Inshore Fishes of Britain and Ireland 0691249016, 9780691249018

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Inshore Fishes OF BRITAIN AND IRELAND

Seasearch is a volunteer underwater survey programme for recreational divers and snorkellers. The information they gather is used to increase our knowledge of the marine environment and contribute towards its conservation. For further information about Seasearch, or to participate in the programme, visit the website.

Inshore Fishes OF BRITAIN AND IRELAND

Lin Baldock and Frances Dipper Series editor Charlotte Bolton

Published by Princeton University Press 41 William Street, Princeton, New Jersey 08540 99 Banbury Road, Oxford OX2 6JX 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 [email protected] Text copyright © 2023 by Lin Baldock and Frances Dipper Photographs copyright © 2023 as cited on photographs and on pages 8–9. Also: p. 46 main, Dan Burton/naturepl.com; p. 46 inset, Alex Coan / Shutterstock; p. 50 main, Alex Mustard/202VISION/ naturepl.com; p. 56 top, Severe/Shutterstock; p. 71 bottom left, WaterFrame/Alamy Stock Photo; p. 113 top, Pascal Kobeh/naturepl.com; p. 151, David Keats/Fourbeard Rockling/cc-by-2.0; p. 247 top, DeSergio Hanquet/naturepl.com; p. 264, Florian Graner/naturepl.com; p. 265, Manuel E. Garci/ Shutterstock Illustrations copyright © 2023 by Marc Dando 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 2023930189 ISBN 978-0-691-24901-8 Ebook ISBN 978-0-691-25147-9 Series Publisher Julie Dando, WILDNATUREPRESS Ltd., Plymouth Printed in Slovakia 10 9 8 7 6 5 4 3 2 1

Main cover photograph: Male Lumpsucker Cyclopterus lumpus guarding a mass of blue-grey eggs in a rocky crevice. Chesil Cove, Dorset. Matt Doggett. Spine: Atlantic Mackerel Scomber scombrus shoal circling near the surface. Kinlochbervie, Highland. Cathy Lewis. Back cover: A group of Rock Cook Centrolabrus exoletus on a vibrantly coloured reef. Isle of Man. Iain Dixon. Title page: Norwegian Topknot Zeugopterus norvegicus, on a bivalve shell. Loch Ailort, Highland. Lin Baldock. Contents page: A Painted Goby

Contents About the authors

6

Acknowledgements

8

Introduction

11

How to use this book

14

Find your fish

16

Photographing fish – why

20

Photographing fish – how

21

Don’t be fooled – identification pitfalls

24

Fish habitats

28

Sharks

35

Free-swimming silvery fishes in open water

45

Free-swimming silvery fishes near the seabed

59

Colourful fishes near the seabed

81

Flattened fishes on the seabed

99

Non-flattened fishes on the seabed

149

Changing fish distributions

266

Parasites of fish

269

Associations with other species

272

Protected species and conservation status

274

Where to find out more

276

Seasearch surveying and recording

278

Biosecurity and non-native species

278

Taxonomic list of fishes included in this guide

280

Index

284

About the authors Lin Baldock Lin is a biologist with a background in marine and freshwater biology, and has been involved in environmental consultancy for many years. Prior to that, she was involved in research programmes with the University of Queensland, Australia; University of Southampton, UK; University of Toronto, Canada; and Cambridge University, UK. Lin is also a qualified commercial diver. Lin has been diving for over 40 years, recording marine life both as a professional and as a volunteer diver. Since 2016 she has been the Seasearch regional coordinator for Dorset, sharing her wealth of knowledge and experience with volunteers. With over 4,000 dives in her log book, Lin has dived all round Britain and Ireland enjoying the great diversity of marine life in these islands. Her interest in fishes was sparked when she realised there was a need to identify small, seabed dwelling fish, especially gobies, while recognising that there was no field guide to many of these species.

6

ABOUT THE AUTHORS

RY

Frances Dipper Frances has always loved the sea, despite being brought up on a farm in deepest Warwickshire. She started her marine journey at Port Erin in the Isle of Man, where she learnt to dive, met dolphins and studied the sex-life of wrasses for her PhD, falling in love with fish along the way. She then spent a few years with the Nature Conservancy Council, based in landlocked Huntingdon, but carrying out surveys and recording marine life all around the UK. During that time, and later, Frances was involved with others in the early days of running ‘citizen science’ projects for the Underwater Conservation Society, now the Marine Conservation Society. Subsequently, as a freelance marine consultant and lecturer, she dived extensively in the UK, Middle East and Far East, running expeditions and courses for divers and naturalists, including Seasearch Fish Identification. Over the years Frances has written more than 20 books on marine life and ocean environments for children and adults. In 2003, her JBu Dorling Kindersley children’s book Guide to the Oceans won the Royal Society Aventis Prize for Junior Science Books. Her most ambitious (and largest) recent book is The Marine World: A Natural History of Ocean Life, Wild Nature Press/Princeton University Press. Although no longer scuba diving, she still finds plenty to record along Britain’s wonderful shoreline, with the Porcupine Marine Natural History Society (PMNHS) and Seasearch.

Series editor: Charlotte Bolton Charlotte’s early life on a farm in the East Midlands was about as far from the sea as you can get. Similarly, it offered no clues as to where she would eventually end up – 50m from the sea at Chesil Cove. It did, however, instill a deep love of nature and collecting ‘treasures’ in matchboxes. Having learned to dive in Gozo in 2002, regrettably late in life, it soon became apparent that diving in the UK was the best way to fulfil her need to be underwater. The start of that journey was also the beginning of her engagement with Seasearch as a volunteer. A PhD in theoretical radiation chemistry, followed by a 15 year spell working at the Medical Research Council’s Radiation & Genome Stability Unit and then as an IT manager at the University of Cambridge, helped when she decided to give in to the pull of the ocean and find a job in marine conservation. A brief return to academic study at the University of Southampton for an MRes in Ocean Sciences enabled her to take on the job of Marine Data & Survey Officer RG (including Dorset Seasearch) at Dorset Wildlife Trust. This, in turn, led on to stepping up to National Seasearch Coordinator when Chris Wood retired in 2016. Charlotte is still happiest underwater recording what she sees, and expects

Acknowledgements Firstly we would like to acknowledge Paul Kay, who has generously provided invaluable help and advice drawn from his years of field fish identification. We are especially grateful to a number of other individuals who have helped us considerably by providing information and images of some particularly difficult groups of fish. Unravelling the dragonets would not have been possible without the tremendous efforts made by Chris Lewis in comparing all available information on the three species found in British and Irish waters and systematically teasing out the critical differences. Peter Bardsley, Sarah Bowen, Paul Naylor, Rob Spray and Dawn Watson also supplied images for the dragonet identification project. Joe FitzGibbon provided a tremendous range of images of the Smallheaded Clingfish and seasnails. Martin and Sheilah Openshaw provided unpublished information about the Undulate Ray Project (pp. 110–111). Matt Doggett and Martin Openshaw added information on the ecology and behaviour of Black Seabream (pp. 74–75). Paul Naylor wrote and provided images for Tompot Blenny social structure and territories (p. 169). Declan Quigley helped disentangle British and Irish records for scorpion fishes (Scorpaenidae) and Doug Herdson was particularly helpful with records of rare species and vagrants, especially from southwest England. Peter Miller stimulated our interest in the gobies, challenging us to find good field characters whereby the British and Irish species could be reliably identified. Lin would also like to especially thank her dive buddies Mike Markey, Sheilah Openshaw, Mike Rushworth, Ray Scott, Tina Scott, and Richard Yorke, who provided useful feedback on various versions of this guide. We would particularly like to thank all those who generously provided photographs for this guide. Many were taken by active Seasearch divers and other associates of Seasearch. Photographers are listed below and acknowledged by their initials on each photograph. AS AT CB CH CL CP CR CW DW FD GeB GL GrB HS HW ID JaG JBr JBu JC JD JF

Ana Santos (Instagram: CyberOceans) Angela Thomas Charlotte Bolton Charles Hood Cathy Lewis Craig Pinder Chris Rickard Chris Webb Dawn Watson Frances Dipper George Brown Gerald Legg Graham Brown Holger Schuhmann Hugh Waite Iain Dixon Jason Gregory John Breen John Buckley James Conroy Jake Davies Joe FitzGibbon

8

ACKNOWLEDGEMENTS

JH JiG JL JoB KA KB KF KH KLe KLo KM KN LB LH LKa LKe LM MD MG MM MO MoD

John Hepburn Jim Greenfield James Lynott Jon Bunker Kirsty Andrews Karen Boswarva Kathryn Fowler Keith Hiscock Kerry Lewis Kate Lock Kevin McIlwee Kate Northen Lin Baldock Lara Howe Lucy Kay Libby Keatley Leigh Morris Matt Doggett Matt Green Mike Markey Martin Openshaw Michael O’Donnell

MSl MSo NO NP OST PBa PBo PBu PLi PLo PM PNa PNe PW

Matt Slater Michael Southwood Nick Owen Nick Pfeiffer Daniel Wise (Orkney Skate Trust) Peter Bardsley Paul Boniface Paul Burridge Paula Lightfoot Patrick Louisy Penny Martin Paul Naylor Phil Newman Phil Wilkinson

RG RS RY SBl SBo SD SM SS ST TH TM TS VC

Rik Girdler Rob Spray Richard Yorke Sam Blampied (Blue Marine Foundation/ University of Plymouth) Sarah Bowen Sue Daly Shannon Moran Sally Sharrock Steve Trewhella Tim Harvey Tamsyn Mann Tina Scott Vanessa Charles

We would also like to thank Charlotte Bolton and Angus Jackson at Seasearch, and Julie Dando at Wild Nature Press, for their invaluable input in all aspects of this guide; Marc Dando for his immaculate illustrations; John Richardson for his meticulous proofreading; and Robert Kirk at Princeton University Press.

Seasearch The Seasearch programme was developed in partnership between the Marine Conservation Society (MCS), The Wildlife Trusts, statutory nature conservation bodies and others. It is overseen by MCS and coordinated and delivered locally by a mixture of Wildlife Trusts and individuals under contract to the MCS. Financial support for the Seasearch programme comes mainly from MCS, NatureScot and, in recent years, from Natural England and Natural Resources Wales. We have also received funding through projects EU LIFE Recreation ReMEDIES, Darwin Tree of Life and the Guernsey Biodiversity Partnership.

MM

Goldsinny Wrasse Ctenolabrus rupestris

10

INTRODUCTION

Introduction This field guide covers the wide range of fishes living in British and Irish waters. In particular, it focuses on those species likely to be seen by divers, snorkellers and shore walkers, without needing any specialist equipment other than a slate or notebook for recording and/or a camera. There are nearly 400 species of fishes accepted as part of the marine fauna of Britain and Ireland and included in the Marine Species of the British Isles and Adjacent Seas (MSBIAS marinespecies.org/msbias/) list. It is not the aim of this book to include them all, many of which are deepwater species. Instead, this guide describes 157 of them, each encountered regularly or occasionally within diving depth, while also mentioning others. Included are the jawless lampreys and hagfishes (Petromyzonti and Myxini) as well as the more familiar ray-finned bony (Actinopterygii) and cartilaginous (Elasmobranchii) fishes. Historically, naturalists have used a variety of remote sampling methods (netting, dredging, trawling, explosives) to collect fishes and produce descriptions of dead specimens which often look very different from their living state. As an example, colour seems an obvious way to describe a fish. Yet, many of the older texts either do not mention it or the description given is completely unlike that of the living animal and therefore of little use to divers and snorkellers observing them in situ. The limitations of using colour as a fish identification aid, and other possible identification confusions, is covered on pages 24–27 and will hopefully persuade you not to be fooled by a first or fleeting glance. Seasearch does not condone the taking of specimens to aid identification. The vast majority of the photographs in this guide have been taken in the wild (except for some images of rarely seen southern visiting species), enabling you to recognise each fish in its natural environment.

MD

Undulate Skate Raja undulata

INTRODUCTION

The growth of scuba diving, and in particular digital camera technology, has revolutionised recording of the underwater world. Fish, being mobile and often very fast-moving, can be exceedingly tricky subjects to photograph. Pages 20–23 provide some hints and techniques to enable you to achieve the best possible shot for identification purposes. Many species are quite cooperative when it comes to being photographed, but others are not and you may only have one chance to grab an image before your subject has vanished. With practice comes reliable recognition of fish species, with fewer photographs or merely a sighting all that is needed to confirm your identification. Fish welfare is paramount and some fishes are protected by legislation from disturbance (including photography) meaning you may need a licence to cover such intentional activities. This and fish welfare are covered on pages 274–275. The data collected by the Seasearch volunteer community are used by a variety of bodies, including those tasked with the statutory duties of protecting the marine environment, therefore accuracy in recording is imperative. This guide, like others in the series, includes information on ‘similar species’ to help you avoid any possible confusion and also indicates a level of confidence as to what can be recorded based on what you saw. It is always better to be conservative in your level of identification (e.g. record at a higher taxonomic level such as family) than be over-confident and wrong in assigning a species name. Both scientific and vernacular names have been included on the species accounts, as well as in the index. While the vernacular names are interesting (and often entertaining, especially the regional variations), the scientific name is best used to avoid any confusion. We have followed the MSBIAS subset of the World Register of Marine Species (WoRMS marinespecies.org) to indicate the accepted scientific name at the time of writing.

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Norwegian Topknot Zeugopterus norvegicus

12

INTRODUCTION

ID

Wreckage provides a safe refuge for this lurking Ling Molva molva. Unst, Shetland.

All of the Seasearch data are available via the National Biodiversity Network Atlas (nbnatlas.org) and Ireland’s National Biodiversity Data Centre (biodiversityireland.ie). These websites can be searched to find out which species have been recorded where. If you have dived in different areas around the coasts of Britain and Ireland, you will already have noticed that the distribution of marine life varies geographically and between different habitats – you will not see the same marine life in a sheltered Scottish sealoch as you will in an exposed rocky reef in the Channel Islands. However, fishes don’t read field guides, so you may see a fish in ‘the wrong place’ (geographically or habitat) during your dive or snorkel. This may be because it is a juvenile which occupies a different habitat to the adult fish, it may be diseased or sick (so its behaviour is abnormal), or it may have been displaced by localised weather conditions or wider climate change. Or perhaps there may not yet be enough data to know exactly what is the norm. Geographical range and habitat are also useful considerations when trying to name your fish. Within each species account we have given information on known abundance and distribution based on reported sightings (including angling records as well as underwater observations), in addition to information on the usual habitat and depth-range. Each of these pieces of information may be needed to confirm your identification – beware of assigning a name purely on the basis of a photograph alone. Finally, do keep in mind that it is always possible to see a fish in an unexpected place – someone has to be the first to see a new arrival to these waters. We hope that by using this field guide, and reporting your sightings to Seasearch, you may be that person. Even if you never have that particular honour, we hope that this guide will enhance your enjoyment of the marine environment as you learn more about its fishy inhabitants.

INTRODUCTION

How to use this book The fishes in this book are not arranged in standard taxonomic order because most divers and snorkellers do not categorise them in that way. Instead, the situation in which the fish is most likely to be observed is used as the primary way to group them together. The species accounts begin with those fishes that generally live in open water (the so-called ‘pelagic’ fishes) starting with the sharks and then the bony fishes. However, for clarity, all sharks – including two seabed-living species – are described together. The guide then covers fishes seen swimming around in the water column, just above the seabed. Finally, those species that are usually observed living on or in the seabed, be it rocky reef or sediment (the ‘benthic’ fishes), are described. This final section includes bony, cartilaginous and jawless fishes. Within each of these major sections, similarshaped fishes are grouped together as far as possible. To assist you in finding the right part of the guide refer to pages 16–19 illustrating the general outline, shape and appearance of your observed fish. This should lead you to the correct group or family to begin your search. SCIENTIFIC NAME and VERNACULAR NAME

Zeugopterus norvegicus Norwegian Topknot

(Günther, 1862)

SPECIES CITATION The surname of the person who gave the scientific name and year of publication.

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LKe

GENERAL DESCRIPTION

KEY FEATURES The main identification features for the species. SIMILAR SPECIES Other species with which it could be confused and how to distinguish them.

14

Top The narrow oval shape and prominent scales of this left-eyed fish indicate it is a Norwegian Topknot. Knoydart, Highland. Above Relatively large, clearly visible scales.

LB

Rock-dwelling Norwegian Topknots can take on startling colours. Isle of Man.

