colder seas of the Northeast Atlantic are cold temperate oceanic species.

Surface

Lower course of a river Freshwater habitat

Bay

Open ocean Pelagic

Estuary Brackish habitat

Inshore island

Seamounts

Midwater

Semi-pelagic

Insular shelf Upwelling

1000m

Batoids (ray) 1896m

Continental shelf species

Continental shelf

Continental break

Continental slope

Insular slope

Insular slope

Abyssal plain

Abyssal plain

Trough

4000m

Batoids (skate) 4156m

Continental rise

3000m

Chimaeras 3100m

Sharks 4500m

Continental slope or deepsea species

Deepsea species

2000m

Coastal species

Insular shelf

Lower slope

Maximum known depths

Semi-oceanic species

Upper slope

200m

Benthic or demersal Bottom

Insular species

Semi-oceanic species

Offshore island

Oceanic species

Bentho–pelagic

Marine habitats and topographic features

EUROPEAN SEAS – HABITATS

11

20

64

19

21

59

60

22

23

24 limit of Northeast Atlantic

62 25

26 27 Map of Large Marine Ecosystems (LMEs) in our region 19 64 20 21

East Greenland Shelf Arctic Sea Barents Sea Norwegian Sea

59 60 22 23

Iceland Shelf Faroe Plateau North Sea Baltic Sea

The continental shelf itself can be separated into two areas: a nearshore, or coastal habitat that includes bays and estuaries and which usually extends out to about 50m depth, and an offshore, or outer continental shelf habitat that extends from 50m to about 200m depth. Many of the sharks, skates and rays that inhabit nearshore coastal waters will be familiar to anglers, divers and others who spend time near the sea. Chimaeras are unlikely to be encountered here, though there are some exceptions, such as the many steep-sided sea lochs found along the Norwegian coast, where some chimaeras may be found within diving depths.

12

INTRODUCTION

24 25 27 26

Celtic Biscay Shelf Iberian Coastal Canary Current Mediterranean Sea

62 Black Sea

Spotting sharks in offshore waters, including the outer continental shelf, pelagic and deepsea habitats, is a different prospect, but a variety of common oceanic sharks can be seen in pelagic waters not too far offshore, such as the Basking Shark Cetorhinus maximus or Porbeagle Shark Lamna nasus, but the only batoid that might be regularly encountered is the Pelagic Stingray Pteroplatytrygon violacea. Although the deepsea habitat is more diverse and supports a large number of species, the chance of encountering a deepsea shark, skate or chimaera is low, unless you are on a fishing boat or research ship.

Chondrichthyes species are can be seen in their habitat throughout the region, from angelsharks inhabiting shallow warm waters around the Canary Islands (left) to deepsea species like chimaeras in the cold waters off the Norwegian coast (right)

The European marine habitat is a vast area that encompasses the mostly cold-temperate Northeast Atlantic and the much warmer Mediterranean Sea. It comprises about 18 million square kilometres, an area nearly twice that of the European landmass, and has a coastline around 250,000km long. The region covered in this book also includes the islands of the Azores, Canaries and Madeira archipelagos. The Mediterranean Sea extends from the Strait of Gibraltar to the Bosphorus, and this book also includes the Black Sea. The region includes two major FAO (Food and

Agriculture Organisation) fishing areas: the Northeast Atlantic (Major Fishing Area 27) and the Mediterranean and Black Seas (Major Fishing Area 37). It also encompasses 13 Large Marine Ecosystems (LMEs). LMEs are regions of the world’s oceans with distinct bathymetry, hydrography, marine productivity and food chain interactions. As their name suggests, these are large areas, in the order of 200,000km2 or greater, encompassing coastal waters, including river basins and estuaries, out to the edge of continental shelves and the outer margin of major ocean currents (see map opposite).

Table 4. Physical statistics of the North Atlantic, Mediterranean and Black Sea and the number of chondrichthyan species (sharks, rays, skates and chimaeras) known to occur in those areas

Average depth Deepest point Area

North Atlantic

Mediterranean Sea

Black Sea

approx. 3,600m

1,500m

1,253m

4,500m Kings Trough

5,267m Calypso Deep, Ionian Sea

2,212m

41,490,000km2 (NE Atl. ~1/3 area)

2,500,000km2

436,400km2

Surface temperature

8.0–18.0°C

5.0–31.0°C

0.5–26.0°C

Bottom water temp.

1.5–4.0 °C

12.9–13.1°C

6.5–8.0°C

(35‰) 35.2–36.7‰

38‰

17‰

Average salinity Chimaeras

9

2

0

Batoids

58

39

2*

Sharks

79

45

2**

* 2 native, another 1 vagrant (Gymnura altavela) ** 2 native, another 4 vagrant (Squatina squatina, Alopias vulpinus, Scyliorhinus canicula and Sphyrna zygaena)

EUROPEAN SEAS – HABITATS

13

CONSERVATION AND MANAGEMENT An overview

by Ali Hood, Director of Conservation at The Shark Trust

The evolution of conservation management activities in Northeast Atlantic and Mediterranean waters is complex, with multiple actors representing myriad interests. The European marine habitat is vast with a coastline of ~250,000km. This geographic scope presents a region with almost 40 coastal States complicated by extremes of wealth and political stability, of temperature and bathymetry. As well as comprising some of the most anthropogenically pressured habitats for elasmobranchs globally, it is also a region with sharks on the menu. In this chapter the term ‘sharks’ refers to all chondrichthyans (sharks, rays and chimaeras). This section seeks not to present a comprehensive report on decades of conservation development and activity, but to deliver an overview, sign-posting readers to organisations and further materials, while profiling some of the species central to the conservation narrative of the region. The inauguration of the European Elasmobranch Association in 1996, and the closely associated inception of a number of national shark conservation organisations, provides a convenient 25 year timeframe (see below). It is generally appreciated that sharks are inherently vulnerable to over-exploitation due to their late maturity, low fecundity and slow growth. The retention of sharks and batoids from target and mixed fisheries, and international market demand for shark and batoid products (including fins, meat and liver oil), has expanded over recent decades. Yet, where shark finning was previously the key driver for shark fisheries, the retention of sharks for meat is now an important and expanding consideration. Meat imports increased 42% by volume between 2000 and 2011. Pair this demand with sharks’ inherent biological vulnerability, and the result is declines in many elasmobranch populations. This is particularly apparent in Mediterranean and Northeast Atlantic waters, where over 53% and 32%, respectively, of chondrichthyans face an elevated risk of extinction, according to the IUCN Red List of Threatened Species.

NORTHEAST ATLANTIC AND MEDITERRANEAN TIMELINE This timeline illustrates conservation progress in the region over the past 25 years. It is not comprehensive, but serves to project the growing momentum of conservation management actions. Yet while listings increase, other urgent conservation priorities fail to secure much needed measures, and action and implementation often lag behind.

14

INTRODUCTION

Fisheries interests in the region are significant. The long history of shark fisheries is evidenced by the number of gear types named after the sharks that they were designed to target, from the ‘squaenera’ deployed to target angelsharks (Squatina spp.) in Italy, to the ‘cazonal’ used to catch smoothhounds (Mustelus spp.) in the Canary Islands. Black and white archive photographs show fish quays laden with species now rarely encountered across vast tracts of their previous range. And, while coastal fisheries may now be depleted of previously common species, shark fishers continue to fill their holds from high seas waters. Across the region, decades of poor catch reporting have left many species data-limited, with aggregated landings data (for example ‘sharks nei’ or ‘skates and rays nei’; ‘nei’ stands for not elsewhere included) often masking concerning changes in catch composition. Species-specific landings data are key to informed fisheries management, and improved species identification is central to this. While the Mediterranean is characterised by small scale (mixed) fisheries, Northeast Atlantic shark fisheries are dominated by a small number of countries, accounting for a significant percentage of European Union (EU) and global shark landings. Spain ranks second in the world for shark catch, and has fleets active throughout the world’s oceans. Illegal, unreported and unregulated (IUU) fisheries are a focus of attention for many of the regional fisheries management organisations, such as International Commission for the Conservation of Atlantic Tunas (ICCAT) and the General Fisheries Commission for the Mediterranean (GFCM). (See Table 6 (p.26) for other regional bodies.) The EU, with its 27 Member States and extensive fishing fleet, exerts both influence and impact throughout this region as a fishing power, and as the proponent for both regional and international regulation. The consequences of the UK’s exit from the EU in January 2020 are yet to be fully

1991–1994

1995

1996

Proposals to establish EEA discussed

Barcelona Convention SPA/ BD signed EEA (see p.17 for country member groups established in this year)

European Elasmobranch Association (EEA) established

appreciated. But, given the conservation stance favoured by the UK in recent decades, the loss of this key counterpoint to the more pro-sharkfishing Member States within the EU’s negotiating forum may be keenly felt. Commercial fishers are not the only stakeholders with interest in sharks in the region. Recreational sea anglers have long targeted sharks for sport, albeit increasingly as catch and release. Ecotourism adds another facet to the burgeoning tourist industry, catering to an appetite for wildlife watching, while the coastal developments that cater to tourism may themselves damage vital nearshore habitats. In 1999, the UN Food and Agriculture Organization (FAO) adopted the International Plan of Action for the Conservation of Sharks (IPOA-Sharks). In 2003, this approach was reflected in the publication of the voluntary Action Plan for the Conservation of Cartilaginous Fishes (chondrichthyans) in the Mediterranean Sea by the Barcelona Convention’s Regional Activity Centre for Specially Protected Areas (RAC/SPA). In 2009, the EU finally adopted the Community Plan of Action for Sharks (CPOASharks) – although both documents are yet to deliver on many of their objectives. In recent years, the development by NGOs of speciesspecific Action Plans has helped identify necessary actions at appropriate scales, and foster greater collaboration. So, while recognising the troubling conservation status of the region’s elasmobranch populations, progress has been made within the 25 year timeframe presented here. Conservation and management of sharks has advanced at national, regional and international levels, although management for batoids has noticeably lagged behind that of sharks, and patchy implementation of voluntary measures and regulations hinders compliance. Key regulations and legislation are listed in Table 6 (p.26) and an overview of the region is presented over page.

BASKING SHARKS Cetorhinus maximus (p.277) Hunted for fins, meat and liver oil, Basking Sharks were caught commercially into the mid 1990s, eventually targeted solely for their high value fins. Listed under UK domestic protection in 1998, EU Fishing Regulations in 2001, CITES Appendix II in 2003, and CMS Appendix I & II in 2005, Basking Sharks have successfully mig­ rated from commercial targets to arguably one of the world’s most protected elasmobranchs. There are no legal directed fisheries in Northeast Atlantic or Mediterranean waters. Much heralded as wildlife ambassadors, commercial interests in Basking Sharks now reflect the growing ecotourism sector. Similarly, citizen science initiatives embrace the public interest in reporting sightings, and submission of fin images can support photo­identification. On the water, codes of conduct for water­users help guide safe shark encounters. Unfortunately incidents of bycatch, entanglement and vessel collision persist.

THE COMMON SKATE COMPLEX (pp.96–99) Skate and ray nomenclature often causes confusion, with some species of the family Rajidae (the hardnose skates), being referred to as rays (e.g. Thornback Skate Raja clavata is often called the Thornback Ray). A diversity of colloquial common names further muddies the waters. And, with skate landed in aggregate in Northeast Atlantic waters until ~2008, changes in catch composition largely went unnoticed. The large­bodied Common Skate Dipturus batis was historically a key part of the catch composition. Subject to overfishing, their numbers declined dramatically, seeing them listed as Critically Endangered (2006). Yet, the confusion here is not one of name alone – the Common Skate, no longer common. Genetic studies published in 2010 concluded that the Common Skate was not one, but two species. Some ninety years after two visually similar skate species had been conflated as Common Skate, they were separated once more. The two species identified as the Common Skate complex have new taxonomic names allocated: the Blue Skate Dipturus batis (p.96) and the more northerly, and larger, Flapper Skate Dipturus intermedius (p.98).

1997

1998

1999

2001

2002

EEA (see p.17 for country member groups established in this year)

Basking Shark UK protec­ tion

First shark listed on the Convention on Migratory Species (CMS) Appendix II: Whale Shark (See Table 5); UN Food and Agriculture Organization (FAO) adopted the International Plan of Action for the Conservation of Sharks (IPOA­Sharks) First North Sea TAC for ‘skates and rays’

Basking Shark first listed on Common Fisheries Policy

First elasmobranchs listed on the Convention on International Trade in Endangered Species (CITES) Appendix II: Basking Shark and Whale Shark (See Table 5) SPA/BD ratified

2003

First EU Finning Regulation adopted; the Action Plan for the Conservation of Cartilaginous Fishes (Chondrichthyans) in the Mediterranean Sea adopted in the framework of the UNEP/MAP Barcelona Convention EEA (see p.17) contd. on p.16

CONSERVATION AND MANAGEMENT

15

The region

IUCN Red List status

Chimaeras, batoids and sharks in the region

146 Chimaeras, batoids and sharks in the Mediterranean

86 Chimaeras, batoids and sharks in Europe (NE Atlantic)

137 CITES* Appendix I and II listed species in the region

Analysis by the IUCN Species Survival Commission’s Shark Specialist Group estimates that, globally, 24% of chondrichthyan species are likely threatened with extinction. This high rate of risk, caused primarily by overfishing, distinguishes this group of fishes as among the most threatened of the world’s vertebrate groups.

EU – % of species threatened

18 CMS** Appendix I and II listed species in the region

23

32% Europe Red List

† ††

*The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)

Critically Endangered (CR)

15

**The Convention on the Conservation of Migratory Species of Wild Animals (CMS)

Endangered (EN)

17

Vulnerable (VU)

10

Near Threatened (NT)

14

Least Concern (LC)

48

Data Deficient (DD)

27

Total assessed

132

BLUE SHARKS AND MAKO SHARKS Bycatch in high seas fisheries is a significant threat to pelagic elasmobranchs. Beyond the EEZ (Exclusive Economic Zone) of any one country, the high seas are regulated by Regional Fisheries Management Bodies. Blue Shark Prionace glauca (p.343) is the most heavily fished species globally. Generally unregulated, in 2019 ICCAT adopted the first catch limit for sharks in international waters for Blue Sharks in the North and South Atlantic. Shortfin Mako Isurus oxyrinchus (p.282), and Longfin Mako Isurus paucus (p.283), are exceptionally vulnerable and a pressing conservation concern. Repeatedly overlooked for management, Shortfin Mako is now subject to clear advice from ICCAT scientists, who in 2017 advised a prohibition on retention of mako in the North Atlantic. CITES Appendix II listing was adopted for Short and Longfin Mako in 2019.

2004

contd. from p.15

16

2006

2007

2008

†

7 12

3 4

EU Red List includes Mediterranean species

††

Nieto et al. (2015)

9

5

2009

2010

2011

International The Shark EU adopts EEA Bigeye Thresher Angelshark, Common Common and Commission for Alliance Porbeagle (see p.17 for country retention Skate (see p.15), Blackchin the Conservation Campaign is quota member groups prohibited Undulate Ray, White Skate Guitarfishes of Atlantic Tunas launched. established in (ICCAT); the EU retention prohibited in all retention (ICCAT) adopts Basking Shark this year) Community Plan EU Community Waters; prohibited shark finning and White OSPAR List of of Action for Porbeagle retention in EU regulation Shark retention threatened and Sharks (CPOAprohibited for EU vessels Community (fin:carcass ratio) prohibited in declining species Sharks) adopted internationally; Spurdog Waters EU Community includes 11 EEA (see p.17) 0t quota Waters elasmobranchs EEA (see p.17)

INTRODUCTION

THE EUROPEAN ELASMOBRANCH ASSOCIATION (EEA) Established in 1996, the EEA’s objectives are to advance research, sustainable management, conservation and education of chondrichthyans throughout Europe and the Mediterranean. The EEA represents non-profit organisations, with countries represented by a single member group. There are currently 13 active member groups*:

Mediterranean – % of species threatened

Year national member groups established –1995: 1 Deutsche Elasmobranchier-Gesellschaft (DEG)*, 2 Gruppo Ricercatori Italiani sugli Squali, Razze e Chimere (GRIS)*; 1997: 3 Shark Trust*, 4 Association Pour l’Etude et la Conservation des Sélaciens (APECs)*, 5 Associação Portuguesa para o Estudo e Conservação de Elasmobrânquios (APECE)*, 6 Shark Foundation*; 7 The Irish Elasmobranch Group (IEG)*; 2001: 8 Uno Squalo per Amico (San Marino); 2003: 9 SUBMON*; 2008: 10 Shark Lab Malta*; 2009: 11 Hai-Alliansen I Norge (HAI Norge)*; 2010: 12 Nederlandse Elasmobranchen Vereniging (NEV)*; 2016: 13 iSea*; 2019: 14 Sharks in Israel*.

53% 11

1

eulasmo.org

THREATENED ENDEMIC SKATES OF THE MEDITERRANEAN Three species of endemic skate are found in the Mediterranean: 1 the Critically Endangered Maltese Skate Leucoraja melitensis (p.106), 2 the Endangered Rough Skate Raja radula (p.128), and 3 the Least Concern Speckled Skate Raja polystigma (p.127). While there are no specific conservation measures for the Rough Skate, the Maltese Skate is listed as a prohibited species by the GFCM.

6 2

8 13

10

14 3

2 1

2012

2013

2015

2016

2018

2019

2020

The General Fisheries Commission for the Mediterranean (GFCM) prohibits retention of the 24 species of elasmobranchs listed in Annex II of the Barcelona Convention SPA/BD Protocol (see Table 5)

EU adopts Fins Naturally Attached (FNA)

North East Atlantic Fisheries Commission adopts FNA

EEA (see above for country member groups joining in this year)

GFCM adopts FNA; Turkey prohibits retention of 14 elasmobranchs including: angelsharks (3 spp.); Giant Devil Ray; Common and Blackchin Guitarfishes; and Shortfin Mako. Whale Shark retention prohibited in European Waters

ICCAT: first International catch limit adopted in Atlantic for Blue Shark EEA (see above for country member groups joining in this year)

EU adopts Blue Shark quota UNEP/MAP Cartilaginous Fishes Action Plan updated

CONSERVATION AND MANAGEMENT

17

IUCN Red List status

Northeast Atlantic

The IUCN Red List of Threatened Species is intended to be an easily and widely understood system for classifying the extinction risk of species. It divides species into nine categories:

NE 6.6%

CR 8.8%

Not Evaluated Species that have not yet been evaluated against the Red List criteria. ● Data Deficient (DD) Species for which there is inadequate information to make an assessment of risk of extinction. ● Least Concern (LC) Species that do not qualify for a threatened category or Near Threatened. ● Near Threatened (NT) Species that have been evaluated as being close to, or likely to qualify for a threatened category in the near future. ● Vulnerable (VU) Species for which the best available evidence indicates it is considered to be facing a high risk of extinction in the wild.

EN 11.7%

All species in the Northeast Atlantic 137 sp.

DD 18.2%

VU 5.8% NT 11.7% LC 37.2%

NT 11.1%

CR 8% EN 14.7%

Chimaeras 9 sp.

NE 5.3%

Sharks 75 sp.

DD 30.7%

VU 5.3% CR 11.3% LC 88.9%

EN 9.4%

NE 9.4%

DD 3.8%

LC 25.3%

Batoids 53 sp.

VU 7.6%

NT 13.2%

18

INTRODUCTION

NT 10.7%

Comparison of Red List species found in both the Northeast Atlantic (drawing upon EU listings) and Mediterranean LC 45.3%

● Endangered (EN) Species for which the best available evidence indicates it is considered to be facing a very high risk of extinction in the wild. ● Critically Endangered (CR) Species for which the best available evidence indicates it is considered to be facing an extremely high risk of extinction in the wild. ● Extinct in the Wild (EW) This category is for species that are known only to survive in cultivation or captivity. ● Extinct (EX) This category is for species when there is no reasonable doubt that the last individual has died.

Mediterranean

CR 19.8%

NE 10.5% All species in the Mediterranean 86 sp.

DD 18.6%

EN 12.8%

For further information on all these categories and all the latest status updates visit: iucnredlist.org

VU 8.1%

LC 17.4% NT 12.8%

NE 6.1% CR 22.5%

Sharks 49 sp.

DD 28.6%

Chimaeras 2 sp. NT 50%

EN 14.3%

LC 50%

NE 17.1%

CR 17.1%

Batoids 35 sp.

EN 11.5%

VU 5.7%

VU 10.2%

NT 6.1%

LC 12.2%

DD 5.7%

LC 22.9% NT 20% CONSERVATION AND MANAGEMENT

19

Northeast Atlantic Mention Europe in the context of shark conservation and it is inevitable that, while Europe itself extends beyond the borders of the EU, it is the EU and its fisheries interests that loom large. Widely acknowledged as a dominant force in global shark fisheries, consumption and trade, three of the 27 EU Member States rank in the top 20 shark catching nations globally, with Spain second only to Indonesia. Although the EU’s domestic target fisheries have declined along with Northeast Atlantic shark populations, the EU exerts a strong influence on global ocean policy and presents a significant voting block in environmental fora. With EU Member States keen consumers of shark products (e.g. Italy ranked 3rd for shark imports globally during 2000–2011) the significant weight of the fishing industry lobby is keenly felt. While the EU acts to centralise many of the regulatory decisions that affect sharks, national governments have autonomy to adopt domestic legislation. Spain, for example, despite its position as a key shark catcher, has the most comprehensive domestic legislation of any EU Member State. However, Spain’s domestic Prohibition on fishing for more than 30 species is not reflected in the waters of other Northeast Atlantic countries. The result is a patchwork of measures across the region, leaving sharks to unwittingly run the gauntlet. Between 2006–2013 the Shark Alliance campaign coordinated advocacy efforts across Europe. The CPOAShark (2009) was a key campaign objective, and the CPOA-Shark prioritised the need to tighten the EU shark finning regulation (see box, right). From 2009–2011 there was also a significant increase in the number of elasmobranchs included in the EU’s annual Fishing Opportunities (TACs and Quotas) document, listing management for Common Skate Dipturus batis (see box p.15) and Angelshark Squatina squatina for the first time. But while the CPOA had set the stage for sweeping improvements in shark fisheries management and protection policies, some 10 years after adoption, progress has generally been disappointing and many elasmobranchs remain without effective management. Beyond a plethora of specific EU instruments, the waters of the Northeast Atlantic fall under the jurisdiction of the OSPAR and HELCOM Regional Seas Conventions and multiple Regional Fishery Bodies, and within the remit of intergovernmental organisations (see Table 6, p.26). Each of these has the capacity to adopt measures which may be binding or non-binding. These additional instruments also address the fact that not all the waters of the Northeast Atlantic are under the jurisdiction of EU Member States. For example, the Exclusive Economic Zone (EEZ) of Morocco, a country with significant shark

20

INTRODUCTION

fishing interests, nudges into the south of the region. The longline fleets of southern Europe and Morocco dominate the shark landings of the North Atlantic. Acknowledging this, in recent years advocacy efforts have focused on the adoption of binding ICCAT Recommendations for Blue Shark Prionace glauca and Shortfin Mako Isurus oxyrinchus. In 2019 a significant milestone was reached with the adoption of the first international catch limits for Blue Sharks, while Shortfin Makos remain without catch limits despite scientific advice for a prohibition in the North Atlantic.

SHARK FINNING Shark finning is the practice of removing a shark’s fins at sea and discarding the carcass overboard. It is a highly wasteful practice and a major barrier to effective fisheries management (Fin Guide p.369). In 2003 the EU adopted a Shark Finning Regulation which, while banning finning itself, permitted removal of fins at sea, on the proviso that both fins and carcass were retained. Compliance was monitored through a fin : carcass weight ratio, however this was set higher (5% whole weight) than other fishing nations (e.g. US 5% dressed weight). In addition, the EU permitted fins and carcasses to be landed in separate ports – further complicating the enforcement process and allowing less scrupulous operators to land fins from finned and discarded sharks. Fins Naturally Attached (FNA) is now widely accepted as best practice for regulating shark finning as it eases enforcement, aids species identification, prevents high grading (the mixing of fins from high value species with smaller, or lower value carcasses), which in turn improves landings data. Following an effective campaign by the Shark Alliance, FNA was adopted by the EU in 2013 and is applicable to the EU fleet globally. FNA has also been adopted by NEAFC (2015), and GFCM (2018).

Partial cut – fins are cut along the majority of their length leaving a small attachment to the carcass and then flapped against the carcass and tied in place.

The Mediterranean Where the Northeast Atlantic has a relatively clear focal point in the form of the EU, the Mediterranean is the counterpoint: a highly complex, multijurisdictional region surrounded by over 20 countries and territories, across three continents. European influences are dominant in the west, with the waters and fisheries of the 11 EU Mediterranean coastal states addressed in the main through EU regulations. Non-EU countries are governed by domestic legislation and commitments to regional bodies and Multilateral Environmental Agreements (MEAs). Many Mediterranean countries are Party to ICCAT, all are Party to the Barcelona Convention, GFCM and its elasmobranch measures, and all bar Turkey are Signatories to the Convention on Migratory Species (CMS). There has been a significant decline in species richness throughout the Mediterranean, coinciding with reported declines in elasmobranch abundance. More than a decade since Mediterranean chondrichthyans were first assessed, the IUCN reports that there is no sign of improvement in the regional status of sharks, skates and rays. Overfishing is the key threat, complicated by the fishing sector’s historically important economic role in the region. Subsistence or small-scale fisheries (SSF) are deeply rooted in the fabric of the Mediterranean, with SSF playing a significant social and economic role. Indeed, 84% of the fishing fleet, some 70,000 vessels, operate in SSF, generally supplying local markets. Perhaps the key constraint to delivering effective conservation or management activities is reaching this SSF sector, with fishing villages often located along remote coastlines. The dispersed nature of the region’s fishing activity makes quantifying species-specific elasmobranch bycatch challenging. This is further hampered by the significant level of aggregated catch reporting: over 65% of all reported elasmobranch catches in the Mediterranean are landed in the aggregate. Because a number of governments have lagged behind in implementing existing regulations (primarily GFCM/42/2018/2), fishers and fisheries enforcement officers may be unaware of existing regional recommendations – the result often being the sale of all bycatch regardless of regional conservation management status. Efforts to address the commercialization of threatened species have often been led by the NGO community and have included: an increase in bycatch observer coverage; education programmes for fishers and retailers; and an expansion of advisory and identification materials (see Table 6).

While overfishing remains the primary threat, habitat degradation is also a key concern. The Barcelona Convention’s Specially Protected Areas Regional Advisory Centre (RAC/ SPA) provides a valuable coordinating role in the region.

GUITARFISHES Giant Guitarfishes are the world’s most threatened marine fishes, and the Critically Endangered Blackchin Guitarfish Glaucostegus cemiculus (p.181) is native to the Mediterranean. Also found in region are the Endangered Common Guitarfish Rhinobatos rhinobatos (p.182). Both species are caught and retained in mixed and target fisheries along the North African coast. Guitarfishes are a high value ray with the meat consumed locally. Little is known about actual landings, catch composition, seasonality, market demand, or trade. These guitarfishes are listed as prohibited species by the GFCM, but this regulation is poorly implemented, leaving them exposed to unregulated fishing pressure.

GIANT DEVIL RAY Capture and retention of 30 Giant Devil Ray Mobula mobular (p.163) by a Turkish vessel in 2017 exposed troubling gaps in the compliance with GFCM regulations, which prohibit their landing and selling. Amongst the world’s least fecund marine fish, the Giant Devil Ray is vulnerable to overexploitation due to its late maturity, lengthy gestation, and exceptionally small numbers of offspring – typically producing one pup every two to three years. Landing and selling the Giant Devil Ray is banned in the Mediterranean under GFCM/42/2018/2, yet bycatch still occurs. Triggered by the 2017 Turkish landings, and associated conservation concerns, the Turkish Government added the Devil Ray to their domestic prohibited species list in 2018.

CONSERVATION AND MANAGEMENT

21

Securing conservation management Safeguarding the future of elamobranchs is a long-term commitment, particularly when considering waters as depleted as the Mediterranean, and as pressured as the Northeast Atlantic. Current progress reflects decades of effort, yet many species and their critical habitats remain vulnerable in the absence of management. It is clear that existing conservation measures are not enough.

Conservation communities As shark populations have declined, there has been a growth in the number of groups and organisations voicing interest in elasmobranchs, including environmental Non-Governmental Organisations (NGOs), the research community, fisheries interest groups, governments and an increasingly vocal general public. The public attitude to sharks can be as diverse as ‘the public’ themselves which, in the context of shark conservation, might encompass a range of constituencies from SCUBA divers and recreational sea anglers, to wildlife enthusiasts, beach-goers and the consumer. Over the past 25 years, the public’s attitude to the natural environment has evolved and public influence on decision-making with it. Previously, sharks were most likely encountered on a visit to an aquarium, as a menu item, or on the end of a fishing line. This hasn’t much changed, although now sharks are also a big ticket for ecotourism – with operators in the region responding to growing interest in seeing sharks in the wild. This evolving fascination with sharks is most clearly reflected in the proliferation of citizen science projects. These are often sightings projects which engage ‘citizens’ on land and sea as recorders, noting occasional sightings (see Box) or undertaking regular surveys. The result is many more eyes on the water, strandline or fish market, and collation of a greater volume of data and information over a wider geographic range than could be achieved by the research community working alone. The widescale use of smart phones adds valuable technical capacity, with cameras, GPS and access to multiple recording platforms and public fora providing new and growing data streams. Similarly, social media feeds represent a surprising source of records and sightings. Yet, despite a more informed public, the consumer market for shark products remains strong – with shark meat still popular and shark products still widely used. At the same time, sectors of the recreational community continue to prize shark angling, with the targeting of vulnerable species, such as Porbeagle Lamna nasus, evident in the Northeast Atlantic.

22

INTRODUCTION

Securing change Public campaigning is often a key element of conservation change. Indeed, effective campaigning is a common theme underpinning many of the ‘wins’ illustrated on the earlier timeline. Mobilisation of shark conservation groups across Europe under the Shark Alliance campaign is a positive example. But the conservation landscape is changing. Where the shark fin trade was the key driver, retention of sharks for meat is now a major consideration. In this context the conservation community must update its narrative and avoid oversimplification of messaging. There is not a single solution to the challenges of shark conservation, and campaigns must be nuanced to reflect this. Simply calling for bans, whether on specific products or the shark fin trade, will not stop sharks being caught or killed. Such a limited approach may, in fact, inadvertently divert attention from the real threat: that despite some progress, most shark, skate and ray populations continue to be fished with no limits.

CITIZEN SCIENCE: THE GREAT EGGCASE HUNT The Shark Trust’s public recording project, the Great Eggcase Hunt, gathers georeferenced data for shark, skate and chimaera eggcases found primarily around the United Kingdom, but increasingly from across Europe, the Mediterranean, and beyond. While acting as a useful tool to engage the public in shark conservation, records can also indicate presence and diversity of oviparous species in different regions. Eggcases (or ‘mermaid’s purses’) vary according to species (see p.42). By examining various features (size, shape, whether they have horns or curled tendrils, presence of lateral keels etc.) it is possible to determine which species the eggcase came from. To assist with identification, the Shark Trust has developed resources for those eggcases most likely to be found on northwest European shores. Once identified, submission to the Great Eggcase Hunt database is encouraged, with a photo to allow for reliable verification of records. www.eggcase.org

Challenging times Securing effective conservation management and seeking implementation of and compliance with existing measures at national, regional and international levels is crucial. Collaborative conservation strategies, such as that published by the Global Sharks and Rays Initiative, and species-specific regional action plans (see angelshark box below) provide structured roadmaps for delivery of conservation objectives. The findings of such reports, where effectively communicated, can help secure much needed policy decisions. Constraints to effective conservation management are commonplace, but may also differ between the Northeast Atlantic, particularly EU waters, and those of the Mediterranean. These constraints reflect political, economic, legal and social factors. In a region as diverse as the Mediterranean, cultural and linguistic diversity are also key considerations; efforts must be taken to prevent language from acting as a barrier to delivering effective conservation management (for example, by translating identification guides and advisory materials into multiple languages). Efforts to secure and maintain the focus of decision-makers, and to ensure that governments engage across their institutions – linking the decisions of Environment Ministries with delivery through Fisheries Ministries – is key. The implementation of CITES listings for elasmobranchs – such as controls on the international trade in Appendix II listed species – is an example of this. Furthermore, where CITES-listed species are caught and landed from a country’s EEZ but not traded internationally, there is an even greater urgency to see domestic management enforced. The Blackchin Guitarfish Glaucostegus cemiculus (CITES Appendix II) and Common Guitarfish Rhinobatos rhinobatos provide a example of this disconnect: both species are landed in significant numbers on the North Africa coast, despite being prohibited through regional regulations adopted by the GFCM Parties. This is where conservation advocates can come to the fore, moving swiftly across the science-policy interface, holding governments and the fishing industry to account for commitments made, while championing scientific advice as the foundation of effective conservation and fisheries management. Finally… The past 25 years have seen significant change in elasmobranch conservation and management, and shifts in government positions and public perceptions. Advocacy and ‘awareness’ campaigns have established an understanding that chondrichthyans are vital to a healthy marine environment.

Yet, while we continue to focus on much-needed catch limits, we must also ensure governments and regulators demand improved landings data, and end the reporting of landings using aggregated categories. Better data can underpin more accurate stock assessments – the building blocks of clear, unambiguous scientific advice. We need governments to adhere to the science, as it provides the basis for sustainable fisheries and alerts to the need for strict protection for more vulnerable species. Maintaining the economic viability of a fishery should not be achieved by continued retention of threatened species. With many elasmobranchs caught as incidental bycatch, bolstering catch limits with bycatch mitigation and avoidance measures is key. This may include the adoption of spatial, temporal and technical measures, within EEZs and on the high seas. Conservation and management of chondrichthyans is a complex business. But it is relatively simple to get involved, whether you are a researcher, an advocate, a conservationist or simply passionate about sharks and their relatives. The key thing is to engage.

COLLABORATION: ANGELSHARKS Angelsharks have been identified as one of the most threatened families of chondrichthyans in the world, with many species requiring urgent conservation action. The Angel Shark Conservation Network (ASCN) was established to facilitate dialogue and information sharing on angelshark conservation efforts, particularly throughout the range of the three Critically Endangered species found in the Eastern Atlantic and Mediterranean Sea: Squatina aculeata, S. oculata and S. squatina. The Mediterranean Angel Sharks: Regional Action Plan sets out a roadmap focusing efforts to restore these enigmatic species to robust populations in the region. Goals are centred around the predominant threats to angelsharks: fisheries and habitat degradation, with an underlying goal for the implementation of legislation and regulations to ensure both the species and their critical habitats are better protected. To allow a tailored approach in this multijurisdictional region and engage regional stakeholders, a series of Subregional Action Plans focus on subareas of the Mediterranean which are considered high priority for conservation action. www.sharktrust.org/angelsharks

CONSERVATION AND MANAGEMENT

23

Conservation and fisheries management resources IUCN Red List status EU

IUCN Red List status Med.