GENERAL DESCRIPTION This is the smallest of the three topknots which occur around Britain and Ireland, growing to a maximum length of about 12cm, but usually not more than 8cm. The body is a more elongated oval shape than the other two topknots. The scales are large in proportion to the size of the fish, easily seen and are smooth, lacking the skin papillae present in the other two species (with the exception of scattered papillae on some scales). The mouth is set at about a 45° angle in relation to the longitudinal body axis. Colouring is highly variable, the fish blending in with the seabed around, ranging from greyish freckles on plain, muddy sediments, to bright hues of pink and orange on maerl or bedrock encrusted with coralline algae and bryozoa. The pectoral fin is frequently held almost upright. This small fish occurs in a wide range of habitats including soft, silty sediment, maerl beds and rocky reefs from about 5m to over 50m. KEY FEATURES Large, smooth, easily visible scales. Mouth at 45° to longitudinal body axis. Often covered with large patches of bright colour. SIMILAR SPECIES Other topknots. Both the Topknot (p. 143) and Eckstöm’s Topknot (opposite) have specific markings absent in the Norwegian Topknot. ABUNDANCE AND DISTRIBUTION This appears to be a common topknot all around Britain and Ireland. However, there are few records from diving depths from southern England.

HOW TO USE THIS BOOK

➊ ➌ ➋ 10 m 25 m

FLATTENED FISHES ON THE SEABED – Scophthalmidae 145

➍

➊ HABITAT These icons show the habitat(s) in which species can be found. Bedrock and boulders Rocky substratum which may be vertically or horizontally inclined, or broken down into smaller pieces (boulders larger than head-size).

Wreckage Covers all artificial hard substrata (wood, metal etc.).

Sand and gravel This includes all smaller pieces of stone-derived material and small pieces of empty shells or dead maerl.

In water column (pelagic) Found in open water away from the seabed or any other features.

Close to the seabed (benthopelagic) Found in close proximity to the seabed or other features.

On or in the seabed (benthic) Lying on or buried within the seabed.

Above icons highlighted in orange indicate applicable habitats.

SIZE A guide, using parts of the human ➋ body, to the size of a typical specimen.

IDENTIFICATION CONFIDENCE ICONS ➌ Indicating the level of difficulty in identification and a guide to the appropriate level of recording for Seasearch data submissions.

to first thumb joint – 1.5–5cm

finger tip to elbow – 30–40cm

finger length – 5–10cm

finger tip to shoulder – 40–60cm

Often a close look or photo needed to check features and avoid confusion with similar species.

finger tip to wrist – 10–20cm

feet to waist – 60–100cm

Difficult to identify, photo and knowledgeable advice may be required to confirm before recording.

finger tip to mid forearm – 20–30cm

length of a body or more – 100cm plus

Should be easy to identify, potentially by sight alone.

DEPTH Shore includes the lower shore, rockpools and shallow sublittoral habitats down to about ➍ 10m depth. Mid-depth is from 10–25m depth. Deep is below 25m. 10 m 25 m

lower shore and shallow water 0–10m

mid-depth 10–25m

deep water more

Find your fish Use the outline shapes and notes below to guide you to the pages where you are most likely to find the fish you want to identify.

Unusually shaped fishes Dory p. 96

Boarfish p. 97

Seahorses pp. 248–249

Sunfish p. 57

Triggerfish p. 79

Free-swimmers, silvery shoals (mostly) in open water Herrings pp. 46–47 One short dorsal fin; deeply forked caudal fin.

Mackerel p. 50 Two dorsal fins set far apart, followed by small finlets; deeply forked caudal fin.

Horse Mackerel p. 51 Two dorsal fins set close together; forked caudal fin; conspicuous bony scales along lateral line.

Seabass p. 53 Thick-bodied and large; two dorsal fins set close together, the first spiny.

Grey mullets pp. 54–55 Two short dorsal fins set far apart; grey lengthwise stripes.

Sandeels pp. 48-49 Small and elongate; pointed snout; single long dorsal fin; forked caudal fin; swim in fluid shoals, may dive into sand.

16

FIND YOUR FISH

Sandsmelts p. 52 Small; two short dorsal fins set far apart; bright silvery/coloured line from head to tail.

Garfishes p. 56 Elongate with very long slender jaws; swims near surface.

Sharks Sharks pp. 35–43 Mouth under head; gill slits on side (no gill cover); asymmetrical caudal fin.

Angelshark – see Flattened fishes living on the seabed.

Free-swimmers near seabed, silvery or colourful Codfishes pp. 60–69 Three dorsal fins and two anal fins; most have single chin barbel.

Wrasses pp. 81–93 Mouth with thick lips; one long dorsal fin; caudal fin rounded (convex); large colourful scales.

Seabreams pp. 70–78 Deep-bodied; one long dorsal fin; slightly forked caudal fin.

Seabass and grey mullets – see Free-swimmers, silvery shoals (mostly) in open water opposite. Triggerfishes – see Unusually shaped fishes opposite.

Flattened fishes living on the seabed Skates and rays pp. 100–117 Vertically compressed; mouth and gill slits on underside; long thin tail.

Flatfishes pp. 122–145 Laterally compressed; both eyes close together on topside; fringe of fins from head to tail.

Anglerfish pp. 146–147 Vertically compressed; huge mouth with fringe of skin tassels; large fan-shaped pectoral fins; individual fin rays on back.

Angelshark p. 120 Vertically compressed; wide wing-like pectoral and pelvic fins.

Seabed-living fishes – elongate Eels pp. 260–261 One long, conjoined, continuous fin around the body; hides in holes etc.

Rocklings p. 151–155 Small; three to five barbels on snout; first dorsal fin hidden, second long.

Ling p. 156 Large; one chin barbel; two dorsal fins; first short, second long.

Tadpole Fish p. 157 Broad head, small chin barbel, prominent white lips; first of two dorsal fins minute, second long; usually only head seen.

Pipefishes pp. 240–247 Long tubular snout; body with armoured segments (not visible in some); single short dorsal fin; tiny caudal fin.

Sticklebacks pp. 250–251 One dorsal fin preceded by sharp individual spines.

Blenny-like fishes pp. 174–179 Single long dorsal fin; rounded caudal fin.

Red Bandfish p. 262 Upward-facing mouth, large eyes; one long, conjoined, continuous fin around body; red colour; lives in vertical mud burrows.

18

FIND YOUR FISH

Seabed-living fishes – small seabed sitters Blennies pp. 162–171 Eyes near top of head, head tentacles (except Shanny); one long dorsal fin; pelvic fins reduced to two long rays.

Gobies pp. 180–211 Eyes near top of broad head, no head tentacles; two dorsal fins; pelvic fins form a sucker.

Clingfishes pp. 212–217 Rather flattened triangularshaped head, eyes near top; one dorsal fin near caudal fin; pelvic fins form a sucker.

Blenny-like fishes – see Seabed-living fishes – elongate opposite.

Seabed-living fishes – medium to large seabed sitters Sea scorpions pp. 252–258 Stout body with broad, spiny head and fins; two dorsal fins.

Pogge p. 259 Body with heavy armour of plates; upturned snout, mouth fringed by short barbels, two short dorsal fins.

Gurnards pp. 230–237 Steep angular profile to armoured head; pectoral fins with three finger-like feelers; two dorsal fins.

Red Mullet pp. 160–161 Steeply rounded profile to head, a pair of long conspicuous chin barbels; two short dorsal fins.

Weeverfishes pp. 238–239 Large head with upward sloping mouth, eyes high up; first of two dorsal fins short with venomous spines, second long; usually buried in sediment.

Dragonets pp. 222–229 Flattened triangular head; two dorsal fins, the first triangular and very tall in males.

Sea snails pp. 220–221 Stout body; underslung mouth; single long dorsal fin; pelvic fins form a sucker.

Lumpsucker pp. 218–219 Stout, thick body covered with hard plates, spines and knobs; two dorsal fins, the first buried in flesh in adults.

Wolffish pp. 158–159 Huge head with protruding teeth; one long dorsal fin; usually only head visible.

Photographing fish – why Seasearch species and habitat recording relies on a combination of visual observations, note taking, photographs and video. The traffic-light identification confidence icon (see p. 15) shown in each species account indicates if a fish can be easily recognised (even without a photograph – with sufficient experience), or whether a photograph of a particular feature or characteristic is required for confirmation. Even with the latter, it may still be tricky to record beyond genus or family level. Either way, it is extremely useful to have still and/or video images of fishes undisturbed in their natural habitat. Such images show what a live, unstressed fish typically looks like and the images can be examined in comfort after the dive. Underwater footage and photos can capture both ordinary and unusual behaviours, with a good library of images for a single species or group helping tease out some identification problems. One of the persistent problems for field identification is that most fish were originally described from dead animals and the colours of a dead fish rarely give an accurate idea of colour in life (see Don’t be fooled pp. 24–27 and Eckström’s Topknot Zeugopterus regius p. 144). Similarly, dead fish cannot offer a good indication of the variability in appearance in the natural environment.

PW

20

PHOTOGRAPHING FISH – WHY

Photographing fish – how In the hands of a competent diver or snorkeller, an underwater camera can provide valuable images of many aspects of fish appearance and behaviour. The following are some ideas of how to get the best out of your images. Requirements for obtaining a good image for identification. Consider the best angle of view for your fish: top-down views of flatfish are best; most other fish are better photographed from the side, and at the same level as the fish to show body proportions and the arrangement of the fins (p. 35 sharks or p. 47 herrings).

●

Make sure the image shows critical features needed for identification. This comes with experience and knowledge of which characteristics are important. These features do not necessarily all have to be in the same image, provided the fish will stay around long enough for you to take images from different angles. For example, take top-down, full-fish views of flatfish to give an idea of overall shape (pp. 124–125), before moving in for detail of the head. If you are photographing a rockling, try to show how many barbels there are on the head (p. 150) or the detail of scale distribution on small Pomatoschistus gobies (p. 187). However, you may have only one chance to get your photograph: the image of the Scalerayed Wrasse Acantholabrus pailloni on p. 93 was the only one obtained, but clearly shows the critical features needed to identify the fish with confidence.

●

Ensure images are in focus.

●

Ensure images are well-lit – an underexposed image loses information as the exposure has to be pushed digitally.

●

Use a torch or focus light so the camera is able to focus quickly on the subject.

●

In some cases it might be helpful or critical to get an accurate estimate of the size of the fish underwater. If so, including a scale-bar or similar in one image might be a useful approach. While the subject is very likely to swim away while you position the scale-bar next to it, photographing the fish and then the same area of seabed with the scale-bar in place should be sufficient to give a good idea of size.

●

However, and above all, do not think you need to obtain a perfect image. Any photograph will be better than relying purely on memory. Not all species can be identified from photographs, but for some, even a poor photograph can be useful, especially with experience.

RG

Some species require a side-on view. The Leopard-spotted Goby Thorogobius ephippiatus requires a careful approach to avoid scaring them back into the nearby crevice.

RY

A group of Poor Cod Trisopterus minutus are often seen in these reef habitats; a side-on view allows the species to be distinguished from the similar Bib Trisopterus luscus.

LB

A top-down image of a flatfish (in this instance a Dab

22

PHOTOGRAPHING FISH – HOW

MM

The gloomy waters under a pier are a good hunting ground for a shoal of European Seabass Dicentrarchus labrax.

Remote systems It is also possible to set up remote systems which run for much longer periods of time than a diver can ever spend underwater. For example, video data have been pivotal in understanding the breeding behaviour of Black Seabream Spondyliosoma cantharus around their nests in Dorset (pp. 74–75). Cameras were deployed for a week or more, programmed to collect short video clips, especially at dawn and dusk. Images captured show territorial defence, egg-laying and subsequent care, followed by abrupt nest abandonment after hatching. Some of the images in this guide have been taken using a baited remote underwater video (BRUV) system which attracts marine life to a bait source attached to a camera stand. The resulting footage allows a close-up view of animals, including some fish species that are not amenable to being photographed by a diver. While conventional open-circuit scuba diving produces noisy bubbles and vibrations, closed-circuit rebreathers can mostly overcome this problem.

Fish welfare In line with the Seasearch philosophy of ‘look but don’t touch’, handling of even relatively tough intertidal fishes is strongly discouraged.

●

Minimise stress to the fish you are recording. For example, do not try to bring fish living in crevices out into open water. Note, too, that stress can alter the colour and general appearance of a fish.

●

If you do turn over boulders, cobbles, shells, etc. in your search for fish, whether intertidally or underwater, do remember to return them to their original arrangement before you go.

●

Keep flash images of any one fish to a minimum, ideally not more than two or three.

●

Some fish species should not be intentionally photographed without a special licence. Refer to the section on protected species (pp. 274–275) for details of the relevant legislation.

●

Don’t be fooled – identification pitfalls While the overall shape of a fish will provide the first clue to its identity (see pp. 16–19), many other features need to be considered to arrive at a firm identification. These include the number and arrangement of fins, particularly dorsal and anal fins; the shape of the lateral line; the presence and number of head and snout appendages such as barbels; and colour and colour patterns. However, some of these features need to be used with care to avoid being fooled by the fish. The most common pitfalls are described here.

Fins and barbels The number, size and shape of a fish’s fins can be very useful clues to its identity. For example, the silverycoloured European Seabass Dicentrarchus labrax has two separate dorsal fins on its back, while the similarly sized silvery Saithe Pollachius virens has three. In fact, any free-swimming fish with three separate dorsal fins, found within diving depths in British and Irish waters, will belong to the codfish family. However, care is needed when counting fins underwater as fish can, and do, raise and lower their fins at will. For example, fish will often swim with their fins folded flat, making it impossible to know how many dorsal fins they have, as illustrated by the photographs of the Rock Cook Centrolabrus exoletus.

LB

LB

Rock Cook Centrolabrus exoletus look very different with the dorsal fin lowered compared to raised.

Similarly, head barbels are a useful identification feature for some families of fish, such as codfishes (pp.  60–69), rocklings (pp. 150–155) and Red Mullet Mullus surmuletus (pp. 160–161). With rocklings, the number of chin barbels is important in separating the species. However, care is needed because if some barbels are lying flat or blend in with the head colour, it can be easy to miscount them. This is in addition to the general difficulty in counting barbels underwater. Photographs, especially close-ups of the head, are useful in this respect. However, even then the angle from which the photograph is taken may mean that not all barbels are visible and a close scrutiny of the photograph will be needed. Red Mullet, in particular, can fold either one or both of their very mobile chin barbels flat under the chin.

LM

This Red Mullet Mullus surmuletus

24

ST

This rockling clearly has five barbels, narrowing identification down to one of two species: the Northern Rockling Ciliata septentrionalis or the Five-bearded Rockling Ciliata mustela.

Colour variations Colour and particularly consistent markings, such as spots on fins and bars through the eye, can be very useful in fish identification. However, it should be remembered that colour in some species is highly variable and wide-ranging. Good examples of such natural variation are seen in seasnails Liparis spp. (pp. 220–221) and Butterfish Pholis gunnellus (pp.  174–175). Likewise, colour patterns and markings can vary in their intensity. Bib Trisopterus luscus (p.  66) provide an example of more subtle colour variants that can cause confusion. Many Bib have distinct, characteristic light and dark vertical stripes. However, both pale and dark variants without any obvious stripes at all may occur. The similar Poor Cod Trisopterus minutus (p.  67) does not usually have stripes but can display faint stripes at night. Colour and pattern may also change or be intensified LB during breeding, particularly in males (see Colour change and The bright colours on this pair of Eckström’s Topknots Zeugopterus regius do not camouflage below).

Colour change and camouflage To add to the potential confusion, many fish species also have the ability to change colour completely. They do this in order to provide camouflage in different habitats and under variable light conditions. In particular, small bottom-living fishes that live and hunt out in the open, will be targeted by larger predators and blending in with the background is one way of avoiding predation. Flatfishes, such as scaldfishes (pp. 136– 139) and topknots (pp. 142–145), have a particularly well-developed ability to adopt camouflage colours. Colour changes can also occur as part of the reproductive cycle, especially to attract a mate (or mates). Male Three-spined Sticklebacks Gasterosteus aculeatus (p. 251) are well-known for developing eye-catching red bellies and throats during the breeding season. Some fishes can be identified very easily when in their breeding colours, particularly males which, in most cases, are the ones to develop breeding colours. In dragonets (pp. 222–229), the male’s breeding colours allow confident identification to species level, while females and juveniles closely resemble each other. Even stress can cause subtle colour changes and, of course, the colour of dead fish is often radically different from that in life. Traditionally, scientific descriptions of most fishes used dead specimens. As such, they may be inaccurate where colour of fish in the field is concerned. The speed with which such colour changes occur varies from almost instantaneous and temporary, such as the white blanching of the head in male Cuckoo Wrasse Labrus mixtus (pp. 88–90) during courtship (see p. 89), to slower and long-term. If a fish moves into a particular habitat, it may slowly adapt to the colour of the seabed and surroundings. The Long-spined Sea Scorpion Taurulus bubalis is a good example, exhibiting colours ranging from predominantly red through to browns and greys, with variable darker bars and speckles. This species has a relatively small home range so, for example, an individual living on a rocky reef dominated by red algae is likely to adopt red coloration. Long-spined Sea Scorpions living in chalk areas off the Norfolk coast, are often blotched with white. Some of these variations are shown on p. 253. For the same reason – predator evasion – some fish species change their colour and patterning between night and day, making themselves less visible, especially at dawn and dusk. Some goby species appear to darken at night, while Red Mullet (pp. 160–161) become predominantly red – as they do when living at depth where red light is absent.

MM

The body colours of this Norwegian Topknot

26

Some species occupy different habitats at different stages of their life cycle and change their colour and behaviour accordingly. Juvenile rocklings (p. 150) live in shoals in open water near the surface and have greenish backs and silvery flanks. As they settle down to a seabed-living existence, their colour changes to predominantly brown. Red Mullet are similarly camouflaged when they are juveniles living above the seabed, changing to their brighter adult colours when they settle to a life on the seabed. The mechanisms behind the ability to change colour and vary the intensity of patterning in fishes, are complex. While considerable research has been undertaken, exactly how each species accomplishes such changes requires further work. With some exceptions, colour changes in fishes are relatively slow and are under hormonal control. In contrast, colour changes in fast-moving cephalopods are rapid and controlled by the animal’s nervous system. The changes are brought about by specialised cells called chromatophores, that contain different pigments and can contract and expand to reveal their colours.

LB

This Dab Limanda limanda is almost invisible on sandy sediment.

Although generally well-camouflaged against the rocks, the dark-outlined yellow oval marking of this Lemon Sole Microstomus

Fish habitats Each of the species accounts in this book carries a set of ‘habitat icons’ (see p. 15). These indicate the habitat(s) in which a particular species is normally found – an additional factor that can help with identification. The four major habitats indicated by the icons are: Rocky areas, Sediment areas, Wreckage and Water Column and are described below. Two further icons expand the spatial water column information, indicating species that live in the water column but near the seabed and species that live on the seabed.

Rocky areas Rocky areas may comprise bedrock or immobile boulders. The rock provides a hard surface for the attachment of turfs formed by animals and seaweeds. These habitats, together with the physical structures of the rock such as cracks, crevices and overhangs, can support a wide range of fish species. Intertidal and shallow rock habitats are often dominated by seaweeds, which offer shelter and refuge to many fish. Deeper water reefs may support kelp forests, with the maximum depth to which these seaweeds are found depending on location. Seaweeds need light to photosynthesise, however light penetration varies: kelp off much of the Dorset coast is limited to depths of up to 10m, while in the clearer waters off the west coasts of Ireland and Scotland, kelp can grow at over 40m. Below the limits at which seaweeds can survive, and in darker, shallower areas such as overhangs and caves, rocky areas are dominated by animals such as sponges, sea mats (bryozoans) and sea firs (hydroids). Intertidal rocky shores may have rockpools which can contain a variety of fish species such as Shanny Lipophrys pholis, Montagu’s Blenny Coryphoblennius galerita, Rock Goby Gobius paganellus and the rare Giant Goby Gobius cobitis. Large pools can even have small shoals of juvenile grey mullet Chelon spp. and European Seabass Dicentrarchus labrax in them. As the tide rises, more fish move in temporarily to the area. Some species of fish found in the subtidal tend to be confined to rocky reef habitats: the Leopard-spotted Goby Thorogobius ephipphiatus, blennies, some topknots, Bib Trisopterus luscus, Poor Cod Trisopterus minutus and Ling Molva molva. All of these take advantage of dark overhangs and deep, narrow fissures where they can rapidly hide to escape predators.

KF

A Tompot Blenny Parablennius gattorugine

28

FISH HABITATS

LB

Wrasse such as this Goldsinny Wrasse Ctenolabrus rupestris are frequently observed in this kelp- and seaweed-dominated shallow reef habitat.

Sediment Areas A wide range of habitats is covered within this category, from soft mud, coarse shell sand and maerl (see below), to so-called mixed ground (a combination of fine sediments as well as pebbles, cobbles and small boulders) and seagrass beds. While fewer divers visit sediment areas, these can be surprisingly rich in terms of the species found on and in them, including fishes.

LH

Catsharks Scyliorhinus

CB

Maerl beds are a good place to look carefully for small gobies such as this Painted Goby Pomatoschistus pictus.

As with other habitats, fish inhabiting sediment areas can be found living both on and above the seabed. However, they can be well-hidden, buried or part-buried in the sediment and also camouflaged to match the seabed. Some may be similarly concealed amongst vegetation such as seagrass or loose seaweed drifting over the sediment, which some fish can mimic in colour, form and motion. This can, therefore, be a challenging habitat in which to find fish, but familiarising yourself with their specific habitat preferences will help you to locate and identify them. Soft, muddy sediments prevail in sheltered areas and are inhabited by species such as the burrowdwelling Red Bandfish Cepola macrophthalama, many gobies, Spotted Dragonet Callionymus maculatus and skates – particularly Flapper Skate Dipturus intermedius and Thornback Skate Raja clavata. Records of muddy habitat from Seasearch divers have expanded knowledge of the distributions of some fish originally thought to have limited geographical ranges, or to be found only in deeper water, or offshore, around Britain and Ireland. Several such species have now been recorded in Scottish sea lochs including the Norway Goby Pomatoschistus norvegicus, Jeffreys’s Goby Buenia jeffreysii and Spotted Dragonet, while Steven’s Goby Gobius gastevensi, originally considered to be a southern offshore, deepwater species, is now regularly recorded as shallow as 12m on silty reefs and mixed sediments in southwest England. In some areas with reasonable current and a good supply of fine sediment, matted beds formed by several species of very small tube-dwelling amphipod crustaceans develop. These are a good place to look for flatfishes such as the Brill Scophthalmus rhombus, Turbot Scophthalmus maximus and Common Sole Solea solea for whom these areas are rich feeding grounds. In exposed sites where currents and wave action mean that the sediment is washed around, the mobile sand allows fish to conceal themselves. Many species will partially or completely bury themselves by

30

FISH HABITATS

and juvenile bony fishes (flatfishes, dragonets, weeverfishes and sandeels) and skates are found in these habitats exhibiting this hiding behaviour. In areas where the sediment is coarser and more stable (mixed ground) fish are unable to bury themselves and camouflage becomes crucial: dragonets, a whole range of gobies, Two-spotted Clingfish Diplogaster bimaculata, flatfishes and skates are well-adapted to be able to blend into this habitat. Mixed ground holds fish which are at home amongst its variable-sized material. Sea scorpions sit motionless, appearing to mimic large pebbles until their unsuspecting prey appears. As they grow, Pogge Agonus cataphractus leave the softer, sandy sediments favoured by juveniles for mixed ground, where they too will lie motionless amongst the pebbles and cobbles. Sharp eyes are needed to pick out such animals. Extensive beds of maerl cover some areas of sand and shell gravel. This seaweed consists of hard, pink lumps and twiggy growths formed by several species of red coralline algae that lie loosely and unattached on the seabed. Along with shell-rich sediments, they are important habitats for fishes including dragonets, flatfishes (especially topknots), small gobies (such as Guillet’s Goby Lebetus guilleti and the Diminuitive Goby Lebetus scorpioides, as well as the inevitable Painted Goby Pomatoschistus pictus) and many more. Maerl provides a foothold for other seaweeds and numerous invertebrates, which in turn supply food and hiding places for small fishes, many of which are impressively coloured to match the background.

Seagrass Sublittoral beds of seagrass Zostera marina can be found in well-lit areas of stable, sheltered sediment and are an important nursery area for many fishes – a factor often acknowledged by their designation as conservation areas. Look out for juvenile wrasse, Black Seabream Spondyliosoma cantharus, Pollack Pollachius pollachius, Sand Smelt Atherina presbyter and European Seabass. Some pipefishes can be considered real seagrass specialists since their shape and colour resembles seagrass. It also provides an excellent habitat for seahorses (but these should not be intentionally sought out and photographed without a licence).

MD

Wreckage and other artificial substrata This habitat includes shipwrecks and other fabricated structures such as piers and marina pontoons. It is, in many ways, not dissimilar to rocky reefs as the structures offer a stable surface which can be colonised by both seaweeds and animals, depending on depth and location. Wrecks surrounded by sediment can act as focal points attracting large shoals of fishes such as Bib and Pollack, as well as offering hiding places for species such as the Tompot Blenny Parablennius gattorugine and, of course, Conger Eels Conger conger – a classic inhabitant of so many wrecks. Piers provide a great selection of different habitats attractive to fishes, often in shallow, easily accessible water. Dark areas beneath the piers attract shoals of Bib and Poor Cod that hover just above the seabed, while shoals of Sand Smelt hang high in the water column, a target for fast-moving groups of predatory European Seabass and even the occasional Cormorant Phalacrocorax carbo. A selection of wrasse can often be seen searching for prey among the seaweeds and animal turf that grow on wreckage. Corkwing Wrasse Symphodus melops are adept at building and defending nests tucked into the corner of pier and wreck structures, while Ballan Wrasse Labrus bergylta, and, more rarely, Baillon’s Wrasse Symphodus bailloni, methodically forage in such places. As a result, these sites are often good locations for fish-watching, especially later in the season when the fishes have become habituated to the presence of snorkellers and divers. Discarded rubbish, commonly dropped off piers and pontoons and lying on the seabed, can provide nooks and crannies for a wide range of small fishes such as Tompot Blenny, Black-faced Blenny Tripterygion delaisi, Rock Goby and Two-spotted Goby Pomatoschistus flavescens, especially as it becomes covered in seaweed and invertebrates. Debris and litter, while artificial and undesirable, can provide fish habitat. While there are good arguments for collecting small items of litter, if doing so does not compromise your safety as a diver, it should always first be checked before removal. ‘Just’ an old tin can, a china mug or a polystyrene cup may be a temporary home for a small fish or other animal. Black Goby Gobius niger have been found guarding eggs in all these items.

LH

32

FISH HABITATS

Water column Life up in the water column is a challenging environment for both fishes and fish watchers (see Freeswimming silvery fishes in open water, pp. 44–57). Predators of fish can appear from all directions in this three-dimensional habitat. Spectacular shoals may materialise briefly, but the fish are often put off by divers’ bubbles – snorkellers and re-breather users excel here. It is a challenge to photograph many of these open water species, their bodies are often highly reflective and they may be nearly invisible if viewed from above. It is often difficult to get close enough to identify these fish with confidence e.g. fast moving shoals of small fish of the herring family (pp. 46–47). The Garfish Belone belone and Atlantic Saury Scomberesox saurus (p. 56), while rare, are more likely to be found by snorkellers than divers in this habitat. Large open water (pelagic) specialists do appear in this environment from time to time – e.g. Sunfish Mola mola, Basking Shark Cetorhinus maximus, Blue Shark Prionace glauca, and reward sharp eyes and attention. Snorkellers are again often at an advantage in observing these species.

LH

MD

Huge numbers of tiny fish fry (unidentifiable to species) can be seen in shallow water, here among long fronds of Mermaid’s Tresses Chorda filum.

A rare and exciting underwater sighting of an Ocean Sunfish Mola mola just below the surface. These are more commonly spotted from boats as they bask and lazily flap

MD

A Smallspotted Catshark Scyliorhinus canicula

34

SHARKS

Sharks

Class Elasmobranchii It is generally easy to recognise a shark, whether it is a species that swims in open water or one that spends most of the time lying on the seabed. Sharks have the mouth on the ventral side of the head, rather than at the end of the snout, and five pairs of gill slits on either side (six or seven in a few deepwater species). All their fins have relatively short bases and are rather stiff. The paired pelvic fins are set well back along the ventral surface instead of just behind the head, and with very few exceptions, the caudal fin is not symmetrical, with the upper caudal lobe longer than the lower. These features and others are shown in the diagram below. Like skates and rays, these are cartilaginous fishes with a pliable skeleton of cartilage rather than bone. Of the 21 species known to be present in British and Irish coastal waters all year round, seven species from five families are described in this section. Divers are most likely to encounter seabed-living species such as catsharks from the family Scyliorhinidae, but do sometimes record open water sharks (from the families Cetorhinidae, Carcharhinidae, Triakidae or Squalidae). The Angelshark Squatina squatina (family Squatinidae, pp. 120–121) is an unusually shaped, flattened shark that could, at first glance, be confused with a skate or ray and for that reason is included in Flattened fishes living on the seabed pp. 98–147. See ‘Field Guide to Sharks, Rays and Chimaeras of Europe and the Mediterranean’ in Where to find out more pp. 276–277 for full descriptions of all sharks found in European waters. first dorsal fin

lateral line eye

nostril

second dorsal fin

spiracle

anal fin

caudal fin

pelvic fin

mouth gill slits

pectoral fin

The main shark features (using Nursehound Scyliorhinus stellaris as an example).

TS

SHARKS

Cetorhinus maximus Basking Shark

(Gunnerus, 1765)

PBa

Above Basking Shark feeding at the water surface. Small Isles, Highland. Right The cavernous mouth and gills used to filter food (plankton) from the water. Porthkerris, Cornwall.

GENERAL DESCRIPTION This is a very large shark in the family Cetorhinidae. It is the largest shark in British and Irish waters and can grow to over 10m, but most are considerably smaller. It has a pointed snout, very small eyes and five huge gill slits which almost surround the head. Often it is the large, triangular first dorsal fin and the caudal fin projecting above the surface that indicate the shark’s presence. This shark is often seen swimming with its huge mouth wide open as it filters vast quantities of water for the plankton on which it feeds. Colour is typically grey to brownish and there may be mottled markings along the flanks. This is not an aggressive shark and is harmless to divers. It is an open water (pelagic) species usually seen cruising just below the surface in coastal waters and out to the edge of the continental shelf. Long-term tracking of tagged sharks shows movements covering thousands of kilometres and descending to depths of well over 1,000m (see Basking Shark recording opposite). KEY FEATURES A large shark cruising just below the water surface with its huge mouth wide open. SIMILAR SPECIES None. ABUNDANCE AND DISTRIBUTION This shark typically appears off western coasts of Britain and Ireland and in the Irish Sea between May and October, with a few reports also from eastern English and Scottish coasts. Classified as Endangered, it has

36

SHARKS – Cetorhinidae

SS

10 m 25 m

Basking Shark recording In the twentieth century, Basking Sharks were targeted for the valuable oils which could be extracted from their huge livers, and were hunted almost to local extinction in the seas around Britain and Ireland. Today, the Basking Shark is protected in waters around Britain, Ireland and the Isle of Man. Since the early 2000s, studies of individual sharks, using photo recognition of unique marks on the dorsal and caudal fins and, more recently, using satellite tagging, have provided information on the seasonal migrations of Basking Sharks and identified regional hotspots for this species in British and Irish waters. These studies have revealed the seasonal migrations of the Basking Shark in the northeast Atlantic. Sharks tagged in the Sea of the Hebrides, western Scotland, occupied shallow coastal waters in the summer months (July to September), moving to deeper continental shelf waters from autumn onwards. The Celtic and Irish seas are an important corridor for sharks moving between hotspots off southwest England (Cornwall), the Isle of Man and the Sea of the Hebrides. Autumn migrations see some sharks off the west coast of Ireland, in the Bay of Biscay and as far south as Morocco. Others remain close to Scotland throughout the winter. The work carried out from 2012–2014 showed an estimated population of about 200 sharks in an area between the Scottish islands of Mull, Coll and Tiree during that period, with some individuals showing site fidelity. This area has now been designated the Sea of the Hebrides Marine Protected Area (MPA) by the Scottish Government, with the Basking Shark one of the key protected features in the MPA. The tracking of individuals shows the sharks routinely swim large distances. A female Basking Shark tagged off the north coast of Donegal, Ireland, was reported 33 days later to the west of the Isle of Barra in the Outer Hebrides, before reappearing nearly three years later off the coast of Massachusetts, USA, having travelled a straight-line distance of over 4,600km. A four-year study of Basking Sharks tagged off the west coast of Scotland and the Isle of Man showed the sharks moving straight-line distances of over 3,600km in the autumn. While most remain in waters around Britain and Ireland, others moved to the Bay of Biscay or even further south off the coasts of Spain, Portugal and Morocco. Migration takes place in the upper 50–200m of the water column, with occasional excursions to depths of over 1,000m.

NP

SHARKS

Prionace glauca Blue Shark

(Linnaeus, 1758)

MD

A Blue Shark twists away from the photographer showing its long pectoral fins and white-rimmed black eyes. Cornwall.

GENERAL DESCRIPTION Even a glimpse of this graceful shark underwater should be enough for identification. With a slim streamlined body and long pointed snout, the Blue Shark has evolved for sustained swimming. It has exceptionally long pectoral fins, a tall upper caudal lobe, two dorsal fins and an anal fin. The large, black eyes are characteristically rimmed with white, while the upper body is a deep blue, as is suggested by both vernacular and scientific names (‘glauca’ means bluish grey). Like any large predator, this shark should be treated with respect and caution. Constantly on the move searching for fish and squid prey, they have been known to investigate other moving objects – such as divers and boats. KEY FEATURES Pelagic, blue-backed shark with a long snout, white-rimmed eyes and long, blue pectoral fins. SIMILAR SPECIES Porbeagle Lamna nasus and Shortfin Mako Isurus oxyrinchus, but unlikely to be confused, unless seen from a distance. These two species are from a different family (Lamnidae rather than Carcharhinidae) and are not covered separately here. ABUNDANCE AND DISTRIBUTION This is a migratory species that makes complex, trans-Atlantic journeys between feeding and pupping areas. Inshore sightings are rare and divers or snorkellers will usually see them near the surface in summer on targeted boat trips, mostly in the southwest of Britain (especially Cornwall) and Ireland. These sightings can be recorded on a Seasearch form but the circumstances should be highlighted as the abundance of animals in the area will be skewed by the food provided. Once immensely abundant, the Blue Shark is now listed as Near

38

SHARKS – Carcharhinidae

10 m 25 m

Squalus acanthias Spurdog

Linnaeus, 1758

JL

Above A Spurdog uncharacteristically photographed in reef habitat. Note the sparse, rather large white spots on the flank of the shark. Loch Etive, Argyll & Bute. Right First dorsal fin showing the prominent spine at the front. Loch Slapin, Skye.