IUCN Red List status Global

Heptranchias perlo

DD

DD

NT

Spurdog

Squalus acanthias

EN

EN

VU

Gulper Shark

Centrophorus granulosus

CR

CR

DD

Leafscale Gulper Shark

Centrophorus squamosus

EN

EN

VU

Portuguese Dogfish

Centroscymnus coelolepis

EN

LC

NT

Angular Roughshark

Oxynotus centrina

VU

CR

VU

Sawback Angelshark

Squatina aculeata

CR

CR

CR

Smoothback Angelshark

Squatina oculata

CR

CR

CR

Angelshark

Squatina squatina

CR

CR

Whale Shark

Rhincodon typus

Smalltooth Sandtiger

Odontaspis ferox

CR

CR

VU

Bigeye Thresher

Alopias superciliosus

EN

EN

VU

App II

App II*

Common Thresher

Alopias vulpinus

EN

EN

VU

App II

App II*

Basking Shark

Cetorhinus maximus

EN

EN

EN

App II

White Shark

Carcharodon carcharias

CR

CR

VU

App II

Shortfin Mako

Isurus oxyrinchus

DD

CR

EN

App II

App II*

Longfin Mako

Isurus paucus

DD

DD

EN

App II

App II*

Porbeagle

Lamna nasus

CR

CR

VU

App II

App II*

Tope

Galeorhinus galeus

VU

VU

VU

Starry Smoothhound

Mustelus asterias

NT

VU

LC

Smoothhound

Mustelus mustelus

VU

VU

VU

Blackspotted Smoothhound

Mustelus punctulatus

VU

VU

DD

Silky Shark

Carcharhinus falciformis

DD

VU

App II

Oceanic Whitetip Shark

Carcharhinus longimanus

EN

CR

App II

Dusky Shark

Carcharhinus obscurus

DD

DD

EN

Sandbar Shark

Carcharhinus plumbeus

EN

EN

VU

Blue Shark

Prionace glauca

NT

CR

NT

Scalloped Hammerhead

Sphyrna lewini

DD

Great Hammerhead

Sphyrna mokarran

DD

Smooth Hammerhead

Sphyrna zygaena

DD

CR

Common Skate complex: Blue Skate Flapper Skate

Dipturus batis Dipturus intermedius

CR

CR

CR

Black Skate

Dipturus nidarosiensis

NT

Maltese Skate

Leucoraja melitensis

CR

CR

CR

Sandy Skate

Leucoraja circularis

EN

CR

EN

Thornback Skate

Raja clavata

NT

NT

NT

Spotted Skate

Raja montagui

LC

LC

LC

White Skate

Rostroraja alba

CR

EN

EN

Spiny Butterfly Ray

Gymnura altavela

CR

CR

VU

Giant Manta Ray

Mobula birostris

VU

App II

Giant Devil Ray

Mobula mobular

EN

App II

Smalltooth Sawfish

Pristis pectinata

CR

CR

CR

App I

Largetooth Sawfish

Pristis pristis

CR

CR

CR

App I

Blackchin Guitarfish

Glaucostegus cemiculus

CR

App II

Common Guitarfish

Rhinobatos rhinobatos

Common name

Scientific name

Sharpnose Sevengill Shark

24

INTRODUCTION

CR

App II*

App II

App II

App II* App I*

App II* App II App II

App II*

CR

App II

App II*

VU

App II

App II*

NT

EN

MoU*

CR EN

EN

CITES

EN

CITES

CMS & CMS MoU*

ICCAT

Barcelona & GFCM*

OSPAR

Annex III App II*

Annex III

●

Annex III

● ● ●

Annex II* Annex II* Annex II* App I & II*

Annex II*

App II

App I & II*

App II

App II*

x x**

●

App II

App II* App I & II*

App II

App I & II*

App II

App II*

App II

App II*

App II

App II*

Annex III Annex II*

o

App II

●

●

Barcelona Convention for the Protection of the Mediterranean Protocol concerning Specially Protected Areas and Biological Diversity (SPA/BD) Annex II: Endangered and threatened species Annex III: Species whose exploitation is regulated

Annex II* Annex II* Annex II* Annex III Annex III

OSPAR The OSPAR list of threatened and/or declining species.

Annex III App II

App II*

x**

App II

App I*

x

International Commission for the Conservation of Atlantic Tunas (ICCAT) ICCAT: o management measure applies; ** exemptions apply; x prohibitions apply. Shark finning is regulated in the ICCAT Convention Area through a fin to carcass ratio.

App II*

General Fisheries Commission for the Mediterranean (GFCM) Adopted a prohibition on the retention, transshipment, landing, storage, display and sale of 23 species of elasmobranchs listed on Barcelona SPA/BD Annex II through GFCM/36/2012/3 (since superseded by GFCM/42/2018/2). Fins Naturally Attached was adopted in 2018.

Annex III App II

o

Annex III

App II

App II*

x

Annex II*

App II

App II*

x

Annex II*

App II

App II*

x

Annex II* Annex II*

●

Annex II* Annex II* ● ● Annex II* Annex II* App II

App I & II*

App II

App I & II*

Annex II*

App I

App I & II*

Annex II*

App I

App I & II*

App II

The Convention on International Trade in Endangered Species of Wild Fauna & Flora (CITES) CITES Appendix I: International commercial trade is prohibited except in exceptional circumstances. CITES Appendix II: Trade is controlled under specific conditions using permits.

The Memorandum of Understanding on the Conservation of Migratory Sharks (Sharks MOU) CMS MoU Annex I: lists species that have an unfavorable conservation status and which require international agreements for their conservation and management, or would significantly benefit from the international cooperation that could be achieved by an international agreement.

Annex II* o

Table 5. Key wildlife treaties and management instruments

The Convention on the Conservation of Migratory Species of Wild Animals (CMS) CMS Appendix I: Species are to be strictly protected. CMS Appendix II: CMS Parties have committed to work internationally towards conservation.

Annex II*

App II

Key wildlife treaties and management instruments (Table 3) list a fraction of the species found in the region, and offer no protection to many of the most vulnerable. As our knowledge on elasmobranch populations and the threats they face expands, and IUCN Red List reviews are undertaken, it becomes clear that many species currently listed as Data Deficient are likely threatened and the scope of conservation actions should be expanded. Listing species on a regulation, however, does not guarantee implementation.

●

EU Regulations Total allowable catches (TACs) or fishing opportunities, are catch limits (expressed in tonnes) that are set for most commercial fish stocks, but many elasmobranchs have no catch limits, and exceptions may apply. TACs and Quotas are subject to annual/biennial change. Details on current TACs and Quotas can be found on eur­lex.europa.eu and condensed versions are presented as Fisheries Advisories (Table 6, p.26). Prohibited Species are listed in four key Council Regulations: (EU) No. 2015/812: EU Landings Obligation (EU) No. 2019/1241: EU Technical Measure (EU) No. 2015/2102: EU Regulation on GFCM (EU) 2018/2025: Fishing opportunities for Union fishing vessels for certain deepsea fish stocks including sharks. EU Landings Obligation (EU) No 1380/2013: The landing obligation requires all catches of regulated commercial species onboard to be landed and counted against quota, unless the species is prohibited or exemptions apply.

Annex II* Annex II*

App I & II*

Annex II*

CONSERVATION AND MANAGEMENT

25

This table does not present national conservation or management legislation but signposts international and regional instruments, resources and recording platforms. All listings are regularly subject to change. Table 6. International and regional instruments, resources and recording platforms

Organisation

Further information

Website

Fisheries Management Regional Fishery Bodies: GFCM

General Fisheries Commission for the Mediterranean

fao.org/gfcm

ICCAT

International Commission for the Conservation of Atlantic Tunas

iccat.int

ICES

International Council for the Exploration of the Sea

ices.dk

LDAC

Long Distance Advisory Committee

ldac.eu

NEAFC

North East Atlantic Fisheries Committee

neacf.org

NWWAC

North Western Waters Advisory Committee

nwwac.org

EU Regulations: EU Deepsea fish stocks

Regulation (EU) 2018/2025

EU Landings Obligation

Regulation (EU) No. 2015/812

EU Regulation on GFCM

Regulation (EU) No. 2015/2102

EU Technical Measure

Regulation (EU) No. 2019/1241

Fishery Advisories

EU Regulations and handling guides. Updated annually, multilingual

sharktrust.org/advisories

FAO FishStat Plus

Fishery statistical time series

fao.org/fishery/statistics

TACs and Quotas

Council Regulation (EU) No. 2020/123 NB: updated annually

eur­lex.europa.eu

Multilateral Environment Agreements Barcelona

The Convention for the Protection of the Marine Environment and the Coastal Region of the Mediterranean, Mediterranean Action Plan The Regional Activity Centre for Specially Protected Areas (RAC/SPA)

unenvironment.org/unepmap rac­spa.org

Bern

The Convention on the Conservation of European Wildlife and Natural Habitats

coe.int/en/web/bern­convention

CBD

Convention on Biological Diversity

cbd.int

CITES

The Convention on International Trade in Endangered Species of Wild Fauna and Flora

cites.org

CMS

The Convention on the Conservation of Migratory Species of Wild Animals

cms.int

CMS MoU

The Memorandum of Understanding on the Conservation of Migratory Sharks

cms.int/sharks

HELCOM

The Helsinki Convention on the Protection of the Marine Environment of the Baltic Sea Area

helcom.fi

OSPAR

Convention for the Protection of the Marine Environment of the Northeast Atlantic

ospar.org

UNEP/RSCAPs

United Nations Environment Programme/Regional Seas Programme

unenvironment.org/explore­ topics/oceans­seas

Resources and contacts ASCN

Angel Shark Conservation Network

angelsharknetwork.com/#maps

EEA

European Elasmobranch Association

eulasmo.org

EUAC

European Union of Aquarium Curators

euac.org

GSRI

Global Sharks and Rays Initiative

globalsharksraysinitiative.org

26

INTRODUCTION

Organisation

Further information

Website

Resources and contacts (contd.) IUCN Red List of Threatened Species

For species’ conservation status

iucnredlist.org

IUCN Shark Specialist Group

For a wealth of information on biology, distribution, population status and conservation actions

iucnssg.org

Shark League

Shark League for the Atlantic and Mediterranean

sharkleague.org

Shark Trust

Science-based, shark conservation charity founded in 1997

sharktrust.org

TRAFFIC

Wildlife Trade Specialists

traffic.org

ASCN

Angel Shark Sightings Map

sites.zsl.org/angelsharks

CIESM

The Mediterranean Science Commission’s Shark Task Force records observations of rare species

ciesm.org/forums/Sharks.html

MECO

The Mediterranean Elasmobranch Citizen Observation project

facebook.com/theMECOproject

MEDLEM

Mediterranean Large Elasmobranch Monitoring

arpat.toscana.it/medlem

Shark Trust

Elasmobranch Public Sightings Database

sharktrust.org/sightings­database

Recording platforms

The Great Eggcase Hunt A Shark Trust initiative: identification and recording resources (see p.22)

Further reading Given the plethora of papers published on chondrichthyan issues in the Northeast Atlantic and Mediterranean, no attempt has been made to present a comprehensive reference list – and no offence is intended to any authors omitted. This list is a selection of publications which, in the main, address more wide reaching issues such as regional population status, actions plans or trade data. Barker, J. et al. 2016. Angelshark Action Plan for the Canary Islands. Zoological Society of London, United Kingdom. Bradai M.N., et al. 2012. Elasmobranch of the Mediterranean and Black sea: status, ecology and biology. Bibliographic analysis. Studies and Reviews. General Fisheries Commission for the Mediterranean. No. 91. Rome, FAO. 103pp. Bräutigam, A. et al. 2015. Global Priorities for Conserving Sharks and Rays: a 2015–2025 strategy. The Global Sharks and Rays Initiative. 28pp. Cavanagh, R.D. & Gibson, C. 2007. Overview of the Conservation Status of Cartilaginous Fishes (Chondrichthyans) in the Mediterranean Sea. IUCN, Gland, Switzerland and Malaga, Spain. Vi + 42pp. Dent, F. & Clarke, S. 2015. State of the global market for shark products. FAO Fisheries and Aquaculture Technical Paper No. 590. Rome, FAO. 187pp. Dulvy, N.K. et al. 2014. Extinction risk and conservation of the world’s sharks and rays. eLife, 3: e00590. Dulvy N.K. et al. 2016. The Conservation Status of Sharks, Rays and Chimaeras in the Mediterranean Sea [Brochure]. Malaga, Spain: IUCN. FAO. 2018. The State of Mediterranean and Black Sea Fisheries. General Fisheries Commission for the Mediterranean. Rome. 172pp. Licence: CC BY-NCSA 3.0 IGO. FAO FishStat Plus – Universal software for fishery statistical time series. Rome. www.fao.org/fishery/statistics/software/fishstat/en (updated to 2017).

eggcase.org

Gibson, C., Valenti, S.V., Fordham, S.V. and Fowler, S.L. 2008. The Conservation of Northeast Atlantic Chondrichthyans: Report of the IUCN Shark Specialist Group Northeast Atlantic Red List Workshop. IUCN Species Survival Commission Shark Specialist Group. Newbury, UK. viii + 76pp. Gordon, C.A. et al. 2017. Eastern Atlantic and Mediterranean Angel Shark Conservation Strategy. The Shark Trust, United Kingdom. Gordon, C.A. et al. 2019. Mediterranean Angel Sharks: Regional Action Plan. The Shark Trust, United Kingdom. 36pp. IUCN/SSC. 2008. Strategic Planning for Species Conservation: A Handbook. Version 1.0. Gland, Switzerland: IUCN Species Survival Commission. 104pp. IUCN 2020. The IUCN Red List of Threatened Species. Version 2020–2. https://www.iucnredlist.org. Lawson, J.M. & Fordham, S.V. 2018. Sharks Ahead: Realizing the Potential of the Convention on Migratory Species to Conserve Elasmobranchs. Shark Advocates International, The Ocean Foundation, Washington, DC, USA. 76pp. Mancusi, C. et al. 2020. MEDLEM database, a data collection on large elasmobranchs in the Mediterranean basin. Mediterranean Marine Science. 21(2), 276-288. Nieto, A. et al. 2015. European Red List of marine fishes. Luxembourg: Publications Office of the European Union. Okes, N. & Sant, G. 2019. An Overview of Major Shark Traders, Catchers and Species. TRAFFIC, United Kingdom. SPA/RAC–UN Environment/MAP. 2012. Guidelines for shark and ray recreational fishing in the Mediterranean. SPA/RAC–UN Environment/MAP. 2020. Action Plan for the Conservation of Cartilaginous Fishes (chondrichtyans) in the Mediterranean Sea; by: Bradai, M N., Ed SPA/RAC. Tunis, 18 pp. Turkoglu, M. et al. (eds.) 2018. Marine Ecology: Biotic and Abiotic Interactions. IntechOpen.

Ferretti, F. et al. 2016. Squatina oculata. The IUCN Red List of Threatened Species 2016: e.T61418A16570000. Mediterranean assessment.

CONSERVATION AND MANAGEMENT

27

� �

� HOW TO USE THIS BOOK

The structure of this book will be familiar to anyone who has used other species field guides. Where this field guide differs from most, is that the illustrated dichotomous (branching) key guides are found throughout the book. The first key (pp.43–44) starts with the cartilaginous fish, which takes you to further key guides, first to orders, then families and genera and finally species. We recommend always using the dichotomous key when trying to identify a particular species (even if you already think that you know what it is). To further help identification, spreads throughout the guide show similar looking species together for comparison. Each order and family has its own introduction with the overall habitat and ecology for the group as well as key identification characters. This introductory section also reviews briefly the biology and status of the taxonomic group. The introduction to each family is followed by a page entry for every species occurring in the region. The species is identified by one widely used English name, its scientific name and its FAO 3-Alpha code. Species appear in alphabetical order of their scientific names within each family, firstly the genus, then the species name. Each species description is accompanied by colour illustrations of the lateral and ventral view for sharks (except for angelsharks which have dorsal and ventral views), a lateral view for chimaeras, and dorsal and ventral views for batoids. Scale bars indicate the approximate sizes of the species (in cm) at different ages, when known. Total body length (TL) measurements are given in cm, measured as the ‘point to point’ distance (i.e. not over the curve of the body) from the tip of the snout to the tip of the caudal fin (tail). Where available, these include total length at birth, maturity and maximum size. For chimaeras, body length (BDL) and precaudal length (PCL) are sometimes used (see p.363). For devil rays, eagle rays, cownose rays and stingrays, disc width (DW) is used as the overall measurement. For egg-laying species, we have tried to indicate the size of eggcase and length of young when they hatch and there are separate sections comparing these eggcases (see later in this introduction). ‘Mature’ indicates the size at which the species first reaches sexual maturity (this is often different for males and for females; the latter are generally larger) and where possible we have indicated for both. The ‘Maximum’ length is often the largest recorded, not the maximum that a species could reach (which may be much larger). Weights have not been given as they are not often

28

INTRODUCTION

recorded in scientific literature because they are highly variable, depending upon the time of year, state of pregnancy, recent meals and so on. Length, on the other hand, is a more constant, reliable and useful measure of size (and age) of animal. Length:weight conversion tables are available for many species, to allow anglers to estimate the weight of their catch without removing it from the water and possibly injuring the animal. The description text includes each species’ shape and other distinctive features. The drawings on pp.30–34 identify the body parts referred to in the text. There are also sections on colour and dentition. Dentition descriptions include tooth counts (where known); this is the total number of tooth rows along both jaw lines (left and right) of the upper and lower jaws. This figure is not the total number of teeth to be found in the jaw as this would include all the series of teeth in the rows, it is only the outermost series, the functional teeth, that are the rows counted (see p.35). Throughout the book, key guides help identify teeth for a particular group or, in the case of sharks, to species level. These key guide dentition illustrations are of all the functional teeth, from one side of the upper and lower jaws; accompanying scale bars indicate the size of these adult teeth. Distribution is provided as a map. It is quite possible that many species have a wider regional distribution than illustrated, especially in poorly recorded species. Solid blue in the maps refers to known distribution, lighter blue is possible distribution.

Distribution is indicated in dark blue for known occurrence and light blue for possible distribution. The Azores distribution is sometimes shown as an inset, as above, where there is a wideranging east–west distribution.

� � Habitat describes where the animal most commonly lives, including the depths below sealevel, in metres, where it has been reported. Biology summarises information known about species reproduction; behaviour, including movements and migrations; and characteristic feeding activities and prey. Also included in this section is information on eggcases, where applicable. Pages throughout the book illustrate these eggcases, where they are known, drawn to scale for that page. For more information on eggcases and to record any eggcase found, visit www.eggcase.org (see p.22). IUCN Red List status (see also pp.24–25) is current in July 2020, but updated twice a year (see www.redlist.org for more recent assessments). Brief information about the conservation, management and fisheries status of the animal is also given. On the right hand side of the page there is a summarised visual guide in the form of icons. Starting from the top is the ease of identification icon, then the depth guide which shows the range of depth recorded for that species, and sometimes at which depths it more commonly occurs (darker yellow tint). Below that are a series of icons (see right) for temperature range, habitat, reproductive method, litter/eggcase number (if known), maturity age, maximum age, where the species is found in the water column and finally its diet. NR is used to denote data not recorded. The last set of icons relate to its conservation and management status. The glossary of technical terms is provided on pp.352–356. Regional maps showing sea depths, sea currents, sea salinity, average sea temperatures and marine climate zones are on pp.357–359. To help with recording, the field observation section covers chimaeras, batoids and sharks, pp.361–370, and finally a section on shark fins on pp.371–378.

EASE OF IDENTIFICATION Should be easy to identify Often a close inspection needed to identify Difficult to identify Temperature range

0°C

Habitat Mud / Sand / Rock / Pelagic / Kelp forests Reproductive method Number of young/eggcases

0

Oviparous / Oviviparous / Viviparous / Oophagus

0

Gestation period (months)

♂

0

♀

0

Maturity age

♂

0

♀

0

Maximum age Where found in water column Surface (0–200m) / midwater (>200m) / bottom (lives on bottom) Diet Shellfish / scavenger / piscivorous teleosts / crustaceans / invertebrates (general) / cephalopods / mammals-birds / piscivorous chondrichthyans /

P

parasitic / planktivorous

IUCN RED LIST STATUS

NE DD LC NT VU EN CR

CITES APPENDIX LISTING

(see definitions on p.18)

I

CITES Appendix I International commercial trade is prohibited.

Not Evaluated

II

CITES Appendix II Trade is regulated through permits.

Data Deficient

CMS APPENDIX LISTING

Least Concern

I

Appendix I Threatened migratory species

Near Threatened

II

Appendix II Migratory species whose status would benefit from international cooperation

Vulnerable

BARCELONA CONVENTION LISTING

Endangered Critically Endangered

II

Annex II Endangered and threatened species

III

Annex III Species whose exploitation is regulated

HOW TO USE THIS BOOK

29

Topography bulbous tip

vent

sharp denticles Front tenaculum position of front tenaculum fin spine eye

Ventral view of claspers first dorsal fin second dorsal fin

snout

lateral line canal

caudal filament

upper lobe of caudal fin clasper

mouth prepelvic tenaculum

soft operculum gill opening

Lateral view – chimaera

vomerine dental plate

nostril

palatine dental plate

Ventral view – chimaera mouth

30

INTRODUCTION

anal fin lower lobe of caudal fin Prepelvic tenaculum

pectoral fin

lateral line canals

pelvic fin

tongue

mandibular dental plate

alar thorns (male)

pectoral fin (or wing) both pectoral fins, head and trunk = disc

caudal fin

interdorsal thorn(s) malar thorns (male)

second dorsal fin

rear lobe of pectoral fin

first dorsal fin

pelvic fin

eye rostrum

tail lateral caudal thorns

snout tip rostrum thornlets

median caudal thorns

orbital thorns spiracle nuchal thorns scapular thorns

mid dorsal thorns

Dorsal view – skate

gill slits nasal aperture

anterior lobe of pelvic fin posterior lobe of pelvic fin

mouth claspers

snout upper jaw lower jaw nasal curtain

vent

Ventral view – skate TOPOGRAPHY

31

first dorsal fin spine eye

second dorsal fin spine precaudal pit

spiracle

caudal keel

nostril mouth gill openings

pectoral fin

pelvic fin

first dorsal fin eye

caudal fin caudal peduncle end of base of second dorsal fin to ventral caudal fin origin

second dorsal fin

spiracle

anal fin

nostril mouth

pectoral fin

gill openings

pelvic fin

clasper

Lateral views – (top) female squalid shark; (bottom) male houndshark pectoral fin pelvic fin

mouth

vent

nostril

preanal ridge caudal fin

claspers

anal fin

Ventral view – male houndshark head tip of snout to last gill opening

trunk last gill opening to vent

tail vent to tip of caudal fin precaudal tail vent to caudal fin origin

snout tip to mouth

Ventral view showing body regions referred to in text

32

INTRODUCTION

upper caudal margin

posterior tip

terminal lobe

epaxial web

terminal margin

upper lobe

hypaxial web

upper origin subterminal tip subterminal notch

subterminal margin

upper postventral margin

lower origin

postventral margins

posterior notch lower postventral margin

preventral margin ventral tip

hypaxial web lower lobe

Caudal fin topography apex fin web anterior margin

posterior margin

fin insertion

fin origin

inner margin

free rear tip free rear tip fin base

fin base fin origin

fin insertion

Spineless dorsal fin posterior margin

apex fin web anterior margin

posterior margin

spine

free rear tip

anterior margin fin web

fin base

fin origin

fin insertion

inner margin

apex

Pectoral fin topography

Spined dorsal fin

Dorsal fin topography TOPOGRAPHY

33

circumnarial groove

lifted anterior nasal flap

incurrent aperture

circumnarial fold excurrent aperture

barbel

nasoral groove mouth

anterior nasal flap symphyseal groove

anterior nasal flap

symphysis

Orectolobid shark

incurrent aperture

excurrent aperture

excurrent aperture

anterior nasal flap

upper labial furrow

lower labial furrow Requiem shark

Head (ventral) topography

upper eyelid

notch

secondary lower eyelid

nictitating lower eyelid

nictitating lower eyelid

subocular pocket

Eyes of (top) requiem sharks and (bottom) catsharks

34

INTRODUCTION

incurrent aperture

posterior nasal flap Nostril of squalid shark

medial lobe

Tooth types and tooth count Since the earliest documented taxonomic studies of sharks, dental morphology has been a key factor in helping to distinguish between shark species. For the most part, shark teeth are developed in accordance with the predation type associated with that species and vary accordingly. Additionally, in some cases teeth may alter with maturity to better suit their use as prey and predation behaviour changes. Perhaps the strongest variation in dentition may be seen within the same set of jaws of some species. Though not obvious in all species of sharks, this variation, known as heterodonty, often results in the development of broader, more distinctive teeth in the upper jaw and narrower, less robust teeth in the lower jaw. In nearly all species, heterodonty is strongly evident from one section to another within one quadrant of the upper or lower jaw, resulting in the placement of the largest, most useful tooth forms in the anterior section of the jaw and smaller, lower crowned teeth posteriorly. Each quadrant of a jaw can be broken down into sections of rows (or files) that include one or more of the following tooth types, symphyseal, anterior, intermediate, anterolateral (where there is no differentiation between anterior and lateral teeth), lateral, anteroposterior (teeth in the symphyseal region where there is no differentiation between anterior and posterior teeth) and posterior teeth.

Equally important in many cases, the tooth count, often referred to as dental meristics, may play an instrumental role in distinguishing species of sharks when tooth morphology alone cannot. Tooth counts are recorded as a total per each quadrant of an upper and lower jaw, but may even be further specified by each section of a jaw according to tooth type and placement. The most widely used method, total counts, may be shown broken down by upper left side total, centrally located teeth and then right side total, followed by a similar count of the lower jaw. Each jaw half is divided at the centre, called the symphysis, by small groups of teeth referred to as symphyseal teeth, or sometimes as even smaller teeth known as alternates and medials. As a simple rule of thumb, teeth at the centre of a jaw that are one half the size or smaller of adjacent teeth are usually shown as a ‘symphyseal count’ in a meristic formula. For example, the jaw illustrated below would likely be counted as 24–2–24 /16–3–16 or as a total of 50 upper jaw, 35 lower jaw (as used in this book). It should be noted, though that in some genera, e.g. Mustelus, the tooth count may strongly vary within each species and therefore may not prove to be diagnostic. In any event, when a specimen is documented for scientific purposes and the jaws cannot be kept, it is advisable to carefully record the tooth count.

symphyseal Us

anterior intermediate Ui Ua anterior La

posterior Up

lateral Ul lateral Ll

posterior Lp

symphyseal Ls Smalltooth Sandtiger, Odontaspis ferox, jaws

TOPOGRAPHY

35

CARTILAGINOUS FISHES DENTITION GUIDE Transverse notch Root

Transverse groove

Mesial root lobe

Distal root lobe Distal shoulder

Basal groove Basal ledge

Distal cusplets

Mesial cusplets Basal section

Distal serrations

Mesial margin

Mesial shoulder

Crown foot Distal margin

The following six pages offer a quick overview of the tooth types of the main groups of cartilaginous fish in the region, from the fused tooth plates of the chimaeras to the single blade-like teeth of many sharks. The batoids are shown here in the jaw, as these (usually) minute teeth are not often found out of the jaw, unlike many of the shark teeth. Like sharks, they do shed their teeth, although some batoid species retain their teeth for quite a time (e.g. cownose rays). Again, like sharks, they possess teeth adapted to their prey, and some species have such minute teeth that they are not used for feeding (e.g. mobulid rays). Shark teeth are shown to species level in the key guides found throughout the book.

Apical section Mesial serrations

Apex

Primary cusp (crown)

Labial view of a shark tooth

Chimaera dentition

posterior part used for grinding

pair of vomerine dental plates (fused)

pair of mandibular dental plates (fused)

upper

lower

pair of palatine dental plates used for grinding Hydrolagus lusitanicus

Skate dentition

anterior part forms a gripping biting beak with the vomerine dental plates

tritors, very hard heavily mineralised ridges

Skate have a similar dentition arrangement to the majority of batoids with their numerous small teeth placed either in a pavement pattern or in parallel rows, or in combination of both. They are usually very similar in shape (low crowned) and size; but sexual dimorphism may occur, for example Raja clavata. Female R. clavata have the low crowned homodont dentition but the males have differentiated tooth shapes, heterodont dentition, with tall cusped teeth in the anterior jaw and low button-like teeth in the posterior jaw.

Raja clavata male

36

CARTILAGINOUS FISHES DENTITION GUIDE

Raja clavata female

Stingray dentition

Cownose ray dentition

Teeth relatively large and flat, male stingrays have a cusp (illustrated) to some of their teeth.

Pavement teeth, loosely interlocked, with the median row the widest.

Pteroplatytrygon violacea

Rhinoptera sp.

Electric ray dentition

Mobulid ray dentition Teeth that are small and in many species may be nonfunctional for feeding due to a planktivorous diet.

Teeth are small with a pointed cusp, and increase in number with age, ranging from 38 rows in juveniles to 66 rows in adults.

Tetronarce nobiliana

Mobula sp.

Guitarfish dentition

Sawfish dentition

Both these families have hundreds of interlocked small to minute functional teeth forming a pavement.

Rhinidae

Pristis sp. CARTILAGINOUS FISHES DENTITION GUIDE

37

Cow shark dentition  p.193

10mm

Bramble shark dentition  p.198

10mm

Gulper shark dentition  p.213

BLUNTNOSE SIXGILL SHARK

Dogfish shark dentition  p.206

10mm

CARTILAGINOUS FISHES DENTITION GUIDE

Hexanchus griseus

Upper and lower teeth similar; strongly compressed and bladelike, with a cusp and up to three side cusplets in adults.

BRAMBLE SHARK

Echinorhinus brucus

Upper and lower teeth dissimilar; uppers smaller than lowers, high cusped and blade-like; lowers broader and overlapping forming a continuous saw-like cutting edge.

GULPER SHARK

10mm

38

Upper and lower teeth dissimilar; uppers smaller, narrower with a main cusp and often smaller cusplets, lowers large, broad and saw-like, with a series of cusps and cusplets.

Centrophorus granulosus

Upper and lower teeth similar; compressed, low crowned, broad based and overlapping forming a continuous saw-like cutting edge.

SPURDOG

Squalus acanthias

Lanternshark dentition  p.222

10mm

Sleeper shark dentition  p.234

10mm

Upper and lower teeth usually dissimilar in region (exception Centroscyllium with similar lowers to uppers); uppers smaller, narrower with a main cusp and often smaller cusplets, lowers with hooked crowns overlapping forming a continuous saw-like cutting edge.

SMOOTH LANTERNSHARK

Etmopterus pusillus

Upper and lower teeth dissimilar; uppers smaller and lanceolate; lowers compressed and blade-like, overlapping to form a continuous saw-like cutting edge.

PORTUGUESE DOGFISH

Centroscymnus coelolepis

Roughshark and kitefin shark dentition  p.244 and 247 Upper and lower teeth dissimilar; uppers much smaller than lowers, lanceolate; lowers highly compressed broad and bladelike overlapping forming a continuous saw-like cutting edge.

10mm

Angelshark dentition  p.254

10mm

KITEFIN SHARK

Dalatias licha

Upper and lower teeth similar, moderately differentiated along the jaw; conically shaped widening rapidly to a broad base.

ANGELSHARK

Squatina squatina

CARTILAGINOUS FISHES DENTITION GUIDE

39

Planktivorous shark dentition  p.276 (mackerel shark order)

Planktivorous shark dentition  p.260 (carpetshark order)

Upper and lower teeth similar in both species; minute hook-shaped single cusp; C. maximus over 200 in both jaws, R. typus over 300. 10mm

10mm

BASKING SHARK

WHALE SHARK

Cetorhinus maximus

Upper and lower teeth similar; moderately compressed, with alternating pattern, but not overlapping; central cusp is flanked by 2 to 6 lateral cusplets.

Carpetshark dentition  p.260

NURSE SHARK

10mm

Catshark dentition  p.294

Rhincodon typus

Ginglymostoma cirratum

Upper and lower teeth similar; small with acute narrow cusps, often lateral cusplets, not blade-like; posterior teeth can be comb-like.

Pseudotriakis microdon teeth are similar to catshark teeth but far more numerous and appear in the jaw comb-like, see pages 289 and 309.

SMALLSPOTTED CATSHARK

10mm

Houndshark dentition  p.314 Both genera different. Upper and lower teeth similar; small placed into an interlocking pavement pattern, sometimes with cusps and cusplets.

Both genera different. Upper and lower teeth similar; blade-like, compressed; anteroposteriors with oblique cusps and cusplets; medial teeth narrower and upright.

10mm

SMOOTHHOUND

40

Mustelus mustelus

CARTILAGINOUS FISHES DENTITION GUIDE

Scyliorhinus canicula

TOPE

Galeorhinus galeus

10mm

Goblin and sandtiger shark dentition  p.268

SANDTIGER SHARK Carcharias taurus

10mm

Thresher and mackerel shark dentition  p.272 and 280

10mm

Requiem shark dentition  p.322

10mm

Hammerhead shark dentition  p.347

10mm

Upper and lower teeth similar; teeth large, awl-shaped, with or without lateral cusplets present; large anterior teeth followed by smaller intermediate teeth.

Upper and lower teeth similar; teeth relatively large to very large, broadly triangular and serrated to long and slender, with smooth-edged cusps.

BIGEYE THRESHER

Alopias superciliosus

Upper and lower teeth dissimilar; uppers usually with erect to slightly oblique cusps usually serrated; lowers usually with oblique to erect narrow serrated cusp (Galeocerdo cuvier exception with blade-like cusp).

SANDBAR SHARK

Carcharhinus plumbeus

Upper and lower teeth relatively similar; teeth moderately large, more or less blade-like with moderately broad cusps and no lateral cusplets; teeth weakly differentiated across the jaws.

SMOOTH HAMMERHEAD

Sphyrna zygaena

CARTILAGINOUS FISHES DENTITION GUIDE

41

CARTILAGINOUS FISHES EGGCASE GUIDE fins

spindle or bottleshaped capsule

horns

maximum eggcase width W

capsule length (excluding horns) CL

keel

capsule

Horns extend from each of the four corners to aid in securing the eggcase to the substrate, sometimes keels present.

Skate eggcases  p.81 The capsule itself is spindle or bottleshaped with fins either side which can be very wide.

Chimaera eggcases  p.48 42

long curling tendrils

CARTILAGINOUS FISHES EGGCASE GUIDE

capsule

Long, curling tendrils extend from each of the four corners to aid in securing the eggcase to the substrate.

Catshark eggcases  p.293

CARTILAGINOUS FISHES KEY GUIDE 1a One gill slit  Chimaeras p.47

one gill slit

1b Five to seven gill slits  Sharks and rays  �

five to seven gill slits

2a Body flat, ray-like  �

2b Body not ray­like  Sharks p.189

CARTILAGINOUS FISHES KEY GUIDE

43

3a Mouth usually on underside of head (exception are the mobulid rays); gills on underside of head; pectoral fins attached to sides of head  Skates and rays p.66

pectoral fin attached to side of head

pectoral fin attached to side of head

mouth on underside of head

mouth subterminal

gills on underside of head

gills on underside of head

3b Mouth terminal, gills lateral on head, pectoral fins not attached to sides of head  Angelsharks p.253

gills on side of head pectoral fin not attached to side of head

mouth terminal

44

CARTILAGINOUS FISHES KEY GUIDE

CHIMAERAS

CHIMAERAS CHIMAERIFORMES Chimaeras in the region

Description

The waters of the Northeast Atlantic and Mediterranean region are home to one of the most diverse assemblages of Chimaeriformes, with nearly 20% of all known species (9 of 52) occurring here. Two families, the short-nosed (Chimaeridae) and long-nosed (Rhinochimaeridae) chimaeras, are well represented with six and three species, respectively. Most short-nosed chimaeras found in the region occur only in the Atlantic Ocean, with the exception of the Atlantic Chimaera Hydrolagus affinis whose distribution extends into the southwest corner of the Indian Ocean. In contrast, the long-nosed chimaeras are predominantly wide-ranging, with two of the three regional species also found globally, and only one restricted to the North Atlantic Ocean. In Northeast Atlantic waters, the short-nosed chimaeras are the more diverse group with all six regional species present. Just two species are known to occur in the Mediterranean Sea – the Rabbitfish Chimaera monstrosa (the most common short-nosed chimaera) and the Largeeyed Rabbitfish Hydrolagus mirabilis, each found in both Northeast Atlantic and Mediterranean waters; no shortnosed chimaeras are endemic to the Mediterranean. While the distribution of the Portuguese Chimaera Hydrolagus lusitanicus, Pale Chimaera Hydrolagus pallidus and Opal Chimaera Chimaera opalescens appears restricted to the Northeast Atlantic, the Atlantic Chimaera Hydrolagus affinis ranges much further, into the western Atlantic and eastern Atlantic – along the African coast to the southwestern Indian Ocean off the Eastern Cape, South Africa. As a group, the long-nosed chimaeras have a much wider geographic distribution. Two species present in the region (Small-spined Chimaera Harriotta haeckeli and Narrow-nosed Chimaera Harriotta raleighana) are found in all three major ocean basins, while the Atlantic Longnosed Chimaera Rhinochimaera atlantica primarily occurs in the Atlantic Ocean, it’s distribution just extends into the southwest Indian Ocean, off South Africa (other records of this species from the Indian Ocean require critical examination for comparison with the Pacific Long-nosed Chimaera Rhinochimaera pacifica). Interestingly, no longnosed chimaeras are known to occur in the Mediterranean.

Respective snout shape and length – short and blunt versus long and narrow – can easily separate the two chimaera families found in the region. Within each family, however, species-specific identification can be somewhat difficult unless one knows what to look for when separating out individual species. The family Chimaeridae comprises two recognised genera. Although morphologically and genetically similar, they can be separated on the basis of whether an anal fin is present (Chimaera) or absent (Hydrolagus). Once this has been determined, other characteristics to look for include: the shape of the second dorsal fin margin (whether it is wavy or relatively straight); body size, if the individual has been determined to be an adult (is it a small-bodied or large-bodied species?); eye diameter; and height of the first dorsal fin spine relative to the height of the first dorsal fin (is it greater or less than the fin height at its apex?). This family can be roughly categorised as those with a large body and massive head, and smallbodied species with a relatively small head and conical snout. Noting any patterning can be helpful, as is general overall body coloration. However, care should be taken as coloration within chimaera species can vary widely and even overlap with that of other species. Specific details for separating species can be found in the Species Key Guide on page 50. The family Rhinochimaeridae – with two recognised genera – can be separated by the lateral profile of their head and snout. The knife-nosed chimaeras’ (Rhinochimaera) head and long snout are relatively straight in profile and have tubercles along the margin of the upper caudal fin lobe. This differs from the narrownosed chimaeras (Harriotta), which have a concave head and snout profile and lack tubercles along the margin of the upper caudal fin lobe. Details for separating species can be found in the Species Key Guide on page 59. The Sickle-finned Chimaera Neoharriotta pinnata, a vagrant species only recently confirmed here (see p.351), can be separated by the presence of an anal fin.

46

CHIMAERAS CHIMAERIFORMES

Habitat and ecology The Chimaeriformes are found in all oceans except for Antarctic waters. As a group, they remain very poorly known as most species inhabit the deep sea along outer continental shelves, slopes, seamounts and ridges, generally from depths of 500m to over 3,100m. Most are rarely encountered but, based on limited information and depending on species, they may occur over soft sandy or mud bottoms, as well as rocky reefs with high vertical relief. Use of remotely operated vehicles (ROVs) has shown some species to be very particular in their habitat preference, favouring soft bottoms or rocky reefs. All known chimaera species are oviparous (egg layers) in their mode of reproduction. Aside from this, almost nothing else is known about their reproductive cycle,

fecundity or age and growth. Those species for which feeding data are available mostly appear to consume benthic invertebrates including worms, crustaceans, bivalves, gastropods, cephalopods and brittlestars, as well as small fishes. Further compounding the lack of life history data is that many species are infrequently encountered and often misidentified. Only the Rabbitfish has been somewhat studied, but even the habitat preference and ecology of this species remains poorly understood. The long-nosed chimaeras are almost entirely unknown. Even though some species are occasionally caught in large numbers, information on their life history and diet remains sparse.

Chimaera families key guide 1a Snout short and blunt  Chimaeridae p.50

1b Snout long and tapered  Rhinochimaeridae p.59

CHIMAERA FAMILIES KEY GUIDE

47

Chimaera species eggcase guide The eggcases of chimaeras can be separated by family, but at the genus and species level it is difficult since species often overlap in their distribution so unless the eggcases are removed from a female or she is observed depositing eggcases it is very difficult to relate eggcases to individual species.

Chimaeridae

Rhinochimaeridae

Teardrop shaped with small lateral flanges and a dorsal surface that has a raised keel along the midline. The anterior end of the spindle is bulbous and tapers posteriorly to an elongate tail sheath. Along each side of the tail sheath is a series of small pores that open during the later stages of the embryos development.

Wide ribbed lateral flanges with a teardrop shaped central spindle. The dorsal side is convex and the ventral side is concave. Like the Chimaeridae eggcases, there are a series of small pores along the posterior edges of the central spindle. wide ribbed lateral flange

central spindle

raised keel

lateral flange

convex dorsal side

tail sheath 10mm actual size 10mm 75% actual size

RABBITFISH Chimaera monstrosa

Example of a Hydrolagus eggcase Hydrolagus collei

10mm actual size

pp.54–57

p.52

ATLANTIC LONG-NOSED CHIMAERA Rhinochimaera atlantica p.62

48

CHIMAERA SPECIES EGGCASE GUIDE

Short-nosed chimaeras Chimaeridae The Rabbitfish Chimaera monstrosa was among the first species of cartilaginous fishes to be named by the Swedish botanist Carolus Linnaeus in 1758. It was in fact the only chimaera to be described from European waters for the next 110 years. In 1868, the Portuguese naturalist Felix Antonio de Brito Capello (1828–1879) described a second short-nosed chimaera, the Atlantic Chimaera Hydrolagus affinis, from a specimen captured off Setubal, Portugal. Thirty-six years later, in 1904, the Norwegian zoologist Robert Collett (1842–1913) described the Largeeyed Rabbitfish Hydrolagus mirabilis, based on a specimen collected south of the Faroe Islands. It would then be 86 years before a fourth short-nosed chimaera would be discovered in European waters – the Pale Chimaera Hydrolagus pallidus, officially named in 1990. This was followed by two more species in 2005 and 2011 – the Portuguese Chimaera Hydrolagus lusitanicus and Opal Chimaera Chimaera opalescens, respectively. All three species named since 1990 inhabit very deep water, from around 900m to at least 2,500m. Most were collected during exploratory deepsea surveys or encountered as commercial fisheries expanded into deeper waters.

The original descriptions of all six short-nosed chimaeras present in the region were based on specimens collected in Northeast Atlantic waters, with none described from the Mediterranean. The only short-nosed chimaera species commonly caught in the region – accounting for up to 15% of biomass in some fisheries – is the common Rabbitfish. Although frequently discarded, Rabbitfish are retained in some fisheries and sold at market. All other short-nosed chimaeras are infrequently caught, mostly in deepsea fisheries, and usually discarded. The IUCN Red List conservation status for five of the six short-nosed chimaeras in Northeast Atlantic waters is Least Concern due to their deepsea habitat, relatively wide geographic distribution and lack of fishing pressure throughout much of their range. The exception is the Rabbitfish, which has been assessed as Near Threatened due to the frequency of capture in fisheries. Of the two chimaeras known to occur in the Mediterranean, only the Rabbitfish has been assessed, also as Near Threatened. The other Mediterranean chimaera, the Large-eyed Rabbitfish, appears to be rarely encountered.

Rabbitfish, Chimaera monstrosa, Norway

CHIMAERIDAE SHORT-NOSED CHIMAERAS

49

Short-nosed chimaera species key guide 1a Anal fin present  Chimaera  �

1b Anal fin absent  Hydrolagus  �

anal fin

no anal fin

2a First dorsal fin spine longer than fin height;

fin spine longer than fin tip

strongly mottled and with longitudinal stripes; iris silvery  C. monstrosa p.52

iris silvery

strongly mottled fin spine shorter or equal to fin tip

2b First dorsal fin spine shorter than or equal to fin height; uniformly iridescent, not strongly mottled; iris black  C. opalescens p.53

iris black

not strongly mottled

50

SHORT-NOSED CHIMAERA SPECIES KEY GUIDE

3a Second dorsal fin margin concave  H. mirabilis p.56

3b Second dorsal fin margin straight  �

concave

straight

4a Body pale grey to white; all fins pale with

fins pale

blue tinge; pectoral fin length up to 1.5 times fin width  H. pallidus p.57

pectoral fin length up to 1.5 times fin width

pale grey to white fins dark

4b Body rose brown to purplish black; all fins dark tinged purplish to violet pectoral fin length more than 1.5 times fin width ➎ pectoral fin length more than 1.5 times fin width rose brown to purplish black

5a Body uniform dark brown to black; upper caudal fin lobe height slightly greater than lower caudal fin lobe height; pectoral fin length same as or less than 1.9 times fin width; eye diameter greater than 20% of head length H. affinis p.54 pectoral fin length same as or less than 1.9 times fin width

5b Body rose to light brown except for whitish area on head; upper caudal fin lobe height less or equal to lower caudal fin lobe height; pectoral fin length 1.9 to 2.3 times fin width; eye diameter less than 20% of head length  H. lusitanicus p.55

upper caudal lobe height slightly greater than lower

uniform dark brown to black upper caudal lobe height less or equal to lower

body rose to light brown

pectoral fin length 1.9 to 2.3 times fin width SHORT-NOSED CHIMAERA SPECIES KEY GUIDE

51

RABBITFISH

Chimaera monstrosa

first dorsal fin high and triangular

CMO 0

fin spine extends beyond fin tip

50

eyes large with silvery iris

second dorsal fin long and relatively straight very long whip-like tail, 44–160% TL

200m

200

700m

700 1,000 1,500

1,663m 2,000

distinct longitudinal stripes extending on to fins

male

3,000 3,750

large head and slender-bodied

Mature size

Birth size

~53.5cm PCL

unknown

(40cm BDL)

Maximum size

~67cm PCL (50cm BDL)

Maximum size

~100cm TL 4.7–8.0°C

5mm

9–12

Adult male frontal tenaculum

♂ 13.4 ♀ 11.2 ♂ 30 ♀ 26 20mm 5mm

Adult male prepelvic tenaculum

Adult male claspers

NT Also called Ratfish. Description Medium-sized chimaera; elongate, slender body tapering from large head to whip-like filamentous tail. Eyes large; iris is silvery with golden pupil. First dorsal fin high and triangular; fin spine extends beyond fin tip. Second dorsal fin margin relatively straight, not undulated. Tail 44–160% of TL. Colour Distinct reddish-brown body. Light mottling and longitudinal stripes along sides of trunk, extending onto fins. Habitat Benthic, mostly found along the upper continental slope from 200– 700m, sometimes to 1,000m or more; maximum reported depth 1,663m. Prefers mud or soft substrate seabeds and water temperature of 4.7–8.0°C. Biology Oviparous, with eggs deposited during the spring and summer; young hatch after 9–12 months. Age at maturity: males 13.4 years, females 11.2 years. Maximum age: males 30 years, females 26 years. Diet is mostly benthic invertebrates. Eggcases Slender, tadpole-shaped. Tapers posteriorly to filamentous tip, with lateral flanges; texture is smooth to the touch. See p.48. IUCN Red List Status Near Threatened North Sea and Mediterranean populations may be distinct from each other.

52

CHIMAERAS CHIMAERIFORMES

Azores

OPAL CHIMAERA Chimaera opalescens first dorsal fin high and narrowly triangular

WCH 0

fin spine does not extend beyond fin tip

50

eyes large with black iris

second dorsal fin long and relatively straight

200

whip-like tail, 20–70% TL 700

800m

1,000 1,500

1,975m large head and heavy-bodied

male

2,000 3,000

fine pale longitudinal stripes on caudal peduncle, 3 under lateral line, 1 above

3,750

Mature size

♂62cm PCL

Birth size

(95cm TL)

unknown

Mature size

Maximum size

78cm PCL

Maximum size

110cm TL

♀68cm PCL (92cm TL)

4.3°C

5mm

NR

Adult male frontal tenaculum

♂ NR ♀ NR ♂ NR ♀ NR 20mm 5mm

Adult male prepelvic tenaculum

NR Adult male claspers

LC

Description Large, heavy-bodied chimaera; tapering from large head to long whip-like filamentous tail. Eyes large; iris black with the pupil appearing pale green. First dorsal fin high and narrowly triangular; fin spine same height or below fin tip. Second dorsal fin margin relatively straight, not undulated. Pectoral fins extend just to origin of pelvic fins when laid backwards. Colour Body uniformly iridescent, mostly golden, greenish, or light brown to tan. Slightly darker dorsally, but not strongly mottled, except caudal peduncle with fine pale longitudinal stripes; three below lateral line, one above. Juveniles darker, more bronzy. Habitat Found from 800–1,975m. Occurs over soft substrate seabeds. Shows preference for water temperature of, or near to, 4.3°C. Biology Oviparous, nothing else known of its life history or diet. Eggcases Unknown. IUCN Red List Status Least Concern due to the majority of its depth range being deeper than most deepsea fisheries.

CHIMAERIDAE SHORT-NOSED CHIMAERAS

53

SMALL-EYED RABBITFISH Hydrolagus affinis

CYA 0

first dorsal fin high and triangular

second dorsal fin long and relatively straight

eyes large, usually more than 20% of head length

height of upper caudal fin lobe slightly greater than height of lower caudal fin lobe

50 200

300m filamentous tail very short

700

1,000m

1,000 1,500 2,000

no light coloured areas on head large head and heavy-bodied

2,410m

uniform dark brown to black with the fins tinged purplish

3,000 3,750

pectoral fin length about the same as or less than 1.9 times width

Birth size

Mature size

310cm

broad head snout bluntly rounded and broad

3,750

no black tip to upper caudal fin lobe prominent light lateral line heavy-bodied Mature size

♀>482cm

Maximum size

~550cm

6.3–20.5°C female

47–108 12? ♂ 11–14? ♀ 18–35? 80?

LC Description Large, heavy-bodied shark. Broad head and mouth. Eyes a bright, reflective greenish in live specimens. Single dorsal fin and an anal fin. Colour Grey or tan to blackish with a conspicuous light lateral line, more apparent on younger sharks. Below lighter on newborns, darker in larger juveniles and adults. Dentition Upper jaw 18–20 (26–46) rows, lower jaw 13 (20–36) rows. See p.193. Habitat A common deepsea shark mostly found along outer continental shelves and upper slopes down to 2,500m. This shark will make excursions into the midwater and pelagic zones. Younger sharks may be found inshore, including bays. Biology Viviparous, litters 47–108. Gestation possibly 12 months; pupping grounds poorly known, but Bay of Biscay may be one such area where neonates appear seasonally. Longevity unknown. Diet includes marine mammals, other sharks and rays, bony fishes, and cephalopods. IUCN Red List Status Least Concern due to minimal fisheries interactions and a zero Total Allowable Catch for deepwater sharks in EU waters.

196

COW AND FRILLED SHARKS HEXANCHIFORMES

Azores

BIGEYE SIXGILL SHARK Hexanchus vitulus eyes large; greenish in live specimens

above uniform dark to light brownish-grey

HXN 0

dorsal fin base separated from caudal fin origin by about twice the fin base length

single dorsal fin

90m

50 200

702m

700 1,000

upper caudal fin lobe with black tip; prominent in young, fading in adults

six paired gill openings

1,500 2,000

slender body

3,000 3,750

trailing edges of all fins have white or dusky margins

Max. size

Birth size

Mature size

♂>123cm

40–45cm

Mature size

♀>142cm

♂157cm

Max. size

♀180cm NR

most fins with white trailing edges, but sometimes dusky short, bluntly pointed snout

male 13–26

NR ♂ NR ♀ NR ♂ NR ♀ NR narrowish head

DD Description Slender, medium-sized shark. Narrowish head with bluntly pointed snout and broadly acute mouth. Six paired gill slits. Small, single dorsal fin; origin over the posterior half of base, or just behind insertion point, of the pelvic fin. Anal fin smaller than dorsal fin. Colour Uniform dark to light brownish-grey above, becoming lighter to white below. Upper caudal fin lobe with black tip in young, fading in adults. Trailing edges of the fins have white to dusky margins. Dentition Upper jaw 18–25 (26–46) rows, lower jaw 9–11 rows. See p.193. Habitat A little-known deepsea shark of continental slopes and upper slopes from 90–702m. Usually found near the bottom, but does make excursions into the midwater column. Biology Viviparous, litters 13–26, but nothing is known about its reproductive cycle. Longevity unknown. Diet poorly known, but includes bony fishes, cephalopods and crustaceans. IUCN Red List Status Data Deficient due to insufficient information on its life history and population trends.

HEXANCHIDAE COW SHARKS

197

BRAMBLE SHARKS ECHINORHINIFORMES The bramble sharks are a small group consisting of one family and genus and two species, distinctive from other sharks by their very large, thorn-like dermal denticles. These are stout-bodied sharks characterised by a broad, flat head; five paired gill slits (all in front of the pectoral fins); two spineless dorsal fins set close together and far back on the trunk (the first originating slightly behind the pelvic fins); and no anal fin. Coloration is a uniform charcoal grey to blackish, sometime brownish, becoming slightly lighter ventrally, with no distinct blotches, bars or spots. These are very large sharks reaching over 300cm, and possibly more than 450cm, in length.

Although widely distributed in all major oceans, bramble sharks’ occurrence is sporadic. These are deepsea sharks, mostly found over soft or rocky bottoms and at the heads of submarine canyons. They are primarily found from 200–1,200m, but in some locations may come close inshore and are even caught seasonally off beaches adjacent to submarine canyons. Despite occasionally being taken as bycatch in bottom trawl and longline fisheries, bramble sharks are uncommon in most locations. Depending on region, bramble sharks’ conservation status ranges from Data Deficient to Endangered.

Bramble sharks Echinorhinidae Until recently, the bramble shark family was included in the dogfish shark order Squaliformes. However, based on morphological and genetic data, they are now separated into their own order, Echinorhiniformes. This is the smallest shark order, with only two species recognised. These are wide-ranging species, with the Bramble Shark Echinorhinus brucus found scattered throughout the Atlantic and Indian Oceans, with some records from the Western Pacific. The Prickly Shark Echinorhinus cookei, by comparison, occurs predominantly in the Pacific Ocean. Bramble sharks are voracious feeders on invertebrates and bony and cartilaginous fishes. These sharks are quite social, often found in groups of up to 30 or more individuals. Although the Bramble Shark E. brucus has never been reported as common in the Northeast Atlantic and Mediterranean and is rarely ever observed, it has been assessed as Endangered.

U1

Ls1

U2

L1

U3

L2

U4

L3

U5

L4

L5

U6

L6

U7

L7

U8

L8

U9

L9

BRAMBLE SHARK Echinorhinus brucus 20–28 upper jaw, 18–26 lower jaw

10mm actual size

198

The thorn-like dermal denticles of the Bramble Shark Echinorhinus brucus are unlike those of the Prickly Shark E. cookei which are closely spaced and relatively small and stellate. The Bramble Shark's are whitish, larger, circular based with slight furrows and although numerous are sparsely and irregularly distributed over the body. These dermal denticles range in size from relatively small to very large with groups of two to ten of the larger ones sometimes fusing into plates that measure more than 2.5cm across, the largest of which can be up to 22cm.

BRAMBLE SHARKS ECHINORHINIFORMES

L10

U10

L11 L12

U11

BRAMBLE SHARK Echinorhinus brucus above medium grey to reddishbrown or blackish; sometimes with red or black spots or blotches

first dorsal fin originating behind pelvic fin origin

SHB 0

two spineless close-set dorsal fins, less than fin length apart

18m 50

eyes large; greenish in live specimens

200m

200 700

900m

1,000

1,214m 1,500

five paired gill openings

covered with spiky denticles and enlarged thorns

2,000

cyclindrical, heavy-bodied

no anal fin

3,000

moderately large pelvic fins

Birth size

40–55cm

Mature size

Mature size

3,750

Maximum size

♂150–187cm ♀189–231cm

326cm (?400cm) NR

moderately long, wide, blunt snout

female 10–52

NR ♂ NR ♀ NR ♂ NR ♀ NR wide mouth also ventrally covered with spiky denticles and enlarged thorns

Description Large, cylindrical, heavy-bodied shark covered with large, conspicuous, irregularly scattered thorn-like denticles. Two spineless dorsal fins set behind pelvic fin origins. No anal fin. Colour Medium grey, reddish-brown or blackish above, becoming lighter below. May sometimes have red or black spots or blotches on the body. Fin edges are blackish. Dentition Upper jaw 20–28 rows, lower jaw 18–26 rows. Teeth are similar in both jaws, with cusps strongly oblique outwardly and flanked by 1–3 lateral cusplets. See opposite. Habitat A bottom-dwelling shark, found from 18–1,214m. Occasionally found close inshore in cold-temperate waters where upwelling occurs. However, this species mostly occurs at depths between 200–900m. Biology Viviparous, with number of young ranging from 10–52 per litter; litter size varies by region. Nothing is known of its reproductive cycle or age and growth. Diet consists mainly of bony fishes, occasionally smaller sharks and crustaceans. IUCN Red List Status Endangered due to suspected population declines, although nothing is known about historic or current population trends in the Northeast Atlantic and Mediterranean.

EN

Azores

ECHINORHINIDAE BRAMBLE SHARKS

199

I II

� DOGFISH SHARKS & RELATED SPECIES SQUALIFORMES Worldwide, the dogfish sharks (Squaliformes) are the fourth most diverse chondrichthyan, and second most diverse shark order, comprising 22 genera and 135 species. This diversity is exceeded only by the skates (Rajiformes), ground sharks (Carcharhiniformes), and stingrays and their relatives (Myliobatiformes). In total, the dogfish shark order contains 11% of all known chondrichthyan species and over 25% of all shark species. The order is well represented in the Northeast Atlantic and Mediterranean region, with all six families present, along with 15 of 22 genera and 26 species. The sleeper sharks (Somniosidae) are best represented in the region with six genera and eight species, followed by the gulper sharks (Centrophoridae) with two genera and six species. The species-rich lanternsharks (Etmopteridae) – one of the largest shark families worldwide, with over 50 species – is relatively under-represented, with two genera and just four species occurring here. Another relatively diverse family, the dogfish sharks (Squalidae) – with two genera and at least 37 species globally – are similarly underrepresented, with only a single genus and three species occurring in the region. While the roughshark (Oxynotidae) and kitefin shark (Dalatiidae) families are represented in the region by just two and three species, respectively,

worldwide, both families are relatively small, containing only five and ten species. Of the seven genera absent from the region, four are in the kitefin shark family, two in the lanternshark family, and one in the dogfish shark family; globally, five of these genera contain only a single species. The classification structure of the Squaliformes has remained largely unchanged, with the most recent genus described in 1990. The most notable change has been the reassignment of the bramble shark family into its own order. Although the families and genera have generally remained stable, several genera have species complexes, including the dogfish (Squalus) and gulper sharks (Centrophorus) – both of which are currently the focus of taxonomic research. The dogfish sharks are small to very large sharks with a cylindrical or compressed body; a flattened or conical snout; five paired lateral gill openings; two dorsal fins, with or without spines; and no anal fin. Coloration is variable, ranging from light to very dark hues or with shades of grey, brown or black; some species may be uniformly coloured, while others are lighter below. Similarly, some species display prominent markings such as spots, while others are relatively plain coloured.

Birdbeak Dogfish, Deania calcea, Canary Islands, Spain

200

DOGFISH SHARKS AND RELATED SPECIES SQUALIFORMES

Kitefin Shark, Dalatias licha, Hawaii

The number of dogfish shark species has increased exponentially over the past two decades, a period during which more than 30% of species in the order were described. Indeed, more new species have been added to the order since 2000 than at any time in the previous 250 years. On average, 2.2 new dogfish sharks were named each year between 2000–2019; this compares to an annual average of 0.7 during the 1900s and 0.2 during the 1800s. Of the 25 dogfish sharks known to occur in the region, most were named prior to 1900, with five named between 1904–1929, and one each in 1964 and 1988. Since this time, no new dogfish shark species have been named from the Northeast Atlantic and Mediterranean region, with the majority coming from the Indo-Pacific. As well as continued exploration of the deep sea, the increase in new species being discovered and named is also the result of improved taxonomic resolution in some groups. Several species previously thought to be wideranging are now considered to be regional endemics. This is especially true for the genera Etmopterus and Squalus: since 2000, the number of new species discovered and named in these genera has increased by 35% and 56%, respectively. As well as several regional endemics, these two genera also have some of the widest-ranging sharks, with the likes of the Spurdog Squalus acanthias and Smooth Lanternshark Etmopterus pusillus, exhibiting global distributions.

As a group, dogfish sharks are circumglobal in their distribution, found from polar latitudes (the only sharks to occupy polar seas, including under pack ice) to the tropics. These sharks display remarkable adaptability, occurring in most marine habitats and ecosystems. Found from shallow bays – enclosed and open – to continental and insular shelves, slopes and submarine ridges, dogfish sharks occupy epipelagic, mesopelagic and bathypelagic environments. As well as shallow rocky reefs, estuaries and sandy bottoms, these sharks inhabit depths of over 3,000m, where the order generally dominates benthic shark diversity and abundance. Dogfish sharks are of moderate importance in commercial fisheries around the world, with the exception of certain species in the family Squalidae which support commercially important targeted fisheries for their meat and squalene oil contained in their livers. Dogfish shark fins, however, tend to be small with relatively low commercial value in the shark fin trade. Most dogfish sharks have a conservation status of Least Concern, or Data Deficient due to a lack of data on life history and population trends. However, several commercially important species are listed as Endangered or Critically Endangered, the result of unsustainable catch levels in targeted and non-targeted fisheries.

SQUALIFORMES DOGFISH SHARKS AND RELATED SPECIES

201

Dogfish sharks and related families key guide 1a First dorsal fin originating behind pelvic fin origin; dorsal fins close-set, less than fin length apart; covered with spiky denticles and enlarged thorns  Echinorhinus brucus p.199

first dorsal fin originating behind pelvic fin origin

dorsal fins close-set, less than fin length apart

covered with spiky denticles and enlarged thorns dorsal fins set apart more than fin length apart

1b First dorsal fin originating in front of pelvic fin origin; dorsal fins set apart, more than fin length apart; no enlarged thorns

�

no enlarged thorns

first dorsal fin originating in front of pelvic fin origin

2a Body very high and compressed, triangular in cross-section; dorsal fins extremely high

 Roughsharks (Oxynotidae) p.244

2b Body low and more cylindrical in cross-section; dorsal fins low

�

3a Dorsal fin spines without grooves; strong caudal

strong caudal keels present

keels always present on caudal peduncle; subterminal notch absent from caudal fin; upper precaudal pit usually present; teeth similar in both jaws

 Dogfish sharks (Squalidae) p.205

upper and lower teeth similar

3b Dorsal fin spines, if present, with lateral grooves;

subterminal notch present

strong caudal keels usually absent on caudal peduncle; subterminal notch present on caudal fin; upper precaudal pit absent; teeth dissimilar in upper and lower jaws

�

upper and lower teeth dissimilar

202

DOGFISH SHARKS AND RELATED FAMILIES KEY GUIDE

4a Underside of body, flanks and tail usually with dark to black markings made up of photophores.

 Lanternsharks (Etmopteridae) p.221 underside of body, flanks and tail with dark and black markings with light organs

4b Underside of body, flanks and tail usually without black markings containing photophores

�

underside of body, flanks and tail with no dark and black markings of photophores

5a Upper teeth relatively broad and blade-like; lowers low and broad

 Gulper sharks

(Centrophoridae) p.211 head flanged laterally from under eye to nostril

5b Upper teeth relatively narrow, not blade-like; lowers high and broad

�

head not flanged laterally from under eye to nostril

6a Head moderately broad and somewhat

snout flat

flattened or conical; snout flat; in region most genera have dorsal fin spines except for Scymnodalatias p.238 and Somniosus p.240–1

 Sleeper sharks (Somniosidae)

head moderately broad

p.231

6b Head narrow and rounded-conical; snout conical; in region only Dalatias licha p.249 can be difficult to distinguish from some sleeper sharks but the combination of uniform dark with white to pale fin margins and no fin spines is definitive

head narrow snout conical

 Kitefin sharks (Dalatiidae) p.248

DOGFISH SHARKS AND RELATED FAMILIES KEY GUIDE

203

Dogfish sharks Squalidae Dogfish sharks (Squalidae) are common where they occur, and easily distinguished from other families by a combination of a short to moderately long snout; cylindrical body; large spiracles set behind the eyes; a short, transverse mouth; and low, blade-like teeth, similar in both jaws. These sharks have two dorsal fins, each preceded by a fin spine. The first dorsal fin originates about opposite, or slightly behind the pectoral fins, with a strongly falcate second dorsal fin originating opposite, or well behind the pelvic fin inner margins. The caudal peduncle has strong, low lateral keels, leading to a strongly heterocercal caudal fin with no subterminal notch. Coloration is usually plain or with light and dark markings on fins, sometimes with white spots on the body. These are small to medium-sized sharks, ranging from 40–120cm total length, with some species reaching 150–180cm. Worldwide, the family has two genera, Cirrhigaleus and Squalus, with three and 34 species, respectively (as well as several species not yet described). The genus Squalus is rather complicated, with many species difficult to tell apart without precise measurements of features and vertebral counts. In the Northeast Atlantic and Mediterranean region, only the genus Squalus is present with three species, of which the precise identification of two is pending, awaiting taxonomic resolution. Dogfish sharks are circumglobal in their distribution, occurring in most cold-temperate to tropical waters, and usually associated with continental landmasses, islands, seamounts and ridges. These sharks are found from close

inshore – including bays and estuaries – to far offshore in the tropics where they are mostly found in deep water to at least 1,446m, often overlapping with other deepsea families including the gulper sharks (Centrophoridae), lanternsharks (Etmopteridae), sleeper sharks (Somniosidae), roughsharks (Oxynotidae) and kitefin sharks (Dalatiidae). As a group, dogfish sharks are mostly demersal, but are known to be pelagic, especially newborns. All dogfish sharks are live-bearing, producing up to 32 pups per litter following a gestation period possibly extending to two years for some species. These are slowgrowing sharks, with some species estimated to take over 30 years to mature and reach a maximum age of up to 100 years. Dogfish sharks are highly mobile and migratory, with some crossing ocean basins. They can be very social, at times forming large aggregations and will even forage in groups. They are voracious feeders, targeting bony fishes, cephalopods, crustaceans and occasionally other small sharks. Dogfish sharks are caught in targeted fisheries and are an important bycatch in mixed bottom fisheries for bony fishes. They are caught primarily in bottom trawls, but also by deepsea longlines and gillnets. Over the past 70 years, dogfish sharks have supported some of the world’s largest shark fisheries, particularly in the North Atlantic. Depending on region, the conservation status for individual species ranges from Data Deficient to Endangered. In some regions, this situation is further complicated by the lack of taxonomic resolution for a number of species.

Spurdog, Squalus acanthias, Norway

204

DOGFISH SHARKS AND RELATED SPECIES SQUALIFORMES

Dogfish shark species key guide 1a First dorsal fin origin usually behind or sometimes over pectoral free rear tips; origin of first dorsal spine well behind pectoral free rear tips; medial lobe minute or absent from anterior nasal flaps; usually white spots present on flanks  Squalus acanthias p.207

origin of first dorsal fin spine well behind pectoral free rear tips usually white spots on flanks

first dorsal fin usually behind or sometimes over pectoral free rear tips

1b First dorsal fin origin usually in front of pectoral free rear tips; origin of first dorsal spine usually over inner margins of pectorals and generally in front of their free rear tip; medial lobe well developed on anterior nasal flaps; no white spots present on flanks  �

origin of first dorsal fin spine over inner margins of pectorals no white spots on flanks

first dorsal fin in front of pectoral free rear tips

2a Distance from snout tip to inner margin of nostril greater than distance from inner edge of nostril to front of upper labial furrow  Squalus blainville p.208

long snout: distance from snout tip to nostril greater than nostril to upper labial furrow

2b Distance from snout tip to inner margin of nostril less than distance from inner edge of nostril to front of upper labial furrow  Squalus megalops p.209

short snout: distance from snout tip to nostril less than nostril to upper labial furrow

DOGFISH SHARK SPECIES KEY GUIDE

205

Dogfish shark similar species comparison dorsal fin spines; usually spotted

no dorsal fin spines; usually spotted

SPURDOG Squalus acanthias Maximum size 121cm p.207

STARRY SMOOTHHOUND Mustelus asterias

dorsal fin spines; unspotted

Maximum size 140cm p.316 no dorsal fin spines; rarely spotted

LONGNOSE SPURDOG Squalus blainville Maximum size 92cm p.208

SMOOTHHOUND Mustelus mustelus

dorsal fin spines; unspotted

Maximum size 174.5cm p.317

From a distance smoothhounds (Mustelus spp.) can sometimes be confused with spurdogs (Squalus spp.). On close inspection, the spurdogs’ dorsal fin spines can be discerned, as can the subterminal notch of the smoothhounds.

SHORTNOSE SPURDOG Squalus megalops Maximum size 77cm p.209

Dogfish shark species dentition guide U1

U1

L1

U2

L1

U3

L2

U1 U1 U2 U3

U4

L3 U4

U5

L4 U5

U6

U7

L6

L5

U6

U7

U8

U8

L7

U9

U10 U11 U12 U13 U14

L8

U9 U10

L9

L10

L11

10mm 175% actual size

SPURDOG Squalus acanthias 26–30 upper jaw, 22–24 lower jaw

U13

LONGNOSE SPURDOG Squalus blaniville 27–30 upper jaw, 24–28 lower jaw L1

L1

L2

L3

L4

U1

U2

U3

U4

L5 U5

L6 U6

L7 U7

U8

L8

L9 L10 L11

L13

*This species is poorly described and frequently misidentified with other Squalus species.

U9 U10 U11 U12

SHORTNOSE SPURDOG Squalus megalops 25–27 upper jaw, 22–24 lower jaw L1 L1

206

L2

L3

L4

L5

L6

L7

L8

L9

L10

L11

*This species is poorly described and frequently misidentified with other Squalus species.

DOGFISH SHARK SPECIES DENTITION GUIDE AND SIMILAR SPECIES

SPURDOG Squalus acanthias above greyish to greybrown; conspicuous white spots on flanks, that may fade in large adults

first dorsal fin origin usually behind or sometimes over pectoral free rear tips

DGS origin of first dorsal fin spine well behind pectoral free rear tips

0

upper caudal fin lobe broad and paddle-like with no subterminal notch

second dorsal fin spine larger than first

50

200m

upper precaudal pit present

200 700 1,000 1,500

1,978m

no anal fin

medial lobe minute or absent from anterior nasal flaps

lateral keels on caudal peduncle present

2,000 3,000 3,750

Birth size

18–30cm

moderately long pointed snout

Mature size

♂58-64cm

Mature size

Max size

♀74-93cm ♂95cm

Maximum size

♀124cm

7–15°C

becoming white below

female

1–32 18–24 ♂ 11+ ♀ 10–20 ♂ 40+ ♀ 40+

Also known as Piked Dogfish. Description Medium-sized dogfish. Narrow, moderately long snout. Two dorsal fins, each preceded by a fin spine. No anal fin. Lateral keels on caudal peduncle; an upper precaudal pit. No subterminal notch on caudal fin. Colour Greyish to grey-brown dorsally, becoming white below, with conspicuous lines of white spots or dashes that may fade in large adults. Dentition Upper jaw 26–30 rows, lower jaw 22–24 rows. Teeth blade-like with a single oblique cusp, similar in both jaws. See opposite. Habitat A common nearshore to offshore shark. Occupies a variety of habitats, from sea lochs, bays and estuaries, to well offshore along the outer continental shelf and upper continental slopes. Found from the surface to the bottom in shallow to very deep water; to depth of 1,978m but mostly shallower than 200m. A highly migratory species, often moving in large, dense aggregations from nearshore to offshore; usually within water temperatures of 7–15°C. Biology Viviparous, with litters ranging from 1–32. Mating occurs primarily during the winter months, with gestation time of 18–24 months; birth occurs during late summer and early winter months. Age at maturity ranges from 11 or more years for males, 10–20 years for females, with a maximum age of at least 40 years. A voracious feeder on bony fishes, cephalopods and crustaceans. IUCN Red List Status Endangered Sensitive to overexploitation by fisheries.

II

III

EN

Azores

SQUALIDAE DOGFISH SHARKS

207

LONGNOSE SPURDOG Squalus blainville origin of first dorsal spine over inner margins of pectorals first dorsal fin origin nearly over pectoral fin insertion

QUB

first dorsal fin with narrow, acute apex and white margin above dusky grey to brown with no white spots

medial lobe well developed on anterior nasal flaps

16m

second dorsal fin with narrow, acute apex and white margin

0 50 200

upper precaudal pit present

667m

700 1,000 1,500 2,000

no anal fin

long snout: distance from snout tip to nostril greater than nostril to upper labial furrow

Birth size

19–23cm

Mature size

Mature size

Maximum size

♂45–50cm ♀50-65cm

♂80cm

broad head long, broadly pointed snout

3,000

lateral keels on caudal peduncle present

*This species is poorly described and frequently misidentified with other Squalus species.

3,750

Maximum size

♀92cm

NR

becoming white below

female

1–9 NR ♂ 4–9 ♀ 5–10 ♂ 25 ♀ 32

Description A relatively large, stocky to moderately slender-bodied dogfish. Broad head with moderately long, rounded mouth. Fin spine preceding each dorsal fin. No anal fin. Lateral keels on caudal peduncle; an upper precaudal pit. No subterminal notch on caudal fin. Colour Dusky grey to brown above, lighter below. No white dashes or spots along flanks. Edges of dorsal fins and posterior pectoral fins lighter to white. Dentition Upper jaw 27–30 rows, lower jaw 24–28 rows. Teeth similar in both upper and lower jaws, having a single smooth-edged cusp. See p.206. Habitat Very little-known due to confusion with other species. Believed to inhabit continental shelves and upper slopes, on or near the bottom, from 16–677m. Biology Viviparous, with litters ranging from 1–9, and 1–6 in the eastern Mediterranean Sea; two-year reproductive cycle. Age at maturity is between 5–10 years for females, 4–9 years for males, with a maximum age of 32 years and 25 years, respectively. Diet includes a variety of bony fishes and crustaceans. This species, or a similar one, is known to form large aggregations similar to the Spurdog Squalus acanthias. IUCN Red List Status Data Deficient due to problems in the identification of this species. It is likely that most life history studies on this species in the Northeast Atlantic and Mediterranean Sea involved 2 or 3 different species.