VC

GENERAL DESCRIPTION This small, slim dogfish shark (family Squalidae) grows to not more than c. 1.2m in length. Both dorsal fins have a spine in front of them, with the first dorsal fin spine shorter than the second. Unlike most other sharks, Spurdog do not have an anal fin. The paired pelvic fins are set well back on the body just in front of the second dorsal. Colour is dark grey with a pale underside and sparse, large white spots on the dorsal surface and flanks which may be inconspicuous in older fish. This is a long-lived, slow-growing species with a maximum reported age of 75 years and bears live young. This seabed-living shark is generally found in soft sediment areas rather than around reefs, in water depths from 20m to over 200m. KEY FEATURES A prominent spine in front of both the first and second dorsal fins. No anal fin. SIMLAR SPECIES The Starry Smoothhound (p. 41) lacks the spines in front of the dorsal fins and it has an anal fin. Smoothhounds (houndsharks) are in the family Triakidae (see also Tope, p. 40). ABUNDANCE AND DISTRIBUTION The Spurdog has a predominantly western distribution around Britain with scattered reports from Scotland and East Anglia. There are many records from the Irish Sea and it occurs throughout Irish waters but is only occasionally seen by divers. The Spurdog is listed as Endangered throughout its European range.

10 m 25 m

Galeorhinus galeus Tope

(Linnaeus, 1758)

CH

Above This close view shows the plain grey colour of the upperside, the paired pelvic fins and the anal fin set well back near the lower caudal fin. Off Clovelly, north Devon. Left A small Tope swims swiftly past a baited video camera. Jersey, Channel Islands.

SBi

GENERAL DESCRIPTION This small shark has a pointed, moderately long snout and two dorsal fins, the second much smaller than the first (less than half the height). Like other sharks, it has an asymmetrical caudal fin, although Tope have a prominent, triangular lower caudal lobe. It is usually a dull, uniform, predominantly grey colour, perhaps with brown overtones on the dorsal surface and flanks; lighter underneath. Tope hunt for small fishes in midwater and crustaceans and molluscs on the seabed. They can be found in small groups which is why the species is also known as the School Shark. KEY FEATURES Slender, greyish shark with a small and inconspicuous second dorsal fin. SIMILAR SPECIES Smoothhounds (opposite) are similar in size and colour, but their two dorsal fins are similar in height. Smoothhounds also prefer to remain on or near the seabed, only occasionally being seen in midwater. Spurdog (p. 39) have prominent dorsal spines and lack the anal fin seen underneath the second dorsal in Tope. ABUNDANCE AND DISTRIBUTION Found all round Britain and Ireland, generally in water less than 50m deep, with some southward migration for the winter. Classified as Vulnerable in European waters.

40

SHARKS – Triakidae

adult

juvenile

10 m 25 m

Mustelus asterias Starry Smoothhound

Cloquet, 1819

SD

Above Note the characteristic small white spots scattered on the head and dorsal surface. Sark, Channel Islands. Right Showing the large golden eye with black pupil. Kimmeridge, Dorset. LB

GENERAL DESCRIPTION This small, slender shark grows up to 1.4m in length. The two almost identically sized dorsal fins are large for the size of the fish and there is an anal fin immediately below the second dorsal. It is a steel grey or brownish colour with a scatter of numerous small, evenly sized white spots on the dorsal surface and upper flanks above the lateral line. The eye is golden or yellowish. It gives birth to live young and can reach 20 years old. This shark occurs on sandy, gravelly seabeds and it may also be seen in rocky areas in water depths from less than 5m to over 500m. KEY FEATURES First and second dorsal fins about the same size. Anal fin present. Numerous white spots on dorsal surface. Golden or yellowish eye. SIMILAR SPECIES Spurdog (p. 39) have a large spine at the front of each dorsal fin and lack an anal fin. The Smoothhound Mustelus mustelus (not described separately) is an almost identical species but lacks spots. However, there is considerable confusion between the two smoothhounds: if the description fits, but white spots are lacking, then record as ‘Mustelus sp’. ABUNDANCE AND DISTRIBUTION This fairly common shark has a western and southern distribution around England as far north as East Anglia. It is also found around Wales, with many records from all throughout the Irish Sea, as well as a few reports from western Ireland. In European waters, Mustelus asterias is listed as Near Threatened, while Mustelus mustelus is listed as Vulnerable.

10 m 25 m

Scyliorhinidae Catsharks Catsharks have a long body with two small dorsal fins set well back, both behind the pelvic fins, unlike most other sharks whose first dorsal fin is postioned well before the pelvic fins. They are often found lying on the seabed, in a very wide range of habitats. These small sharks have long been known as dogfish which is technically incorrect. Although this is a huge, worldwide family, only two species are generally found within diving depths around Britain and Ireland; these are described in detail below. Recently hatched juvenile catsharks are very pale in colour with indistinct darker spots and bands and it is not possible to distinguish the two species at this stage in their development (see p. 35). They take on adult characteristics at about 20cm in length.

Scyliorhinus canicula Smallspotted Catshark

(Linnaeus, 1758)

LM

RY

Main Larger spots on the fins contrast with small spots all over the body. Loch Sunart, Highland. Inset The almost black eye typical of this species. Isle of Man.

GENERAL DESCRIPTION Formerly known as the Lesserspotted Dogfish. This is a slim, lightly built catshark which grows to about 1m in length. Background colour is generally pale brown or grey over which many small, dark brown, grey or almost black spots are densely scattered all over the body. Some spots on the fins are larger than those on the body. Adults have very dark, almost black eyes. This catshark can be found lying on the seabed in a wide range of habitats from very shallow water to depths of over 450m. KEY FEATURES Long, slim, seabed-living shark with two small dorsal fins set well back. Covered in small dark spots, larger spots on fins. SIMILAR SPECIES The Nursehound is a more heavily built shark with fewer, larger spots. ABUNDANCE AND DISTRIBUTION The Smallspotted Catshark is common and found all around British and Irish coasts, although there are fewer records from the east coasts of England and Scotland.

42

SHARKS – Scyliorhinidae

10 m 25 m

Scyliorhinus stellaris Nursehound

(Linnaeus, 1758) LB

Above Large spots on all fins and over the body characterise this catshark. Falmouth, Cornwall. Right The greenish amber eye colour. Lyme Bay, Dorset. RG

GENERAL DESCRIPTION Also known as the Greaterspotted Catshark or Bull Huss, this catshark grows to a maximum length of just over 160cm and has a stocky, solid looking body with a blunt snout. Background colour is generally light greyish or brownish and there are large, dark brown spots all over the body and fins. Some spots may merge into blotches or may be in closely set groups of three or four spots. Spots on the fins are a similar size to those on the body. The eye colour is greenish or amber. This catshark can be found lying on the seabed in a wide range of habitats from about 10m to over 350m. KEY FEATURES Long, stocky body with two small dorsal fins set well back. Covered in large, dark spots and blotches which are the same size on the body and fins. SIMILAR SPECIES Smallspotted Catshark, but a catshark over about 100cm in length is likely to be a Nursehound. The main distinctions between the two species are size of spots and eye colour. ABUNDANCE AND DISTRIBUTION The Nursehound is less commonly recorded by divers than the Smallspotted Catshark and has a southwest distribution in Britain and Ireland with numerous records from the Irish Sea. Classified as Near Threatened in European waters.

CB

A juvenile showing that even small individuals about 20cm in length can be confidently identified. Off Folkestone, Kent.

10 m 25 m

PBa

A close approach to a silvery shoal of Atlantic Horse Mackerel

44

FREE-SWIMMING SILVERY FISHES IN OPEN WATER

Free-swimming silvery fishes in open water Hanging about in midwater is not something most divers do much of – except perhaps on decompression and safety stops. However, many fishes spend their entire lives swimming and feeding in open water, leading a so-called ‘pelagic’ existence, with little if any connection to the seabed. With nowhere to hide, most live within the protection of large shoals or schools and are camouflaged by ‘countershading’ with a darker dorsal surface and silvery white ventral surface. Flowing, silvery shoals of small fishes such as herring, mackerel and sandeels are not easy to identify. Photographs always help (even to confirm that a positive identification is not possible). Noting behaviour is also helpful e.g. the sinuous swimming of sandeels. Not all pelagic fishes live in large shoals in open water, especially those not reliant on plankton for food. For example, European Seabass Dicentrarchus labrax are predatory fish and small schools often hunt in the vicinity of rocky reefs. Open water sharks have no need for the protection provided by shoaling, but countershading helps disguise them from their prey.

PBa

A shoal of Atlantic Horse Mackerel Trachurus trachurus

FREE-SWIMMING SILVERY FISHES IN OPEN WATER

Clupea harengus Atlantic Herring

Linnaeus, 1758

Above A shoal of Atlantic Herring Clupea harengus seen from below in a cave. Scotland. Right Unmistakably an Atlantic Herring with all the distinguishing characteristics clearly visible.

GENERAL DESCRIPTION Almost always encountered in shoals, the Atlantic Herring is a slender, highly reflective, silvery fish with a laterally compressed body. It has a prominent, up-curved lower jaw, a single short dorsal fin about half way along the dorsal surface, a deeply forked caudal fin and no visible lateral line. The dorsal surface is a dark, greenish blue, with flanks and ventral surface being silvery white. The other three common herring-like species (Sprat, Pilchard and Anchovy, see opposite) found around Britain and Ireland have broadly the same shape and appearance as Atlantic Herring, although the latter can be much larger, reaching up to 40cm. There are also subtle differences in colouring (Atlantic Herring and Pilchard tend towards green, whereas Sprat and Anchovy are more blue). If identity is uncertain, record as ‘Clupeiformes’ or ‘shoals of small silvery fishes’. KEY FEATURES Intensely silvery fish that live and swim in shoals in open water. Single short dorsal fin (very difficult to see underwater). Grows much larger than Sprat, Pilchard or Anchovy. SIMILAR SPECIES The four common species of herrings (Clupeiformes) found around Britain and Ireland (Herring, Sprat, Pilchard and Anchovy) are very difficult to tell apart. Only Atlantic Herring grow larger than 20cm. The shoals of juveniles commonly seen in sheltered bays are usually undistinguishable from the other three species to divers underwater. Sand Smelt in shoals looks similar, but has a distinct iridescent or dark line along its flanks (two dorsal fins but rarely visible in shoaling fish). ABUNDANCE AND DISTRIBUTION Common all around Britain and Ireland, but as they live in open water, shoals are rarely encountered by divers. Shoals of juveniles frequent sheltered bays. 10 m

25 m

46

Sprattus sprattus Atlantic Sprat Sardina pilchardus European Pilchard Engraulis encrasicolus European Anchovy

(Linnaeus, 1758) (Walbaum, 1792) (Linnaeus, 1758)

Atlantic Herring

toothed keel (juveniles only)

FD

Atlantic Sprat

toothed keel

European Pilchard

ridges on gill cover

European Anchovy JaG

Top An Atlantic Sprat in a rockpool. Aberystwyth, Ceredigion. Above Shoal of Atlantic Sprat. Loch Carron, Highland.

shorter lower jaw

mouth well behind eye

GENERAL DESCRIPTION These three species are all small, silvery, shoaling fishes and share most of the characteristics of their larger relative, the Atlantic Herring (opposite). Shoals of ‘herring’ are very difficult to tell apart underwater, but if a close-up photograph of an individual or individuals is achieved, a clear, side-on view may allow identification beyond family level, using the features shown above. Shoals swimming near the bottom may flow round a stationery diver (until they exhale). At night, individuals may be more scattered and swim near the seabed, giving better photographic opportunities. KEY FEATURES AND SIMILAR SPECIES Atlantic Sprat Sprattus sprattus Very similar to, but smaller than Atlantic Herring and less likely to be seen inshore than juveniles of the latter. Dorsal surface a brighter blue than the greenish tinge seen in Atlantic Herring. European Pilchard (Sardine) Sardina pilchardus Many (but not all) have a line of dark spots running along the flanks more or less in line with the eyes (these rarely group show up underwater). Dorsal surface generally greenish. The gill cover has clear ridges radiating across it from behind the eye. European Anchovy Engraulis encrasicolus Closely related to herrings but belongs species to a different family (Engraulidae). A slender-bodied fish with a conical snout – the result of the lower jaw being much shorter than the upper; neither Sprat nor Pilchard have such an underslung jaw. The large mouth reaches well back behind the eyes. Colour silvery with a blue dorsal surface (sometimes called Blue Anchovy). ABUNDANCE AND DISTRIBUTION All three species are common all around Britain 10 m

25 m

Ammodytidae Sandeels

RY

The large size of these sandeels indicates they are probably greater sandeels Hyperoplus sp. Jersey, Channel Islands.

GENERAL DESCRIPTION Shoals of silvery sandeels are generally seen swimming close to, or some metres above, sandy areas of seabed. When close to the bottom they have a habit of diving head-first into the sand if approached. The five species are all long, slim fish, slightly laterally compressed, with a protruding lower jaw forming a pointed snout. The caudal fin is forked and a single dorsal fin runs nearly the length of the body. While the species can rarely be identified underwater, the arrow-like shape and behaviour should allow recording as ‘Ammodytidae’. With a closer look and experience, the two ‘greater’ sandeels can be distinguished from the three ‘lesser’ sandeel species by their larger size.

Greater sandeels Hyperoplus lanceolatus (Le Sauvage, 1824) Hyperoplus immaculatus, also known as Corbin’s Sandeel, (Corbin, 1950). Any sandeel longer than 25cm or so can be recorded as ‘Hyperoplus sp’. Hyperoplus lanceolatus has a black spot on either side of the snout (visible in reasonably close-up photographs) and is the one normally encountered in shallow water.

Lesser sandeels Ammodytes tobianus Linnaeus, 1758 Ammodytes marinus, also known as Raitt’s Sandeel, Raitt, 1934 Gymnammodytes semisquamatus Smooth Sandeel (Jourdain, 1879) Small sandeels under 25cm long should be recorded as ‘Ammodytidae’ because they cannot be identified to species underwater and may be lesser sandeels or the young of greater sandeels.

48

SS

A sandeel pokes its head out after diving

Ammodytidae Sandeels

(continued)

CP

Sandeels over seagrass, includes a single Sprat Sprattus sprattus. Portland, Dorset.

KEY FEATURES Long thin silvery fish, with a pointed snout that swim sinuously in shoals over sandy areas. May dive into the sand. SIMILAR SPECIES Other small silvery shoaling fish such as Sand Smelt (p. 52) or Sprat (p. 47), but the elongated shape of sandeels and their sinuous swimming motion should allow this family to be identified. ABUNDANCE AND DISTRIBUTION The species differ in detailed abundance and distribution from north to south in Britain and Ireland. In general, however, sandeels are common around all coasts.

group

species

ID

10 m 25 m

Scomber scombrus Atlantic Mackerel

Linnaeus, 1758

Above A school of Atlantic Mackerel feeding at the surface. The pattern on the dorsal surface is distinctive, even at a distance. Coll, Inner Hebrides. Right An uncommon close encounter. St Abbs, Berwickshire.

GENERAL DESCRIPTION Like other members of its family (Scombridae), the fastswimming Atlantic Mackerel has a streamlined, spindle-shaped (rounded in crosssection and tapering at both ends) body, a narrow caudal peduncle and a deeply forked caudal fin. The second of the two widely separated dorsal fins is followed by a series of five small finlets, not easy to see underwater. Along the dorsal surface, above the lateral line, is a distinctive pattern of dark, zebra-like lines, on an iridescent blue to green background. Usually swimming in shoals and always aware of potential predators, Atlantic Mackerel are not easy to approach. KEY FEATURES A slim fish with a distinctive pattern of dark, wavy lines on the dorsal surface and a silvery white ventral surface. Usually seen in open water, sometimes above kelp forests. SIMILAR SPECIES The unrelated Atlantic Horse Mackerel (opposite) is a similar shoaling species but has a distinctive dip in the lateral line and a black spot on the gill cover. Atlantic Chub Mackerel Scomber colias (not described separately) is an occasional southern vagrant but rarely comes inshore. ABUNDANCE AND DISTRIBUTION Although rarely seen by divers, this is a very

50

PBa

10 m 25 m

Trachurus trachurus Atlantic Horse Mackerel

(Linnaeus, 1758)

PBa

The lateral line, with its distinctive sharp dip, and vertical ridges below is clearly visible in this image. Tory Island, Donegal.

GENERAL DESCRIPTION The Atlantic Horse Mackerel has a streamlined shape, forked caudal fin and narrow caudal peduncle, all designed for fast swimming. The lateral line is distinct and has wide, bony scales (scutes) that show up most clearly after the point at which it dips down. The two dorsal fins are not easy to see underwater, but are set close together, the second one longer, with a higher front section. The pectoral fins are long, exceeding the length of the head. The colour is a uniform silver (especially in juveniles), with a dark blue-black dorsal surface and a rounded black spot on the rear top edge of the gill cover. Despite its vernacular name, this species is in the family Carangidae, not Scombridae. This is a shoaling fish, with adults mostly found offshore and young commonly closer inshore. Juveniles are well-known for sheltering beneath the tentacles of large, stinging jellyfish such as the Lion’s Mane Cyanea capillata, as are Whiting (p. 68). KEY FEATURES A mackerel lookalike, but with an obvious lateral line that dips distinctively downwards under the second dorsal fin, from which point the wide bony scales show up clearly. A usually conspicuous black spot on gill cover. SIMILAR SPECIES Atlantic Mackerel, although Atlantic Horse Mackerel lack the distinctive patterning of wavy dark lines seen in the former. The similar Mediterranean Horse Mackerel Trachurus mediterraneus (not described separately) has not yet been recorded in British or Irish waters. ABUNDANCE AND DISTRIBUTION Rarely seen by divers but found all around Britain

10 m 25 m

Atherina presbyter Sand Smelt

Cuvier, 1829

MM

LB

Top A group of Sand Smelt together during the day, showing the broad, dark stripe along the flank. Swanage, Dorset. Above A fish close to the seabed at night. Weymouth, Dorset

GENERAL DESCRIPTION This is a small silvery fish which swims in leisurely shoals in shallow water. These shoals are not quite as skittish as Sprat or Herring and will often quietly disperse and reform as a diver passes by. Seen side-on, the most noticeable feature is a broad, dark stripe along the flank, which may appear iridescent. This stripe separates a darker, also iridescent, dorsal surface from highly reflective, silver flanks below the stripe (these fish are often called ‘silversides’). Less easy to see underwater are the forked caudal fin, oblique mouth and two short, widely separated dorsal fins, although these may show up in a photograph. On a night dive, individuals can often be seen resting quietly on or near the bottom and this is when close-up photographs can be taken. KEY FEATURES Small, slender fish with iridescent green/blue silvery line along both flanks. Two widely separated dorsal fins. SIMILAR SPECIES Atlantic Sprat (p. 47) and juvenile Atlantic Herring (p. 46) look very similar, especially when viewed from above, but have only a single dorsal fin. However, Sand Smelt often swim with the first dorsal fin folded down which can cause confusion. ABUNDANCE AND DISTRIBUTION Sand Smelt are much more common on south and west coasts of Britain and around Ireland than elsewhere. They are found in sheltered inshore waters (including estuaries and harbours) in summer and move into warmer offshore waters in winter.

52

Dicentrarchus labrax European Seabass

(Linnaeus, 1758)

SD

Above The large silvery scales, darker on the dorsal surface, and lateral line show up clearly on this fish. Sark, Channel Islands. Left These fish are often seen in large shoals, as here in Sark, Channel Islands.

SD

GENERAL DESCRIPTION Also known as Bass. European Seabass are thick-bodied but still streamlined and these brilliantly silver fish can disappear with a flick of their large caudal fin. The two dorsal fins are set so close together that they may appear as one, until the fish erects them. The first dorsal fin consists of sharp spines while the second is soft. Large scales and a clearly defined lateral line are obvious even from some distance away. Although essentially silver all over, the dorsal surface has a darker greyish blue hue and the ventral surface is silvery white. There is often a dark blotch at the top edge of the gill cover but this can be very indistinct. Juveniles have scattered black spots, mostly above the lateral line. European Seabass appear to be very wary of any potential predator and, as such, tend to keep at a distance from divers, often hovering at the limit of visibility. KEY FEATURES Thick-bodied, solid, silvery fish with distinct scales and two close-set dorsal fins. SIMILAR SPECIES Similarly shaped grey mullets (pp. 54–55; family Mugilidae) also have obvious scales and two dorsal fins, but while they can appear silvery, they are much duller and distinctively striped along the flanks. They also have much smaller, blunter mouths. ABUNDANCE AND DISTRIBUTION European Seabass occur all around Britain and Ireland. Generally seen singly or in small groups, often close inshore, including in estuaries, during summer. Larger shoals are mostly found offshore but it is not unusual for divers to see shoals of 50–100 fish.

Mugilidae Grey mullets

CB

Dark grey, longitudinal stripes and large scales identify this fish, foraging in the sand, as a species of grey mullet. The relatively chunky body suggests that this is a Thicklip Grey Mullet, despite the golden colour on the gill cover, which is sometimes found in this species as well as in Golden Grey Mullet. Swanage, Dorset.

GENERAL DESCRIPTION The grey mullets are a large family of silvery grey, torpedo-shaped fishes. The three species that occur around Britain and Ireland all have distinctive grey stripes along the body and large scales – both features usually showing up clearly underwater. They have two well-separated, short-based dorsal fins and, at close quarters, the first dorsal can be seen to consist of only four spines. They have neat, ‘pursed’ mouths and, while they feed mostly on organic material from the seabed, they can frequently be seen taking floating detritus at the surface in places such as marinas. Divers are rarely in a position to tell the species apart underwater and so should record them as Chelon sp., unless a good photograph allows identification to species level. Chelon labrosus Thicklip Grey Mullet (Risso, 1827) Likely to be the most common species seen by divers. It has a very broad upper lip fringed with a moustache of small papillae (see photo opposite). As with Golden Grey Mullet, there may occasionally be a patch of golden colour on the gill cover but Thicklip Grey Mullet is a more heavily built fish. Chelon auratus Golden Grey Mullet (Risso, 1810) Has a golden yellow patch near the top of the gill cover and a thin upper lip. Chelon ramada Thinlip Grey Mullet (Risso, 1827) Has a dark spot at the base of the pectoral fins and a thin upper lip.

CP

54

A grey mullet over a seagrass bed. Portland,

Mugilidae Grey mullets

(continued)

SM

Above The characteristic thick upper lip of a Thicklip Grey Mullet. Helford Estuary, Cornwall.

Thinlip Grey Mullet

Thicklip Grey Mullet

Grey mullets are frequently found in shallow water in sheltered bays, harbours, marinas and estuaries where there is plenty of algae and detritus for them to graze. KEY FEATURES Torpedo-shaped, silvery fishes with longitudinal grey stripes, distinct scales and two widely spaced dorsal fins. SIMILAR SPECIES European Seabass (p. 53) are similar in size and colour, but far more silvery and lack the distinctive, longitudinal stripes of grey mullets. European Seabass also have a larger mouth. ABUNDANCE AND DISTRIBUTION Grey mullets are essentially warm-water fish and are most common in the southern half of Britain and Ireland in summer. Thicklip Grey Mullet are found around most of Britain and Ireland. Golden Grey Mullet have a similar wide distribution, but are much scarcer and only ever common in southern areas. Thinlip Grey Mullet are mainly a summer visitor from further south and can be

Belone belone Garfish Scomberesox saurus Atlantic Saury

(Linnaeus, 1760) (Walbaum, 1792)

JoB

Garfish

no finlets

LB

Top A shoal of Garfish in shallow water. Above left A stranded Atlantic Saury showing the row of finlets in front of the caudal fin which distinguish it from Garfish. Waterville, Kerry. Above right Even a fleeting glimpse and a photograph of the head can identify a Garfish. Portland, Dorset.

Atlantic Saury

GENERAL DESCRIPTION Both of these species (of the order Beloniformes) are extremely thin, elongated, needle-shaped fish with greatly extended jaws that form a flexible beak. The Garfish has a very short dorsal and anal fin set far back on the body, just in front of the caudal fin. In contrast, the Atlantic Saury has a series of small finlets between the caudal fin and both the dorsal and anal fins. Both species have deep green or metallic blue dorsal surfaces, with bright white ventral surfaces. These fish are most likely to be seen by snorkellers as they are found just below the surface as they move inshore during the summer, often associated with shoals of Atlantic Mackerel (p. 50). KEY FEATURES The very long, needle-like jaws are unlike those of any other fishes in British and Irish waters. SIMILAR SPECIES The Short-beaked Garfish Belone svetovidovi (not described sepa­ rately), only recently distinguished from the Garfish, has a shorter beak than either of the other two fish and occurs sporadically off the south coast of Ireland and off Cornwall. It is not likely to be distinguishable in the field, even with good photographs. ABUNDANCE AND DISTRIBUTION The Garfish is relatively common in the south and west of Britain and Ireland, less so off the North Sea coasts of Scotland and England. In contrast, the Atlantic Saury has an oceanic distribution, generally avoiding nearshore areas but can often be found stranded on beaches in the south and west of Britain and Ireland in late autumn and early winter. There was a record from Orkney in autumn 2022.

56

series of finlets between dorsal and anal fins and caudal fin.

Mola mola Ocean Sunfish

(Linnaeus, 1758)

PBa

A rare diver encounter with an Ocean Sunfish, searching for jellyfish near the surface. Horn Head, Donegal.

GENERAL DESCRIPTION While another species of sunfish (Bumphead Sunfish Mola alexandrini), has now taken the title of the world’s heaviest bony fish, the Ocean Sunfish is still an impressive giant. Divers very rarely encounter it underwater but, if seen, it is unmistakable. Sunfish are shaped like a huge disc and do not have a typical caudal fin, but instead have a rounded and often scalloped structure called a clavus. Its only fins are small pectoral fins on each side behind the gill cover, a very tall triangular dorsal fin, and a similar-shaped anal fin – both positioned far back just in front of the clavus. The colour is a blue-grey, plain or sometimes with irregular white blotches. KEY FEATURES Large open-water fish with a disc-shaped body, tall paddle-like dorsal and anal fins and no defined tail. SIMILAR SPECIES Of the four other sunfish species, only the Slender Sunfish Ranzania laevis (not described separately) has been recorded in British and Irish waters, on a handful of occasions prior to 2000. This species is much smaller and more oblong in shape. Sharptail Sunfish Masturus lanceolatus, Bumphead Sunfish and Hoodwinker Ocean Sunfish Mola tecta (only recently described in 2017) only occur further south, the latter in the southern hemisphere. ABUNDANCE AND DISTRIBUTION While this is the most widespread sunfish in the world and has been recorded all around Britain and Ireland, most records are from boats. Divers do very occasionally see these fish though, and more records are

10 m 25 m

MD

A shoal of strongly marked Bib Trisopterus luscus

58

FREE-SWIMMING SILVERY FISHES NEAR THE SEABED

Free-swimming silvery fishes near the seabed A diver finning gently along a few metres above the seabed is likely to see a variety of fishes that live neither on the seabed (pp. 98–265) nor up and out in open water (pp. 44–57). Instead, these fishes spend most time swimming in the few tens of metres above the seabed. Like open-water fishes, they swim all the time and so have a relatively streamlined and fairly standard, tapering body shape. In contrast, fishes living on the seabed are more varied in shape, with adaptations such as the flattened bodies of flatfishes and skates. Many of these silvery fishes will be encountered as individuals or in small groups within kelp forests and around rocky reefs and wrecks. Others prefer to feed over mixed ground and sediments. Divers generally see individuals or small shoals around rocky reefs during the day. However, some species, such as Saithe Pollachius virens, may disperse at night over the sand to hunt for sandeels. Large shoals of Saithe, Atlantic Cod Gadus morhua and others may also hunt in midwater. The majority of these predominantly silvery fishes belong to the codfish family (pp. 60–69) and seabreams (pp. 70–78). Codfishes and seabreams often spend time out in the open, sometimes well above the seabed and so many species are camouflaged by ‘countershading’, with a darker dorsal surface and silvery white ventral surface, in the same way as are truly open water (pelagic) species (pp. 44–57). Some seabed-living (benthic) fishes such as Red Mullet Mullus surmuletus (pp. 160–161) are also free-swimmers above the seabed when they are small juveniles.

LB

A small shoal of paler, more uniformly coloured Bib Trisopterus luscus over a reef with Pink Sea Fans Eunicella verrucosa. Lyme Bay, Dorset.

FREE-SWIMMING SILVERY FISHES NEAR THE SEABED

Gadidae Codfishes Codfishes (Gadidae), also known as gadoids, have three dorsal and two anal fins. The paired pelvic fins on the ventral surface lie under, or just behind, the head, and always begin in front of the pectoral fins (see illustration below). Colour is variable but most have a metallic, silvery sheen. Many, but not all, species have a chin barbel (see table below). These variously mottled and metallic looking silvery fish are found in both coastal and offshore waters, where they live and feed in the water column, predominantly near to the seabed. This family includes some of the most commercially valuable species in the North Atlantic, such as the Atlantic Cod Gadus morhua, as well as some much smaller species. Seven species are likely to be seen by divers around Britain and Ireland and are described in the following pages: Atlantic Cod Gadus morhua, Haddock Melanogrammus aeglefinus, Pollack Pollachius pollachius, Saithe Pollachius virens, Bib Trisopterus luscus, Poor Cod Trisopterus minutus and Whiting Merlangius merlangus. There are a number of other codfishes found in British and Irish waters, such as Norway Pout Trisopterus esmarkii and Blue Whiting Micromesistius poutassou, but these are largely offshore species and so are not included here. three dorsal fins pectoral fin eye (large)

upper jaw

barbel lower jaw

caudal fin

gill cover pelvic fin

two anal fins

lateral line (curved)

The main codfish family features (using Atlantic Cod Gadus morhua as an example).

Chin barbel

Jaws

Lateral line

Black spot base of pectoral fin

Atlantic Cod Gadus morhua

Long

Upper overhangs

Gentle curve, white

No

Haddock Melanogrammus aeglefinus

Short

Upper overhangs

Gentle curve, black

No

Pollack Pollachius pollachius

None

Lower protrudes

Strong curve, dark

No

Saithe Pollachius virens

None

Almost equal

Almost straight, pale

No

Bib Trisopterus luscus

Long

Upper overhangs

Curved

Yes, large

Poor Cod Trisopterus minutus

Long

Upper overhangs

Curved

Some

None (or minute)

Upper overhangs

Gentle curve

Yes

Species

Whiting Merlangius merlangus

60

Other features

Large black blotch on flank

Large eyes

Codfish head gallery PBa

Atlantic Cod Gadus morhua p. 62

OST

Haddock Melanogrammus aeglefinus p. 63 LB

Pollack Pollachius pollachius p. 64

LB

Saithe Pollachius virens p. 65 LB

Bib Trisopterus luscus p. 66

Poor Cod Trisopterus minutus p. 67 ST

Whiting Merlangius merlangus p. 68

LB

A gallery of the seven codfish family species likely to be seen by divers around Britain and Ireland, showing the head similarities and differences (see also table opposite).

Gadus morhua Atlantic Cod

Linnaeus, 1758

PBa

Above Atlantic Cod clearly showing the long, white barbel on the chin and three distinct dorsal fins. Loch Long, Argyll & Bute. Right Juvenile Atlantic Cod showing reddish chequered markings. Loch Long, Argyll & Bute. PBa

GENERAL DESCRIPTION Atlantic Cod is a familiar fish to many people through its popularity as a food fish. An adult Atlantic Cod is a solid-looking fish with a large head, an overhanging upper jaw and a prominent chin barbel. Each of the three dorsal fins begins close to the adjacent fin. The colour pattern consists of close-set, greenish brown to reddish mottles on a paler background. The smoothly curved lateral line appears as a distinctively pale, narrow band, and may not be obvious in young fish. Juveniles are usually reddish with chequered paler markings (see p. 69). Large adults can reach weights in excess of 90kg, but fish over about 15kg are now rare. Adult Atlantic Cod mostly live and feed in offshore shoals, but divers will often see young immature fish inshore, including in wreckage, at reasonable sizes. KEY FEATURES Large head with overhanging upper jaw, chin barbel and pale lateral line. SIMILAR SPECIES Adults are unlikely to be mistaken for any other codfish. Juveniles, however, can be confused with juvenile Atlantic Cod, Pollack and Saithe. These can be distinguished by differences in jaw shape (see pp. 60–61). ABUNDANCE AND DISTRIBUTION While still common all around Britain and Ireland, immense offshore shoals are now a thing of the past, as are very large fish. It is classified as globally Vulnerable.

62

adult

juvenile

10 m 25 m

Melanogrammus aeglefinus Haddock

(Linnaeus, 1758)

OST

Above and left Haddock photographed using a baited underwater video showing the dark lateral line and ‘thumbprint’ blotch on the flank. Marwick, Orkney.