208

DOGFISH SHARKS AND RELATED SPECIES SQUALIFORMES

DD

SHORTNOSE SPURDOG Squalus megalops origin of first dorsal spine just behind pectoral free rear tips first dorsal fin origin over inner margins of pectoral fin

DOP

first dorsal fin with broad, angular apex and dusky tip

second dorsal fin with narrow, acute apex and dusky tip

above dusky grey to brown with no white spots

medial lobe well developed on anterior nasal flaps

0

upper caudal fin lobe relatively broad and acute, with suffuse white tip and margins; no subterminal notch

50 200

upper precaudal pit present

732m

700 1,000 1,500 2,000

slender body

short snout: distance from snout tip to nostril less than nostril to upper labial furrow

no anal fin

*This species is poorly described and frequently misidentified with other Squalus species.

Birth size

23–28cm

Mature size

3,000

lateral keels on caudal peduncle present

Mature size

♂34–51cm ♀37–66cm

3,750

Maximum size

77cm

wide head short, broadly rounded snout

NR

becoming white below

female

1–6 NR 4–15 ♂ 26 ♀ 32

Also known as Spiky Spurdog. Description Small, slender-bodied dogfish. Wide head and short, broadly rounded snout. Two unequal sized dorsal fins, first being erect and moderately high; each dorsal fin preceded by a fin spine. Lateral keels on caudal peduncle; an upper precaudal pit. No subterminal notch on caudal fin. Colour Dusky grey to brown, lighter below; no spots along flanks. This species is poorly known and may involve more than one species. A taxonomic revision of this species is currently under review. Dentition Upper jaw 25–27 rows, lower jaw 22–24 rows. See p.206. Habitat Occurs on or near the bottom, from close inshore to possibly 732m. Common to abundant where it is found. Biology Viviparous, with litters ranging from 1–6, averaging 2–3. Age at maturity for the central Eastern Atlantic population has been estimated at 4–15 years, with a maximum age of 32 years for females and 26 years for males. The large range in age at maturity for both sexes strongly suggests multiple species may be involved or that subregional populations occur within this species. Like other members of this group, this shark feeds on a variety of other small elasmobranchs, bony fishes, cephalopods and crustaceans. IUCN Red List Status Data Deficient due to misidentification with other lookalike species and a lack of catch data.

DD

SQUALIDAE DOGFISH SHARKS

209

Gulper sharks Centrophoridae The gulper sharks (Centrophoridae) are a deepsea, mostly bottom-dwelling group. They are distinguished by a short to very long snout; cylindrical to somewhat compressed body; pectoral fins with short to very long free rear tips; two dorsal fins, each preceded by a fin spine; no anal fin; and a caudal fin with a strong subterminal notch. Dermal denticles are often used to separate species, however in most species the denticles change morphologically with growth, and should be used with caution, if at all. Coloration is uniformly plain, or with light and dark markings on fins, and without black photophore markings on the flanks or caudal fin. The ventral surface may be lighter. Gulper sharks are small to medium-sized sharks, ranging from about 80–170cm total length. Worldwide, the family has two genera, Centrophorus and Deania, with 12 and 4 species, respectively. Both genera and six species are present in the Northeast Atlantic and Mediterranean region. The Centrophoridae has a complicated taxonomic history, such that the number of species will likely change in the near future. This is because, depending on size, species in the group can be difficult to separate. Many of the external morphological characteristics used in the past do not hold up well, as new research demonstrates they may change with growth. Further complicating this while the scientific names of gulper sharks in the region are mostly well known, at times they have been incorrectly attributed to the wrong species. For example, the scientific name for the Gulper Shark, Centrophorus granulosus, has been attributed to both a large and a small species from the region, while the scientific name Centrophorus lusitanicus is also frequently used in guides and other books. The most recent research into this group has found that C. granulosus and C. lusitanicus are one and the same: a large gulper shark (up to 170cm total length) found globally. A smaller species (~100cm), the Dumb Gulper Shark Centrophorus uyato – found globally, including in the Northeast Atlantic and Mediterranean – is the only representative of the gulper shark family found in the Mediterranean. Records of C. granulosus from the Mediterranean are the result of misidentification of this species with C. uyato. Gulper sharks are found in cold-temperate to tropical waters in all oceans, in association with continental shelves and slopes, islands, seamounts and ridges. They are a deepsea group, found from 200m to over 4,000m, though most species occur at depths less than 1,500m. Occasionally, specimens have been recorded in continental shelf waters up to 20m deep, however this is most exceptional. While the Centrophoridae family lacks

210

the specialised epipelagic species found in other groups such as the Dalatiidae, at least one – the Leafscale Gulper Shark Centrophorus squamosus – does venture into the open ocean on occasion. All gulper sharks are live-bearing (viviparous) producing up to 17 young per litter, although some species may produce just 1–2 per pregnancy. Although very little is known about the life history of these sharks, they appear to be very slow-growing, with some species not maturing until an age of 30 years. These are voracious feeders on bony fishes, cephalopods and crustaceans, but also on small sharks and rays. Several species are known to be highly social, forming large aggregations. In some regions of the world, these are the most common deepsea sharks. Globally, gulper sharks form an important component of targeted and non-targeted deepsea fisheries. Historically, in the Northeast Atlantic and Mediterranean region these sharks were commercially important target species and an important bycatch; however, many of these fisheries have since collapsed. The conservation status of most gulper shark species in the region remains somewhat unclear, largely due to the poor taxonomic resolution in the group. Currently, two species are assessed as Endangered, one Data Deficient and three are yet to be evaluated.

Gulper Shark, Centrophorus granulosus, Hawaii

DOGFISH SHARKS AND RELATED SPECIES SQUALIFORMES

Gulper shark species key guide 1a Preoral snout length less than

preoral snout length less than mouth to pectoral fin origin

the distance from mouth to pectoral fin origins; dermal denticles on back without pitchfork-shaped crowns  Centrophorus �

1b Preoral snout length greater

dermal denticles without pitchfork-shaped crowns preoral snout length greater than mouth to pectoral fin origin

than the distance from mouth to pectoral fin origins; dermal denticles on back with pitchfork- dermal denticles shaped crowns with pitchforkshaped crowns  Deania �

2a Pectoral fins lack extended free rear

no extended free rear tip at all ages

tips. Note: in specimens 31cm

above uniform grey or grey-brown

Mature size

subcaudal keel present; no anal fin

3,750

Mature size

♂43–67cm

3,000

♀62–80cm

Maximum size

97cm

very long head

NR

female

5–7 NR ♂ NR ♀ NR ♂ NR ♀ NR

slightly lighter below

extremely long, flattened snout small pectoral fins

DD

Description Snout extremely long and flattened. Extremely long, low first dorsal fin; second dorsal fin spine much higher than the first. Presence of subcaudal keel on caudal peduncle distinguishes this species from Deania calcea. Colour Uniform grey or grey-brown, with no distinctive markings. Dentition Upper jaw 26–31 rows, lower jaw 26–30 rows. See p.213. Habitat A little-known deepsea shark found on or near the bottom along continental slopes from 275–1,785m. Biology Viviparous, with 5–7 young per litter; nothing else known about its reproductive cycle. Diet includes small bottom-dwelling and midwater fishes (including lanternfishes), cephalopods and crustaceans. This shark sometimes forms large aggregations. IUCN Red List Status Data Deficient due to insufficient data on fisheries landings and life history information.

CENTROPHORIDAE GULPER SHARKS

219

Lanternsharks Etmopteridae Lanternsharks (Etmopteridae) are dwarf to medium-sized sharks mostly less than 100cm in length, with some as small as 16cm. These sharks have short to long snouts; cylindrical to slightly depressed bodies; two dorsal fins, each preceded by a fin spine, the second being much longer than the first; no anal fin; and a caudal fin with a moderately strong to absent subterminal notch. Coloration is plain with conspicuous light and dark markings on the fins and body. Lanternsharks are notable in having elaborately patterned, to inconspicuous and diffuse, photophore patches – known as photomarks – on their flanks and ventral surface. Distinct photomark patterns on the head, trunk and fin bases can be used to separate species. On the flanks, a sharp colour demarcation between the dorsal and ventral surfaces is apparent in some species, but is more diffuse in others. Worldwide, the family comprises four genera and over 50 species, though two genera (Aculeola, Trygonognathus) contain only a single species each, while another genus (Centroscyllium) has seven species. The vast majority of lanternshark species (>40) are found in the genus Etmopterus. Although this is one of the largest shark families, two genera and just four species are present in the Northeast Atlantic and Mediterranean region. Lanternsharks are circumglobal in their distribution, occurring from high latitude, cold-temperate to low latitude, tropical waters. Found in association with

continental landmasses, islands, seamounts, ridges and submarine canyons, these sharks are generally bottomdwelling although some species are more semi-pelagic in their behaviour. Lanternsharks are mostly found from 100m to at least 2,250m, with one species possibly descending to 3,550–4,500m. While some species are wide-ranging, most exhibit a more restricted distribution, including some which appear to be regional endemics with a very narrow range. All lanternsharks are live-bearing, producing litters of 3–20 young. However, the reproductive cycle and general life history remains sketchy for most species. Ageing studies for the group are few but, depending on species, longevity may range from 13–57 years. Lanternsharks feed mostly on small bony fishes, cephalopods and crustaceans, although some larger species will also eat small sharks. The photophores on these sharks are functional bioluminescent organs that camouflage them from other predators and allow them to ambush prey. Lanternsharks are highly social, forming large aggregations often segregated by size, sex and maturity; it has been hypothesised they hunt in packs to subdue large prey such as cephalopods. Lanternsharks are of little importance in commercial fisheries since they are mostly small species, with many being smaller than the fishing gear used and thus escaping capture. The conservation status of most lanternshark species is Least Concern or Data Deficient.

Bioluminescence in Velvet Belly Lanternshark, Etmopterus spinax, Norway

220

DOGFISH SHARKS AND RELATED SPECIES SQUALIFORMES

Lanternshark species key guide 1a Upper and lower teeth similar, both comb-like with cusps and cusplets; mouth moderately long and arched upper and lower teeth similar with cusps  Centroscyllium fabricii p.223

mouth arched

1b Upper and lower teeth dissimilar, upper teeth with cusp and cusplets, lower teeth compressed and blade–like with adjacent teeth overlapping or abutting one another; mouth short, nearly straight and transverse  Etmopterus �

upper teeth with cusps

lower teeth blade-like

mouth nearly straight

2a Without markings on flanks; body mostly uniformly coloured; no caudal fin markings  Etmopterus princeps p.224 no caudal fin markings without markings on flanks

2b With markings on flanks; caudal fin markings present

�

with markings on flanks

caudal fin markings present

3a Lateral flank markings present, but indistinct; lateral body colour relatively uniform; skin smooth  Etmopterus pusillus p.225

body colour relatively uniform

flank markings indistinct

3b Lateral flank markings distinct; body colour sharply demarcated between lateral and ventral margins; skin rough  Etmopterus spinax p.226 body colour sharply demarcated

flank markings distinct

LANTERNSHARK SPECIES KEY GUIDE

221

Lanternshark species dentition guide U1 U2 U3 U4

U5

U6

U12 U13 U8 U9 U10 U11

U7

U14

U21 U15 U16 U17 U18 U19 U20

L17 L18 L19

L9 L10 L11 L12 L13 L14 L15

L1 L2 L3 L4 L5 L6 L7 L8

L1

L1

U2

L2

U3

L3

U4

L4

L25

U25 U26

L27

L5

U5

L6

U6

L7

L8

U7

GREAT LANTERNSHARK Etmopterus princeps 29–32 upper jaw, 40–50 lower jaw

U9

U8

L9 L10

10mm 500% actual size

L11

L12

U10

L13

U11

L14

U12

U30

L31

L15

U13

L16

L17

SMOOTH LANTERNSHARK Etmopterus pusillus 23–30 upper jaw, 35–44 lower jaw

SMOOTH LANTERNSHARK (for comparison)

Etmopterus pusillus

5mm 800% actual size

VELVET BELLY LANTERNSHARK Etmopterus spinax 22–32 upper jaw, 26–40 lower jaw

222

L29

U28

BLACK DOGFISH Centroscyllium fabricii 45–75 upper jaw, 43–76 lower jaw

~10mm 500% actual size U1

L23

L21

U23

U32

L33

BLACK DOGFISH Centroscyllium fabricii moderately large, robust first dorsal fin spine large eyes; greenish in live specimens

CFB

small low first dorsal fin with no markings second dorsal fin spine robust, considerably curved and much larger than first

0

second dorsal fin higher and larger than first

50

180m

200 700 1,000 1,500

large nostrils 2,000

no markings small pectoral fins with no markings

moderately stout body

2,250m

above uniform blackish-brown; no discrete photomarks or lighter marks

3,000 3,750

Mature size

Birth size

15–20cm extremely short moderately short snout rounded snout

♀51–70cm

Maximum size

Mature size

107cm

♂46–63cm

teeth similar in both jaws

3.5–4.5°C

female

4–40 NR ♂ NR ♀ NR ♂ NR ♀ NR

wide, broadly arched mouth

short head

same colour below as above

Description Moderately stout body. Two dorsal fins, each preceded by a fin spine; the first dorsal fin is low relative to the higher second dorsal. Colour Uniform blackish-brown, without white fin markings or discrete photomarks on body. Dentition Upper jaw 45–75 rows, lower jaw 43–76 rows. Teeth have a single narrow cusp flanked by 1–2 smaller cusplets, and are similar in both jaws (a characteristic that separates them from the genus Etmopterus where the teeth differ between the upper and lower jaws). See opposite. Habitat One of the most abundant deepsea sharks, often found in large aggregations along outer continental shelves and slopes from 180–2,250m. At higher latitudes this shark may occur closer to the surface, especially during the winter with reduction in daylight hours. This shark is most commonly caught where bottom water temperatures are 3.5–4.5°C. Biology Viviparous, with litters of 4–40 pups, averaging 16; litter sizes vary by region. These sharks may not have a defined reproductive season, and may breed and give birth year-round, as females with developing young at different stages are found throughout the year. Diet consists of small bony fishes, cephalopods and crustaceans. IUCN Red List Status Least Concern due to its widespread distribution and depth range, which provides a refuge from most fisheries.

ETMOPTERIDAE LANTERNSHARKS

LC

223

GREAT LANTERNSHARK Etmopterus princeps small, robust first dorsal fin spine

ETR

small, low first dorsal fin; posterior margin slightly paler second dorsal fin spine robust, slightly curved and much larger than first

large eyes; greenish in live specimens

0

second dorsal fin higher and larger than first; posterior margin slightly paler

50

conti. slopes 350m

200 700

800m 1,000m

1,000 1,500

large nostrils

2,000

2,200m large, heavy-bodied lanternshark

above uniform black to blackishbrown; no discrete photomarks or lighter marks

medium-sized pelvic fins with no markings

caudal fin with subterminal notch and no markings

3,000

lower rise 3,750m

3,750

4,500m Mature size

Birth size

12–17cm extremely short snout

teeth dissimilar in upper and lower jaws

♀62cm

Mature size

♂57cm

Maximum size

♀89cm

4–5°C

same colour below as above

female

7–18 NR ♂ NR ♀ NR ♂ NR ♀ NR

broad head

Description A very large, heavy-bodied lanternshark. Broad head. Dorsal fins each proceeded by a fin spine. Relatively short tail. Colour Black to blackishbrown with no conspicuous darker or lighter bands, blotches or spots. This is one of the largest of all known lanternshark species. Dentition Upper jaw 29–32 rows, lower jaw 40–50 rows. Teeth dissimilar: upper teeth with a central cusp flanked on each side by 1 or more lateral cusps; lower teeth with a single blade-like cusp. See p.222. Habitat Found on or near the bottom of continental slopes from 350–2,200m, and on the lower rise from 3,750–4,500m, appears to be most abundant between 800–1,000m. In Icelandic waters this species appears to segregate by depth and size, with larger individuals occurring shallower than 600m, and smaller individuals found in deeper water. Biology Viviparous, with litter size ranging from 7–18, averaging 10. These sharks appear to have two seasonal reproductive peaks: in June and July, and again in October. Diet consists of small bony fishes (mostly lanternfishes), cephalopods, and crustaceans. IUCN Red List Status Least Concern due to its widespread distribution and depth range, as well as lack of target fisheries.

224

DOGFISH SHARKS AND RELATED SPECIES SQUALIFORMES

LC

SMOOTH LANTERNSHARK Etmopterus pusillus large, slender first dorsal fin spine

ETP 0

small, low first dorsal fin; entire fin pale

second dorsal fin higher and larger than first, entire fin pale

second dorsal fin spine slender, nearly straight and larger than first

large eyes; greenish in live specimens

50

274m

200 700

1,000m

1,000 1,500

2,000m?

large nostrils moderately large, slender-bodied lanternshark

Birth size

15–16cm extremely short snout

teeth dissimilar in upper and lower jaws

Mature size

♂31cm

3,000

caudal fin with no subterminal notch; posterior margin pale to white, with very dark to black tips

medium-sized pelvic fins with posterior margin pale

above pale or dark brown to blackish

Mature size

♀38cm

3,750

Maximum size

♂48cm, ♀50cm NR

live specimens becoming darker to nearly black below

female

1–6 NR ♂ 5–9 ♀ 8–11 ♂ 13 ♀ 17

short head

2,000

posterior margin pale

DD Description A moderately large, slender-bodied lanternshark, with a relatively long tail. Colour Pale or dark brown to blackish dorsally; live specimens becoming darker ventrally. After preservation, dark ventral surface becomes lighter. Dentition Upper jaw 23–30 rows, lower jaw 35–44 rows. Teeth dissimilar: upper teeth with a slender central cusp and one or more lateral cusplets on its flanks, lower teeth with low, blade-like cusp. See p.222. Habitat Occurs on or near the bottom from 274–1,000m or more, possibly to 2,000m. Also oceanic over very deep water, found from surface to 700m. Biology Viviparous, with litters ranging from 1–6, averaging 3–4. Little is known about their seasonal reproductive cycle except that pregnant females are common from November to April, while males are most active during August. Females mature between 8–11 years, males 5–9 years, with a maximum age of 17 years and 13 years, respectively. Diet consists of small bony fishes (mostly hake and lanternfishes) and occasionally other small dogfish, cephalopods and crustaceans. IUCN Red List Status Data Deficient due to a lack of available catch data.

ETMOPTERIDAE LANTERNSHARKS

225

VELVET BELLY LANTERNSHARK Etmopterus spinax above brownish, sometimes pinkish large eyes; greenish in live specimens

0

small, low first dorsal fin; all of fin white except for a few dark marks

second dorsal fin higher and larger than first; all of fin white except for a few dark marks

second dorsal fin spine slender, slightly curved and much larger than first

slender first dorsal fin spine

ETX 50

70m 200m

200

600m

700 1,000 1,500

large nostrils

small pectoral fins; most of fin white

moderately stout, firm-bodied lanternshark

distinctive, very dark to black flank and tail markings

medium-sized pelvic fins with most of fin white

2,000m

2,000

caudal fin with subterminal notch; most of fin white with narrow black posterior margin

3,000 3,750

Mature size

Birth size

Mature size

♂ 25–35cm

8–14cm extremely short snout

teeth dissimilar in upper and lower jaws

♀31–41cm

abruptly black below

Maximum size Maximum size ♀45cm

♂41cm

NR female 1–21 NR ♂ 4–6 ♀ 4–5 medium-sized pelvic fins with most of fin white

broad, flattened head

Description A moderately stout, firm-bodied lanternshark. Broad, flattened head, a relatively long abdomen and a short tail. Colour Brown dorsally, becoming abruptly black on the underside of snout and abdomen; displays distinctive flank markings. Dentition Upper jaw 22–32 rows, lower jaw 26–40 rows. Teeth dissimilar: upper teeth with central cusp flanked by 1–3 pairs of lateral cusplets; lower teeth blade-like with a single cusp. See p.222. Habitat A common species found on, near or well off the bottom along the outer continental shelf and slopes at depths of 70–2,000m, but mostly between 200–600m. Biology Viviparous, with litters ranging from 1–21, averaging 7–8. Reproductive cycle undefined; it is speculated these sharks may have a 2–3 year period between pregnancies. Age at maturity is 4–5 years for females, 4–6 years for males, with a maximum age of 9–11 years and 7–8 years, respectively. Diet consists of small benthopelagic bony fishes, suggesting the species feeds well off the bottom, as well as cephalopods and crustaceans. Diet changes with growth: smaller sharks feed more on shrimps, medium-sized sharks consume bony fishes and crabs, and large individuals feeding on bony fishes, cephalopods and crustaceans. IUCN Red List Status Near Threatened in the Northeast Atlantic due to possible declines in some areas. Least Concern in the Mediterranean Sea, with population densities and structure remaining stable despite fishing pressure in some areas.

226

♂ 7–8 ♀ 9–11

small pectoral fins; most of fin white

DOGFISH SHARKS AND RELATED SPECIES SQUALIFORMES

NT

Azores

LC

Deepsea spined shark species comparison These shark species are often very difficult to identify and only then with very close examination. The group not only includes the smallest species of shark, but often the most poorly understood. Deepsea spined sharks are caught in mixed deepsea fisheries (using bottom trawls, bottom-set gillnets and bottom-set longlines) that have expanded throughout the Northeast Atlantic. Catches of deepsea spined sharks in these fisheries are decreasing – probably due to catch restriction measures (TACs and a ban on the use of gillnets at depths of over 200m), although population decline may also be a factor. The shark species are arranged in maximum size order. Sharks on this page are all less than 85cm in length; p.228 lists species with a maximum size of 85–110cm; p.229 shows those exceeding 120cm.

SPINED PYGMY SHARK Squaliolus laticaudus Maximum size 28cm � dark coloration with obscure black markings � most fin webs pale/white � 2nd dorsal fin very long � very small 1st dorsal fin spine; no 2nd dorsal fin spine

VELVET BELLY LANTERNSHARK Etmopterus spinax Maximum size 45cm � pale above, abruptly black below � white fin webs � 2nd dorsal fin larger � 2nd dorsal fin spine larger

SMOOTH LANTERNSHARK Etmopterus pusillus Maximum size 50cm � dark coloration with obscure black markings � pale dorsal fin webs � 2nd dorsal fin larger � fin spines roughly similar

SHORTNOSE SPURDOG Squalus megalops Maximum size 77cm � lighter below; no spots; edges of pectoral fins white � 1st dorsal fin larger � 2nd dorsal fin spine larger � lateral keels on caudal peduncle

VELVET DOGFISH Zameus squamulosus Maximum size 84cm � uniform coloration, very dark to black, no distinct markings � dorsal fins small � fin spines very small

DEEPSEA SPINED SHARK SPECIES COMPARISON

227

GREAT LANTERNSHARK

Etmopterus princeps

Maximum size 89cm � uniform dark coloration, no distinct markings � 2nd dorsal fin larger � 2nd dorsal fin spine larger

LONGNOSE SPURDOG

Squalus blainville

Maximum size 92cm � lighter below; no spots; edges of dorsal fins and pectorals white � 1st dorsal fin larger � equally sized large dorsal fin spines � lateral keels on caudal peduncle

ARROWHEAD DOGFISH

Deania profundorum

Maximum size 97cm � extremely long, flattened snout � long, lowish 1st dorsal fin with small fin spine � 2nd dorsal fin much higher with larger fin spine � subcaudal keel on caudal preduncle present

LONGNOSE VELVET DOGFISH

Centroselachus crepidater

Maximum size 105cm � uniform dark coloration, no distinct markings � 2nd dorsal fin larger with lighter posterior margins � very small fin spines � prominent ridge extending forward from 1st dorsal fin

BLACK DOGFISH

Centroscyllium fabricii

Maximum size 107cm � uniform dark coloration, no distinct markings � 2nd dorsal fin larger � 2nd dorsal fin spine very large

KNIFETOOTH DOGFISH

Scymnodon ringens

Maximum size 110cm � uniform dark coloration, no distinct markings � 2nd dorsal fin slightly larger � fin spines very small � large broad mouth with obvious teeth

228

DEEPSEA SPINED SHARK SPECIES COMPARISON

AFRICAN GULPER SHARK

Centrophorus lesliei

Maximum size 120cm � slightly paler below � very long 1st dorsal fin base, much longer than any other regional species � 1st dorsal fin spine shorter than 2nd dorsal fin spine � free rear tips of pectoral fins very long in adults

ROUGHSKIN DOGFISH

Centroscymnus owstoni

Maximum size 120cm � uniform dark coloration, no distinct markings � 2nd dorsal fin larger � fin spines inconspicuous � long lateral ridges along lower flanks

PORTUGUESE DOGFISH

Centroscymnus coelolepis

Maximum size 122cm � uniform dark coloration, no distinct markings � 2nd dorsal fin larger � fin spines very small � very short snout

BIRDBEAK DOGFISH

Deania calcea

Maximum size 122cm � extremely long, flattened snout � extremely long, low 1st dorsal fin with small fin spine � 2nd dorsal fin much higher with larger fin spine � subcaudal keel on caudal preduncle absent

DUMB GULPER SHARK

Centrophorus uyato

Maximum size 128cm � slightly paler below � relatively high triangular 1st dorsal fin � equally sized, moderately large fin spines � free rear tips of pectoral fins moderately long

LEAFSCALE GULPER SHARK

Centrophorus squamosus

Maximum size 164cm � uniform coloration, no distinct markings � 1st dorsal fin larger � equally sized, moderately large fin spines � very rough texture to skin � free rear tips of pectoral fins short

GULPER SHARK

Centrophorus granulosus

Maximum size 173cm � slightly paler below � long 1st dorsal fin � equally sized, moderately large fin spines � free rear tips of pectoral fins very long

DEEPSEA SPINED SHARK SPECIES COMPARISON

229

Sleeper sharks Somniosidae Sleeper sharks (Somniosidae) are small to gigantic sharks ranging in length from about 50cm to over 600cm. These sharks have a short to moderately long, fairly broad to moderately flattened snout; cylindrical to somewhat compressed body; two dorsal fins, with or without fin spines; low, angular – but not falcate – pectoral fins with short, rounded rear tips; no anal fin; and a caudal fin with a strong subterminal notch. The mouth is nearly transverse with small thin lips, small needle-like upper teeth and large compressed, blade-like lower teeth. Spiracles are large and set close behind the eyes. Lateral ridges are present on the abdomen, but not on the caudal peduncle, except for the genus Somniosus. Coloration is plain or with light and dark markings on the body and fins. No photophores or black photomarks are present on the flanks and caudal fin. The sleeper sharks are a small, relatively diverse family comprising six genera and 16 species, of which six genera and eight species occur in the Northeast Atlantic and Mediterranean region. Sleeper sharks have a nearly circumglobal distribution from polar to tropical waters, with the Greenland Shark Somniosus microcephalus one of the few shark species to commonly occur in polar waters. Several species are very wide-ranging while others appear to be regional endemics. A few species have very patchy distributions in both the northern and southern hemispheres. For example, the Knifetooth Dogfish Scymnodon ringens, a common species in the Northeast Atlantic, is also found around New Zealand. Similarly, the Frog Shark Somniosus longus, known from

Japan, is also found around New Zealand and off Chile, but nowhere else. The family is most diverse in cold to warm-temperate waters, but also in tropical deep water. This is generally a deepsea group, inhabiting outer continental shelves and upper slopes from 200m to at least 3,675m, with most species found from 1,000–1,500m. At high latitudes, sleeper sharks may occur in relatively shallow water (2,000m relatively short tail broad, rounded, moderately long snout; preoral length about half the distance from mouth to first gill slits, and less than mouth width

stocky body

Birth size

short upper labial furrows

3,000

no lateral ridges along lower flanks

Mature & Maximum size

♂41cm

unknown

3,750

Mature size

♀unknown

very small upper teeth; narrow blade-like lowers

Maximum size

♀?80cm

NR

long head

female NR NR ♂ NR ♀ NR ♂ NR ♀ NR

postoral grooves long, about same length as upper labial furrows

long, broadly arched mouth

Description Long head with a long, broad, rounded snout and long, broadly arched mouth. Eyes oval. First dorsal fin originates about midbody, with a free-rear tip just in front of pelvic fin origins; no dorsal fin spines. Colour Uniform dark brown, with no blotches or other distinctive markings. Dentition Upper jaw 43 rows, lower jaw 32 rows. Upper teeth very small and narrow; lower teeth bladelike. See below. Habitat Open ocean over seamounts along the Mid-Atlantic Ridge near the Azores at 300–580m with bottom depths of 2,000m or more. Biology Unknown; an adult female, reportedly measuring 80cm total length, contained ‘several’ embryos. Diet unknown. IUCN Red List Status Data Deficient This rare deepsea species is known only from two, possibly three specimens. U1 U3 U5 U7 U9 U11 U13 U15 U18

U21 ~5mm

L1

238

L3

L5

L7

L9

L11 L13

L16

2,000

43 upper jaw, 32 lower jaw

DOGFISH SHARKS AND RELATED SPECIES SQUALIFORMES

NR DD

KNIFETOOTH DOGFISH Scymnodon ringens small first dorsal fin spine large oval eyes; greenish in live specimens moderately long gill slits

uniform dark brown to black, above and below

small, low first dorsal fin with no markings; originating behind pectoral fins

SYR 0

second dorsal fin is larger than first, with no markings

50

second dorsal fin base is about twice the distance of second 200m dorsal fin insertion to upper caudal fin origin

second dorsal fin spine larger than first

200 700 1,000 1,500

1,600m

2,000

broad, relatively short snout; preoral length about two thirds the distance from mouth to first gill slits, and less than mouth width

Birth size

unknown

3,000

robust body no lateral ridges along lower flanks

3,750

relatively large, broad caudal fin, with weak subterminal notch and no markings

Mature size

Maximum size

unknown

110cm

lanceolate upper teeth, large triangular, blade-like lowers very long upper labial furrows

thick, high head

NR female NR NR ♂ NR ♀ NR ♂ NR ♀ NR

very large, broadly arched mouth

NR

postoral grooves very short, much shorter than upper labial furrows

LC

Description A thick, high head, robust, broad snout, and very large, broadly arched mouth. Fin spines precede each dorsal fin, with the second being larger than the first. Colour Uniform dark brown to black, with no distinctive markings. Dentition Upper jaw 50 rows, lower jaw 29 rows. Upper teeth small and lanceolate; lower teeth large, triangular and blade-like. See p.234. Habitat A common, but little-known deepsea shark found along the continental slope from 200–1,600m. Biology Viviparous, but nothing else known. Immense, triangular, razor-edged lower teeth suggest this is a formidable predator capable of attacking and dismembering relatively large prey items. IUCN Red List Status Least Concern due to its population being stable or increasing, and its deepsea habitat.

SOMNIOSIDAE SLEEPER SHARKS

239

GREENLAND SHARK Somniosus microcephalus relatively small, round eyes with a posterior notch; greenish in live specimens

moderately long gill slits

heavy, cyclindrical body

no first dorsal fin spine

GSK 0m

relatively small, low first dorsal fin with paler margins, originating well back, slightly closer to pelvics than pectorals

second dorsal fin about same size as first with paler posterior margin

0 50

180m

no second dorsal fin spine

warmer water

200 700 1,000

1,400m

2,000

low keel on caudal peduncle broadly pointed, long snout; preoral length about half the distance from mouth to first gill slits and about the same as mouth width

moderately large pectoral fins with paler posterior margin

Birth size

no lateral ridges along lower flanks uniform grey or medium brown, above and below; occasionally with transverse bands, small dark and light spots and blotches Mature size

♂~300cm

40–50cm lanceolate upper teeth; short short upper oblique lowers labial furrows

2,647m 3,000

medium-sized pelvic fins with no markings

Mature size

♀~400–450cm

3,750

large caudal fin with subterminal notch and pale posterior margin Maximum size

640cm ?756cm 0.6–12°C

moderately large pectoral fins with paler posterior margin

female 10? NR ♂ NR ♀ NR ♂ NR ♀ NR long, broadly arched mouth

postoral grooves long, much longer than upper labial furrows

Description A very large, heavy, cylindrical-bodied shark. Two small, spineless dorsal fins; the first dorsal fin is slightly closer to pelvic fins than pectoral fins. No anal fin. Low keel on caudal peduncle. Colour Mostly a uniform grey or medium brown. Occasionally with transverse bands, small dark and light spots, and blotches. Dentition Upper jaw 35–39 rows, lower jaw 45–57 rows. Upper teeth lanceolate; lower teeth short and low, with strongly oblique cusps. See p.234. Habitat A common deepsea shark of continental and insular shelves and slopes. Found close inshore, in shallow bays and river mouths, in the Arctic and boreal Atlantic during colder months. Retreats to much deeper water, from 180–>1,400m, as the temperate increases during warmer months, and when moving through lower latitude waters. It has been recorded to a maximum depth of 2,647m. Preferred water temperature is 0.6–12°C. At times, these sharks appear to migrate vertically in the water column, moving far off the bottom. Biology Viviparous, with very little information available on fecundity; a single female over 500cm in length contained 10 embryos, each about 37cm in length. This appears to be a very slow-growing shark that may take decades to reach maturity. A voracious feeder on bony fishes, these sharks are also known to regularly consume marine mammals including seals and small cetaceans. IUCN Red List Status Near Threatened due to possible population declines and conservative life history characteristics.

240

1,500

DOGFISH SHARKS AND RELATED SPECIES SQUALIFORMES

NT

LITTLE SLEEPER SHARK Somniosus rostratus relatively small, round eyes with a posterior notch; greenish in live specimens

moderately short gill slits

no first dorsal fin spine

SOR

relatively small, low first dorsal fin; originating well back, slightly closer to pectorals than pelvics

0

second dorsal fin slightly smaller than first with long free rear tip

50

180m

no second dorsal fin spine

200 700 1,000 1,500

keel on caudal peduncle short, rounded snout; preoral length about half the distance from mouth to first gill slits, and about the same as mouth width

slightly darker, moderately large pectoral fins

21–28cm

short upper labial furrows

uniform brownish to blackish, without transverse bands, spots or blotches

relatively small pelvic fins, set well back with no markings

Mature size

3,750

Maximum size

♀80cm

143cm

Mature size

♂71cm

moderately large pectoral fins with indistinct, dusky posterior margin

moderately large caudal fin with subterminal notch and a long lower lobe

NR male

8–17 NR ♂ NR ♀ NR ♂ NR ♀ NR

short; broadly arched mouth

2,000 3,000

no lateral ridges along lower body flanks

Birth size

lanceolate upper teeth, short oblique lowers

2,200m

postoral grooves long, much longer than upper labial furrows

DD

Description A small somniosid shark. Short, rounded snout. Two equal-sized, spineless dorsal fins; first dorsal fin is closer to the pectoral fins than the pelvic fins. Short keels on the caudal peduncle. Long ventral caudal lobe. Colour Uniform blackish without transverse dark bands, small light spots or blotches. Dentition Upper jaw 53–63 rows, lower jaw 31–38 rows. Upper teeth lanceolate; lower teeth semioblique with low roots. See p.234. Habitat A small little-known, rare to uncommon sleeper shark of the outer continental shelves and slopes. Occurs on or near the bottom from 180–2,200m. Biology Viviparous, with litters of 8–17; little else known about its reproductive cycle. Nothing is known about its age at maturity or longevity. The diet of this shark consists mostly of cephalopods, other bottom-dwelling invertebrates and demersal fishes. IUCN Red List Status Data Deficient due to its rarity.

SOMNIOSIDAE SLEEPER SHARKS

241

VELVET DOGFISH Zameus squamulosus relatively small, low first dorsal fin; originating well back, closer to pectorals than pelvics

large, long oval eyes; greenish in live very short specimens gill slits

minute first dorsal fin spine

SSQ 0

second dorsal fin is larger than first with relatively long free rear tip and no marking minute second dorsal fin spine

over very deep water

second dorsal fin base is about the same as the distance from second dorsal fin insertion to upper caudal fin origin

50 200

550m 700 1,000

1,450m

1,500 2,000

relatively long snout, preoral length about half the distance from mouth to first gill slits, and about the same as mouth width

no lateral ridges along lower body flanks

slender body

Birth size

~20cm

Mature size

♂47–51cm

Mature size

♀59–69cm

small, lanceolate upper teeth; knife-like cusped lowers relatively long upper labial furrows

3,000

relatively large caudal fin with strong subterminal notch and no markings

uniform dark brown to blackish, above and below

3,750

Maximum size

84cm

NR male 3–10 NR ♂ NR ♀ NR ♂ NR ♀ NR

short, narrow, transverse mouth

postoral grooves very long, much longer than upper labial furrows

DD

Description A small, slender-bodied shark. Relatively long snout; short, narrow mouth with postoral grooves much longer than the short upper labial furrows. Two dorsal fins, each with a small spine preceding it. No anal fin. Caudal fin with a short lower lobe and strong subterminal notch. Colour Uniform blackish to dark brown. Dentition Upper jaw 47–60 rows, lower jaw 32–38 rows. Upper teeth small, lanceolate and without cusps; lower teeth knife-like and cusped. See p.234. Habitat A poorly known epipelagic and oceanic deepsea shark. Usually found on continental and insular slopes, on or near the bottom from 550–1,450m; but also occurs well off the bottom, from near the surface to 580m, in water 2,000–6,000m deep. Biology Viviparous with litters of 3–10; little else known about its reproductive cycle. Diet consists of invertebrates and small bony fishes. IUCN Red List Status Data Deficient due to widespread distribution and lack of data on fishery catches.

242

DOGFISH SHARKS AND RELATED SPECIES SQUALIFORMES

Roughsharks Oxynotidae  Roughsharks (Oxynotidae) are an unmistakable group of very rough-skinned sharks. They are characterised by a short snout that is bluntly rounded or rounded angular in dorsoventral view; very large spiracles set close behind the eyes; and a short, small, nearly transverse mouth, with thick papillose lips. Teeth are well developed: the uppers are small, narrow, erect, smooth-edged cusps; the lower teeth are broad and blade-like. These sharks have high, sail-like dorsal fins, each with a spine preceding; no anal fin; and a caudal fin with a weakly developed lower lobe and a strong subterminal notch. Coloration is a uniformly plain brown to greyish, or with light and dark markings on the body. Roughsharks are small to moderately large, from 70–150cm total length. The roughsharks are a small family with a single genus and five species, of which two species are present in the Northeast Atlantic and Mediterranean region. Roughsharks are thought to be mostly regional endemics, scattered throughout the Eastern Atlantic (including the Mediterranean), western Central Atlantic, Western Pacific, and the Southwest Indian Oceans. These are poorly known deepsea, demersal sharks occupying upper continental and insular slopes and outer shelves from 40m to over 1,000m. Roughsharks have a preference

for rocky reefs, coralline algae, and sandy or muddy bottoms. Roughsharks are live-bearing (viviparous), producing litters of 7–23 young, though very little else is known about their biology. Information on feeding habits is sparse, but diet does include polychaetes, crustaceans and molluscs. Roughsharks also appear to have a preference for the eggcases of other sharks, such as catsharks. The behaviour of these unusual sharks is poorly documented. They are likely sluggish swimmers and may rely on their large oily livers to attain neutral buoyancy to hover and slowly swim above the substrate, tipping their heads downwards to feed. Large, close-set denticles with erect crowns and sharp, very prickly cusps may serve as armour protecting these sharks from predators. Roughsharks do not appear to form aggregations or occur in any abundance, and therefore are relatively uncommon as bycatch in fisheries. Worldwide, most species of roughshark have been assessed as Data Deficient to Near Threatened. However, one species, the Angular Roughshark Oxynotus centrina, has been assessed as Critically Endangered in the Mediterranean due to suspected population declines.

Angular Roughshark, Oxynotus centrina, Catalunya, Spain

OXYNOTIDAE ROUGHSHARKS

243

Roughshark species key guide 1a Spiracles very large, vertically elongated and slit–like or D–shaped, height nearly equal to eye length; supraorbital ridges greatly expanded posteriorly, forming a prominent rounded knob just in front of spiracle on each side that is covered with enlarged denticles; very high sail-like dorsal fins  Oxynotus centrina p.245

very high sail-like dorsal fins supraorbital ridges greatly expanded

spiracles very large and elongated; height nearly equal to eye length extremely high, sail-like dorsal fins

1b Spiracles relatively small and circular or vertically oval, height less than half eye length; supraorbital ridges not greatly expanded and not forming a rounded knob in front of spiracle on each side; extremely high sail-like dorsal fins  Oxynotus paradoxus p.246

supraorbital ridges not greatly expanded

spiracles relatively small and circular; height less than half eye length

Roughshark species dentition guide US1 U1 U2

UL1

U3 U4

U5 U6 U7

US1

UA1

UA2

UA3

UL2 UL1

10mm 150% actual size

L4 L3 L2 LS1

L1

LS1

ANGULAR ROUGHSHARK Oxynotus centrina 9–11 upper jaw, 9 lower jaw

244

ROUGHSHARK SPECIES KEY AND DENTITION GUIDE

L1

L2

L3

L4

SAILFIN ROUGHSHARK Oxynotus paradoxus 13–15 upper jaw, 9–11 lower jaw

L5

ANGULAR ROUGHSHARK Oxynotus centrina enlarged denticle ridge along midline of dorsal fin supraorbital ridges greatly expanded, forming an obvious rounded knob covered in enlarged denticles

first dorsal fin spine leans forward

OXY

compressed body, triangular in crosssection; covered in very rough skin

spiracles very large, slit-like or 'D'-shaped; height nearly as long as eye length

0

second dorsal fin slightly smaller but still high and sail-like

very high, sail-like first dorsal fin second dorsal fin spine small and triangular

50m

moderately large, high caudal fin with subterminal notch and rounded ventral lobe apex

50 200

800m

700 1,000 1,500 2,000 3,000

large, oval eyes; greenish in live specimens moderately short gill slits Birth size

21–24cm large close-set nostrils with large nasal flaps long labial furrows

3,750

background grey to greybrown with darker blotches on head and flanks which become more obscure in adults

lateral ridges along lower flanks

Mature size

(most 500m 700 1,000 1,500 2,000

no large thorns on midback very wide, blunt, short snout with terminal mouth

3,000

long, expanded lower lobe; larger than upper

3,750

above grey-brown with symmetrical dark brownish blotches, scattered with symmetrical round white spots and numerous small blackish spots; white-edged, dark ocelli may be present Mature size

Birth size

Maximum size

♀~89cm

23–27cm

Mature size

concave interorbital space

Maximum size

♂~82cm

♀160cm

♂145cm

NR

large thorns on snout and between eyes

3–8 lateral head folds with no lobes weakly fringed nasal barbels and anterior nasal flaps

Description An angelshark with large thorns on snout and above eyes, but absent or small on midback. Lateral head folds low, without triangular lobes; nasal barbels weakly bifurcated, but not strongly lobate; posterior edges of anterior nasal flaps weakly fringed. First dorsal fin origin usually well behind pelvic fin free rear tips. Colour Grey-brown dorsally with symmetrical round white spots and numerous small blackish spots scattered on dorsal surface. Large dark brownish blotches or spots symmetrically arranged on base of anterior pectoral lobes, free rear tip of pectoral fins, tail base, and under dorsal fins. Symmetrical white-edged, dark ocelli may be present dorsally, on bases of anterior pectoral lobes. Ventral surface white with dusky pectoral and pelvic fin margins. Dentition 15–19 rows in each jaw. See p.254. Habitat A warm-temperate to tropical water angelshark of outer continental shelves and uppermost slopes. Found from 20–500m or deeper, but most common between 50–100m. Found at greater depths in tropical waters than in temperate waters. Biology Viviparous, with litters of 3–8 pups, averaging 6. Gestation believed to be 12 months, with birth occurring from February to April. Very little else is known about its life history. Diet includes small sharks, bony fishes, cephalopods and crustaceans. IUCN Red List Status Critically Endangered due to intense fishing pressure; this species may be locally extirpated from some parts of its range. Misidentification with the other regional angelshark species may preclude more accurate information on its life history and distribution.

256

ANGELSHARKS SQUATINIFORMES

12 ♂ NR ♀ NR ♂ NR ♀ NR

II

CR

ANGELSHARK Squatina squatina very large pectoral fins with width about two-thirds its length

AGN 0m

caudal fin moderately large with base slanting ventrally (hypocercal)

very rough skin texture

0 50

pectoral fins not attached to sides of head

extremely flattened body

>150m?

first dorsal fin small with origin usually above pelvic fin free rear tips

200 700 1,000 1,500

long, expanded lower lobe; larger than upper

2,000 3,000

no large thorns along midback; small thorns present only in young wide, blunt, short snout with terminal mouth Birth size

24–30cm

3,750

above grey to reddish- or greenish-brown, with small symmetrical white spots and blackish spots and dots loosely scattered; white nuchal spots sometimes present; no ocelli

Mature size

♂80–132cm

Mature size

♀126–167cm

Maximum size

♂183cm

Maximum size

♀244cm

NR

patches of small thorns on snout and between eyes

7–25 lateral head folds with single triangular lobe on each side smooth or weakly fringed anterior nasal flaps nasal barbels simple, with straight or spatulate tip

Description An angelshark with very sharp, hooked dorsal denticles, giving it a very rough skin texture. No large thorns along midback, but small thorns present on young that are lost with growth. Lateral head folds with single triangular lobe on each side; nasal barbels simple, with straight or spatulate tip; smooth or weakly fringed anterior nasal flaps. First dorsal fin origin usually above pelvic fin free rear tips, but occasionally behind it. Colour Grey to reddish, or greenish-brown dorsally, with small symmetrical white spots loosely scattered on dorsal head surface, pectoral fin bases, pelvic fin bases and below dorsal fins; no ocelli on dorsal surface. Ventral surface white with dusky fin margins. Dentition 18–22 rows in each jaw. See p.254. Habitat A temperate-water angelshark found along continental shelves from close inshore, in the intertidal, to at least 150m. This shark appears to prefer soft muddy or sandy bottoms. It may penetrate estuaries and brackish water. Biology Viviparous, with litters of 7–25 pups; larger females produce more young. Gestation is 8–10 months; in the Mediterranean Sea birth occurs between December and February, but later in the year (July) in British waters. Very little else is known about its life history. Diet includes small sharks, skates, bony fishes, cephalopods and crustaceans. IUCN Red List Status Critically Endangered Rare or extinct throughout most of its former range due to intense fishing pressure. The Canary Islands appears to be the last major refuge for this species. It is frequently misidentified with the other angelsharks that occur within its range.

8–10 ♂ NR ♀ NR ♂ NR ♀ NR

I&II

SQUATINIDAE ANGELSHARKS

CR

257

CARPETSHARKS ORECTOLOBIFORMES The carpetsharks (Orectolobiformes) are the second most diverse shark order at the family level and the third most diverse order, with 13 genera and 45 species. Only the ground sharks (Carcharhiniformes) and dogfish sharks and their relatives (Squaliformes) exhibit greater diversity. Two of the seven families in the order – the nurse sharks (Ginglymostomatidae) and whale sharks (Rhincodontidae) – occur in the Northeast Atlantic and Mediterranean region, each represented by a single species. Worldwide, both families are small, with the Ginglymostomatidae consisting of just three species and the Rhincodontidae containing a single, wide-ranging species (Whale Shark Rhincodon typus). Both carpetshark species found in the region are rarely recorded. Depending on the family, carpetsharks vary widely in morphological appearance. These sharks range in size from small to enormous (130m 200

no precaudal pit present

700 1,000 1,500 2,000

weak or absent lower lobe snout short, relatively wide and blunt; preoral length about a third the distance from mouth to first gill slits, and shorter than mouth width

stout trunk tapering behind first dorsal fin pectoral fins large and broad with rounded tips

large pelvic fins; about same size as second dorsal fin

anal fin moderately large, about half the area of second dorsal

Mature size

Birth size

♀220–240cm

27–30cm

Mature size

♂210–220cm

relatively small subterminal mouth

3,000

without strong keel on caudal peduncle

Maximum size

♂257cm

3,750

Maximum size

♀308cm

>20°C

nasoral grooves

female

21–34

5–6 ♂ 10–15 ♀ 15–20 large pelvic fins

♂ NR ♀ NR

thick lips ventral surface light yellow to whitish-brown long barbels

pectoral fins large and broad with rounded tips

Description Stout trunk tapering anteriorly behind first dorsal fin; flanks of body without lateral ridges. Mouth subterminal, relatively small. Gills small. Caudal peduncle without strong lateral keels. Caudal fin with subterminal notch. Colour Plain yellowish- to greyish-brown above, to light yellow or whitish-brown below. No spots, saddles or other prominent markings on adults; juveniles with small, dark, light-ringed spots and obscure saddle markings. Dentition Upper jaw 30–42 rows, lower jaw 28–34 rows. See p.260. Habitat Nearshore, coastal shark mostly found in tropical waters, usually around coral and rocky reefs, in soft sediment channels and on sand flats between mangroves. Occurs in less than 1m of water but most common 10–40m, with a maximum depth of at least 130m. These sharks are very social and will aggregate in considerable numbers. Appear to be most active at night when foraging; often seen resting on the bottom during daylight hours. Biology Viviparous, with litters of 21–34 pups. Gestation is 5–6 months, with females giving birth every other year. Age at maturity is estimated at 15–20 years for females, 10–15 years for males. Nurse Sharks feed mostly on bottom-dwelling bony fishes and invertebrates including crustaceans, molluscs and sea urchins. IUCN Red List Status Data Deficient Rarely encountered.

GINGLYMOSTOMATIDAE NURSE SHARKS

DD

261

WHALE SHARK Rhincodon typus gill slits very long; relatively straight vertically; four above pectoral fins very small eyes

very stout trunk tapering behind first dorsal fin

RHN

prominent longitudinal ridges along upper flanks

large first dorsal fin, set far back; origin in front of pelvic fins

second dorsal fin about 1/3 size of first dorsal fin

0

caudal fin semi crescentshaped; dorsal caudal fin margin third as long as the entire shark

50 200

distinct precaudal pit above, absent below

large spiracles

700 1,000 1,500

1,928m very short, blunt and wide snout; preoral length about an eighth the distance from mouth to first gill slits and considerably shorter than mouth width

above distinctive light ‘chequerboard’ patterning on a grey, bluish-grey or greenishbrown background

moderately large pelvic fins, larger than second dorsal fin

anal fin notched, about same size as second dorsal fin

long ventral lobe

3,000

caudal peduncle with strong lateral keels

3,750

pectoral fins large, broad and curved with tapering rounded tips Mature size

Birth size

Maximum size

♀~1000cm

55–64cm

1800cm

Mature size

♂850–900cm

Maximum size

?2100cm

18–30°C

head broad and strongly flattened

nasoral grooves

300+

female

NR ♂ 20 ♀ 27? >31

very wide terminal mouth

ventral surface white

Description Unmistakable shark with a unique chequerboard pattern. Head broad, flattened, with a short snout and very wide terminal mouth in front of eyes. Flanks with prominent longitudinal ridges, the lowest ending as a keel on the caudal peduncle. Large semi crescent-shaped tail fin. Colour Chequerboard pattern of yellow or white spots on grey, bluish-grey or greenish-brown background. Dentition 300+ rows in each jaw. See p.260. Habitat Oceanic to coastal species found in most tropical and warm-temperate seas. Often seen on or near the surface from close inshore, including bays and lagoons, to far offshore. This shark appears to have a preference for water temperatures between 18–30°C. Biology Viviparous, with one specimen producing a litter of at least 300, making it one of the most fecund shark species. These sharks do not appear to have a defined breeding season as newborns are found year-round in the tropics. Age at maturity is about 20 years for males, possibly 27 years for females. Longevity is estimated at 31 years or more. IUCN Red List Status Not Evaluated The Whale Shark has not been assessed in this region due to its rarity. Globally listed as Endangered.

262

CARPETSHARKS  ORECTOLOBIFORMES

2,000

II

I&II

NE

MACKEREL SHARKS LAMNIFORMES The mackerel sharks (Lamniformes) are a relatively small order with only 15 species spread over eight families and ten genera. Morphologically, however, they are one of the most diverse shark groups. In contrast, while smaller orders such as the bramble sharks (Echinorhiniformes), sawsharks (Pristiophoriformes), angelsharks (Squatiniformes) and bullhead sharks (Heterodontiformes) each have a single family and genus, the species are all morphologically very similar in appearance. The Lamniformes have remained relatively stable taxonomically, with the discovery of the Megamouth Shark Megachasma pelagios in 1976 the last significant addition to the order. The eight mackerel shark families are equal in number to the eight families found in the ground sharks (Carcharhiniformes), and also equal to that of the carpetsharks (Orectolobiformes). Five of the families in the order – goblin (Mitsukurinidae), basking (Cetorhinidae), crocodile (Pseudocarchariidae), megamouth (Megachasmidae), and sandtiger (Carchariidae) sharks – are monotypic, containing only a single genus and species; while a sixth family, thresher sharks (Alopiidae), has three species all within a single genus. Of the remaining two families, the sandtiger sharks (Odontaspididae) contain one genera and two species, and the mackerel sharks (Lamnidae) three genera and five species. Seven of the eight mackerel shark families are present in the Northeast Atlantic and Mediterranean region, although the crocodile sharks appear to be limited only to vagrants and the goblin and sandtiger sharks are uncommon to rare. The megamouth sharks (Megachasmidae) are the only family that has not been observed in the region, but it would not be surprising if its sole species, the Megamouth Shark, is eventually documented here. The external appearance of several species in this order is unique and appears unrelated to others. Nevertheless, the mackerel sharks can be characterised by a short to moderately long pointed snout; eyes usually lateral on the head and without nictitating membranes; spiracles, if present, are usually very small and located behind the eyes; no nasal barbels; a large to very large mouth extending well behind the eyes; five paired gill slits, in some species the last two occur above the pectoral-fin origins; two spineless dorsal fins; and an anal fin. Coloration ranges from blue-grey, light to dark brown, reddish, yellowish, or even pink above, usually lighter

below. Some species may have spots or light and dark blotches, and with darker or lighter fin edges. These are small to very large sharks with a maximum length of 122cm to over 800cm. Mackerel sharks are found in all major oceans, predominantly in tropical to warm-temperate waters, although some species occur at higher latitudes in cold water. These sharks are found in a wide range of habitats from the intertidal to the open ocean, to depths of at least 1,600m; none occur in freshwater. Some mackerel shark species are among the fastest swimming fishes in the ocean, yet others are relatively sluggish. Many species in this group are highly migratory, travelling across ocean basins or longitudinally across the equator. Most mackerel sharks are able to maintain their body temperature 2–11°C above that of surrounding waters through an internal heat exchange system called a rete mirabile. The system works through capillaries carrying cold blood alongside, but in the opposite direction to, capillaries carrying warm blood generated by red muscle. The two sets of blood vessels exchange heat so effectively as they pass each other that the heat returns to the body core instead of dissipating into the sea. The system is further augmented in some species, by the shark’s heat-generating red muscle being located next to the spine rather than near the skin. The life history of most mackerel shark species is poorly known. They are live-bearing with at least some species exhibiting a unique reproductive mode (oophagy) whereby the young feed on eggs in utero. Depending on species, litter size may range from one or two, up to 25 pups per pregnancy. The gestation period is not well established for any species, though for some it is estimated to last three years. These are highly specialised sharks and often voracious feeders. Some species are well-adapted, with specialised gill rakers to feed on plankton and krill. Others are active predators, targeting large, highly mobile bony fishes – such as tunas, sharks and rays – as well as marine mammals including whales, dolphins, elephant seals and sea lions. Several mackerel shark species are highly sought after in commercial fisheries, where they are targeted or retained as valued bycatch. Their flesh is considered of good quality for eating and their fins are highly valued in the shark fin trade. Consequently, many mackerel shark species have been assessed as threatened with some, such as the White Shark Carcharodon carcharias, attaining legal wildlife protection in many countries.

LAMNIFORMES MACKEREL SHARKS

263

Mackerel shark key guide 1a Snout extremely elongated, flat and blade-like; precaudal pits and lower caudal lobe absent  Mitsukurina owstoni p.267

precaudal pits absent

lower lobe absent

snout extremely long, flat and blade-like

1b Snout short to moderately long and broadly rounded, but not greatly elongated or blade-like; precaudal pits and lower caudal lobe present

precaudal pits present

�

lower lobe present

snout moderately long and broadly rounded, not elongated and blade-like

2a Caudal fin about as long as trunk of body  Thresher sharks (Alopiidae) �

caudal fin about as long as trunk of body

2b Caudal fin much shorter than trunk of body

�

264

MACKEREL SHARK KEY GUIDE

caudal fin much shorter than trunk of body

3a Upper precaudal pit present; lower pit and lateral keels absent; caudal fin heterocercal, not crescentshaped  Sandtiger sharks

upper precaudal pit present

caudal fin heterocercal

(Carchariidae and Odontaspididae) �

lateral keels absent

lower precaudal pit absent

3b Upper and lower precaudal pits present; lateral keels present; caudal fin crescent-shaped  �

caudal fin crescent-shaped

lateral keels present upper and lower precaudal pit present

4a Teeth large; long and pointed or triangular and blade-like; gill slits large, but not extending onto dorsal surface of head or nearly across throat, and without internal gill rakers  Mackerel sharks (Lamnidae) p.279

gill slits large, not extending onto dorsal surface

teeth large; long and pointed or triangular and blade-like

4b Teeth minute, hook-shaped and not blade-like; gill slits extremely large, extending onto dorsal surface of head and nearly across throat, and with internal gill rakers  Cetorhinus maximus p.277

gill slits very large, extending onto dorsal surface

teeth minute, hook-shaped and not blade-like

5a First dorsal fin similar in size to second dorsal and anal fins, and closer to pelvic fin bases than pectoral fin bases; snout short and slightly depressed; three rows of large upper teeth on each side of jaw symphysis (see page 268, Ua1, Ua2 and Ua3)  Carcharias taurus (Carchariidae) p.269

5b First dorsal fin much larger than second dorsal and

closer to pelvic fins

similar in size

closer to pectoral fins

much larger

anal fins, and closer to pectoral fin bases than pelvic fin bases; snout conical and long; two rows of large upper teeth on each side of jaw symphysis (see page 268 Odontaspis sp., Ua1 and Ua2)

 (Odontaspididae) �

MACKEREL SHARK KEY GUIDE

265

6a First dorsal fin over pectoral fin free rear tip; second dorsal and anal fins are equally large; pelvic fin posterior margin is strongly concave; lower caudal lobe is short; underside of snout is white; central cusp of tooth flanked by two or three cusplets  Odontaspis ferox p.270

anal and second dorsal fins equally large

first dorsal fin origin over pectoral free rear tip

underside of snout white

lower lobe short

posterior strongly concave

two or three cusplets

6b First dorsal fin usually over pectoral fin inner margins; second dorsal fin large and anal fin smaller; anal fin posterior margin is straight; ventral caudal lobe is triangular; underside of snout is dark; uniform dark coloration  Odontaspis noronhai p.266

second dorsal fin larger than anal fin

first dorsal fin origin behind pectoral free rear tip

underside of snout dark

posterior straight

7a Head with a deep horizontal groove extending around each side; eyes are very large, with orbits expanded onto the dorsal head surface; base of first dorsal fin closer to pelvic bases than to pectoral bases  Alopias superciliosus p.274

around each side; eyes relatively small, with orbits not expanded onto the dorsal head surface; base of first dorsal fin about equidistant between pectoral and pelvic fin bases, or closer to pectoral fin bases  Alopias vulpinus p.275

MACKEREL SHARK KEY GUIDE

first dorsal fin closer to pelvic fins

without deep horizontal groove extending around each side

eyes relatively small, orbits not expanded onto dorsal surface

266

only two cusplets

deep horizontal groove extending around each side

eyes very large, orbits expanded onto dorsal surface

7b Head without a deep horizontal groove extending

lower lobe triangular

first dorsal fin about equidistant between pectoral and pelvic fins

Sandtiger sharks Carchariidae and Odontaspididae Sandtiger sharks (Carchariidae and Odontaspididae) are large, fusiform-shaped sharks with a conical snout; a large subterminal mouth; large teeth with a slender central cusp flanked by lateral cusplets; small to moderately large eyes without nictitating membranes; two large dorsal fins; an anal fin; an upper precaudal pit, no lower precaudal pit; and a large asymmetrical caudal fin with an upper margin less than one-third the total length. Coloration ranges from light grey, grey-brown; to dark reddish-brown, chocolate brown or black above. The ventral surface is lighter or similarly coloured. Spots are present on some species. Worldwide, the families are comprised of two genera and three species, all of which occur in the Northeast Atlantic and Mediterranean region – though these species are uncommon to rare. Sandtiger sharks have a wide-ranging, albeit patchy, distribution in most warmtemperate and tropical waters. Depending on the species, sandtiger sharks inhabit nearshore coastal waters including bays and estuaries, but are also found offshore

on outer continental shelves, upper slopes, around seamounts and in the open ocean. They are active, though relatively slow moving, sharks. Information on the life history of these sharks is sparse, however the Sandtiger Shark Carcharias taurus is known to produce litters of two offspring. Sandtiger sharks’ diet consists mostly of other sharks, rays, bony fishes, cephalopods and crustaceans. Two of the three species are deep sea inhabitants and rarely encountered. However, the Sandtiger Shark is a coastal nearshore species common in some regions, and has been targeted by commercial and recreational fishers, and even subjected to eradication programmes. Despite their fearsome toothy appearance, Sandtiger Sharks are usually not aggressive towards divers and have emerged as a popular species in marine ecotourism. Two of the three sandtiger shark species are listed as Critically Endangered in the region, while the third is considered Data Deficient due to its rarity.

Smalltooth Sandtiger, Odontaspis ferox, Canary Islands, Spain

Goblin sharks Mitsukurinidae The family Mitsukurinidae has only a single genus and one extant species, the Goblin Shark Mitsukurina owstoni – although several additional species appear in the fossil record. The Goblin Shark is a uniquely distinct, unmistakable shark with a soft flabby body; an elongated, flattened, blade-like snout; relatively small eyes; and highly protrusible jaws. Coloration in live specimens is pinkish-white with bluish fins. This is a large shark, reaching at least 550–620cm in length. Patchily distributed in the Atlantic, Pacific and Western Indian Oceans, this deepsea species occurs in tropical and

temperate waters. It inhabits outer continental shelves and upper slopes, and around seamounts, from near the surface to at least 1,300m. Goblin Sharks appears to migrate vertically in the water column at night, possibly in search of food. Bony fishes and invertebrates form part of this shark’s diet, though virtually nothing else is known about its life history or ecology. The Goblin Shark has no value in commercial fisheries and is taken only occasionally as bycatch in deepsea fisheries. Goblin Sharks are assessed as Least Concern globally, due to their rarity and deepsea habitat.

CARCHARIIDAE, ODONTASPIDIDAE AND MITSUKURINIDAE SANDTIGER AND GOBLIN SHARKS

267

Sandtiger and goblin shark species dentition guide Ua1

Ua2

Ua3

Ul1

Ul2

Ul3

Ul4

Ul5

Ul6

Ul7

Ul8

Ul9 Up1

Up7

10mm actual size Ll4

Ll3

Ls

La1

Ua1

Ua2

Ua3

Ll2

Ll1

La3

La2

Ui1

Ul1

Ua1

La1

Ua3

Ua2

La2

Ui1

Ul2

Ul3

La3

Ui4

Ul1

Ls2

Ua1

La1

Ua2

Ll1

La2

Ui

Ul1

Lp1

Lp7

Ul5

Ll3

Ul6

Ll4

Ul7 Up1

Ul2

Ul3

Ul4

Ll3

10mm actual size

Ll5

Ll6

Lp7

Lp1

Ul3

Ul5

Ll5

Ul6

Ll6

Ul7 Ul8

Ul11 Up1

Up8

10mm actual size Ll7

Ll8 Ll9 Ll10

Lp1

Lp8

SMALLTOOTH SANDTIGER Odontaspis ferox 46–56 upper jaw, 36–48 lower jaw Ul4

Ul5

Ll3

Ul6

Ll4

Ul7

Ll5

Ul8

Ll6

Ll7

Ul9

Ul11 Up1

268

La1

La2

La3

Ll1

Ll2

Ll8

Ll9

Ll10

BIGEYE SANDTIGER Odontaspis noronhai 34–43 upperjaw, 37–46 lower jaw

SANDTIGER AND GOBLIN SHARK SPECIES DENTITION GUIDE

Up6

10mm actual size Lp1

Ls1 Ls2

Up6

SANDTIGER SHARK Carcharias taurus 36–54 upper jaw, 32–46 lower jaw

Ll2

Ul2

Ul4

Ll2

Ll4

Ls1

Ll6

GOBLIN SHARK Mitsukurina owstoni 35–53 upper jaw, 31–62 lower jaw

Ll1

Ls

Ll5

Lp7

SANDTIGER SHARK Carcharias taurus

very long gill slits

moderately large first dorsal fin, closer to pelvic fins than pectorals; slightly darker with an even darker posterior edge light brown to bronzy, often with scattered small brown or reddish spots

CCT 0

large caudal fin, with long upper lobe and strong subterminal notch

second dorsal fin about same size as first, origin ahead of anal fin; slightly darker with an even darker posterior edge

15–25m 50

upper precaudal pit present

eyes very small

232m

200 700

large terminal lobe

1,000 1,500 2,000

short, slightly flattened, conical snout

lateral keels absent

stout, heavy-bodied

large pectoral fins, slightly darker with an even darker posterior edge

3,000

large anal fin, about same size as first dorsal fin, with dark posterior edge

large pelvic fins, about same size as first dorsal fin; posterior nearly straight, with dark posterior edge

Mature size

Birth size

85–105cm

relatively short lower lobe

Mature size

Maximum size

♀220–230cm

♂190–195cm

3,750

Maximum size

♂257cm

♀325cm

NR distinctly prominent teeth

female 1 NR ♂ 6–7 ♀ 9–10

large, long, arched mouth no postoral grooves

ventral surface lighter to white

large pectoral fins with dark edges, broader on tips

♂ 15 ♀ 17

Also known as Grey Nurse Shark. Description A large, stout, heavy-bodied shark. Short, slightly flattened conical snout with a long mouth containing large, distinctly prominent teeth. Similar sized dorsal, pelvic and anal fins; first dorsal fin closer to pelvic fins. Lateral keels absent; upper precaudal pit present. Asymmetrical caudal fin with a short lower lobe. Colour Light brown to bronzy, often with scattered small brown or reddish spots; ventral surface lighter. Dentition Upper jaw 36–54 rows, lower jaw 32–46 rows. See p.268. Habitat A common coastal, nearshore shark found from depths of less than 1m to 232m, but predominantly between 15–25m. It is most common in warmtemperate and tropical seas, usually occurring in bays and estuaries, on sandy or mud bottoms and on rocky and coral reefs. Biology Oophagous, with a single, very large embryo about 100cm in length in each uterus. The reproductive cycle is thought to be two years in some regions, but a year in others. Age at maturity estimated at 9–10 years for females, 6–7 years for males, with a maximum age of 17 and 15 years, respectively (but over 30 years in aquaria). Sandtiger Sharks feed on a wide range of fishes and invertebrates. IUCN Red List Status Critically Endangered Possibly extinct as the last specimen caught was in 2003. It is suspected that a remnant population of less than 250 adults may still exist, but this has not been confirmed.

CARCHARIIDAE SANDTIGER SHARKS

CR

269

SMALLTOOTH SANDTIGER Odontaspis ferox

very long gill slits

large first dorsal fin originating over pectoral fin free rear tips, with a slightly darker posterior edge

grey, brownish-grey or olive; sometimes with dark reddish spots scattered over body

LOO second dorsal fin smaller than first, about same size as anal fin; origin approximately over pelvic fin insertions with a slightly darker posterior margin

large caudal fin, with long upper lobe and strong subterminal notch

10m

50

300m

upper precaudal pit present

eyes moderately large

1,015m

large pectoral fins, with slightly darker posterior margin but pale edge Birth size

~100cm

distinctly prominent teeth

lateral keels absent

large pelvic fins, smaller than first dorsal fin; posterior margin strongly concave and slightly darker with pale edge

large anal fin, about same size as second dorsal fin, with slightly darker posterior margin

Maximum size

Mature size

♂344cm

♂200-250cm

Mature size

♀300–350cm

2,000 3,000

moderately long, narrow lower lobe

3,750

Maximum size

♀450cm

6–20°C

large pectoral fins with darker mottled posterior margin but pale edge

female NR NR ♂ NR ♀ NR

large, long, broadly arched mouth

♂ NR ♀ NR ventral surface lighter to white

large pelvic fin with darker mottled posterior margin but pale edge

Description A large, stout-bodied shark. Conical, slightly flattened snout and long mouth. Large first dorsal fin originating over the pectoral fin free rear tips, much larger than the second dorsal and anal fins. Colour Grey, brownish-grey or olive above, lighter below; some specimens have dark reddish spots scattered over body. Dentition Upper jaw 46–56 rows, lower jaw 36–48 rows. Long, narrow, prominent teeth, with a central cusp flanked by 2–3 smaller cusplets on each side. See p.268. Habitat A wide-ranging shark found in most warm-temperate and tropical waters; on continental and insular shelves and upper slopes, from 10–1,015m, but mostly less than 300m. Usually associated with mud, sand or rocky reef habitats, Smalltooth Sandtigers appear to make excursions into the water column: in water 2,000–4,000m deep, individuals have been caught in midwater trawls within 70–500m of the surface. These sharks have been caught in water temperates ranging from 6–20°C. Biology Probably oophagous; virtually nothing is known about reproductive cycle or litter size as few adult females have ever been observed. Diet is known to include other sharks and rays, bony fishes, cephalopods and crustaceans. IUCN Red List Status Critically Endangered due to a prolonged absence in catches throughout much of its range in this region. Smalltooth Sandtigers have not been seen in the Mediterranean Sea for over a decade.

270

MACKEREL SHARKS LAMNIFORMES

1,000 1,500

slightly darker posterior margin to caudal fin stout-bodied

200 700

large terminal lobe

relatively long, slightly flattened, conical snout

0

II

Azores

CR

BIGEYE SANDTIGER Odontaspis noronhai moderately long gill slits distinct large eyes; greenish in live specimens

moderately large first dorsal fin with prominent white tip; originating behind pectoral fin free rear tips uniform blackish, dark chocolate or reddishbrown, without spots

ODH 0

large caudal fin, with long upper lobe and strong subterminal notch

second dorsal fin much smaller than first and pelvic fin, but larger than anal fin, origin approximately over pelvic fin insertions

35m 50 200

upper precaudal pit present

700

small terminal lobe

>1,000m

1,000 1,500

slightly darker posterior edge moderately large, slightly flattened, conical snout

bulky body large pectoral fins with a slightly darker posterior margin

large pelvic fins, about same size as first dorsal fin; posterior margin straight and slightly darker in colour

small anal fin, smaller than all other fins

lateral keels absent

~100cm

Mature size

3,000

triangular lower lobe

Maximum size

Birth size

2,000

♂367cm

3,750

Maximum size

♀427cm

♀~326cm, ♂326–342cm distinctly prominent teeth

NR

large pectoral fins with a slightly darker posterior margin

female NR NR ♂ NR ♀ NR ♂ NR ♀ NR

large, long, arched mouth

ventral surface same as dorsal

large pelvic fins, about same size as first dorsal fin, with a slightly darker posterior margin

DD Description A large, bulky shark. Long bulbous snout and long mouth. Eyes very large. Large first dorsal fin, closer to pectoral fins than pelvic fins; second dorsal and anal fins smaller than first dorsal fin. No lateral keels on caudal peduncle; upper precaudal pit present. Asymmetrical caudal fin with a strong lower lobe. Colour Uniform blackish, dark chocolate brown or reddish-brown, without spots; first dorsal fin with a light apical blotch. Dentition Upper jaw 34–43 rows, lower jaw 37–46 rows. Teeth moderately large with high, narrow central cusp flanked by a smaller cusplet on each side. Upper anterior teeth separated from lateral teeth by 1–2 rows of smaller intermediate teeth. See p.268. Habitat Found in midwater in the open ocean; near the bottom on continental and insular slopes; from 35–>1,000m. Biology Probably oophagous; nothing known about its reproductive biology. Diet includes bony fishes and cephalopods. IUCN Red List Status Data Deficient due to a lack of information on this species.