OST

Left A juvenile infected with blackspot (see p. 271) showing the pale edges to the fins. The normally black ‘thumbprint’ blotch behind the pectoral fin is showing as a yellowish mark on this probably sickly fish. Loch Fyne, Argyll & Bute. TS

GENERAL DESCRIPTION At first glance, a Haddock looks similar to a slimline, silverygrey Atlantic Cod, and like the latter, it has a clearly overhanging upper jaw. However, Haddock has some obvious distinctive features: the chin barbel is short and difficult to see underwater, the lateral line is black and there is a large, dark ‘thumbprint’ blotch below the first of the three dorsal fins. The latter is the most evident feature underwater. The first of the three dorsal fins is tall and pointed and young fish may have pale, iridescent blue edges to all fins. Haddock is probably the least likely of all the inshore codfish family members to be seen by divers, as they mostly live in deep, cool water. However, young fish can be found within diving depths and, while preferring dark, shaded places, can be seen in daylight and in shallow water. KEY FEATURES Codfish with a large black blotch behind the gill cover, dark lateral line and tall pointed first dorsal fin. SIMILAR SPECIES Characteristic black blotch should be diagnostic, even in juveniles. ABUNDANCE AND DISTRIBUTION While found all around Britain and Ireland, Haddock is a cold-water species.

Pollachius pollachius Pollack

(Linnaeus, 1758)

RS

Adult Pollack showing the curved lateral line and protruding lower jaw. Above North Norfolk. Left Devon.

SS

GENERAL DESCRIPTION This classic, silvery member of the codfish family will be encountered on many dives in rocky areas, near wrecks and in mature kelp forests. Large individuals often swim leisurely around, usually in small dispersed groups. Almost the entire body is intensely reflective, giving an overall silvery impression, although the dorsal surface is dark and frequently greenish and the ventral surface is white. The lower jaw is longer than the upper and does not have a chin barbel and the lateral line is curved. A quiet approach will allow all these features to be observed underwater. Juvenile and young Pollack have a distinctive coloration (see also p. 69). KEY FEATURES A large, reflective fish with three dorsal fins, a protruding lower jaw with no barbel, and distinctly curved lateral line. SIMILAR SPECIES Easy to confuse with the very similar Saithe (opposite), but look carefully for the Saithe’s straight lateral line and equal-length jaws. Most other codfishes seen by divers (such as Bib Trispoterus luscus p. 66 and Poor Cod T. minutus p. 67) have a chin barbel. ABUNDANCE AND DISTRIBUTION Common all around Britain and Ireland where suitable rocky habitat is available. Young fish are less fussy and also occur in areas of sediment seabed.

PBa

64

Very small Pollack are often a bright golden colour. Cape Wrath,

Pollachius virens Saithe

(Linnaeus, 1758)

LB PBa

Above A dark greenish Saithe with its bright white, nearly straight lateral line and equal-length jaws. Isle of Man. Right Saithe shoal – gold or greenish depending on how the light catches them. Burra Sound, Orkney.

GENERAL DESCRIPTION Also known as Coalfish or Coley. Saithe have the typical shape of a codfish (p. 60) and is one of the species lacking a chin barbel. A dark greenish colour on the dorsal surface can make it difficult to see the three dorsal fins characteristic of this family. Saithe have a straight, light-coloured lateral line and equal length jaws, both of which can show up well in photographs or when observed at night as they swim over the seabed. Saithe tend to form large, cohesive shoals and divers will often see them passing by as a silvery stream of medium-sized fish. Saithe and Pollack can easily be mistaken for one another and if there is any doubt as to which is which, the fish should be recorded as ‘Pollachius sp’. Juveniles have a distinctive, bright coloration (see p. 69). KEY FEATURES Silvery, shoaling codfish with a straight, light-coloured lateral line, equal-length jaws and no chin barbel. SIMILAR SPECIES Pollack (opposite) and Whiting (p. 68) both also lack a chin barbel so their descriptions should also be checked. ABUNDANCE AND DISTRIBUTION Saithe are found all around Britain and Ireland, but have a preference for cooler and offshore waters. Scotland is the exception, where

10 m 25 m

Trisopterus luscus Bib

(Linnaeus, 1758)

MM

Above Large, pale Bib showing three dorsal fins, long chin barbel and black spot at the base of the pectoral fin. Dorset. LB

Left Showing vertical bands. Dorset.

GENERAL DESCRIPTION Also known as Pouting. Bib are deeper-bodied than most other gadoids – the result of a short, near-triangular front with a longer, also near-triangular rear (this can be visualised as two cones with the bases placed together). The first of the three dorsal fins is tall and triangular but when this fin is folded back the shape becomes less obvious. The upper jaw overhangs the lower, which itself sports a single barbel. Typically, Bib have a very light, metallic silvery coppery overall colour, with three or four dark, vertical bands. Some, usually larger, individuals lack any banding and can be either silvery or very dark in colour. There is a black mark at the base of the pectoral fin which may or may not be obvious and distinct. Bib can be easy to approach and many, if not all, of these features may be seen underwater. Bib often shoal in small groups in sheltered spots around shipwrecks and rocky reefs but can be seen elsewhere too. KEY FEATURES Bib are a deep-bodied codfish in which the upper jaw overhangs the lower and there is a chin barbel. They usually have distinct light and dark vertical bands. The first dorsal fin is high and triangular and there is a black mark at base of the pectoral fin. SIMILAR SPECIES The most likely confusion is of young (small) Bib with Poor Cod Trisopterus minutus (opposite), which also have a similar overhanging upper jaw and barbel. The two species often occur together. Poor Cod have a slim body shape, no banding and proportionally larger eyes. Poor Cod (and Whiting p. 68) can both have a less obvious black spot at the base of the pectoral fin. In Poor Cod, the first anal fin starts at a point beneath the gap between the first and second dorsal fins. In Bib, it starts beneath the middle or front of the first dorsal fin (see opposite). ABUNDANCE AND DISTRIBUTION This is a common species all round Britain and Ireland where suitable rocky habitat is present. It is often seen by divers, especially on wrecks.

66

Trisopterus minutus Poor Cod

(Linnaeus, 1758)

MM

Above Two Poor Cod with a group of Bib. The slim body and large eye distinguishes them from Bib. Cornwall. KLo

Left Some Poor Cod show faint banding. Milford Haven, Pembrokeshire.

GENERAL DESCRIPTION Poor Cod are small, slim, metallic silvery or coppery coloured codfish. They have noticeably large eyes for their size, which help distinguish them from the similar Bib (opposite). As with other codfishes, they have three dorsal fins and, like Bib, an overhanging upper jaw and a chin barbel. ‘Poor’ in this instance refers to their small size and, in British and Irish waters, this is the smallest species in the codfish family. They often hang around between large boulders, underneath overhangs and in wrecks. KEY FEATURES A small (rarely exceeding 20cm), slim-bodied codfish, of uniform and unstriped colour (although they may display faint stripes at night), with relatively large eyes and a chin barbel. SIMILAR SPECIES Mixed groups of Bib and Poor Cod are not unusual. Bib have a deeper body, often with distinct vertical bands of dark and light, and a usually distinct black mark at the base of the pectoral fin, while Poor Cod may have a rather indistinct dark mark. In Poor Cod, the first anal fin starts at a point beneath the gap between the first and second dorsal fins. In Bib, it starts beneath the middle or front of the first dorsal fin. ABUNDANCE AND DISTRIBUTION Common all around Britain and Ireland. Sometimes seen in large shoals over sediment. LB

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10 m 25 m

Bib

Poor Cod

Merlangius merlangus Whiting

(Linnaeus, 1758)

ST

Above and left Whiting lack a chin barbel and have dorsal and anal fins edged in white. Weymouth, Dorset.

ST

GENERAL DESCRIPTION Whiting are a rather slimline member of the codfish family. They have a prominent snout due to a slightly overhanging upper jaw and no apparent chin barbel (although young fish may have a minute one). The dorsal surface is a grey-blue to olive brown, which may be faintly mottled when near the seabed, and the flanks are a muted silver. There may be a more or less distinct dark mark at the upper base of the pectoral fin. Colour is not very useful for identification, although the three dorsal and in particular, the two anal fins are usually edged with white (a close look or photograph is needed to reveal this). When fully fanned out, the caudal fin has a square-cut edge. KEY FEATURES A slimline codfish, with protruding upper jaw and no obvious chin barbel. Often a white edge to dorsal and anal fins. SIMILAR SPECIES Other codfishes including Pollack (p. 64), but that species has a protruding lower jaw. Saithe (p. 66) have a straight, light-coloured lateral line. Whiting, Poor Cod (p. 67) and Bib (p. 66) may all have a dark spot at the base of the pectoral fin. ABUNDANCE AND DISTRIBUTION Common all around Britain and Ireland especially

68

Codfish juveniles and colour variations Juvenile codfishes/gadoids often have a quite different colour and pattern to adults. When they are small and vulnerable, young fish often live in a different habitat to the adults and their colour provides appropriate camouflage within these habitats. While juvenile Atlantic Cod (p. 62), Pollack (p. 64) and Saithe (p. 65) shelter amongst seaweeds and rocks, adults are typically out in the open, although some adult codfishes also show variations in colour. The photographs below show codfish juveniles and colour variants.

LKa

DW

Juvenile gadoid, unidentifiable to species. Cley, Norfolk.

Cod, Gadus morhua. Isle of Arran.

LB

JaG

Cod, Gadus morhua. Isle of Arran.

Poor Cod, Trisopterus minutus. Loch Duich, Highland..

LB

LB

Saithe, Pollachius virens. Loch Ailort, Highland.

Pollack, Pollachius pollachius. Isle of Skye, Highland.

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Pollack, Pollachius pollachius. Swanage, Dorset.

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Sparidae Seabreams Seabreams are deep-bodied, oval-shaped fish. They have a single, relatively low, long dorsal fin which is spiny at the front, soft at the rear. The rear of the shorter anal fin is directly below the rear of the dorsal fin and the large caudal fin is deeply forked. These fish have complicated life histories, with some maturing as males first (Gilthead Sparus aurata and Blackspot Seabream Pagellus bogaraveo), others as females first (Black Seabream Spondyliosoma cantharus and Couch’s Seabream Pagrus pagrus); all are long-lived fish. While seabreams are largely warmwater inhabitants, a few appear regularly off our coasts, especially in the summer, with around 12 species reported in total, some very rare. Three seabreams – Black, Couch’s and Gilthead Seabream, return to the southern coasts of England, Ireland and to Cardigan Bay in Wales to breed. These three species, along with Common Two-banded Seabream Diplodus vulgaris, are described in detail on pp. 72–78. Several other species are now being increasingly recorded around British and Irish coasts. The four seabream described below are thought to be seasonal visitors to British and Irish waters and a good photograph, together with expert opinion, will be required to confirm identity.

Boops boops Bogue This slim-bodied seabream is silver-grey in colour with a dark lateral line and a number of parallel dark lines on the flanks. It can be found inshore in small, midwater shoals. While rare in northeast Atlantic waters, there are now regular reports during autumn and winter from southwest England and the Channel Islands. Occasionally there are sightings from southwest Ireland (County Kerry) and it has been reported from southwest Scotland. It seems to have been recorded more frequently since the 2000s.

(Linnaeus, 1758)

CB

A shoal of Bogue showing the dark lines on the flanks. Gozo.

Diplodus sargus White Seabream

(Linnaeus, 1758)

This deep-bodied seabream is a silvery colour and may have darker vertical bars on the flank. It always has a rounded, black blotch on the caudal peduncle and caudal fin with a dusky margin. This species has been reported from Cornwall and is regularly caught in late summer and autumn around the Channel Islands. White Seabream. Canary Islands.

Pagellus erythrinus Common Pandora This moderately slim seabream has an almost straight, pointed snout. Adults are a silvery colour with scattered blue spots on the upper flanks, while juveniles have a pinkish hue. This fish is a regular, albeit uncommon, summer visitor to southwest England and Ireland. It could be confused with Couch’s Seabream Pagrus pagrus (p. 76). Common Pandora. Cerbère, France.

70

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(Linnaeus, 1758)

Pagellus bogaraveo Blackspot Seabream

(Brünnich, 1768)

Blackspot Seabream has relatively large eyes and a rather plump, silvery coloured body. There is a small, rectangular, black spot on the lateral line immediately above the pectoral fin. Only dead fish assume the red colour which gives them one of their vernacular names (Red Seabream). Juveniles, which may lack the black spot, are more likely to be encountered by divers in shallower water (less than 30m) over sediment. Records of this fish have fluctuated over the years, but they now appear to be turning up PLo again more regularly in commercial catches. This fish is considered to be common in deep water (150m+) Blackspot Seabream. Aquarium. off southwest Ireland, in the southwest approaches to the English Channel and in the Irish Sea. In Irish waters, juveniles have been reported from Galway Bay and from around the wreck of the SS Laurentic off County Donegal. It is classified as Near Threatened globally. The four seabream listed below are rare to our region and have only occasionally been recorded in British and Irish waters. Dentex dentex Common Dentex (Linnaeus, 1758) In the past, recorded as far north as Scotland but none from Britain in the last 25 years. Very rare in Irish waters. Oblada melanura Saddled Seabream (Linnaeus, 1758) Only two British records from Cornwall. Pagellus acarne Axillary Seabream (Risso, 1827) A few records from the Channel Islands and one or two from Britain. Sarpa salpa Salema (Linnaeus, 1758) Extremely rare, southwest England.

PLo

Common Dentex, Îles d’Hyères. France.

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Saddled Seabream. Gozo. HS

Axillary Seabream. Croatia.

Spondyliosoma cantharus Black Seabream (Linnaeus, 1758)

MD

A male patrolling an area of rock cleared of sediment to attract a female to lay eggs. Poole Bay, Dorset.

GENERAL DESCRIPTION This fish grows to c. 50cm and has the deep oval body shape, small mouth and large forked caudal fin typical of a seabream. Colour and patterning is variable. Before the males establish territories, both sexes are pale, silvery fish with females displaying a horizontal pale bar on the flank, especially when near courting males. Males defending territories and trying to attract females to their nest are black, with up to three white vertical bars on the flank, the central one brightest; this is a colour phase which comes and goes very rapidly. Relaxed males guarding nests are a steel blue colour and have a broad gold band on the forehead between the eyes. Sometimes there may be just a hint of paler vertical bars on the flanks. Divers are most likely to see male Black Seabream when they are defending nests containing eggs close to hatching, which they are loath to abandon. If underwater visibility is very good, divers can watch Black Seabream activity from afar as the fish patrol their territories. However, it appears that Black Seabream are very sensitive to the presence of divers in the water. Remote video recordings have demonstrated that the fish ignore the arrival of the dive boat, but as soon as the splash of divers entering the water is felt, the fish move away, although occasionally divers do see faint, ghostly fish still patrolling, albeit at the limit of the underwater visibility.

LB

72

A juvenile Black Seabream shoaling in the company of small Two-spotted Gobies.

Spondyliosoma cantharus Black Seabream

MD

A dark male fish and a female with a pale horizontal bar. Kimmeridge, Dorset.

(continued)

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A male fish guarding eggs on rock with a shoal of Black Seabream in the background. Kimmeridge, Dorset.

Adult Black Seabream select nest sites on smooth, level bedrock usually covered in a layer of mobile sediment which prevents the growth of fauna and flora. Most reports of the nest sites have been from depths of less than 25m. The fish have been recorded at depths of up to 60m at other times of year. Juvenile Black Seabream occupy the water column just above the seabed and have a distinctive colour pattern. The dorsal half of the fish is a pale silver grey or brownish, while the ventral half is white with dark stripes along the flank and the dorsal midline. Juveniles can be seen from mid-July onwards in a range of shallow water habitats, especially seagrass beds and rocky reef with seaweed. Here, they shoal in the company of other similarly sized fishes such as juvenile Poor Cod (p. 67) and Bib (p. 66) and, when very small, with Two-spotted Gobies (p. 209). KEY FEATURES The nests, with or without eggs, are often the only evidence that the fish is, or has been, present. Even if the fish is not seen, the presence of nests should be recorded. SIMILAR SPECIES Gilthead Seabream (p. 77), although this has a steeper head profile and distinctive markings. Also check other rarer visiting seabreams (see pp. 70–71). ABUNDANCE AND DISTRIBUTION The Black Seabream is known to breed along the English south coast from East Sussex to Dorset, where it may be a fairly common fish, and in areas of Cardigan Bay in Wales. Juvenile fish occur more widely in shallow water habitats from the Thames Estuary and all along the south coast of England, as well as in the Channel Islands. There are scattered records of juvenile fish in estuaries in Devon and Cornwall and up the western coasts of England and Wales, with rare reports from Scotland. There are very infrequent records of adults from all Irish coasts with most coming from County Kerry.

MD

Juveniles amongst seagrass in late summer. Studland, Dorset.