ODONTASPIDIDAE SANDTIGER SHARKS

271

GOBLIN SHARK Mitsukurina owstoni

LMO 0

small first dorsal fin; origin over pectoral fin inner margins moderately long gill slits

live specimens pinkish-white to white with bluish tinged fins

second dorsal fin about same size as first; origin over pelvic fin inner margins

large caudal fin, very long upper lobe

50

100m

200

upper precaudal pit absent

700

eyes very small

1,000

1,300m 1,500 2,000

very large, elongated, flattened snout

soft, flabby body

moderately large pelvic fins, about same size as anal fin

moderately large pectoral fins; slightly darker with narrow, paler posterior edge

Birth size

80–100cm

very long tail

Mature size

♂260–380cm,

no lower lobe 3,000

moderately large anal fin, larger than either dorsal fin; insertion very close to caudal fin lower lobe origin

Mature size

3,750

Maximum size

♀>400cm

♀620cm

Maximum size

♂380cm

NR distinctly prominent teeth

female NR NR ♂ NR ♀ NR

large, long, arched mouth highly protrusible jaw

ventral surface slightly paler to white

moderately large pelvic fins with narrow paler posterior edge

♂ NR ♀ NR

LC

Description A large, soft, flabby-bodied shark. Snout elongated, flattened and blade-like with highly protrusible jaws. Relatively small eyes. Colour Pinkish-white to whitish, with bluish fins. Dentition Upper jaw 35–53 rows, lower jaw 31–62 rows. Long, narrow single-cusp teeth, similar in both jaws. See p.268. Habitat Deep sea, outer continental shelf and upper slopes from about 100– 1,300m. It is speculated this shark may occupy a midwater habitat based on their soft, flabby body and light colour, at least one individual has been captured at a depth of less than 50m in water 2,000m deep. Biology Probably oophagous; virtually nothing is known about its life history. Adults are very rare, most observations of this species are of smaller juveniles 24, 50? ventral surface white

large pelvic fins with broad dusky margins and white tips

II Description A thresher shark with moderately large eyes that do not extend onto head. No deep horizontal groove above the gills. Very long, narrowly pointed pectoral fins. Long, curving caudal fin upper lobe, nearly as long as the rest of the shark. Colour Bluish-grey or dark grey, with white patches extending above pectoral and pelvic fin bases; white below. Dentition Upper jaw 32–52 rows, lower jaw 25–50 rows. See p.273. Habitat Found from nearshore, including bays, to far offshore; from the surface to 650m. Biology Viviparous, with 2–7 pups (average 4) per litter; pupping and nursery areas usually found close inshore. Gestation time is 9 months, with birth occurring in spring and summer months. Age at maturity varies by region: males from 3–7 years, females 3–9 years, with a maximum age of at least 24, possibly 50, years. These sharks feed on small schooling fishes and invertebrates including crabs and cephalopods. IUCN Red List Status Endangered due to suspected population declines of 60%.

III

EN

Azores

ALOPIIDAE THRESHER SHARKS

275

Basking sharks Cetorhinidae The family Cetorhinidae comprises a single genus and one extant species – the Basking Shark Cetorhinus maximus, with a worldwide distribution in all major oceans. This is a massive shark, reaching at least 1,000cm, possibly 1,200cm in length – making it the second largest fish in the ocean after the Whale Shark. Characteristics of this species include a pointed snout, huge subterminal mouth with minute hooked teeth, and enormous gill openings that nearly encircle the head. Coloration is a uniform blackish to grey-brown or blue-grey. Basking Sharks are coastal pelagic species, usually observed at the surface where water temperate is between 5–21°C. They are found close inshore – including enclosed bays – from the surfline to the continental shelf edge, and into the open ocean. This shark is highly migratory, known to make long-distance migrations across ocean basins and transequatorially between hemispheres. Basking Sharks are very social and frequently seen in small to very large groups,

often numbering hundreds of individuals. Almost nothing is known about the life history and ecology of this shark. Females produce litters of 1–6 young, though pupping and nursery grounds remain unknown. They are very specialised feeders, with gills that sieve out plankton as they slowly swim with mouths agape, passing hundreds of tons of water over their gills per hour. Although usually seen at the surface, Basking Sharks actually spend most of their time in much deeper water, following thermoclines at depths of 300–1,264m. For centuries, Basking Sharks were fished for their liver oil (used in lamps and as a source of vitamin A), meat and fins. However, fishing pressure was so intense that populations collapsed in many parts of the world. In some regions, protective measures appear to have helped populations rebound, though in other areas, despite similar measures, Basking Shark populations remain low. Globally, the Basking Shark is assessed as Endangered due to the lack of population recovery.

Basking Shark, Cetorhinus maximus, Isle of Coll, Scotland

BASKING SHARK Cetorhinus maximus 200+ upper jaw, 200+ lower jaw

lower jaw teeth

10mm 330% actual size

276

MACKEREL SHARKS LAMNIFORMES

BASKING SHARK Cetorhinus maximus gill openings enormous, nearly encircling the head

first dorsal fin very large, high, erect and nearly triangular; midbase between snout tip and caudal fin

eyes very small

BSK second dorsal fin less than half size of first; origin ahead of anal fin stout, heavy-bodied

0

caudal fin large and lunate with strong subterminal notch strong lateral keels

50

200m

200

warmer waters

700 1,000

1,264m 1,500

large lower lobe

feeding

2,000 3,000

conical, pointed snout

above and below, blackish to greybrown, grey or bluegrey; often with lighter linear mottling on flanks

moderately large anal fin, similar in size to second dorsal fin and less than half size of first

crescent-shaped upper and lower precaudal pits

Mature size

Birth size

Maximum size

♀>800cm

~150–200cm

>1097cm

Mature size

♂ 750–800cm

very large, broad pectoral fins

3,750

5–21°C

minute hooked teeth

female 1–6 NR ♂ NR ♀ NR

huge, broad, rounded (variable in young juveniles) subterminal mouth

♂ NR ♀ NR

crescent-shaped lower precaudal pit underside of head and abdomen often with irregular white blotches

large pelvic fins, much smaller than first dorsal fin

Description A very large shark, second in size only to the Whale Shark, but easily distinguished from it by a pointed snout; huge subterminal mouth; enormous gill slits that nearly encircle the head; modified gill rakers; strong lateral keels on caudal peduncle and a huge lunate caudal fin. Colour Blackish to grey-brown, grey or blue-grey above and below, on body and fins; lighter linear striping and spots along flanks. Ventral surface sometimes lighter, often with irregular white blotches on underside of head and abdomen. Dentition Minute and hooked. Habitat A pelagic species usually observed from the coast to the continental shelf edge and slope; often associated with coastal and oceanic fronts. These sharks make long transoceanic and transequatorial migrations, but as they move into warmer waters will usually remain at depths of 200–1,264m, where the water temperature is about 5°C. Biology Oophagous, with litters of 1–6; reproductive cycle, including gestation period, is unknown. Records of individuals 280m

200 700 1,000 1,500

snout short and broadly rounded or broadly parabolic

2,000

anal fin with deeply notched posterior margin

fairly stocky body

Mature size

Birth size

♀129–185cm

56–75cm

upper labial furrows short and inconspicuous

3,000 3,750

above grey-brown with inconspicuous white band on flanks; tips and posterior edges of fins often dusky, but no conspicuous markings

pectoral fins large, semifalcate; narrowly rounded or pointed apices; length of anterior margins about 17–22% of total length

nostrils with very short, low, poorly developed anterior nasal flaps

strong, narrow lower lobe

Mature size

♂129–180cm pectoral fins large, semifalcate; narrowly rounded or pointed apices; dusky tips

Maximum size

♀234cm

Maximum size

♂224cm

15–30°C female

1–14 8–12 ♂ 8–14 ♀ 7–16

snout broadly rounded or broadly parabolic

19–25 internarial width 0.9–1.3 in preoral length

white below

Description Medium-sized shark. Snout short and rounded. First dorsal fin extremely tall and triangular; origin over or ahead of pectoral fin insertions. Interdorsal ridge narrow. Colour Grey-brown above with an inconspicuous white band on flanks. Tips and posterior edges of fins often dusky, but no conspicuous markings. White below. Dentition Upper jaw 27–32 rows, lower jaw 25–32 rows. Upper teeth broad, erect, triangular and serrated. Lower teeth erect, narrow, with serrated cusps. See p.324. Habitat An abundant, inshore and offshore, coastal-pelagic shark of temperate and tropical waters. Found over continental and insular shelves and in deep water adjacent to them, as well as on oceanic banks. Common around bay mouths, inside shallow muddy or sandy bays, harbours and at river mouths. Avoids sandy beaches and the surf zone, coral reefs and rough bottoms. Occurs from the intertidal to at least 280m. Biology Viviparous with litter size varying between regions, ranging from 1–14, with 5–12 most common. Gestation is 8–12 months, varying between regions. Age at maturity is 8–14 years for males, 7–16 years for females, with a maximum age of 19–25 years. Feeds on bottom-dwelling bony fishes, invertebrates and on occasion, other small elasmobranchs. IUCN Red List Status Endangered due to severe declines from historical population levels.

III

CARCHARHINIDAE REQUIEM SHARKS

EN

341

� � �

�

TIGER SHARK Galeocerdo cuvier origin of first dorsal fin above pectoral fin insertions or inner margins; free rear tip well in front of pelvic fins

TIG first dorsal fin moderately large and falcate; bluntly pointed apex; posterior margin curving; free rear tip long, more than half dorsal fin base

nostrils small,; eyes fairly large, without internarial posterior notches space about 3 large, slit-like spiracles times nostril width

0

second dorsal fin much smaller than first, height about 40% of first dorsal height or less; origin slightly forward of anal fin origin with long free rear tip

interdorsal ridge very prominent

50 200

upper precaudal pit transverse and crescentic

700

large, slender caudal 1,112m fin with an acutely pointed tip snout very short; preoral length about equal to internarial space and much less than mouth width

prominent lateral keels on caudal peduncle gill slits moderately long

fairly stout body, becoming more slender behind the pectoral fins

pectoral fins moderately broad and semifalcate

Birth size

46–89cm anterior nasal flaps short and broadly triangular, not tubular labial furrows very long; uppers over twice as long as lowers and nearly reaching anterior ends of eyes

anal fin about as large as second dorsal fin, with short preanal ridges and a deeply notched posterior margin

above grey with a unique, distinct colour pattern of dark vertical bars and spots; bold in young but fading out in adults Mature size

♀250–350cm

Mature size

♂226–292cm

Maximum size

♂370cm

white below

newborns and juveniles are more prominently marked

3,000 3,750

Maximum size

♀>550cm ?740cm

10–82 12–16 ♂ 7–10 ♀ 8–10

female snout bluntly rounded or nearly truncate in dorsoventral view

Description Large shark with a stout body and broad head. Snout very short and bluntly rounded. Mouth very large; upper labial furrows very long, extending to front of eyes. Spiracles relatively large. Prominent lateral keels on caudal peduncle. Colour Grey with distinct pattern of vertical dark bars and spots on dorsal surface; very bold in young but fade with growth. Dentition Upper jaw 18–26 rows, lower jaw 18–25 rows. Cockscomb-shaped with prominent serrations; similar in both jaws. See p.324. Habitat Uncommon in the region, but wide-ranging in coastal-pelagic, tropical to warm-temperate waters. Tiger Sharks are usually found on, or adjacent to, continental and insular shelves from the surface to at least 1,112m. They often occur in river estuaries, close inshore off wharves and jetties, in coral atolls and lagoons. These sharks are also known to make excursions far offshore, but are not a truly oceanic species. Biology Viviparous, with litter size ranging from 10–82. Gestation is 12–16 months; mating usually occurs in spring, with birth in the spring and summer months. Age at maturity varies regionally, ranging from about 7–10 years for males, 8–10 years for females, with a maximum age of 20–25 years. A voracious omnivorous feeder, eating a wide variety of marine life as well as being somewhat of a ‘garbage can with fins’ in its consumption of carrion and all manner of inedible objects. IUCN Red List Status Data Deficient due to a lack of information.

342

GROUND SHARKS CARCHARHINIFORMES

1,500 2,000

strong, narrow lower lobe with an acutely pointed tip

>20°C

pectoral fins moderately broad and semifalcate with diffuse dusky posterior margins

1,000

20–25

DD

� � � BLUE SHARK Prionace glauca nostrils small; internarial space about 2.5–3.0 times the nostril width

first dorsal fin origin well behind pectoral fin rear tips; midbase much closer to pelvic than pectoral fin bases

BSH first dorsal fin low and falcate; narrowly rounded at apex; posterior margin curving

eyes large, without posterior notches

0

second dorsal fin much smaller than first, height half first dorsal fin height or less; origin slightly posterior to anal fin origin

50

upper precaudal pit transverse and crescentic

no interdorsal ridge

spiracles absent

200 700

caudal fin large, narrow with lateral >1,160m undulations on dorsal margin snout very long: preoral length greater than internarial space and mouth width

low lateral keels on caudal peduncle

rather slender body above uniform intense deep blue

gill slits moderately long

pectoral fins long, narrow and somewhat falcate; origins from under interspace between third and fourth gill slits to under fourth gill slit Mature size

Birth size

♂182–281cm

35–50cm anterior nasal flaps very short and broadly triangular, not tubular labial furrows very short with uppers shorter than lowers

anal fin slightly larger than second dorsal fin, with short preanal ridges and a deeply notched posterior margin

Mature size

♀>221cm pectoral fins long, narrow and somewhat falcate tips and part of posterior margins dusky

long, narrow ventral lobe

3,000 3,750

Maximum size

Maximum size

♂311cm

♀383cm

8(10–20)27°C female 1–135

♂ 4–6 ♀ 5–7 abruptly white below

20

head narrow, only moderately depressed

Description Body rather slender. Head narrow. Labial furrows short. Eyes large. Spiracles absent. First dorsal fin closer to the pectoral fin bases than the pelvics. Interdorsal ridge absent. Second dorsal less than a third size of first. Pectoral fins long, narrow and pointed. Caudal peduncle with a weak keel. Caudal fin narrowlobed with a long ventral lobe. Colour Intense deep blue above, white below, without any patternation. Dentition Upper jaw 24–31 rows, lower jaw 24–34 rows. Teeth of upper jaw broad, triangular, erect, curved, and serrated. Lower teeth cusps slender, and variably serrated. See p.324. Habitat A wide-ranging, oceanic-epipelagic shark, occurring from the surface to at least 1,160m. Although an offshore species it may venture inshore, especially at night, and often in areas with a narrow continental shelf or off oceanic islands. Biology Viviparous, with litter size from 1–135, averaging 35. Gestation is 9–12 months, with pups born in the spring and summer. Age at maturity ranges from 4–6 years for males, 5–7 years for females, with a maximum age of about 20 years. This shark feeds mostly on relatively small prey, especially bony fishes and squid. Other invertebrates, small sharks and mammalian carrion are readily taken, with seabirds occasionally caught at the surface. IUCN Red List Status Near Threatened in Northeast Atlantic waters and Critically Endangered in the Mediterranean Sea due to population declines. The Mediterranean Sea population is considered distinct from the Atlantic population, and appears to have undergone significantly greater population decline.

1,500 2,000

9–12 snout narrowly parabolic in dorsoventral view

1,000

II

III

NT

CARCHARHINIDAE REQUIEM SHARKS

CR

343

� � �

�

MILK SHARK Rhizoprionodon acutus first dorsal origin usually over or slightly in front of pectoral free rear tips spiracles absent eyes rather large, dorsoventrally oval, without notches

RHA

first dorsal fin relatively small and falcate, bluntly pointed apex, posterior margin dusky and nearly straight; free rear tip moderately long,

gill slits moderately small

0

second dorsal fin much smaller than first, a third the height or less; origin ranges from above last third of anal fin base to over its insertion

50

200m interdorsal ridge rudimentary

200

upper precaudal pit transverse and crescentic

700 1,000

caudal fin large with lateral undulations on dorsal margin; dusky posterior margins

snout long usually over 16 enlarged pores just behind mouth angle

slender-bodied above grey, grey-brown or purplish-brown

pectoral fins moderately broad and triangular, slightly falcate light posterior margins; origins below 3rd gill slit

relatively small, high pelvic fins; origins behind first dorsal fin free rear tip

anal fin considerably larger than second dorsal with long preanal ridges and slightly concave posterior margin

Birth size

Mature size

♂♀75cm

25–40cm anterior nasal flaps very short and narrowly triangular, not tubular

nostrils small

1,500 2,000

no lateral keels present on caudal peduncle

3,000

strong, narrow ventral lobe

3,750

Maximum size

100cm ?178cm >20°C

pectoral fins moderately broad and triangular, slightly falcate

1–8 female

12 2

pale below

snout narrowly parabolic in dorsoventral view long upper and lower labial furrows

head fairly broad, only moderately depressed

Description Slender shark. Upper and lower labial furrows long. First dorsal origin usually over or slightly in front of pectoral fin free rear tips. Second dorsal fin origin ranges from above last third of anal fin base to over its insertion. Preanal ridges long. Colour Grey, grey-brown or purplish-brown above. Pectoral fins with a light margin. Pale below. Dentition Upper jaw 23–27 rows, lower jaw 22–26 rows. Teeth serrated in adults. See p.325. Habitat An inshore and offshore shark of the continental shelves, from depths of less than a metre down to about 200m. It often occurs off sandy beaches, in midwater or near the bottom; occasionally found in estuaries, but it does not tolerate very low salinities and does not range into freshwater. Biology Viviparous, with litters from 1–8, 2–5 most common. Gestation is 12 months with young being born in the summer. Age at maturity is about two years with a maximum age of at least 8 years. The Milk Shark feeds primarily on bony fishes but also takes cephalopods and other invertebrates. IUCN Red List Status Least Concern due to its wide distribution and productive life history characteristics.

344

GROUND SHARKS CARCHARHINIFORMES

>8

LC

� � Hammerhead sharks Sphyrnidae The hammerhead sharks (Sphyrnidae) are a small but unique family, with a laterally expanded head in a distinctive hammer or mallet-shaped profile. Eyes are circular, or nearly so, with nictitating eyelids, no spiracles, and a short, triangular anterior nasal flap. These sharks have two dorsal fins, the first being moderately to very large, and a second that is much smaller than the first. An anal fin is present. The caudal fin has a strong lower lobe and undulations, or ripples, present along the dorsal caudal margin. Coloration is a light grey to brownish above and white below, without any distinctive patterns. These are small to very large sharks with a maximum total length ranging from 90cm to over 550cm. The hammerhead shark family comprises two genera and nine species. Of the three species occurring in the Northeast Atlantic and Mediterranean region, two are rare. Hammerhead sharks are wide-ranging in warmtemperate to tropical waters in all major oceans. They occur mostly over continental and insular shelves and in

adjacent waters; no hammerheads are truly oceanic. Although hammerhead sharks will enter estuaries, none are known to penetrate freshwater to any extent. These sharks are found from the surfline to depths of at least 275m, possibly to 1,000m or more. Hammerhead sharks are live-bearing, with litters of 2–50 young following a 7–12 month gestation. They are voracious feeders on a variety of sharks, rays, bony fishes, cephalopods, crustaceans and other invertebrates; in its juvenile stage, one species appears to consume seagrass. These are active swimming sharks with some species being quite social, aggregating in small to large groups, often numbering hundreds of individuals. Hammerhead sharks are taken in targeted and nontargeted fisheries worldwide. The conservation status of species in the region ranges from Data Deficient to the Smooth Hammerhead Sphyrna zygaena which is assessed as Critically Endangered in the Mediterranean.

Newborn Smooth Hammerhead, Sphyrna zygaena, South Africa

SPHYRNIDAE HAMMERHEAD SHARKS

345

� �

�

Hammerhead shark species key guide 1a Anterior margin of head nearly straight; prenarial grooves absent or hardly developed; first dorsal fin tall and strongly falcate; pelvic fins large and falcate; second dorsal and anal fins equally very large and falcate; teeth strongly serrated at all sizes  Sphyrna mokarran p.349 First dorsal tall and falcate

Anterior margin of head nearly straight

prenarial grooves weak or absent

second dorsal and anal fins equally large and falcate

teeth strongly serrated– see opposite page

large and falcate

1b Anterior margin of head moderately convex; prenarial grooves well developed; first dorsal usually semifalcate; pelvic fins with nearly straight posterior edges; second dorsal fin smaller than anal fin; teeth weakly serrated in adults  � Anterior margin of head moderately convex

prenarial grooves present

First dorsal semifalcate

second dorsal fin smaller than anal fin

teeth weakly serrated– see opposite page

2a Prominent median indentation on anterior margin of head; free rear tip of second dorsal fin nearly reaching upper caudal fin origin; anal fin base noticeably larger than that of second dorsal fin  Sphyrna lewini p.348

nearly straight

2b No median indentation on anterior margin of head; free rear tip of second dorsal fin well ahead of upper caudal fin origin; anal fin base about as large as second dorsal fin base  Sphyrna zygaena p.350

Prominent median indentation No median indentation

346

free tip nearly reaching caudal fin origin

free tip well ahead of caudal fin origin

Anal fin base much larger than second dorsal

Second dorsal and anal fin base about equal

HAMMERHEAD SHARK SPECIES KEY GUIDE

� � Hammerhead shark species dentition guide US1 US1

Ua1

Ua2

Ua3

Ua4

Ul1

Ul2

Ul3

Ul4

Ul5

Ul6

Ul7

Ul8

Ul9

Up1 Up2

10mm 80% actual size

LS1 La1

La2

La3

La4

Ll1

Ll2

Ll3

Ll4

Ll5

Ll6

Ll7

Ll8

Lp1 Lp2 Lp3

upper and lower anterior teeth with moderately long, moderately broad cusps, smooth or weakly serrated, posterior teeth mostly cuspidate, not keeled and molariform

SCALLOPED HAMMERHEAD Sphyrna lewini 30–36 upper jaw; 30–35 lower jaw

US2 Ua1

Ul4

Ua2

Ua3

Ua4

Ul1

Ul2

Ul3

Ul5

Ul6

Ul7

Ul8

Ul9

Ul10

Ul11 Up1 Up2

US1

10mm 67% actual size

LS1 LS2

La1

La2

La3

La4

Ll1

Ll2

upper and lower anterior teeth with moderately long, stout cusps, strongly serrated edges; posterior teeth mostly cuspidate, not keeled and molariform

US1 US2

Ua1

Ua2

Ua3

Ua4

Ul1

Ll3

Ll4

Ll5

Ll6

Ll7

Ll8

Ll9

Ll10 Lp1 Lp2

GREAT HAMMERHEAD Sphyrna mokarran 35–39 upper jaw; 34–38 lower jaw

Ul2

Ul3

Ul4

Ul5

Ul6

Ul7

Up1

10mm 75% actual size

LS1 LS2 LS3

La1

La2

La3

Ll1

upper and lower anterior teeth with moderately long, very stout cusps and smooth or weakly serrated edges; posterior teeth mostly cuspidate, not keeled and molariform

Ll2

Ll3

Ll4

Ll5

Ll6

Ll7

Lp1 Lp2

SMOOTH HAMMERHEAD Sphyrna zygaena 29–32 upper jaw; 25–31 lower jaw HAMMERHEAD SHARK SPECIES DENTITION GUIDE

347

� � �

�

SCALLOPED HAMMERHEAD Sphyrna lewini well-developed prenarial grooves

SPL 0

first dorsal fin origin over or behind pectoral fin insertions; free rear tip ahead of pelvic fin origins

moderately falcate first dorsal fin; dusky posterior margin

moderately large, circular eyes; rear of eyes slightly ahead of upper symphysis of mouth

low second dorsal fin, less than anal fin height; weakly concave posterior margin; inner margin about twice fin height, almost reaching upper caudal fin origin; free tip nearly reaching caudal fin origin

50 200

no interdorsal ridge

700

1,043m

1,000 1,500 2,000

preoral snout about 1/5–1/3 of head width

3,000

grey-brown above pelvic fins not falcate, with straight or slightly concave posterior margins

pectoral fins moderately large, hardly falcate; narrowly rounded to pointed narrow apices Birth size

38–56cm anterior margin very broadly arched in adults with a prominent median indentation

Mature size

♂140–165cm

anal fin larger than second dorsal, rather long; origin well ahead of second dorsal origin; posterior margin deeply notched

Mature size

♀212–250cm

lower lobe with dusky tip

Maximum size

3,750

Maximum size

♂295cm

♀430cm

pectoral fins moderately large, hardly falcate; narrowly rounded or pointed narrow apices, tips and most of posterior margin dusky to black

>20°C all types 13–41

female

9–10 ♂ 10 ♀ 15 posterior margin long and angled broad, narrow-bladed head, width 24–30% of total length (mostly above 26%)

white below

35 pelvic fins not falcate, with straight or slightly concave posterior margins; no dusky or dark tips or margins

Description Large hammerhead shark. Head broad and narrow-bladed; anterior margin very broadly arched in adults; prominent median indentation. First dorsal fin moderately falcate; origin over or behind pectoral insertions; free rear tip in front of pelvic origins. Second dorsal fin low with weakly concave posterior margin; inner margin about twice fin height; free rear tip almost reaching upper caudal origin. Pelvic fins non-falcate. Anal fin posterior margin deeply notched. Colour Grey-brown above. White below with dusky to black pectoral fin tips. Dentition Upper jaw 30–36 rows, lower jaw 30–35 rows. Moderately broad cusps, smooth to weakly serrated edges. See p.347. Habitat A coastal-pelagic, semi-oceanic species occurring in warm-temperate to tropical waters over continental and insular shelves, and in deep water adjacent to them. Occurs from the intertidal and surface to at least 1,043m. Biology Viviparous, with litter size from 13–41; gestation is 9–10 months. Males mature at about 10 years, females at about 15 years, with a maximum age of approximately 35 years. The Scalloped Hammerhead takes a wide variety of fish as prey, but also invertebrates (especially cephalopods). IUCN Red List Status Data Deficient due to a lack of information in European waters.

348

GROUND SHARKS CARCHARHINIFORMES

II

II

II

DD

� � � GREAT HAMMERHEAD Sphyrna mokarran prenarial grooves absent or hardly developed

first dorsal fin origin over or slightly behind pectoral fin insertions; free rear tip ahead of pelvic fin origins

SPK

moderately small, circular eyes; rear of eyes ahead of upper symphysis of mouth

0

high second dorsal fin, about equal to anal fin height; strongly concave posterior margin; inner margin about equal to fin height, ending well in front of upper caudal fin origin

strongly falcate, high first dorsal fin

50

300m

no interdorsal ridge

200 700

caudal fin with narrow, pointed terminal lobe

1,000 1,500 2,000

preoral snout less than 1/3 of head width pectoral fins large, falcate; pointed narrow apices

3,000

above greybrown with no prominent fin markings

Mature size

Birth size

strong, narrow lower lobe with narrow pointed tip

Maximum size

♀250–300cm

50–70cm anterior margin of head nearly straight in adults with a median indentation

pelvic fins strongly falcate, with strongly concave posterior margins

anal fin about as large or larger than second dorsal fin; origin below second dorsal fin origin; posterior margin deeply notched

Maximum size

♂380cm

Mature size

♂234–269cm

3,750

♀550cm

>21°C

pectoral fins large, falcate; narrow, pointed apices, tips and most of posterior margin dusky to black when young, fades with growth

6–42

female

11 5–6 posterior margin long and transverse broad, narrow-bladed head, width 23–27% of total length (mostly above 23%)

white below

♂ 42 ♀ 44 pelvic fins strongly falcate, with strongly concave posterior margins, tips and most of posterior margin dusky to black when young, fades with growth

Description Large hammerhead shark. Anterior margin of head nearly straight in adults with a median indentation. First dorsal fin strongly falcate with free rear tip in front of pelvic fin origins. Second dorsal fin high with strongly concave posterior margin and inner margin about equal to fin height. Pelvic fins falcate with strongly concave posterior margins. Anal fin posterior margin deeply notched. Colour Greybrown above. White below, without fin markings in adults. Dentition Upper jaw 35–39 rows, lower jaw 34–38 rows. Anterior teeth with moderately long, stout cusps, strongly serrated edges. Posterior teeth mostly cuspidate. See p.347. Habitat A coastal-pelagic and semi-oceanic tropical hammerhead occurring close inshore to well offshore, over continental shelves, island terraces, in passes and lagoons of coral atolls, as well as over deep water near land. Depth range is from very near the surface to at least 300m. While the Great Hammerhead often favours continental and insular coral reefs, recent tracking studies have shown this shark will move at least 500km, and off the continental shelf. Biology Viviparous, litter size varies between regions ranging from 6–42. Gestation is 11 months; pups are born in the spring and summer. Age at maturity is about 5–6 years, maximum age of about 42 years for males and 44 years for females. Targets a variety of prey, but seems especially to favour stingrays and other batoids, groupers and sea catfishes.

IUCN Red List Status Data Deficient due to a lack of information in European waters.

II

II

II

SPHYRNIDAE HAMMERHEAD SHARKS

DD

349

� � � SMOOTH HAMMERHEAD Sphyrna zygaena first dorsal fin origin over pectoral fin insertions

SPZ

relatively large, moderately falcate first dorsal fin; free rear tip well in front of pelvic fin origins

well-developed prenarial grooves moderately large, circular eyes; rear of eyes slightly behind upper symphysis of mouth

low second dorsal fin, less than anal fin height; weakly concave posterior margin, free rear tip finishes well short of upper caudal fin origin

0

caudal fin large with lateral undulations on dorsal margin

50

>200m

no interdorsal ridge

200 700 1,000 1,500

strong, narrow ventral lobe preoral snout about 1/5 to less than 1/3 of head width

3,000

above dark olive or dark grey-brown

pectoral fins moderately large, not falcate; straight or slightly concave posterior margins; narrowly rounded or pointed, narrow apices with dusky tips

pelvic fins not falcate, with concave posterior margins

50–61cm

posterior margin long and angled

anal fin slightly larger than second dorsal; origin ahead of second dorsal origin; posterior margin deeply notched

3,750

Maximum size

Birth size

anterior margin of head very broadly arched in adults and without a median indentation

2,000

Mature size

Maximum size

♂256cm

♀400cm

♂♀210–240cm

>10°C

pectoral fins moderately large, not falcate; straight or slightly concave posterior margins; narrowly rounded or pointed, narrow apices; dusky tips and posterior margin

20–50

female

10–11 15 ♂ 25 ♀ 24 white below broad, narrow-bladed head; its width 26–29% of total length (mostly above 26%)

pelvic fins not falcate, with concave posterior margins; slightly dusky posterior margins

Description Large hammerhead shark. Head broad and narrow-bladed; anterior margin broadly arched and without a median indentation. First dorsal fin moderately falcate with free rear tip in front of pelvic fin origins. Second dorsal fin low, smaller than anal fin. Pelvic fins non-falcate. Anal fin posterior margin deeply notched. Colour Dark olive or dark grey-brown above. White below, undersides of pectoral fin tips dusky. Dentition Upper jaw 29–32 rows, lower jaw 25–31 rows. Anterior teeth with moderately long, very stout cusps and smooth or weakly serrated edges. Posterior teeth mostly cuspidate. See p.347. Habitat The most cool-water tolerant member of the family. This large, active coastal-pelagic and semi-oceanic hammerhead occurs from close inshore, to shallow water over continental and insular shelves, to well offshore. Found from the surface to at least 200m along the edge of the continental shelf. Biology Viviparous, with litters from 20–50; gestation 10–11 months. Maximum age is 25 years for males and 24 years for females. Feeds on a variety of bony fishes, small elasmobranchs and invertebrates. IUCN Red List Status Data Deficient in Northeast Atlantic waters due to a lack of information, but Critically Endangered in the Mediterranean Sea due to steep population declines and possible localised extinction in parts of its range.

350

GROUND SHARKS CARCHARHINIFORMES

II

II

II

DD

CR

VAGRANTS

CROCODILE SHARK Pseudocarcharias kamoharai

NIGHT SHARK Carcharhinus signatus

Size Birth: 40–43cm Mature: ♂ 74–81cm; ♀ 87–98cm, Maximum: ♀ 122cm; ♂ 110cm Identification A small, slender spindle-bodied shark with large eyes, long gill slits, with long prominent teeth, highly protrusible jaws, small pectoral fins, weak keels, precaudal pits, and an asymmetrical tail fin. Colour Grey to grey-brown above, lighter below, and with light-edged fins. Habitat Usually found well offshore, far from land, from the surface to 590m deep. Individuals occasionally strand on beaches, but it is not known why this occurs. Biology Viviparous, with 4 pups per litter, but no known seasonality to their reproductive cycle. These sharks feed on midwater bony fishes and cephalopods. Distribution Known from the Northeast Atlantic from a single individual that washed up on a beach in SW England. Absent in the Mediterranean Sea. Globally this shark occurs in most tropical oceanic waters. IUCN Red List Status Globally assessed as Least Concern.

Size Birth: 60–72cm Mature size: ♂ 160–190cm; ♀ 180–205cm Maximum size: ♀ 280cm; ♂ 215 cm Identification Slim shark with long, pointed snout, small jaws, small pectoral fins, large eyes, oblique-cusped serrated upper teeth, front of first dorsal over pectoral fins, both dorsals low with elongated rear tips, interdorsal ridge present. Colour Grey-brown above, white below, no conspicuous fin markings. Habitat Deepsea coastal and semi-oceanic, on or along outer continental and insular shelves and off upper slopes. Prefers 50–100m, ranges 0–600m. Biology Viviparous, yolk-sac placenta, 4–18 (usually 12–18) pups per litter. Age at maturity is about 8 years for males, 10 years for females; maximum age is at least 17 years, possibly 31 years. Feeds on small active bony fishes, squid and shrimp. Distribution Possible vagrant record from Madeira, but mostly found in tropical and warm temperate West Africa from Senegal to northern Namibia. IUCN Red List Status Globally assessed as Vulnerable.

PSK

CCS

SICKLEFIN CHIMAERA Neoharriotta pinnata Size Birth Size: ~13–23cm TL, 7–10cm BDL Mature size: ♂ & ♀ 105–127cm TL, 88–105cm PCL, 50–60cm BDL, Maximum size: ♀ 147cm PCL, 122cm TL, 69cm BDL; ♂ 130cm TL, 108cm PCL, 60cm BDL Identification A narrow elongated, slightly flattened, blunt– edged snout, first dorsal–fin spine height greater than fin apex, second dorsal fin uniform in height, pectoral fins short and broad, pelvic fins rounded, anal fin distinct and curved, caudal fin with short terminal lament, frontal tenaculum prominent in adult males. Colour Uniform light to dark chocolate brown, without any distinctive blotches, spots or stripes. Habitat Depth range mostly from 150–750m, but with extreme records from the surface to 4,513m deep.

Biology Oviparous, but nothing else known. Diet includes invertebrates and bony fishes. Eggcase Large (25–30cm long, 9–10cm wide), spindle-shaped, with an anterior constriction, a long posterior tube and very wide, thin lateral flanges, with narrow transverse ridges numbering 60–61; capsule is black with pale amber coloured flanges. Distribution Known from a single specimen caught in the southern Bay of Biscay; previously known from Mauritania to Walvis Bay, Namibia in West Africa. IUCN Red List Status Globally it is assessed as Near Threatened Uncommon along the West African coast except in deepsea bottom trawl surveys where it is infrequently caught.

CNN VAGRANTS

351

APPENDICES Appendix 1: Glossary Abdominal ridges or keels. In some sharks, paired longitudinal dermal ridges that extend from the bases of the pectoral fins to the pelvic fin bases. Abyss. See p.360. Abyssal plain. See pp.11 and 360. Alar thorns. Paired patches of thorns on the outer disc of all mature male skates. See p.31. Anal fin. See p.11. Anterior. Forward, in the [longitudinal] direction of the snout tip. Anterior disc margin. Leading edge of disc or wings of batoids. See p.31. Anterior margin. See p.33. Anterior nasal flap. See p.34. Anterior pectoral fin radials. Forward most radials on batoid disc. See p.71. Apex (plural, Apices). In precaudal fins, the distal tip, which can be acutely pointed to broadly rounded. Apical. In oral teeth, towards the tip of the crown or cusp. Can also be used as indicating direction towards the apex or tip of a fin, fin-spine, etc. Barbels. Long conical paired dermal lobes on the snouts of sharks, which may serve to locate prey. Sawsharks have barbels on the underside of the snout in front of the nostrils (as in sturgeon), but most barbelled sharks have them associated with the nostrils. Base. In precaudal fins, the proximal part of the fin between the origin and insertion, extending distally, and supported by the cartilaginous fin skeleton. In the caudal fin, that thickened longitudinal part of the fin enclosing the vertebral column and between the epaxial and hypaxial lobes or webs of the fin. In oral teeth, the proximal root and crown foot, in apposition to the distal cusp. In denticles, the proximal anchoring structures, often with four or more lobes, holding the denticles in the skin. Bathyal. See p.360. Bathypelagic zone. The sunless zone of the water column, usually beyond 1,000m depth. Some oceanic sharks may transit the epipelagic, mesopelagic and bathypelagic zones to the bottom while migrating vertically. See p.360. Benthic or Demersal. Referring to organisms that are bottom-dwelling. Benthopelagic. Species occurring on the bottom as well as in pelagic habitats. Bioluminscence. Light produced by biochemical means in some organisms. Biomass. The total quantity or weight of all plant and animal material in a given area or volume. Bivalves. Large class of molluscs that have a hard calcareous shell made of two parts or ‘valves’, these are usually bilaterally symmetrical. Blade. In oral teeth, an arcuate, convex-edged section of the cutting edge of the crown foot, without cusplets. Body ridges. Elongated longitudinal dermal ridges on the sides of the trunk and precaudal tail in certain carpet sharks (Orectolobiformes); present in the Whale, Zebra, and some bamboosharks. Body. Can refer to an entire shark, sometimes restricted to the trunk and precaudal tail. Brackish. Waters within the mid ranges of salinity, having more salinity than freshwater, but not as much as seawater, for example estuarine water. Bycatch. The part of a catch taken incidentally in addition to the target species towards which fishing effort is directed. In a broad context, this includes all non-targeted catch including byproduct, discards and other interactions with gear. Capsule length. Length of an eggcase excluding the horns or tendrils. See p.42. Carcharhinoid. A ground shark, a member of the order Carcharhiniformes, and including the catsharks, false catsharks, finbacked catsharks, barbeled houndsharks, houndsharks, weasel sharks, requiem sharks, and hammerheads.

352

APPENDICES

Cartilaginous fishes. Members of the class Chondrichthyes. Caudal crest. A prominent saw-like row of enlarged pointed denticles along the dorsal caudal margin and sometimes along the ventral caudal margin of the caudal fin. Found in certain sharks, especially some catsharks. Caudal fin. See pp.30, 31, 32 and 33. Caudal keels. See p.32. Caudal peduncle. See p.32. Cephalic fin. One of a pair of horn-like fins on either side of the head of a mobulid ray that are an anterior extension of the pectoral fin. Cephalic tenaculum. See frontal tenaculum. Cephalopods. A member of the class Mollusca, cephalopods includes the octopus, squids, and nautilus. Ceratotrichia. Slender soft or stiff filaments of an elastic protein, superficially resembling keratin or horn (from the Greek keratos, horn, and trichos, hair). Ceratotrichia run in parallel and radial to the fin base and support the fin webs. The prime ingredient of shark-fin soup. Chondrichthyan. Referring to the class Chondrichthyes. Chondrichthyes. The class Chondrichthyes (from Greek chondros, cartilage, and ichthos, fish), a major taxonomic group of aquatic, gill-breathing, jawed, finned vertebrates with primarily cartilaginous skeletons, one to seven external gill openings, oral teeth in transverse rows on their jaws, and mostly small, toothlike scales or dermal denticles. Chondrichthyes include the living elasmobranchs and holocephalans and their numerous fossil relatives, and also can be termed shark-like fishes or simply sharks. Circumglobal. Occurring around the world. Circumnarial fold. A raised semicircular, lateral flap of skin around the incurrent aperture of a nostril, in heterodontoids, orectoloboids, and a few batoids, defined by a circumnarial groove. Circumnarial groove. A shallow groove defining the lateral bases of the circumnarial folds. Circumtropical. Occurring around the tropical regions of the world. CITES. Convention on International Trade in Endangered Species of Fauna and Flora. An international agreement which aims to ensure that international trade in specimens of wild fauna and flora does not threaten the survival of species. Appendix I of CITES lists species threatened with extinction. Appendix II includes ‘species not necessarily threatened with extinction, but in which trade must be controlled in order to avoid utilisation incompatible with their survival’. www.cites.org Claspers. Paired copulatory organs present on the pelvic fins of male cartilaginous fishes, for internal fertilisation of eggs. Class. One of the taxonomic groups of organisms, containing related orders; related classes are grouped into phlya. Classification. The ordering of organisms into groups on the basis of their relationships, which may be by similarity or common ancestry. Common name. The informal vernacular name for an organism, which may vary from location to location. Concave. An outline or surface that curves inwards. Continental rise. The gently sloping base of the continental shelf made up of sediment deposits; see also Rise. See p.11. Continental shelf. See pp.11 and 360. Continental slope. See pp.11 and 360. Convex. An outline or surface that curves outwards. Crustacean. A mainly aquatic arthropod taxon of the class Crustacea, typically with a hard shell covering the body and includes crabs, lobsters, crayfish, shrimps, prawns, krill, and barnacles. Cusp. A usually pointed large distal projection of the crown. A primary cusp is situated on the midline of the crown foot. Multicuspid refers to oral teeth or denticles with more than one cusp. In lateral trunk denticles, the posterior ends of the crown may have medial and lateral cusps, sharp or blunt projections associated with the medial and lateral ridges.

Cusplet. As with a cusp, but a small projection in association with a cusp, and usually mesial and distal but not medial on the crown foot. Cutting edge. In oral teeth, the compressed sharp longitudinal ridge on the mesodistal edges of the crown. Demersal. Occurring or living near or on the bottom of the ocean (cf. pelagic). Dermal denticle. A small tooth-like scale found in cartilaginous fishes, covered with enameloid, with a core and base of dentine and usually small and often close-set to one another and covering the body. A few non-batoid sharks, many batoids, and chimaeroids generally have them enlarged and sparse or reduced in numbers. Dermal lobes. In wobbegongs, family Orectolobidae, narrow or broadbased, simple or branched projections of skin along the horizontal head rim and on the chin. Disc. Upper body of a batoid that includes the head, pectoral fins and trunk. See p.31. Distal. In any direction, at the far end of a structure. In oral teeth, used in a special sense for structures on the teeth towards the posterolateral mouth corners or rictuses. See apical and basal. Dorsal. Upwards, in the vertical direction of the back. See ventral. Dorsal fin spine. See pp.30 and 32. Dorsal fin. See pp.30, 31, 32 and 33. Dorsal lobe. See upper lobe. Dorsal margin. See upper margin. Drop-off. Steep or sheer underwater cliff or precipice. Ecosystem. The living community of different species, interdependent on each other, together with their non-living environment. Eggcase. A stiff-walled elongate-oval, rounded rectangular, conical, or dart-shaped capsule that surrounds the eggs of oviparous sharks, and is deposited by the female shark on the substrate. It is analogous to the shell of a bird’s egg and is made of protein, which is a type of collagen that superficially resembles horn or keratin. Eggcases often have pairs of tendrils or hornlike structures on their ends, or flat flanges on their sides or spiral flanges around their lengths, which anchor the cases to the bottom. As the egg travels from the ovaries into the oviducts and through the nidamental glands, the eggcase is secreted around it and the egg is fertilised. Livebearing sharks may retain eggcases, and these vary from being rigid and similar to those of oviparous sharks to soft, bag like, degenerate and membranous. Soft eggcases may disintegrate during the birth cycle. Elasmobranch. Referring to the subclass Elasmobranchii. Elasmobranchii. One of the two subclasses of the class Chondrichthyes. Elasmobranchii are the shark-like fishes, the other subclass Holocephali are the chimaeras. The Elasmobranchii includes all the living sharks, batoids, and a host of fossil species. They differ from holocephalans in having five to seven pairs of gill openings, open to the exterior and not covered by a soft gill cover; separate oral teeth not formed as tooth plates; a rigid spined or spineless first dorsal fin and usually a relatively short, rigid, spined or spineless second dorsal fin. Electric organ. Common to all electric fish used for the purpose of creating an electric field, it is derived from modified nerve or muscle tissue. In electric rays it is used for defense and to stun its prey. See p.167. Embryo. An earlier development stage of the young of a live-bearing shark, ranging from nearly microscopic to moderate-sized but not like a miniature adult. See foetus. Endemic. A species or higher taxonomic group of organisms that is only found in a given area. It can include national endemics found in a river system or along part or all of the coast of a given country, but also regional endemics, found off or in adjacent countries with similar habitat, but not elsewhere. Endemism. The ecological condition of a species being restricted in geographical distribution to an area or region. See endemic. Epibenthic zone. The area of the ocean just above and including the sea bottom, from shallow seas to deep abysses, epibenthic sharks live on or near the bottom. See p.360. Epipelagic zone. That part of the oceans beyond the continental and insular shelves, in oceanic waters, from the surface to the limits of where most sunlight penetrates, about 200m. Also known as the sunlit sea or ‘blue water’. Most epipelagic sharks are found in the epipelagic zone, but may penetrate the mesopelagic zone. See p.360.

Euryhaline. An organism that is able to tolerate a large variance in salinity. Excurrent apertures. See p.34. Extant. Applies to a species that is still living. Extinct. Applied to a species or group that has no living representatives. Eye notch. See p.34. Eyespots or ocelli. Large eye-like pigment spots located on the dorsal surface of the pectoral fins or bodies of some sharks including rays, angelsharks, and some bamboo sharks, possibly serving to frighten potential enemies. Falcate. Sickle-shaped. Family. One of the taxonomic groups of organisms, containing related genera; related families are grouped into orders. FAO. United Nations Food and Agriculture Organisation. Fauna. The community of animals peculiar to a region, area, specified environment or period. Fecundity. A measure of the capacity of the maternal adult to produce young. Filter-feeding. A form of feeding whereby suspended food particles are extracted from the water using the gill rakers. Fin base. See base. Fin insertion. See insertion. Fin origin. See origin. Fin radials. Internal skeletal support of fin. Fin web. See p.33. Finning. The practice of slicing off a shark’s valuable fins and discarding the body at sea. First dorsal fin. See pp.30, 31 and 32. Flank. Sides of the shark excluding the head and tail regions. FL. Fork length. A standard morphometric measurement used for sharks, from the tip of the snout to the fork of the caudal fin. Free rear tips. The pectoral, pelvic, dorsal, and anal fins all have a movable rear corner or flap, the free rear tip, that is separated from the trunk or tail by a notch and an inner margin. In some sharks the rear tips of some fins are very elongated. Frontal tenaculum. One of two extra male sexual organs that is unique to chimaeras. It resides in a pouch on top of the head and has a bulbous tip that has many tiny hooks; when mating it has been observed to be used to grasp the posterior edge of the pectoral fin of the female. See p.30. Fusiform. Spindle- or torpedo-shaped, elongated with tapering ends. Gastropod. Largest class of molluscs, many marine species have a hard calcareous shell but others do not have shells and are commonly known as sea slugs. Genus (plural, Genera). One of the taxonomic groups of organisms, containing related species; related genera are grouped into families. The first of two scientific names assigned to each species. Gestation period. The period between conception and birth in live-bearing animals. Gill openings or slits. In elasmobranchs, the paired rows of five to seven transverse openings on the sides or underside of the head for the discharge of water through the gills. Chimaeras have their four gill openings hidden by a soft gill cover and discharge water through a single external gill opening. Habitat. The locality or environment in which an animal lives. Hadal. See p.360. Hadopelagic zone. The pelagic zone inside the deep trenches, 6,000m to about 11,000m, from which no chondrichthyans have been observed or recorded. See p.360. Head. That part of a cartilaginous fish from its snout tip to the last (or first and only in chimaeras) gill slits. Heterocercal. A caudal fin with the vertebral axis slanted dorsally into the fin base, which is also dorsally elevated. Heterodontoid. A bullhead shark, horn shark, or Port Jackson Shark, a member of the order Heterodontiformes, family Heterodontidae. Heterodonty. In oral teeth, structural differences between teeth in various positions on the jaws, between teeth in the same position during different life stages, or between teeth in the same positions in the two sexes. Hexanchoid. A cow shark or frilled shark, members of the order

GLOSSARY

353

�

� Hexanchiformes, and including the sixgill sharks, sevengill sharks, and frilled sharks. Holotype. The single specimen designated as the type of a species by the original author at the time the species name and description was published. Hypaxial web. See p.33. Hypocercal. A caudal fin with the vertebral axis slanted ventrally into the fin base, which is also ventrally depressed. Found only in angelsharks (Squatiniformes) among living sharks. ICES. International Council for the Exploration of the Seas. Ichthyologist. See ichthyology. Ichthyology. The branch of zoology devoted to the study of fish. Incurrent apertures. See p.34. Indo-Pacific. An area covering the Indian Ocean and Pacific Ocean. Indo-West Pacific. An area covering the Indian Ocean and western Pacific Ocean. Inner margin. See p.33. Insertion. See p.33. Inshore. Shallow waters seaward of the surf zone. Insular shelf. See Shelf. Interdorsal ridge. A ridge of skin on the midback of sharks, in a line between the first and second dorsal fins; particularly important in identifying whaler sharks (genus Carcharhinus, family Carcharhinidae). Interdorsal thorn. One or more thorns that are found between the two dorsal fins. See p.31. Intermediate teeth. Small oral teeth between the laterals and anteriors of the upper jaw, found in most lamnoids. Intertidal zone. Shoreline between high and low tide marks that is diurnally exposed to the air by tidal movement. See p.360. Island slope. See Slope. IUCN. The World Conservation Union. A union of sovereign states, government agencies and non-governmental organisations. www.iucn.org Jaws. See mandibular arch. Juvenile. The life stage between hatching from egg or birth to sexual maturity and adulthood. Keel. See caudal keel. Labial cartilages. Paired internal cartilages that support the labial folds at the lateral angles of the mouth. Living neoselachians typically have two pairs of upper labial cartilages, the anterodorsal and posterodorsal labial cartilages, and one pair of ventral labial cartilages, but these are variably reduced and sometimes absent in many sharks. Labial folds. Lobes of skin at the lateral angles of the mouth, usually with labial cartilages inside them, separated from the sides of the jaws by pockets of skin (labial grooves or furrows). Labial furrows or labial grooves. See p.34. Lamnoid. A mackerel shark, a member of the order Lamniformes, and including the sandtiger sharks, Goblin Shark, Crocodile Shark, Megamouth Shark, thresher sharks, Basking Shark, and the makos, Porbeagle, Salmon Shark, and White Shark. Lateral. Outwards, in the transverse direction towards the periphery of the body. See medial. Lateral caudal thorns. A row of thorns found either side of the tail of a skate or ray. See p.31. Lateral keel. See Caudal keel. Lateral line. A sensory canal system of pressure-sensitive cells, that run along the sides of the body, often branching at the head, which detect water movements, disturbances and vibrations. Lateral ridges. Reinforced ridges along the side of the body, one of which is often an extension of the caudal keel. Lateral teeth. Large broad-rooted, compressed, high-crowned oral teeth on the sides of the jaws between the anteriors and laterals. Lateral trunk denticle. A dermal denticle from the dorsolateral surface of the back below the first dorsal fin base. Littoral zone. That part of the oceans over the continental and insular shelves, from the intertidal to 200m. See p.360. Live-bearing. A mode of reproduction in which female sharks give birth to young sharks, which are miniatures of the adults. See Vivipary.

354

APPENDICES

Longevity. The maximum expected age, on average, for a species or population in the absence of human-induced or fishing mortality. Longline fisheries. Commercial fisheries that use a long line with baited hooks attached at intervals. Lower lobe. The lower of the two caudal fin lobes, usually smaller than the upper. See p.33. Lower margin. On the lower caudal fin lobe, the forward margin closest to the caudal peduncle. See p.33. Lower origin. See p.33. Lower postventral margin. See p.33. Malar thorns. Patches of thorns anterior to the eyes of many mature male skates. See p.31. Medial. Inwards, in the transverse direction towards the middle of the body. See lateral. Medial lobe. Small lobe on anterior nasal flap of nostril, see p.34. Medial teeth. Small oral teeth, generally symmetrical and with narrow roots, in one row at the symphysis and often in additional paired rows on either side of the symphysial one. Median thorns. A row of thorns down the centre line of a skate or ray that can extend from behind the mid scapular region and down the tail to the first dorsal fin. See p.31. Migratory. The systematic (as opposed to random) movement of individuals from one place to another, often related to season and breeding or feeding. Knowledge of migratory patterns helps to manage shared stocks and to target aggregations of fish. Molariform. In oral teeth, referring to a tooth with a broad flat crown with low cusps or none, for crushing hard-shelled invertebrate prey. Monospecific. Genus containing only one known extant species. Morphology. The study of the form and structure of organisms as well as their specific structural features. MPA. Marine Protected Area. Any area of the intertidal or subtidal terrain, together with its overlying water and associated flora, fauna, historical and cultural features, which has been reserved by law or other effective means to protect part or all of the enclosed environment. Nape. Back of the neck region. Nares. See Nostrils. Nasal aperture. On the neurocranium, an aperture in the anteroventral surface or floor of each nasal capsule, through which the nostril directs water into and out of the nasal organ. See p.31. Nasal curtain. Greatly expanded anterior nasal flaps, that reach the mouth to form the base of the nasoral grooves, helping direct water flow from the nostrils to the mouth. See p.31. Nasal flap. One of a set of dermal flaps associated with the nostrils, and serving to direct water into and out of them, including the anterior, posterior, and mesonarial flaps. See p.34. Nasoral grooves. Many bottom-dwelling, relatively inactive sharks have nasoral grooves, shallow or deep grooves on the ventral surface of the snout between the excurrent apertures and the mouth. The nasoral grooves are covered by expanded anterior nasal flaps that reach the mouth, and form water channels that allow the respiratory current to pull water by partial pressure into and out of the nostrils and into the mouth. This allows the shark to actively irrigate its nasal cavities while sitting still or when slowly moving. Nasoral grooves occur in heterodontoids, orectoloboids, chimaeroids, some carcharhinoids and most batoids. See p.34. Nictitating lower eyelid. In the ground sharks (order Carcharhiniformes), a movable lower eyelid that has special posterior eyelid muscles that lift it and, in some species, completely close the eye opening. Nictitating upper eyelid. In parascylliid orectoloboids, the upper eyelid has anterior eyelid muscles that pull it down and close the eye opening, analogous to the nictitating lower eyelids of carcharhinoids. Nomenclature. In biology, the application of distinctive names to groups of organisms. Non-target species. Species which are not the subject of directed fishing effort (cf. target catch), including the bycatch and byproduct. Nostrils. The external openings of the cavities of the nasal organs, or organs of smell. See pp.30, 31, 32 and 34. Nuchal thorns. Thorns in skates found on the back of the neck region. See p.31.

� Nursery ground. Area (often inshore and in sheltered waters and with abundant food organisms) where newborn sharks live and feed and grow to a certain size in their life cycle, then move elsewhere. Oceanic. Referring to organisms inhabiting those parts of the oceans beyond the continental and insular shelves, over the continental slopes, ocean floor, seamounts and abyssal trenches. The open ocean. See p.11. Oceanic ridge. Part of the ocean floor where new material is added to plate margins by magma eruptions forming an ever expanding parallel line of deepsea ridges. Ocellus (plural ocelli). Eye-like marking in which the central colour is bordered in a full or broken ring of another colour. Ocular. Of or associated with the eye. Olfactory. Parts of the body that are associated with the sense of smell. Orbital thorns. Thorns found around the eyes, often in a semicircular row. Order. One of the taxonomic groups of organisms, containing related families; related orders are grouped into classes. Orectoloboid. A carpet shark, a member of the order Orectolobiformes, including barbelthroat carpet sharks, blind sharks, wobbegongs, bamboosharks, epaulette sharks, nurse sharks, Zebra Shark, and Whale Shark. Origin. The anterior or front end of the fin base in all fins. The caudal fin has upper and lower origins but no insertion. See insertion. Paired fins. The pectoral and pelvic fins. Palatine. Of or near the palate, in chimaeras it is the posterior pair of the upper dental plates, see pp. 30 and 36. Parallel row of thorns. Rows of two or more thorns running side by side on skates. May be on disc and or tail. Paratype. Specimens other than the holotype designated as paratypes by the author at the time of a new species description. If not designated they become non-type or voucher specimens. Pectoral fins. See pp.30, 31 and 32. Pelagic. Referring to organisms that live in the water column, not on the sea bottom. Pelvic fin. See pp.30, 31 and 32. Photophores. Conspicuously pigmented small spots on the bodies of most lanternsharks (family Etmopteridae) and some kitefin sharks (family Dalatiidae). These are tiny round organs that are covered with a conspicuous dark pigment (melanin) and produce light by a lowtemperature chemical reaction. Phylum. In animal taxonomy it is one of the major groupings dividing organisms into general similarities and comprises of superclasses, classes and all other lower groupings. Placoid scale. See dermal denticle. Population. A group of individuals of a species living in a particular area. (This is defined by IUCN (2001) as the total number of mature individuals of the taxon, with subpopulations defined as geographically or otherwise distinct groups in the population between which there is little demographic or genetic exchange (typically one successful migrant individual or gamete per year or less).) Pores, pigmented. In a few sharks and skates, the pores for the lateral line and ampullae of Lorenzini are conspicuously black-pigmented, and look like little black specks. Posterior. Rearwards, in the longitudinal direction of the caudal fin tip or tail filament. Also caudad. Posterior margin. See p.33. Posterior nasal flaps. See p.32. Posterior notch. See p.33. Posterior tip. See p.33. Postventral margin. See p.33. Preanal ridges. A pair of low, short to long, narrow ridges on the midline of the caudal peduncle extending anteriorly from the anal fin base. Precaudal fins. All fins in front of the caudal fin. Precaudal pit. See p.32. Precaudal tail. See p.32. Predorsal ridge. A low narrow ridge of skin on the midline of the back anterior to the first dorsal fin base. Predorsal space. Space between snout tip and dorsal fin(s). See pp.363 and 367.

Prenarial. In front of the nostrils (nares). Prepelvic tenaculum. One of two extra male sexual organs that is unique to chimaeras. It resides in a pouch in front of the pelvic fin and has many tiny hooks along the anterior edge. See p.30. Preventral margin. In the caudal fin, the margin from the lower origin to the ventral tip of the caudal fin. Pristiophoroid. A saw shark, order Pristiophoriformes, family Pristiophoridae. Productivity. Relates to the birth, growth and mortality rates of a fish stock. Highly productive stocks are characterised by high birth, growth and mortality rates and can usually sustain higher exploitation rates and, if depleted, could recover more rapidly than comparatively less productive stocks. Protrusible. Capable of being thrust forward, term normally applied to jaws. Proximal. In any direction, at the near end of a structure. Pseudo-ocellus. A marking looking like an ocellus. Pupping ground. Area favoured for giving birth and depositing young. Red List of Threatened Species. Listing of the conservation status of the world’s flora and fauna administered by IUCN. www.redlist.org Reticulated. A pattern resembling a net or network. Rostral cartilage. A cartilaginous structure supporting the snout. See p.71. Rostral keel. In squaloids, a large vertical plate on the underside of the rostrum and internasal septum, sometimes reduced, and with the cavities of the subnasal fenestrae on either side of the keel. Rostrum. The cartilaginous anteriormost structure that supports the prenasal snout including lateral line canals and masses of ampullae. It is absent in a few nonbatoid sharks and in many batoids. Row. In teeth, a single replicating line of teeth, running parallel with the jaw, which includes functional teeth and their replacements, derived from one tooth-producing area on the jaw. Saddle. Darker dorsal marking that extends downwards either side of the shark but does not meet on the ventral surface. Scapular thorns. Thorns found on the shoulder region. See p.31. Scientific name. The formal binomial name of a particular organism, consisting of the genus and specific names; a species only has one valid scientific name. Second dorsal fin. See pp.30, 31 and 32. Secondary caudal keels. Low horizontal dermal keels on the ventral base of the caudal fin in mackerel sharks (Lamnidae) and some somniosids. Secondary lower eyelid. The eyelid below or lateral to the nictitating lower eyelid, separated from it by a subocular groove or pocket, and, in many carcharhinoids with internal nictitating lower eyelids, functionally replacing them as lower eyelids. Semi-pelagic. Occasionally living on the bottom but is found mainly far off the bottom in the water column above. Series. In teeth, a line of teeth running from the front of the jaw inward. Serrations. In oral teeth, minute teeth formed by the cutting edge of the crown that enhance the slicing abilities of the teeth. Snout. See pp.30, 31 and 32. Species. A group of interbreeding individuals with common characteristics that produce fertile (capable of reproducing) offspring and which are not able to interbreed with other such groups, that is, a population that is reproductively isolated from others; related species are grouped into genera. Spiracle. A small to large opening between the eye and first gill opening of most sharks and rays, representing the modified gill opening between the jaws and hyoid (tongue) arch. Lost in chimaeras and some sharks. Squalene. A long-chain oily hydrocarbon present in the liver oil of deepsea cartilaginous fishes. It is highly valued for industrial and medicinal use. Squaloid. A dogfish shark, a member of the order Squaliformes, including bramble sharks, spiny dogfish, gulper sharks, lanternsharks, viper sharks, rough sharks, sleeper sharks, kitefin sharks, and cookiecutter sharks. Squatinoid. An angelshark, order Squatiniformes, family Squatinidae. Stock. A group of individuals of a species, which are under consideration from the point of view of actual or potential utilisation, and which occupy a well defined geographical range independent of other stocks of the same species. A stock is often regarded as an entity for management and assessment purposes. Subcaudal keel. In a few dogfish sharks (family Centrophoridae), a single longitudinal dermal keel on the underside of the caudal peduncle.

GLOSSARY

355

Subcircular. Nearly circular. Subquadrate. Nearly square. Subrhombic. Nearly rhombic or diamond-shaped. Subrostral lobe. A shelf-like forward extension under the rostrum formed from the anterior extension of the pectoral fin and rostral cartilage. See p.154. Subterminal margin. See p.33. Subterminal mouth or ventral mouth. Mouth located on the underside of the head, behind the snout. Subterminal notch. See p.33. Subtriangular. Nearly triangular. Subtropical region. The intermediate region between the tropical and temperate zones. Supraorbital crest. On the neurocranium, an arched horizontal plate of cartilage forming the dorsal edge of the orbit on each side; it arises from the medial orbital wall and the cranial roof and extends horizontally from the preorbital process to the postorbital process. It is apparently primitive for shark-like fishes but is variably reduced or absent in some living elasmobranchs. Supraorbital or brow ridge. A dermal ridge above each eye, particularly well-developed in heterodontoids and some orectoloboids. Symphyseal or symphysial groove. A longitudinal groove on the ventral surface of the lower jaw of some orectoloboid sharks, extending posteriorly from the lower symphysis. Symphysial teeth. Larger oral teeth in one row on either side of the symphysis, distal to medials or alternates where present. Symphysials are broader than medials and usually have asymmetrical roots. Symphysis. The midline of the upper and lower jaws, where the paired jaw cartilages articulate with each other. Systematics. Scientific study of the kinds and diversity of organisms, including relationships between them. Tail. See pp.31and 32. Tail fold. Longitudinal folds of skin found on the dorsal (upper) and/or ventral (lower) side of the tail of a ray. Tail spine. One or more serrated stinging spines at the upper base of the tail, see p.140. Target catch. The catch which is the subject of directed fishing effort within a fishery; the catch consisting of the species primarily sought by fishers. Taxon, plural taxa. A taxonomic group at any level in a classification. Thus the taxon Chondrichthyes is a class with two taxa as subclasses, Elasmobranchii and Holocephali, and the taxon Galeorhinus, a genus, has one taxon as a species, G. galeus. Taxonomy. Often used as a synonym of systematics or classification, but narrowed by some researchers to the theoretical study of the principles of classification. Temperate. Two circumglobal bands of moderate ocean temperatures usually ranging between 10° and 22°C at the surface, but highly variable due to currents and upwelling. Including the north temperate zone between the Tropic of Cancer, 23°27’N latitude, to the Arctic Circle, 66°30’N; and the south temperate zone between the Tropic of Capricorn, 23°27’S latitude, to the Antarctic Circle, 66°30’N.

356

APPENDICES

Tentaculate papillae. Small tentacle-like papillae that are found around the spiracle rim of some electric ray species. See p.170. Terminal lobe. See p.33. Terminal margin. See p.33. Terminal mouth. Mouth located at the very front of the animal. Most cartilaginous fishes have subterminal mouths, but some species (Viper Shark, wobbegongs, angelsharks, frilled sharks, Whale Shark, Megamouth Shark, and mantas) have it terminal or nearly so. Thorn. In many batoids, most angelsharks and the Bramble Shark, enlarged, flat conical denticles with a sharp, erect crown and a flattened base (which may grow as the shark grows). Thornlets. Small thorns that are found on the surface of many species of skate. Tooth plate. Continually growing cutting and grinding ‘teeth’ found in chimaeras. See pp.30 and 36. TL. Total length. A standard morphometric measurement for sharks and some batoids, from the tip of snout or rostrum to the end of the upper lobe of the caudal fin. Transverse. Across the long access of the body. Tropical. Circumglobal band of warm coastal and oceanic water, usually above 22°C at the surface (but varying because of currents and upwelling), between the latitudes of 23°27’N (Tropic of Cancer) and 23°27’S (Tropic of Capricorn) and including the Equator. Truncate. Blunt, abbreviated. Trunk. See p.32. Tubercules. Small round nodules found on the skin of rays. Umbilical cord. A modified yolk stalk in placental viviparous sharks, carrying nutrients from the placenta to the foetus. Undescribed species. An organism not yet formally described by science and so does not yet a have a formal binomial scientific name. Usually assigned a letter or number designation after the generic name, for example, Gollum sp. A is an undescribed species of false catshark belonging to the genus Gollum. Unpaired fins. The dorsal, anal, and caudal fins. Upper eyelid. The dorsal half of the eyelid, separated by a deep pocket (conjunctival fornix) from the eyeball. The upper eyelid fuses with the eyeball and the pocket is lost in all batoids. Upper lobe. The upper of the two caudal fin lobes, usually larger than the lower. See p.33. Upper origin. See p.33. Upper postventral margin. See p.33. Vent. The opening of the cloaca on the ventral surface of the body between the inner margins and at the level of the pelvic fin insertions. Ventral. Downwards, in the vertical direction of the abdomen. See dorsal. Ventral fin. See pelvic fin. Ventral lobe. See lower lobe. Ventral margin. See lower margin. Ventral tip. See p.33. Vomer. The anterior pair of the upper dental plates (vomerine plates) found in chimaeras, see p.30 and 36. Wing. The common name for the pectoral fin of skates and rays.

Appendix 2: Regional oceans and seas SEA DEPTHS

0 to 500m

2,001 to 3,000m

4,500m Kings Trough

501 to 1,000m

3,001 to 4,000m

5,267m Calypso Deep

1,001 to 2,000m

deeper than 4,000m

REGIONAL OCEANS AND SEAS

357

SEA CURRENTS 7

6 5 3

1 2 3 4 5 6 7 8

Gulf Stream (warm) North Atlantic drift (warm) Norwegian current (warm) Azores current (warm) Irminger current (warm) East Greenland current (cold) West Greenland current (cold) Canaries current (cold)

2

1 4

8

AVERAGE SEA SALINITY

358

APPENDICES

40.0‰

30.0‰

39.5‰

29.0‰

39.0‰

28.0‰

38.5‰

27.0‰

38.0‰

26.0‰

37.5‰

25.0‰

37.0‰

24.0‰

36.5‰

23.0‰

36.0‰

22.0‰

35.5‰

21.0‰

35.0‰

20.0‰

34.5‰

19.0‰

34.0‰

18.0‰

33.5‰

17.0‰

33.0‰

16.0‰

32.0‰

15.0‰

31.0‰

14.0‰

AVERAGE SEA SURFACE TEMPERATURES 22°C 20°C 18°C 16°C 14°C 12°C 10°C 8°C 6°C 4°C 2°C 0°C -2°C

MARINE CLIMATE ZONES Polar Subpolar (boreal) Cold temperate North Atlantic drift Warm temperate Mediterranean Subtropical Equatorial

REGIONAL OCEANS AND SEAS

359

CONTINENTAL SHELF AND OCEANIC ZONES NERITIC PROVINCE Lagoon

Reef flat

SURF ZONE

INTERTIDAL ZONE

50m

Reef face

INSHORE surf zone to ~50m deep

SUBLITTORAL ZONE

100m

OFFSHORE ~50m to ~200m deep

200m

Continental shelf Continental shelf zones, including reef zones

NERITIC

OCEANIC PROVINCE EPIPELAGIC ZONE

200m 750m

pe

lo

ls

1500m

1000m

Bathyal

ta en

Middle

MESOPELAGIC ZONE

in nt Co

Upper

Lower

2000m

2250m

BATHYPELAGIC ZONE

Upper

3000m Middle

Continental shelf

Abyss

Oceanic seamount

3750m Lower

4500m EPIBENTHIC ZONE Area of ocean just above and including the sea bottom, from shallow seas to ocean trenches

Abyssal plain Abyss

6000m

Hadal

11000m

Oceanic zones

360

APPENDICES

HADOPELAGIC ZONE

Appendix 3: Field observations GENERAL Many readers will use this book for identifying sharks that they see while diving or fishing and will probably mainly come across fairly common and widely distributed species. Even so, it is worth keeping good records of your observations because scientific knowledge of even some of the most widespread species is lacking. Anyone may be able to contribute important new information, particularly if they are in a part of the world where little research is underway. Before handling a live shark, please remember that these animals live supported by water. Their internal organs (gut, liver etc.) do not have the surrounding protection and support provided by the ribs and abdominal muscles of land animals. They can, therefore, be extremely easily damaged if lifted out of the water without good abdominal support (i.e. in a sling). Please take as many measurements as possible in the water alongside the boat, don’t take your shark out to hug it, and try to ensure that it is released in good condition! You may need to spend some time helping the shark to get oxygenated water flowing over the gills again, if it has been motionless for a while. Pushing or pulling it gently through the water (headfirst, naturally) should help. Fish markets, particularly, are some of the best hunting grounds for poorly known or even completely unknown sharks. You may have to get up extremely early in the morning to see the fish as they are landed and before they are chopped up and sold and are advised to wear old clothes and shoes that can be washed (or thrown away) afterwards, but the experience can be really memorable. With luck, stallholders will be enthusiastic and helpful if you show a keen interest in their stock. Where possible the following information should be recorded, whether from live sharks in the water, on hook and line alongside a boat, onboard or onshore, or from dead specimens. i.

Name and address of observer or collector

ii. Date, time, location, habitat and water depth (where available). iii. Other relevant observations (e.g. behaviour). iv. Photographs of the whole specimen, particularly if it is an uncommon record our outside its usual geographic range. These should be taken from the side (standard scientific procedure is to illustrate the left side of the shark), from above, and from below, with close ups of the underside of the head and pectoral fins. Put something in the photograph to provide a known measurement scale. v. Measurements. Anglers like to record weights, but since these are very variable, depending upon time of year, point in the reproductive cycle etc., scientists prefer to record length as well, if not instead of weight. Total length should be recorded as a point-to-point distance, not over the curve of the body (which produces an overestimate of length). Precaudal length, from tip of snout to the tail origin, is

another important measurement and can be easier to record than total length. Other useful measurements are illustrated in the following pages. vi. Record whether male (a photograph of the claspers may be useful in judging maturity) or female, and whether there are any signs of pregnancy. vii. If the specimen is dead, remove and dry a strip of teeth from each of the upper and lower jaws (label them!) or keep the entire jaws. The latter should be pinned to a board to dry in order to prevent distortion. If it is also possible to keep and dry the fins and the vertebral column, these can be very useful in confirming identification of species that are difficult to identify. DNA can also be extracted from dried tissue for scientific studies. viii. If the specimen is dead, small and apparently unusual, it can be useful to keep the whole animal. Freezing is the easiest way to do this in the short term. In the longer term, it will be necessary to fix and preserve the specimen, using formalin and alcohol, but these procedures are usually undertaken in museums because of the difficulties of storing safely these toxic and flammable chemicals. For more information, see Compagno (2001). Remember, that many of the species described in this field guide may well turn out to be two or more very similar species. They may be distinguished by careful examination and measurements, by differences in size (they may mature at quite different lengths), by their use of different habitats and prey species, or because of different (but sometimes overlapping) distribution. Confusion between such similar species makes it very hard to understand their distribution, habitat, life history and other biological characters. Good records can help to overcome these problems. Records of sharks, particularly of unusual species or species recorded outside their usual range, should be sent to the relevant national or state museum, or fishery department, of the country in whose waters they were recorded. County biological record centres may be interested in receiving UK records. At minimum, a good photograph, ideally the specimen itself, should accompany unusual records, particularly if it is the first record from that country or region, but please contact the curator with details before sending in any specimens (particularly if these are large). While every country needs a national fish collection for reference purposes, to help train its fisheries staff and researchers and for the use of visiting scientists, and should be offered new specimens, some institutes may not have the necessary facilities to curate and keep them in good condition. In these cases, or if more than one important specimen has been collected, it may be necessary to send them to one of the major international fish collections as well, or instead.

FIELD OBSERVATIONS

361

HANDLING – best practice*

Where possible, release the fish from the side of the boat, only bring onboard if absolutely necessary ● Never use a gaff

LARGE SKATE AND RAYS

SMALL SKATE AND RAYS

● Correct

● Correct

Whenever possible, lift a skate or ray to move it.

Hold or lift a skate or ray by carefully supporting the snout (avoiding the nostrils) and the base of the tail.

● Incorrect Avoid contact with gills and spiracles, that can be easily damaged.