Black Seabream nests Black Seabream Spondyliosoma cantharus are protogynous hermaphrodites, that is they mature first as females before changing sex to become males. A study of the breeding behaviour of this fish, spanning more than seven years, has been undertaken at sites near Kimmeridge on the Dorset coast. Video cameras have been deployed overlooking the nests, recording the interactions of adjacent males, behaviours of males enticing females to spawn and male parental care of the eggs on the nest. Male Black Seabream create nest sites on smooth, bare surfaces on which a female must then be persuaded to lay her eggs. As suitable surfaces are rarely clear of sediment and larger material, this means that the fish must clear it and male Black Seabream are spectacular bulldozers of the seabed. They shift, many kilos of silt, sand, gravel and short growths of fauna and seaweeds from bedrock or compacted pebbles MD or shell. The sand and gravel can form substantial ramparts Seabed cleared of sediment with batches of eggs showing as pale patches over around the selected site. The the rock. Kimmeridge, Dorset. nest surface is kept free of any silt through vigorous tail fanning by the male fish, while larger pieces are either shoved aside or picked up and spat out beyond the nest perimeter. Nests can measure several metres across.

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74

FREE-SWIMMING SILVERY FISHES NEAR THE SEABED

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A photogrammetric reconstruction of Black Seabream nests over bedrock. Model diver (circled) in centre of image gives an idea of scale. Kimmeridge, Dorset.

Preferred rock types are chalk or smooth mudstone. Male fish are highly protective of the nest sites; any seaweed and mobile or encrusting animal life is removed by the attentive males. Seaweed is bitten through and carried off the nest area, and any mobile animals making an appearance (which may range from whelks and hermit crabs to large Spiny Spider Crabs Maja brachydactyla), are also swiftly and forcibly removed or chased off. Other fishes (including neighbouring male Black Seabream) which might try to eat the eggs are given short shrift and driven away. Even cameras which have been deployed to monitor Black Seabream nests have been forcefully removed from the nest sites. If the male fish considers that the cameras were placed too near their nest, they have been known to knock over the cameras with little difficulty, even if mounted on 2kg dive weights. From egg-laying to hatching takes up to two weeks, followed by the male fish leaving abruptly. Nesting activity typically peaks in May and June but can continue into July, especially when early nesting attempts have been disrupted by stormy weather destroying earlier nests. There are currently three Marine Conservation Zones (MCZs) designated to protect Black Seabream nesting areas: Southbourne Rough and Purbeck Coast, both in Dorset, and Kingmere off Sussex. For more information see mattdoggett.com/the-black-bream-project

MD

A nest with a central slab of rock and low ramparts formed by the male clearing sediment. Photogrammetric reconstruction, Kimmeridge, Dorset.

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Egg predation by Netted Dog Whelk Tritia reticulata.

FREE-SWIMMING SILVERY FISHES NEAR THE SEABED

Pagrus pagrus Couch’s Seabream

(Linnaeus, 1758)

SD

An adult showing the steep forehead and obvious pale tips to the forked caudal fin. Sark, Channel Islands.

GENERAL DESCRIPTION This is a moderately deep-bodied fish with a typical seabream shape, reaching over 50cm in length. The head has a distinct hump/change of angle at the level of the eyes. During the day, live, unstressed fish in the wild are pale in colour tinged with pink and gold, with scattered flecks of iridescence where the light catches the scales. The fins are bright pale blue with the tips of the caudal fin especially eye-catching underwater. There is a narrow blue band across the snout at the level of the eyes which, in turn, have a slightly darker, vertical orange bar running through them. Dead specimens of this fish are tinged dark red, while retaining the pale tips to the caudal fin, hence its American name Red Porgy. Juveniles recorded by divers at night are darker orange/pink to dark red, with pale saddles across the dorsal surface and a dark shadow across the lower part of the head. This tends to be a solitary fish occurring over sandy and rocky seabeds with juveniles occurring in water as shallow as c. 5m. KEY FEATURES Adults are pale and deep-bodied, with eye-catching pale tips to the caudal fin. SIMILAR SPECIES Other seabream species, especially Common Pandora Pagellus erythrinus (p. 70) – although this does not have the steep forehead of Couch’s Seabream. Careful comparison of key features will be necessary, especially with juvenile fish. ABUNDANCE AND DISTRIBUTION Juvenile Couch’s Seabream have been recorded from southern England (Plymouth Sound and Torbay, Devon) with breeding reported from the coasts and estuaries of south Devon and Cornwall. They are still considered rare in southern English waters, despite being described from Cornwall by Jonathan Couch in 1842. This species has been extending its European range northwards since the mid-1990s and large fish are now caught regularly off England’s south coast. The

76

PBu

A strongly coloured juvenile at night, showing the pale tips to the caudal fin. Torbay, Devon.

10 m 25 m

Sparus aurata Gilthead Seabream

Linnaeus, 1758

ST

Above Adult Gilthead Seabream: note the dark horizontal lines on the flank, and dark blotch with a hint of red on the gill cover. The bright bar between the eyes, which gives this fish its vernacular name, is just visible. Portland, Dorset. Right Juvenile seabream likely to be either a Gilthead or Couch’s Seabream (see opposite). Kells, County Kerry. MoD

GENERAL DESCRIPTION This large, deep-bodied seabream reaches up to 50cm and is not often seen by divers, usually just a fleeting glimpse. The overall impression is of a heavily built, silvery fish with slightly darker, narrow, horizontal lines on the dorsal surface and flanks. The head has a distinct hump/change of angle at the level of the eyes and a gold band glinting across the forehead. There is a dark vertical bar across the gill cover with a variable red mark on the lower edge of the bar. The caudal fin has black/dusky tips and trailing edge. This fish typically occurs over sediment areas, often in estuaries, in water depths of less than 5m, down to over 30m. KEY FEATURES Dark vertical bar behind the gills; black tip and trailing edge to the caudal fin. Gold bar across the forehead. SIMILAR SPECIES Other seabream species. Careful comparison of key features will be necessary, especially with small fish. ABUNDANCE AND DISTRIBUTION This seabream has increased in abundance in recent years along the south coast of England. Scattered reports exist up the east coast, as far north as the Firth of Forth, as well as Milford Haven and Cardigan Bay in

10 m 25 m

Diplodus vulgaris Common Two-banded Seabream (Geoffroy Saint-Hilaire, 1817)

SD

An adult displaying the two dark bands which characterise this small seabream. Sark, Channel Islands.

GENERAL DESCRIPTION A silvery seabream reaching up to c. 30cm (usually less). This species has two distinct, wide, dark bands: one in front of the dorsal fin, the other extending from the rear of the dorsal fin around the base of the tail. This fish is usually seen in small groups over reefs and sandy areas in shallow water (c. 5–15m), occurring down to c. 50m, but is very rarely seen by divers in British or Irish waters. KEY FEATURES A small, oval, silvery fish with two dark bands. SIMILAR SPECIES Other small seabream, but the two dark bands should distinguish this fish. ABUNDANCE AND DISTRIBUTION Although rare, this seabream has been recorded off the south coast of England and in the Channel Islands since the early 2000s. There are, as yet, no Irish records.

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10 m 25 m

A shoal in typical habitat. Gran Canaria, Canary Islands.

78

Balistes capriscus Grey Triggerfish

Gmelin, 1789

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A Grey Triggerfish showing the distinctive small mouth and blue-tinged fins. The first dorsal fin, with its spines, is lying flat in this instance. Whitsand Bay, Cornwall.

GENERAL DESCRIPTION This is the only triggerfish species found around Britain and Ireland; the majority live in warm and tropical waters. It has a distinctive steel grey, deep, oval-shaped, laterally compressed body. A small, pursed mouth is filled with canine-like teeth that are often visible. The fish has a tall second dorsal fin and a similar-shaped anal fin, both of which can sometimes be blue-tinged, and with which it swims in a characteristic way, waggling them from side to side. The folding first dorsal fin has one long spine (the ‘trigger’) and two shorter spines, the first of which is used to lock the trigger upright so that the fish can wedge itself firmly in crevices. Young fish are pelagic and can be found drifting amongst surface debris. KEY FEATURES Oval, greyish, laterally compressed fish. Stout spine at the front of the first dorsal fin (difficult to see when folded down). Second dorsal and anal fins tall and blue-tinged. SIMILAR SPECIES None. This is a very distinctive fish with no other similar species in British and Irish waters. ABUNDANCE AND DISTRIBUTION While this fish seems to be regarded as a rare southern visitor, it has been recorded in British and Irish waters for at least the past two centuries. Although fishing and diver sightings have increased significantly since the 1990s, this may be partly due to greater awareness. A greater abundance of this fish may also be due to warmer sea temperatures. It is now regularly reported from the entire south coast of England. There are also records from all around Britain and Ireland, with just a very few from North Sea coasts. Since the late 1990s, there have also been a few autumn and winter records of young fish less than 10cm long, suggesting that they may breed here.

10 m 25 m

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A shoal of colourful Rock Cook Centrolabrus exoletus

80

Colourful fishes near the seabed Silvery fishes that live and swim in the water column, though only a relatively short distance above the seabed, are introduced on pp. 58–79. There are also a number of other species that live just above the seabed, which are brightly coloured. Wrasses remain close to cover and so can afford to use bright colours for recognition and courtship displays. They are frequently seen by divers in rocky areas and it should not be difficult to identify. Two other less colourful species that live near the seabed are John Dory Zeus faber (p. 96) and Boarfish Capros aper (p. 97).

Labridae Wrasses Wrasses have a single, long dorsal fin along the dorsal surface of their elongated oval-shaped body. This fin has a lower spiny front portion and a taller, soft rear portion, while the caudal fin is slightly convex. The lips are thick and usually obvious and the large eyes are slightly bulbous and very mobile. Their bright colours show up even from a distance, while at closer quarters their large scales, often outlined with a contrasting colour, can give them a spotty or chequered appearance. They live mostly in rocky areas with plenty of cover, including kelp forest and rock and boulder slopes. There are two large (Ballan and Cuckoo) and three small (Corkwing, Goldsinny and Rock Cook) wrasse species commonly found around Britain and Ireland. Sizes (typical range) are from 12cm (Rock Cook) to around 50cm (Ballan). Baillon’s Wrasse Symphodus bailloni is an additional small species that has become well established along southern and western coasts. Two further rarely seen species, Scale-rayed Wrasse Acantholabrus pailloni and Rainbow Wrasse Coris julis, have been recorded very occasionally from southwest Britain. Photographs would be needed to confirm their identity and presence if seen. At popular dive locations wrasses often exhibit little fear and sometimes a great deal of curiosity, watching divers with their large, mobile eyes. When not in a hurry, they swim in a characteristic fashion, using their pectoral fins like oars to pull themselves along, while remaining fairly close to the seabed. Wrasse have the ability to change sex, a biological trait covered on pp. 94–95. long single dorsal fin, shorter/spiny at the front and taller/soft at the rear

large eyes mouth with thick lips

gill cover pectoral fin

lateral line pelvic fin

The main wrasse family features (using Ballan Wrasse

anal fin

Slightly rounded/ convex caudal fin

Symphodus melops Corkwing Wrasse

(Linnaeus, 1758)

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Corkwing Wrasse showing the crescent-shaped patch behind its eye and a black spot at the base of the caudal fin. Swanage, Dorset.

GENERAL DESCRIPTION Corkwing Wrasse show typical wrasse features (see p. 81) including body shape and bright, but variable colours. There is a crescent-shaped patch behind the eye and a characteristic dark, rounded spot at the base of the caudal fin, which is usually obvious and consistently seen in most Corkwings. The background colour is generally a brown to green-brown with paler centres to the scales, resulting in a rather spotty appearance. The background is overlain with darker brownish or greenish blotches which can give the fish a mottled appearance. These blotches show as clear horizontal bands in some individuals. Mature males may have obvious turquoise and orange wandering lines in the area around the eyes, blue-centred scales, and blue-spotted and tipped fins. Other, so-called ‘sneaker’ males, resemble females (see pp. 169 and 198 for details of this behaviour). Corkwing Wrasse can reach up to 28cm in length although most are around 20cm long. They are commonly encountered in seaweed-rich, rocky areas, from very shallow water (where they may be seen by snorkellers) to at least 30m depth. KEY FEATURES A wrasse with a curved brown or black blotch immediately behind each eye, which may be bright blue on breeding males. There is a dark roundish spot at the base of the caudal fin which, while it can be clear and obvious, may also be faint and unclear. SIMILAR SPECIES There can be confusion with small Ballan Wrasse (p. 86), but Ballan do not have the Corkwing’s distinctive tail spot. Baillon’s Wrasse (p. 84–85) is a very similar species and some individuals may have a very small, irregularly shaped tail spot. Mature Baillon’s males have obvious pink lips and fins which Corkwing do not. ABUNDANCE AND DISTRIBUTION Found all around Britain and Ireland, but with fewer records from eastern British and Irish coasts where there is less suitable habitat. 10 m

25 m

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Symphodus melops Corkwing Wrasse

(continued)

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During spring and early summer, males may be seen ‘sparring’ over territories, circling and weaving round each other. Males can be seen carrying pieces of algae (especially calcareous pink algae) with which they build their seaweed nests. These elaborate, ball-like structures are usually constructed in rock crevices or amongst seaweed-covered rocks. There is a single entrance through which the male entices the female and she will then lay eggs for the male to attend and guard. Nests have also been found amongst seagrass.

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Symphodus bailloni Baillon’s Wrasse

(Valenciennes, 1839)

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Above Male Baillon’s Wrasse at nest showing pink tints to fins and lips and hints of blue on the head. Poole Bay, Dorset. Right A more drab fish, probably a female. Swanage, Dorset. LB

GENERAL DESCRIPTION Baillon’s Wrasse is very similar in body shape and size to a Corkwing Wrasse (pp. 82–83) and can very easily be mistaken for one. The similarity between the two means that a close look (and preferably a photograph) is needed for a positive identification. Most Baillon’s Wrasse are a predominantly blotchy beige to brown in colour and often have three dark longitudinal lines, especially females (some Corkwings have similar though less well-defined lines). However, mature males in breeding colours stand out as being significantly different, with vivid pink lips and fins as well as blue lines on the head. Females and non-breeding males are most likely to be confused with Corkwings. Like the Corkwing Wrasse, Baillon’s Wrasse usually has a dark spot at the base of the caudal fin, however Baillon’s also have black blotches on the rear (soft) portion of the dorsal fin. One blotch in the middle of the fin is often visible, the second, low down near the body at the rear of the fin, is rarely visible and may be absent. KEY FEATURES The pink lips and fins in breeding males are highly distinctive. Reaching approximately 15–20cm (a hand length), this wrasse has a black blotch or blotches on rear portion of the dorsal fin. SIMILAR SPECIES The most likely confusion is with Corkwing Wrasse. Corkwings have a distinct crescent-shaped blotch behind the eye, while Baillon’s Wrasse do not, though the latter may have a thin, dark line in the same position. Black blotches on the rear of the dorsal fin seen in Baillon’s are absent in Corkwing. ABUNDANCE AND DISTRIBUTION The restricted distribution of this Corkwing-lookalike means that only divers in southwestern parts of Britain and Ireland are likely to see it. Baillon’s Wrasse is now regularly recorded from Dorset (especially Poole Bay), Hampshire and the Channel Islands. There are also now accepted records from Sussex, Pembrokeshire and County Galway in Ireland. Most records are clustered between Portland and the Isle of Wight, with the great majority from Seasearch volunteers.

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Symphodus bailloni Baillon’s Wrasse

(continued)

CB

Baillon’s Wrasse build nests with a neat dome-shaped appearance and a rounded entrance on one side. The nests are constructed with fine seaweed and usually a good percentage of bryozoans. This reflects this species’ preference for rocky areas, mostly below the kelp forest and main algal zones. A scattering of shell fragments or even maerl may help camouflage the nest. While Corkwing Wrasse prefer to hide their nests in crevices and between rocks, Baillon’s Wrasse will build theirs in more open areas.

MM

LB

LB

Juvenile Baillon’s Wrasse (top) showing dark horizontal stripes and black spot towards the rear of the dorsal fin. Juvenile Corkwing (bottom) with less prominent stripes and crescent-shaped mark behind the eye.