LARGE SHARKS

● Correct

Whenever possible, lift a shark or chimaera to move it.

Hold or lift a shark or chimaera under mid-body and the base of the tail.

● Incorrect Dragging or holding a shark or chimaera solely by its tail can easily damage the animal.

APPENDICES

Dragging or holding a skate or ray solely by its tail can easily damage the animal.

SMALL SHARKS AND CHIMAERAS

● Correct

362

● Incorrect

*From the Shark Trust’s best practice handling guides.

● Incorrect Avoid contact with gills, that can be easily damaged.

FIELD OBSERVATIONS – CHIMAERAS TL PCL PD2

D1B

D1B

PD1

IDS

D2B D2AH

DSA

D2PH

D1H

POB

D2PH

D2B D2PH

EYL EYH

CDM CDH

BDL

CVH

HDL

CVM

P2W

P1W

P2A P1A

D1

P2

P2

P1

D2

D2

D1P1

P1BH

P2BH

SVL

PP2 PP1 TL PCL PD1 PD2 HDL POB BDL PP1 PP2 SVL TRL TLL

Total length Precaudal fin length Pre-first dorsal fin length Pre-second dorsal fin length Head length Preorbital space Body length Pre-pectoral fin length Pre-pelvic fin length Snout–vent length Trunk length Vent to upper caudal origin

TRL

TLL

D1B First dorsal fin base length D1H First dorsal fin height DSA Dorsal fin spine length IDS Interdorsal space D2B Second dorsal fin base length D2AH Second dorsal fin anterior height D2PH Second dorsal fin posterior height CDM Upper caudal fin length CDH Upper caudal fin height CVH Lower caudal fin height CVM Lower caudal fin length D1P1 First dorsal fin–pectoral fin length

D1P2 D2P1 D2P2 P1A P1W P1BH P2A P2W P2BH EYL EYH

First dorsal fin–pelvic fin length Second dorsal fin–pectoral fin length Second dorsal fin–pelvic fin length Pectoral fin length Pectoral fin width Pectoral fin base length Pelvic fin length Pelvic fin width Pelvic fin base length Eye length Eye height

FIELD OBSERVATIONS – CHIMAERAS

363

FIELD OBSERVATIONS – SKATES AND RAYS TL DL SMW

POB

OL

IOD

ISD

DW

D1L D2L

SL

DSC AP1L PP1L AP2L

DPF

D1G D5G

MW

INW

PP2L

PNL POL

C1D C2D DCC TL DL DW SMW POB AP1L PP1L IOD OL ISD SL

364

Total length Disc length Disc width Snout to mid wing length Preorbital space Anterior pectoral fin length Posterior pectoral fin length Inter-orbital space Orbit length Inter-spiracular space Spiracle length APPENDICES

DSC DCC V1D V2D D1L D2L DPF AP2L PP2L PNL POL

Snout to vent length Vent to caudal fin tip (tail length) Vent to first dorsal fin length Vent to second dorsal fin length First dorsal fin length Second dorsal fin length Pelvic fins total width Anterior pelvic fin length Posterior pelvic fin length Prenarial length Preoral length

INW MW D1G D5G

Internarial space Mouth width First gill slits space Fifth gill slits space

OTHER RAY FAMILY EXTRA MEASUREMENTS Guitarfishes TL PCLU PD2 PD1 DL POB OL CDM

DWO

IOD ISD DWM

BWP

BD1

BD2 CPV

IDS

ESL

D1A

P2D

D2A

D1L

DIL

D2H

D1H D2L

SVL PNL INM

POL

D5G D1G

ANF INA INW

P2L P2P

NOW

P2A MW

HDL PCLL TL PCLU PCLL PD1 PD2 HDL DIL SVL DL P2D DWM DWO POB IOD

Total length Upper precaudal fin length Lower precaudal fin length Pre-first dorsal fin length Pre-second dorsal fin length Head length Disc length to insert Snout vent length Disc length Pectoral fin to first dorsal fin Disc width, pectoral fin tip to tip Disc width at front of eyes Preorbital space Inter-orbital space

OL ISD ESL DSC BWP BD1 BD2 D1A D1L D1H D2A D2L D2H CDM

Orbit length Inter-spiracular space Eye origin to back of spiracle Snout to cloaca space Body width at pectoral inserts Body width first dorsal insert Body width second dorsal insert First dorsal fin anterior margin First dorsal fin length First dorsal fin height Second dorsal fin anterior margin Second dorsal fin length Second dorsal fin height Caudal fin dorsal margin

CPV P2A P2L P2P PNL NOW ANF INA INM INW POL MW D1G D5G

Caudal fin preventral margin Pelvic fin anterior margin Pelvic fin length Pelvic fin posterior margin Prenarial length Nostril length Anterior nasal flap length Anterior nasal flaps space Lateral margins of nostrils space Internarial space Preoral length Mouth width First gill slits space Fifth gill slits space

FIELD OBSERVATIONS – SKATES AND RAYS

365

Sawfishes TRL SRL

Tooth count

Rp

Rd

Measurements are the same as the guitarfishes plus the following: TRL Total rostrum length SRL Standard rostrum length* SRW Standard rostrum width TW Tip width Rp Right proximal most rostral tooth gap Rd Right distal most rostral tooth gap

TW

SRW SRL* TRL

* Preferred measurement as TRL more subjective and not often possible for removed rostra

Torpedo rays

Stingrays

Sting count

Measurements are the same as skates but the disc width and length are the most important as the tails are often truncated (but DCC can still be measured) and in the case of stingrays they have no dorsal fins.

366

APPENDICES

Measurements are the same as the skate but in addition the dorsal fins and caudal fin can be recorded like the guitarfishes. D1A First dorsal fin anterior margin D1L First dorsal fin length D1H First dorsal fin height D2A Second dorsal fin anterior margin D2L Second dorsal fin length D2H Second dorsal fin height CDM Caudal fin dorsal margin CPV Caudal fin preventral margin

Eagle, cownose and mobulid rays AP

RP2 PCD

DL PD1 DCC

G4 G5

CW

G3 G2

DW D5G P2P

G1

D1G R1G

P2A

HDL

R5G

POL

MW

LFL

OD

SL

INW

PSP POB

POB

SL

Disc length Disc width Head length Anterior projection Cranial width Pre-dorsal length Rostrum to pelvic fin free rear tip Pre-cloacal distance Vent to tail tip (tail length) First gill slit length Second gill slit length

D1H D1L

CFL

PSP

DL DW HDL AP CW PD1 RP2 PCD DCC G1 G2

CFW

OD

G3 G4 G5 D1G D5G R1G R5G P2A P2P POL POB

Third gill slit length Fourth gill slit length Fidth gill slit length First gill slits space Fifth gill slits space Rostrum to first gill slit Rostrum to fifth gill slit Pelvic fin anterior margin Pelvic fin posterior margin Pre-oral length Pre-orbital length

PSP Pre-spiracular length OD Orbit length MW Mouth width INW Internarial space SL Spiracle length D1L First dorsal fin length D1H First dorsal fin height Mobulid rays only CFL Cephalic fin length CFW Cephalic fin width LTL Lower toothband length

FIELD OBSERVATIONS – SKATES AND RAYS

367

FIELD OBSERVATIONS – SHARKS These are the key measurements recorded by scientists who are describing shark species. They may vary slightly between individuals of a single species but together help to differentiate between similar species.

Fin measurements D2L

D1A D1P

D1H

D2A D2P

D2H D1B D1L

D1I P2L P2B P2H P2A

D2B

D2I ANB

P2I

ANA

P2P

ANI

ANH ANP ANL

Dorsal, pelvic and anal fins D1A D1P D1H D1B D1I D1L D2A D2P D2H D2B D2I D2L P2A P2P P2H P2B P2I P2L ANA ANP ANH ANB ANI ANL

368

First dorsal fin anterior margin First dorsal fin posterior margin First dorsal fin height First dorsal fin base First dorsal fin inner margin First dorsal fin length Second dorsal fin anterior margin Second dorsal fin posterior margin Second dorsal fin height Second dorsal fin base Second dorsal fin inner margin Second dorsal fin length Pelvic fin anterior margin Pelvic fin posterior margin Pelvic fin height Pelvic fin base Pelvic fin inner margin Pelvic fin length Anal fin anterior margin Anal fin posterior margin Anal fin height Anal fin base Anal fin inner margin Anal fin length APPENDICES

CDM CSW

CPU CFW

Caudal fin

CFL CPL CPV

CDM CPU CFW CSW CFL CPV CPL CST CTR CTL

Caudal fin dorsal margin Caudal fin upper postventral margin Caudal fin fork width Caudal fin subterminal width Caudal fin fork length Caudal fin preventral margin Caudal fin lower postventral margin Caudal fin subterminal margin Caudal fin terminal margin Caudal fin terminal lobe

CTR CST

CTL

Main longitudinal measurements TL FL PCL PD2 PD1 HDL PG1

IDS

DCS

PSP

POB

ACS

PP1 PPS PP2

PAS PCA

SVL PAL TL Total length FL Fork length PCL Precaudal fin length PD2 Pre-second dorsal fin length PD1 Pre-first dorsal fin length HDL Head length PG1 Prebranchial length PSP Prespiracular length POB Pre-orbital length IDS Interdorsal space

VCL DCS Dorsal fin insert to caudal fin upper origin PP1 Pre-pectoral fin length PP2 Pre-pelvic fin length SVL Snout to vent PAL Pre-anal fin length PPS Pectoral fin insert to pelvic fin origin PAS Pelvic fin insert to anal fin origin ACS Anal fin insert to caudal fin lower origin PCA Pelvic fin insert to caudal fin lower origin VCL Vent to caudal fin posterior tip

FIELD OBSERVATIONS – SHARKS

369

Other measurements

SPL

IOD

HDW

TRW

ABW

TAW CPW

ESL Ventral view

♂

LLA

GIR

CLO NOW

ANF

UL

A

CLB

Girth

CLI

Nostril

Angle of mouth

Clasper

EYL ING

EYH

GS1

MOW

INW

P1L

PRN POR

P1R

MOL Dorsal view IOD Interorbital space ESL Eye to spiracle length SPL Spiracle length HDW Head width TRW Trunk width ABW Abdomen width TAW Tail width CPW Caudal fin–peduncle width ANF Anterior nasal flap length NOW Nostril width ULA Upper labial furrow length

370

APPENDICES

P1I

GS5

P1H P1A

P1P

Pre-first dorsal measurements LLA CLO CLB GIR INW MOL MOW PRN POR EYL EYH

Lower labial furrow length Clasper outer length Clasper base width Girth Internarial space Mouth length Mouth width Prenarial length Preoral length Eye length Eye height

GS1 GS5 ING P1A P1R P1I P1P P1H P1L

First gill slit height Fifth gill slit height Intergill length Pectoral fin anterior margin Pectoral fin radial length Pectoral fin inner margin Pectoral fin posterior margin Pectoral fin height Pectoral fin length

Appendix 4: Regional shark fin guide This guide covers the fins of many shark species that are listed in various regional and international agreements, including CITES Appendix II, and/or that are common in the international dried fin trade. These are: Porbeagle Shark, Oceanic Whitetip, Scalloped Hammerhead, Smooth Hammerhead, Great Hammerhead, Blue Shark and Shortfin Mako.

Primary/Secondary Fin Set One dorsal fin

Secondary fin set

One ventral lobe of the caudal fin A pair of pectoral fins

The following pages focus on dried, unprocessed first dorsal fins because these are the most easily identified of the traded fins for the species covered here. Caution is suggested when using this guide to identify dorsal fins less than 20cm across the base, to avoid possible misidentification of samples from very small sharks. Pectoral fins descriptions help to confirm identification. The key characteristics that can be used to separate the first dorsal fins of the above seven species from other types of shark fins in trade are described. Porbeagle and Oceanic Whitetip first dorsal fins can be rapidly identified

to the species level based on the diagnostic white markings detailed here. The first dorsal fins of the three largest hammerhead sharks, as a group, which are the only hammerhead species that are common in trade, can also rapidly be separated from all other large sharks using two simple measurements that describe their characteristic shape (much taller than they are broad) and colour (dull brown or light grey). Identification of hammerhead shark fins to species requires examination of dorsal and pectoral fin sets or genetic testing. Blue Shark and Shortfin Mako fins are also described.

HOW TO USE THIS GUIDE Step 1. Distinguish first dorsal fins from other highly valued traded fins: pectoral fins and lower caudal lobes (see p.372). Step 2. Look for white first dorsal fin markings, and use the flowchart to identify either Porbeagle or Oceanic Whitetip Sharks or exclude many species with black fin markings. Step 3. Take several simple measurements (p.374) to help identify hammerhead first dorsal fins, which are much taller than they are broad and are dull brown or light grey. Step 4. Check for Blue Shark and Shortfin Mako fins. REGIONAL SHARK FIN GUIDE

371

STEP 1 Distinguish first dorsal fins from pectoral fins and lower caudal lobes a. Check the fin colour on each side Dorsal fins are the same colour on both sides (see both side views below). Pectoral fins are darker above (dorsal view) than underneath (ventral view), see below.

Dorsal fin, left side

Dorsal fin, right side

Pectoral fin, dorsal view

Pectoral fin, ventral view

b. Check the base of the fin Dorsal fins (D) have a continuous row of closely spaced cartilaginous blocks running along almost the entire fin base. When looking at a cross section of the base of a lower caudal lobe (LC1), there is typically only a yellow, ‘spongy’ material called ceratotrichia, which is the valuable part of the lower caudal lobe. In some lower caudal lobes (LC2) there may be a small number of the cartilaginous blocks, but they are usually widely spaced and/or occur only along part of the fin base. Usually the lower caudal lobe has been cut along its entire base when removed from the shark; in contrast, dorsal fins frequently have a free rear tip that is fully intact.

LC1

LC2

D

372

APPENDICES

STEP 2 Identify Porbeagle and Oceanic Whitetip first dorsal fins

START

fin is generally uniform in colour

A STOP in the flowchart below indicates that the fin is not from a species covered in this fin guide.

YES

Go to Step 3

NO distinct white or black markings on fin apex, free rear tip or trailing edge

markings are white

STOP not a species in this fin guide markings are black

free rear tip is white

Porbeagle Shark

apex is white

large, mottled white patch; fin is very broadly rounded

Oceanic Whitetip

apex is pointed with white markings on tip and along trailing edge

STOP not a species in this fin guide

REGIONAL SHARK FIN GUIDE

373

STEP 3 Identify hammerhead shark first dorsal fins

A

Take fin measurements 1 Measure fin origin to apex (O–A) with a flexible tape measure. 2 Measure the fin width (W) at the halfway point of O–A (i.e., if O–A is 10cm, measure W at 5cm along O–A). 3 Divide O–A by W (O–A/W). Origin to apex and fin width (measured from leading edge to trailing edge) are the landmarks found to be the most useful for species identification purposes, as measurements based on fin height, fin base and free rear tip are often too variable and dependent on cut and condition of the fin.

W

1/2 O–A

O STEP 4 fin is ‘short’ (O–A divided by W is less than 2.6)

YES

shape of trailing edge straight or concave

NO

convex (curves outward)

check whether Shortfin Mako (p.376) fin is ‘tall’ (O–A divided by W is greater than 2.6)

Fin is slate greyblue or greyishbrown Blue or Silky Shark

fin is brown or light in colour (see top of p.375)

374

APPENDICES

hammerhead species (see pp.377–378)

probably a thresher

Distinguishing hammerhead dorsals from other tall fins (mako and thresher sharks) Thresher and hammerhead shark first dorsal fins are very tall and slender, mako slightly shorter. Thresher and mako fins are slate grey or dark greyish-brown. Great Hammerhead first dorsal fins have a distinctive curved shape and are much lighter. Scalloped and Smooth Hammerhead first dorsal fins are similar in shape to thresher shark dorsal fins, but much lighter in colour and usually light brown not grey. Shortfin Mako first dorsal fins are dark greyish-brown or slate grey, with a steep-angled leading edge, smooth texture and short free rear tip.

Great Hammerhead Sphyrna mokarran

Scalloped Hammerhead Sphyrna lewini

Shortfin Mako Isurus oxyrinchus Thesher Shark Alopias vulpinus

Distinguishing hammerhead dorsals from other tall fins (guitarfish and Blacktip Sharks) Dorsal fins that are tall and slender and dull brown or light greyish-brown are probably one of three species of hammerhead sharks: Great Sphyrna mokarran, Scalloped S. lewini or Smooth S. zygaena. See descriptions on the pp. 377 and 378.

A Guitarfish

Hammerhead

Guitarfish

Tall dorsal fins can also come from several species of guitarfish, or Blacktip Shark Carcharhinus limbatus. In guitarfish first dorsal fins, cartilaginous blocks do not extend across the entire fin base (Image A). In hammerheads, these cartilaginous blocks are present along almost the entire fin base (Image A). Guitarfish dorsal fins also exhibit a glossy sheen (Image B), and some species also have white spots, unlike the dull brown, uniform coloration of hammerhead dorsal fins.

B Guitarfish first dorsal

Guitarfish second dorsal

Scalloped Hammerhead first dorsal

REGIONAL SHARK FIN GUIDE

375

Some Blacktip Shark first dorsal fins exhibit O–A/W that is close to or slightly greater than 2.5. However, they often (but not always) have a black spot on the dorsal fin apex, and the fin has a glossy appearance that is unlike the dull surface of the hammerheads (Image C).

C

If fins from a single shark have been kept together in sets and are available for comparison, Blacktip Shark pectoral fins are also longer and more slender than the short, broad fins of the hammerheads (Image D).

D

Scalloped Hammerhead

Blacktip Shark

Scalloped Hammerhead

Blacktip Shark

SHORTFIN MAKO Isurus oxyrinchus

page 282

First dorsal fin: dark greyishbrown or slate grey; very erect steep-angled leading edge, moderately straight trailing edge, short free rear tip, thick base; smooth texture.

Pectoral fins Dorsal view

First dorsal fin

Ventral view

Pectoral fins: dorsal surface dark greyish-brown or slate grey, white margin on edge of free rear tip, ventral surface white unmarked; rounded apex, moderately short and broad from leading edge to trailing edge. Conservation status: CITES Appendix II and other international and regional agreements (see p.24).

PORBEAGLE SHARK Lamna nasus

page 284

First dorsal fin: dark blue/black to dark greyish brown, rounded apex with white patch on lower trailing edge onto free rear tip. Dorsal view

Pectoral fins

Ventral view

First dorsal fin

Pectoral fins: short, rounded at apex; ventral surface has dusky coloration from apex throughout midsection of fin and along leading edge. Conservation status: CITES Appendix II and other international and regional agreements (see p.24).

376

APPENDICES

OCEANIC WHITETIP Carcharhinus longimanus

page 338

First dorsal fin: large and broadly rounded (paddle-like); mottled white colour at apex.

Dorsal view

Pectoral fins

First dorsal fin

Ventral view

Pectoral fins: long, broadly rounded at apex; dorsal surface has mottled white colour at apex, ventral surface is typically white but can have mottled brown coloration. ● mottled white colour also present on caudal fin (upper and lower lobe). ● very small juveniles may have mottled black coloration on dorsal, pectoral and caudal fins. Conservation status: CITES Appendix II, prohibited in many Atlantic and Pacific pelagic fisheries (see p.24).

BLUE SHARK Prionace glauca First dorsal fin: dark grey-blue to greyish-brown; rounded apex, trailing edge convex, leading edge with rather a shallow angle; moderate free rear tip. Silky Shark dorsal is same shape but light grey; its pectoral fins are much shorter.

page 343 Dorsal view

Pectoral fins

First dorsal fin Ventral view

Pectoral fins: dorsal surface dark grey-blue or dark greyish-brown, ventral white and unmarked; long and slender from leading edge to trailing edge, radial cartilage visible under skin. Conservation status: no catch limits (in 2020), global catches have declined steeply since 2013, but still the most abundant species in trade for fins and likely also meat. (see p.24)

SCALLOPED HAMMERHEAD Sphyrna lewini

page 348 Dorsal view

First dorsal fin: tall, flattening out toward apex; straight to moderately curved trailing edge (similar to Smooth Hammerhead, less slender than Great Hammerhead first dorsal fin). Pectoral fins

Ventral view

First dorsal fin

Pectoral fins: short and broad with black tips visible at the apex on ventral side. Conservation status: CITES Appendix II and prohibited by some international and regional fisheries agreements (see p.24). REGIONAL SHARK FIN GUIDE

377

GREAT HAMMERHEAD Sphyrna mokarran First dorsal fin: tall, slender from leading edge to trailing edge; elongated and pointed at apex.

page 349

Ventral view

Dorsal view

Pectoral fins

First dorsal fin

Pectoral fins: pointed apex, moderately curved along trailing edge with dusky colour at apex on ventral side and often along trailing edge. Conservation status: CITES Appendix II and a prohibited species in some regional fisheries agreements (see p.24).

SMOOTH HAMMERHEAD Sphyrna zygaena First dorsal fin: tall, sloping more at apex; moderately curved trailing edge (similar to Scalloped Hammerhead, less slender than Great Hammerhead first dorsal fin).

page 350

Dorsal view

Pectoral fins Ventral view

First dorsal fin

Note: Scalloped and Smooth Hammerhead first dorsal fins are so similar they are often extremely hard to differentiate. However, it is not uncommon for valuable fins from an individual to be traded as a set (first dorsal, paired pectoral fins and lower caudal lobe). If this is the case, the two species can be distinguished using the pectoral fins.

Pectoral fins: short and broad with faint to no markings on ventral side. Conservation status: CITES Appendix II and a prohibited species in some regional fisheries agreements (see p.24).

For terminology used in this section, please see p.352. This information is reproduced from Identifying Shark Fins: Oceanic Whitetip, Porbeagle and Hammerheads (Stony Brook University/Pew Environment group, D.L. Abercrombie and D.D. Chapman authors) and Abercrombie et al. 2013. For more information on fin identification, see www.fisheries.noaa. gov/national/international-affairs/shark-conservation and www.fao.org/ipoa-sharks/tools/software/isharkfin/en/

378

APPENDICES

Image credits The publishers would like to thank the following for providing photographs and for permission to reproduce copyright material within this book. Page 13 top left Laura Dinraths / Shutterstock; page 13 top right Joern_k / Shutterstock; page 49 Wild Wonders of Europe / Lundgren / naturepl.com; page 58 NOAA Office of Ocean Exploration and Research; page 68 top Marevision / agefotostock / Alamy Stock Photo; page 68 bottom left David Villegas Rios / Shutterstock; page 68 bottom right kirpad / Shutterstock; page 69 David Shale / naturepl.com; page 70 both Marevision / agefotostock / Alamy Stock Photo; page 72 Paulo Oliveira / Alamy Stock Photo; page 77 Paulo Oliveira / Alamy Stock Photo; page 95 OCEANA © LIFE BaĦAR for N2K; page 103 R. Hughes / Alamy Stock Photo; page 139 Paulo Oliveira / Alamy Stock Photo; page 142 Andrey Nekrasov / imageBROKER / Alamy Stock Photo; page 151 Tobias Friedrich / F1online digitale Bildagentur GmbH / Alamy Stock Photo; page 156 Roberto Nistri / Alamy Stock Photo; page 159 top Maui Topical Images / Shutterstock; page 159 bottom Paulo Oliveira / Alamy Stock Photo; page 161 waterFrame_fba / Alamy Stock Photo; page 167 Jesus Cobaleda / Shutterstock; page 168 Marevision / agefotostock / Alamy Stock Photo; page 169 lidialongobardi77 / Shutterstock; page 175 Marevision / agefotostock / Alamy Stock Photo; page 176 Doug Perrine / Nature Picture Library / Alamy Stock Photo; page 191 Kelvin Aitken / Biosphoto / FLPA; page 200 OCEANA; page 201 Hawaii Undersea Research Laboratory Archive at the University of Hawaii; page 204 Joern_k / Shutterstock; page 210 Hawaii Undersea Research Laboratory Archive at the University of Hawaii; page 220 Jerome Mallefet / Biosphoto / FLPA; page 230 Doug Perrine / Nature Picture Library / Alamy Stock Photo; page 243 Jordi Chias / naturepl.com; page 252 LuisMiguelEsteve / Shutterstock; page 258 Shane Gross / Shutterstock; page 267 Jordi Chias / naturepl.com; page 276 Martin Prochazkacz / Shutterstock; page 278 Masa Ushioda / Stephen Frink Collection / Alamy Stock Photo; page 286 Sue Daly / naturepl.com; page 291 top Florian Graner / naturepl.com; page 291 bottom Sue Daly / naturepl.com; page 309 NOAA Ocean Explorer; page 312 Peter Verhoog / Minden Pictures / Alamy Stock Photo; page 321 Alex Mustard / naturepl.com; page 345 Alessandro De Maddalena / Shutterstock. All illustrations are copyright Marc Dando.

IMAGE CREDITS

379

INDEX A Aetomylaeus bovinus 157 African Gulper Shark 215 African Skate 118 Alopias superciliosus 274 vulpinus 275 ALOPIIDAE 273 Amblyraja 90 hyperborea 91 jenseni 92 radiata 93 Angelshark 257 ANGELSHARKS 252 Angular Roughshark 245 Apristurus 295 aphyodes 297 laurussonii 298 manis 299 melanoasper 300 microps 301 Arctic Skate 91 ARHYNCHOBATIDAE 72 Arrowhead Dogfish 219 Atlantic Chimaera 54 Atlantic Long-nosed Chimaera 62 Atlantic Sawtail Catshark 303 Atlantic Torpedo 171 Azores Dogfish 238

B Basking Shark 277 BASKING SHARKS 276 Bathyraja 73 pallida 74 richardsoni 75 spinicauda 76 Bathytoshia lata 145 BATOIDEA 64 Bentfin Devil Ray 165 Bigelow’s Ray 133 Bigelow’s Skate 133 Bigeye Sandtiger 271 Bigeye Sixgill Shark 197 Bigeye Thresher 274

380

INDEX

Bignose Shark 332 Birdbeak Dogfish 218 Blackchin Guitarfish 182 Black Dogfish 223 Blackmouth Catshark 304 Black Skate 100 Blackspot Smoothhound 318 Blacktip Reef Shark 339 Blacktip Shark 337 Blonde Ray 120 Blonde Skate 120 Blue Pygmy Skate 112 Blue Shark 343 Blue Skate 96 Bluntnose Sixgill Shark 196 Bramble Shark 199 BRAMBLE SHARKS 198 Bronze Whaler 333 Brown Skate 125 Brown Stingray 145 Bull Ray 157 Bull Shark 336 BUTTERFLY RAYS 151

C CARCHARHINIDAE 319 CARCHARHINIFORMES 286 Carcharhinus 325 altimus 332 brachyurus 333 brevipinna 334 falciformis 335 leucas 336 limbatus 337 longimanus 338 melanopterus 339 obscurus 340 plumbeus 341 Carcharias taurus 269 CARCHARIIDAE 267 Carcharodon carcharias 281 CARPETSHARKS 258 CATSHARKS 290 CENTROPHORIDAE 210 Centrophorus granulosus 214

lesliei 215 squamosus 216 uyato 217 Centroscyllium fabricii 223 Centroscymnus coelolepis 235 owstoni 236 Centroselachus crepidater 237 CETORHINIDAE 276 Cetorhinus maximus 277 Chimaera monstrosa 52 opalescens 53 CHIMAERAS 46 CHIMAERIDAE 49 CHIMAERIFORMES 46 CHLAMYDOSELACHIDAE 191 Chlamydoselachus anguineus 194 Common Eagle Ray 158 Common Guitarfish 183 Common Stingray 146 Common Torpedo 174 Copper Shark 333 COWNOSE RAYS 159 COW SHARKS 191 Cuckoo Ray 107 Cuckoo Skate 107 D Dalatias licha 249 DALATIIDAE 247 Dark Electric Ray 171 DASYATIDAE 142 Dasyatis pastinaca 146 tortonesei 147 Deania calcea 218 profundorum 219 Deepsea Ray 75 Deepsea Skate 75 Deepwater Ray 132 Deepwater Skate 132 DEMON CATSHARKS 295 Devil Fish 163 DEVIL RAYS 161 Dipturus 94 batis 96 intermedius 98

nidarosiensis 100 oxyrinchus 101 DOGFISH SHARKS 200 Duckbill 157 Duhamel’s Catshark 306 Dumb Gulper Shark 217 Dusky Shark 340

E Eagle Ray 157 EAGLE RAYS 156 ECHINORHINIDAE 198 ECHINORHINIFORMES 198 Echinorhinus brucus 199 ELECTRIC RAYS 166 ETMOPTERIDAE 220 Etmopterus princeps 224 pusillus 225 spinax 226 F False Catshark 310 FALSE CATSHARKS 309 Flapper Skate 98 Fleshynose Catshark 300 Frilled Shark 194 FRILLED SHARKS 191

G Galeocerdo cuvier 342 Galeorhinus galeus 315 Galeus 302 atlanticus 303 melastomus 304 murinus 305 Ghost Catshark 299 Ghost Skate 134 Giant Devil Ray 163 GIANT GUITARFISHES 181 Giant Manta Ray 162 Ginglymostoma cirratum 261 GINGLYMOSTOMATIDAE 259 GLAUCOSTEGIDAE 181 Glaucostegus cemiculus 182 Goblin Shark 272 GOBLIN SHARKS 267 Great Hammerhead 349 Great Lanternshark 224 Great Torpedo Ray 171

Greenland Shark 240 Grey Nurse Shark 269 GROUND SHARKS 286 GUITARFISHES 180 Gulper Shark 214 GULPER SHARKS 210 Gymnura altavela 152 GYMNURIDAE 151

H HAMMERHEAD SHARKS 345 HARDNOSE SKATES 77 Harriotta haeckeli 60 raleighana 61 Heptranchias perlo 195 HEXANCHIDAE 191 HEXANCHIFORMES 191 Hexanchus griseus 196 vitulus 197 Himantura leoparda 148 HOUNDSHARKS 312 Hydrolagus affinis 54 lusitanicus 55 mirabilis 56 pallidus 57

I Iberian Pygmy Skate 113 Iceland Catshark 298 Isistius plutodus 250 Isurus oxyrinchus 282 paucus 283

J Jensen’s Skate 92

K Kitefin Shark 249 KITEFIN SHARKS 247 Knifetooth Dogfish 239 Krefft’s Ray 109 Krefft’s Skate 109

L Lamna nasus 284 LAMNIDAE 278 LAMNIFORMES 263 LANTERNSHARKS 220 Large-eyed Rabbitfish 56

Largetooth Cookiecutter Shark 250 Largetooth Sawfish 179 Leafscale Gulper Shark 216 Leopard Stingray 148 Leucoraja 102 circularis 104 fullonica 105 melitensis 106 naevus 107 Little Sleeper Shark 241 Longfin Mako 283 LONG-NOSED CHIMAERAS 58 Longnosed Skate 101 Longnose Spurdog 208 Longnose Velvet Dogfish 237 Lusitanian Cownose Ray 160

M MACKEREL SHARKS 263, 278 Madeiran Skate 123 Maderian Ray 123 Maderia Skate 123 Malacoraja 108 kreffti 109 spinacidermis 110 Maltese Ray 106 Maltese Skate 106 Marbled Electric Ray 172 Marbled Torpedo 172 Mediterranean Starry Ray 119 Mediterranean Starry Skate 119 Mid-Atlantic Skate 136 Milk Shark 344 Mitsukurina owstoni 272 MITSUKURINIDAE 267 Mobula birostris 162 mobular 163 tarapacana 164 thurstoni 165 MOBULIDAE 161 MOBULID RAYS 161 Mouse Catshark 305 Mustelus asterias 316 mustelus 317 punctulatus 318 MYLIOBATIDAE 156 MYLIOBATIFORMES 139 Myliobatis aquila 158 INDEX

381

N Narrow-nosed Chimaera 61 Neoraja 111 caerulea 112 iberica 113 Norwegian Skate 100 Nursehound 308 Nurse Shark 261 NURSE SHARKS 259

O Oceanic Whitetip shark 338 ODONTASPIDIDAE 267 Odontaspis ferox 270 noronhai 271 Opal Chimaera 53 ORECTOLOBIFORMES 258 OXYNOTIDAE 243 Oxynotus centrina 245 paradoxus 246

P Pale Chimaera 57 Pale Ray 74 Pale Skate 74 Pallid Skate 74 Pelagic Stingray 149 PENTANCHIDAE 290 Piked Dogfish 207 Porbeagle Shark 284 Portuguese Chimaera 55 Portuguese Dogfish 235 Prionace glauca 343 PRISTIDAE 176 Pristis pectinata 178 pristis 179 PSEUDOTRIAKIDAE 309 Pseudotriakis microdon 310 Pteroplatytrygon violacea 149

R Rabbitfish 52 Raja 114 africana 118 asterias 119 brachyura 120 clavata 121 maderensis 123

382

INDEX

microocellata 124 miraletus 125 montagui 126 polystigma 127 radula 128 undulata 129 Rajella 130 bathyphila 132 bigelowi 133 dissimilis 134 fyllae 135 kukujevi 136 lintea 137 RAJIDAE 77 RAJIFORMES 68 Ratfish 52 REQUIEM SHARKS 319 RHINCODONTIDAE 259 Rhincodon typus 262 RHINOBATIDAE 180 Rhinobatos rhinobatos 183 Rhinochimaera atlantica 62 RHINOCHIMAERIDAE 58 RHINOPRISTIFORMES 175 Rhinoptera marginata 160 RHINOPTERIDAE 159 RHINO RAYS 175 Rhizoprionodon acutus 344 Richardson’s Ray 75 Richardson’s Skate 75 Rostroraja alba 138 Rough Ray 128 ROUGHSHARKS 243 Rough Skate 128 Roughskin Dogfish 236 Round Fantail Stingray 150 Round Ray 135 Round Skate 135

S Sailfin Roughshark 246 Sailray 137 Sailskate 137 Sandbar Shark 341 Sandtiger Shark 269 SANDTIGER SHARKS 267 Sandy Ray 104 Sandy Skate 104 Sawback Angelshark 255

SAWFISHES 176 SAWTAIL CATSHARKS 302 Scalloped Hammerhead 348 School Shark 315 SCYLIORHINIDAE 290 Scyliorhinus 306 canicula 307 duhamelii 306 stellaris 308 Scymnodalatias garricki 238 Scymnodon ringens 239 SELACHIMORPHA 186 Shagreen Ray 105 Shagreen Skate 105 SHARKS 186 Sharpnose Sevengill Shark 195 Shortfin Mako 282 SHORT-NOSED CHIMAERAS 49 Shortnose Spurdog 209 Sicklefin Devil Ray 164 Silky Shark 335 SKATES 68 SLEEPER SHARKS 230 Smalleye Catshark 301 Small-eyed Rabbitfish 54 Small-eyed Ray 124 Small-eyed Skate 124 Small-spined Chimaera 60 Smallspotted Catshark 307 Smalltooth Sandtiger 270 Smalltooth Sawfish 178 Smoothback Angelshark 256 Smooth Hammerhead 350 Smoothhound 317 Smooth Lanternshark 225 SOFTNOSE SKATES 72 Soft Skate 110 SOMNIOSIDAE 230 Somniosus microcephalus 240 rostratus 241 Speckled Ray 127 Speckled Skate 127 Sphyrna lewini 348 mokarran 349 zygaena 350 SPHYRNIDAE 345 Spiky Spurdog 209 Spined Pygmy Shark 251 Spinetail Ray 76

Spinetail Skate 76 Spinner Shark 334 Spiny Butterfly Ray 152 Spotted Ray 126 Spotted Skate 126 Spurdog 207 SQUALIDAE 204 SQUALIFORMES 200 Squaliolus laticaudus 251 Squalus acanthias 207 blainville 208 megalops 209 Squatina aculeata 255 oculata 256 squatina 257 SQUATINIDAE 252 SQUATINIFORMES 252 Starry Skate 93 Starry Smoothhound 316 STINGRAYS 139

W Whale Shark 262 WHALE SHARKS 259 White Ghost Catshark 297 White Shark 281 White Skate 138

Z Zameus squamulosus 242

T Taeniurops grabatus 150 Tetronarce nobiliana 171 Thornback Ray 121 Thornback Skate 121 Thorny Skate 93 Thresher Shark 275 THRESHER SHARKS 273 Tiger Shark 342 Tope 315 TORPEDINIDAE 168 TORPEDINIFORMES 166 Torpedo marmorata 172 sinuspersici 173 torpedo 174 TORPEDO RAYS 168 Tortonese’s Stingray 147 TRIAKIDAE 312

U Undulate Ray 129 Undulate Skate 129

V Variable Torpedo 173 Velvet Belly Lanternshark 226 Velvet Dogfish 242 Violet Stingray 149 INDEX

383