Labrus bergylta Ballan Wrasse

Ascanius, 1767

LH

Above A common adult colour variant. Isle of Man. Right Mottled juvenile colouring. Swanage, Dorset. LB

GENERAL DESCRIPTION This solid-looking, deep-bodied fish clearly shows all the characteristic wrasse features (see p. 81), including prominent lips and a single, long dorsal fin. Colour is variable, typically a mottled mix of blotchy greens and browns. Some individuals have a distinctive spotted colour pattern: a pale background with orange reticulations and orange-edged scales. Colour is no guide to the sex, but large fish with this pattern are often males (males all start life as females – see Changing Sex pp. 94–95). Very young fish are more uniform in colour, typically beige, reddish or green, without blotches, while older, but still immature fish, sometimes have a white line running from head to caudal fin. Ballan are the largest wrasse species in Britain and Ireland, reaching up to 50cm (exceptionally 65cm) in length. Any wrasse over about 20cm (hand length), and which is not the obvious Cuckoo Wrasse (pp. 88–89), is likely to be this species. Ballan are commonly found in kelp forests and rocky areas to at least 30m depth and can often be seen swimming in an unhurried fashion with the dorsal fin folded down, except for the tall soft portion towards the rear. Unlike the smaller Corkwing (pp. 82–83) and Baillon’s Wrasse (pp. 84–85), Ballan Wrasse do not seem to construct nests. Instead, they appear to defend small territories of cleared rock or wreckage within which females are courted before laying eggs onto hard surfaces. One or both fish then patrol the area and protect the eggs until hatching. Pre-spawning courtship between pairs of fish has been observed and filmed by divers, but there is very little documented information on actual egg laying in the wild. KEY FEATURES Large, bold wrasse with prominent thick lips and scales often obvious. SIMILAR SPECIES Small Ballan might be confused with Corkwing, but lack that species’ characteristic tail spot. Rock Cook (p. 91) also lack these markings, but have tiny mouths and distinct, dark, caudal fin bands. ABUNDANCE AND DISTRIBUTION Common in suitable rocky and kelp habitats all around Britain and Ireland, but fewer sightings from the east coast of England and 10 m

25 m

86

Labrus bergylta Ballan Wrasse

(continued)

MSo

Portland, Dorset.

LB

Isles of Scilly.

MM

Isles of Scilly.

MM

Purbeck, Dorset.

LB

Juvenile. Kimmeridge, Dorset.

Swanage, Dorset.

ID

Unst, Shetland.

MD

RS

Labrus mixtus Cuckoo Wrasse

Linnaeus, 1758

MM MM

Above and right Male Cuckoo Wrasse colour variants. Cornwall.

GENERAL DESCRIPTION It would be hard to mistake either a colourful male or a distinctive female Cuckoo Wrasse for any other fish. Males and females have completely different colour patterns, but individuals can also be found with a mixture of male and female colours – see Changing Sex on pp. 94–95. Males have blue-lined heads, with similar blue lines and blotches extending along the bright orange flanks towards a blue-edged caudal fin. Females are a warm pink to reddish orange colour with a pale underside; they also have a distinctive series of alternating black and white marks along the dorsal surface, just below the soft rear part of the dorsal fin, ending just as the caudal fin starts. Cuckoo Wrasse prefer rocky areas below about 10m and can be found well below diving depths, down to around 200m. Males are territorial, particularly so during the breeding season and will sometimes approach and investigate divers, even giving a sharp nip and drawing blood. Females and immature fish can be found in small groups, with or without a mature male. Larger groups with several males and females may also be seen. KEY FEATURES Males have highly distinctive blue and orange colours and markings. Females have a pattern of alternating black and white marks on the rear part of the dorsal surface back to the caudal fin. SIMILAR SPECIES None that are either as colourful or obviously marked as the Cuckoo Wrasse. ABUNDANCE AND DISTRIBUTION Found around most British and Irish coasts, though there are fewer records from the eastern coasts of England and Ireland, where suitable habitat is scarce.

LB

88

Another colour variant of a male Cuckoo Wrasse.

Labrus mixtus Cuckoo Wrasse

(continued)

LM

Above A female Cuckoo Wrasse on a rocky reef. Isle of Man. Right Cuckoo Wrasse are often seen in groups. Here, several females or immature fish are seen exploring rocky reef. Isle of Man. Below A female hovering over rocky reef. Isle of Man.

LB

LB

Courtship Mature males pose for egg-laden females by displaying and blanching pure white over the head. If ready, she will spawn with him, laying her eggs in a nesting hollow cleared between rocks. Actual egg-laying is poorly documented.

Ctenolabrus rupestris Goldsinny Wrasse

(Linnaeus, 1758)

LB

The bulging belly of this fish suggest it may be a female carrying eggs. Loch Nevis, Highland.

GENERAL DESCRIPTION This small, slimline wrasse ranges from a warm light brown, through to a coppery pink in colour, with a pale to white ventral surface. There is an obvious black spot near the top of the caudal peduncle, which is usually distinct and a key characteristic for identifying this wrasse. While there is a second black spot on the front of the dorsal fin, this can only be seen if the fish raises the fin, which it does rarely. Sometimes the flanks are lightly striped and there may be a dark stripe from snout to eye (although this may be difficult to discern in darker fish). Juveniles may also have a white stripe running through the top of the eye. Goldsinny Wrasse prefer rocky reefs, cliffs and boulder slopes with plenty of overhangs, nooks and crannies to provide safe refuge. While they can be found in kelp forest and seaweed zones, they are more usually encountered on deeper dives. Unlike the other wrasse species, they do not build nests. KEY FEATURES Small (12–15cm), slim wrasse with a black spot near the top of the caudal peduncle. SIMILAR SPECIES There should be no confusion with other wrasses. The rare (in British and Irish waters) Scale-rayed Wrasse (p. 93) has a similar tail spot but also other distinctive markings and occurs mostly below 30m. ABUNDANCE AND DISTRIBUTION Regularly sighted all around Britain and Ireland but fewer records from the east coasts of Britain and southeast Ireland where suitable habitat is often lacking. RY

RS

90

Juveniles may have a white stripe running through the eye and pale spots on the lateral line. Top Beesands, Devon.

RS

Goldsinny have sharp teeth to dispatch invertebrate prey. Isle of Man.

Centrolabrus exoletus Rock Cook

(Linnaeus, 1758)

LB

Above An adult Rock Cook showing the characteristic dark bands on the caudal fin and iridescent blue edges to the scales on the dorsal surface. Isle of Man. MM

Left A group with two dull-coloured females, the top one showing clearly the dark bands on the caudal fin. Hand Deeps, Cornwall.

GENERAL DESCRIPTION The Rock Cook is a slender-bodied wrasse with a much smaller mouth than the other British and Irish wrasses. It is also the smallest wrasse found in Britain and Ireland and tends to live and feed in groups, perhaps for safety. Body colour is usually a warm fawn to brown, but varies through to yellowish and orange, sometimes with a mix of these colours. On the dorsal surface, the scales may be edged with an iridescent, almost electric blue colour and there may also be blue edges and speckles on the fins. The ventral surface is usually lighter and may even be whitish. While breeding males are especially bright, all Rock Cooks have blue lines on the head, a curved darker band at the base of the caudal fin and another across the caudal fin edge, sometimes masked by blue. Rock Cooks prefer seaweed-covered rocky areas, especially under kelp where they can forage for invertebrates. They also inhabit seagrass beds. They are known to use their small mouths to pick individual crustacean parasites off larger fish, especially Ballan Wrasse (pp. 86–87) with which they are often found (see Associations p. 272). KEY FEATURES A small wrasse with a small mouth and vertical dark bar(s) across the caudal fin. This fish has a characteristic, slightly uneven swimming motion and the resulting flickers of blue can provide the first clue to its identity. Prefers to live in small groups. SIMILAR SPECIES While the slightly larger Corkwing Wrasse (pp. 82–83) may have similar blue markings, Rock Cook lack the Corkwing’s tail spot and crescent-shaped spot behind the eye. ABUNDANCE AND DISTRIBUTION Locally common all around Britain and Ireland, especially in the south­west. Few records from the east coasts of either, where suitable habitat is often lacking. 10 m

25 m

Rare or rarely seen wrasses Fish that live at the limit of recreational diving depths and in rugged habitats unfrequented by commercial fishers are often thought to be exceptionally rare, while in fact they may simply be under-recorded. The jury is still out on which of these scenarios applies to the Scale-rayed Wrasse in British waters, but the Rainbow Wrasse does seem to be very rare and only an occasional and sporadic visitor from warmer waters further south.

Coris julis Rainbow Wrasse

(Linnaeus, 1758)

LB

Initial phase Rainbow Wrasse showing characteristic dark brown dorsal surface and pale ventral surface. Note the bright blue and black spot on the rear edge of the gill cover, also present in terminal phase male fish. Hondoq, Gozo.

GENERAL DESCRIPTION This long, slim and very active wrasse has several different patterns associated with different life stages, but all have longitudinal bands of different colours and a pale or white ventral surface. The normal (initial) pattern for both females and males is longitudinally striped with brown, white and yellow (sometimes just two colours, dark above and light below). Some females change sex and grow to become large males. These have vibrant stripes and head markings that include green, red, yellow and white. Such males in Atlantic waters (rather than the Mediterranean) may be less obviously striped and have black vertical streaks near the tail. All phases seem to have a bright blue and black spot on the rear edge of the gill cover. This wrasse is relatively common and well-known in the Mediterranean. With ocean warming, it is possible that this southern species may move further north on a more regular basis, hence its inclusion here. KEY FEATURES A slim wrasse with (usually) striped coloration and a blue-black spot on the rear of gill cover. SIMILAR SPECIES No similar species in our waters. ABUNDANCE AND DISTRIBUTION Exceptionally rare in British and Irish waters, with just one or two verified records, from the southwest.

92

Acantholabrus pailloni Scale-rayed Wrasse

(Risso, 1810)

MM

An adult Scale-rayed Wrasse showing pale blotches above the lateral line and a dark mark near the top of the base of the caudal fin. Hand Deeps, Cornwall.

GENERAL DESCRIPTION This rarely recorded fish is unmistakably a wrasse, having the typical characteristics detailed on p. 81. The colour and pattern of both males and females is a warm coppery brown varying from dark to greenish, with a row of five to seven whitish blotches above the lateral line. There is a distinctive black blotch near the top of the base of the caudal fin, with another on the rear portion of the dorsal fin. The chances of encountering this slimline wrasse are small. Similar in size to a female Cuckoo Wrasse (pp. 88–89), its preferred habitat seems to be steep rocky reef from 30m down to 500m, making diver encounters less likely. KEY FEATURES A series of pale rounded blotches running the length of the dorsal surface. Large black blotch on tail stalk and rear of dorsal fin. SIMILAR SPECIES Juveniles lacking obvious white blotches may resemble Goldsinny Wrasse (p. 90). However, the Scale-rayed Wrasse has a black blotch on the rear of the dorsal fin, while Goldsinny Wrasse do not. ABUNDANCE AND DISTRIBUTION A rarely recorded wrasse, though Britain and Ireland are well within its wider range. The few records (from divers and from anglers) include recent sightings from the Isles of Scilly, Cornwall and the Inner Hebrides, as well as some dating back to the 19th century.

Changing sex In the majority of vertebrate animals, including fish, an individual’s sex is determined genetically and remains the same throughout life, from hatching or birth, through to old age and death. However, some ray-finned (bony) fishes have developed an alternative strategy whereby a single individual functions first as one sex and then as the other. Some species start as male and change to female (protandrous species) while others do the reverse, starting life as female and later becoming male (protogynous species). This way of life is most common amongst a few families of predominantly tropical fish, particularly wrasses (Labridae), parrotfishes (Scaridae) and seabream or porgies (Sparidae). In British and Irish waters, Cuckoo Wrasse Labrus mixtus (pp. 88–89), Ballan Wrasse Labrus bergylta (pp. 86– 87) and Black Seabream Spondyliosoma cantharus (pp. 72–73) all undergo female to male sex change while Gilthead Seabream Sparus aurata (p. 77) exhibit male to female sex change. Cuckoo Wrasse In common with many tropical wrasses, the sex change in Cuckoo Wrasse is accompanied by a distinct colour change. Juveniles start out red and develop into mature functioning females. After a variable number of years (7–13 in the Isle of Man population studied by one of the authors*), some individuals change colour and sex and become fully functional blue and orange males. A ‘secondary’ male maintains a territory, holding several females, with which he spawns individually in prepared nesting areas. More diver observations are needed to confirm details of this behaviour. Secondary males are therefore easy to recognise as such. However, in a twist to the story, you can never be totally sure that a pink ‘female’ Cuckoo Wrasse is actually female. While most pink fish will be females, a few eggs hatch as males and these retain the pink coloration. The exact role of these smaller ‘primary’ males remains unclear, but they may take part in group open-water ‘broadcast’ spawning. * Dipper, F.A. and Pullin, R.S.V. (1979). Gonochorism and sex-inversion in British Labridae (Pisces). Journal of Zoology 187(1), 97–112. doi.org/10.1111/j.1469-7998.1979.tb07716.x

CB

Above Adult secondary male Cuckoo Wrasse. Lyme Bay, Dorset. Left A Cuckoo Wrasse in transition, still showing the black and white bars on the dorsal surface but with well-developed blue pattern on the head. Manacles, Cornwall. RY

94

COLOURFUL FISHES NEAR THE SEABED

Below Secondary male Cuckoo Wrasse. Loch Nevis, Highland. Right A secondary male Cuckoo Wrasse with a female on a rocky ledge. Isle of Man.

LB MM

Ballan Wrasse A similar system operates in Ballan Wrasse but for this species there is no colour change accompanying the sex change and mature males and females cannot be differentiated in the field. However, the largest individuals often have a bright pattern of marbled orange on a pale background. Dipper and Pullin (1979) showed that these individuals were invariably older males (as old as 20–30 years) but, as this necessitated killing the fish, sampling was stopped. Left A large, orange Ballan Wrasse almost certainly a male and potentially up to 30 years old. Porthkerris, Cornwall.

MM

Gilthead and Black Seabream In contrast to Cuckoo and Ballan Wrasse, Gilthead Seabream juveniles mature first as males and then, after two or three years, they become functional females. There is no obvious colour change. Gilthead Seabream are broadcast spawners, releasing their eggs in open water. Conversely, Black Seabream juveniles mature first as females and become functional males after five to seven years.

MD

COLOURFUL FISHES NEAR THE SEABED

Zeus faber John Dory

Linnaeus, 1758

MM

Above The unmistakable body shape, prominent long dorsal fin spines, large mouth and central black spot of the John Dory. Purbeck, Dorset. Right Very small juveniles can be pure black. Kenmare Bay, County Kerry.

GENERAL DESCRIPTION The John Dory is unmistakable. It has a very distinctive outline to its laterally compressed, oval body and large mouth. Together, with extremely long spiny fins, fan-shaped caudal fin and central black mark, these features make it quite unlike any other fish found around Britain and Ireland. Adults range from a pale off-white to a dirty yellow-grey with slightly silvery overtones and messy, swirling, darker lines and marks. The large, centrally placed dark spot may have a distinct yellowish outline, although this is not always evident. Juveniles are darker and can be almost black. This stealthy hunter has large, mobile fins whose fine movements allow it to hover almost motionless in the water. Approaching its prey – including small fishes and shrimps – head-on to minimise its profile, it will shoot out its large, protrusible jaws to engulf its victim. KEY FEATURES Laterally compressed, oval-shaped fish with large spiny fins and distinctive round spot in the middle of each flank. SIMILAR SPECIES Unlikely to be confused with any other species around Britain and Ireland. ABUNDANCE AND DISTRIBUTION This is a typically solitary fish which is mostly found

96

LB

Capros aper Boarfish

(Linnaeus, 1758)

MM

Above A shallow water encounter with a Boarfish. Ardnamurchan, Highland. Right Two Boarfish, one with rather plain colouring, the other with strongly coloured vertical stripes. Isles of Scilly. KH

GENERAL DESCRIPTION In shape, Boarfish superficially resemble a miniature John Dory (opposite), with a similar oval body shape, pointed snout and tall, strong spines at the front of the dorsal fin. However, the eyes are much larger relative to the size of its head and it only reaches around 15cm in length. At its brightest, this fish is an overall marbled red or orange, though colour varies through to straw yellow with silvery flanks, especially in shallow (and therefore well-lit) water. Boarfish sometimes display distinct, wide, light and dark, vertical stripes. Breeding males may show numerous, wavy-edged vertical lines of orange-yellow. Although this fish is predominantly found from 100–400m, and can form large shoals, divers do occasionally see individuals in shallower water (less than 30m). KEY FEATURES Small oval fish with prominent spiny fins, pointed snout, large eyes and bright orange to red colour. SIMILAR SPECIES None. Small John Dory (opposite) and Grey Triggerfish (p. 79) are a vaguely similar shape, but colour and markings mean that confusion is highly unlikely. ABUNDANCE AND DISTRIBUTION Mainly found on southern and western coasts of Britain and Ireland as far north as Scotland (and Norway). While it is sometimes caught by trawlers in large numbers, possibly due to an influx in some years from further south, diver sightings are infrequent and reported mostly from the southwest of Britain and Ireland.

ID

An Angler Lophius piscatorius

98

FLATTENED FISHES ON THE SEABED

Flattened fishes on the seabed Fishes that spend the majority of their lives down on the seabed encompass a huge range of shapes and sizes. They generally swim only relatively short distances when necessary, though some such as European Plaice Pleuronectes platessa are capable of longer migrations during breeding. Fishes (and other animals) that live on the seabed are termed ‘benthic’ and are part of the ‘benthos’. For these species, the ability to swim fast and furiously is not important, although they must be, and are, able to make a quick dart for safety if danger threatens. Instead of a streamlined body and fins designed for fast swimming and manoeuvering, as seen in open water pelagic species (pp. 44–57) and fishes that live near the seabed (pp. 58–97), benthic fishes have evolved a wide variety of often inefficient shapes. To avoid predation and for stealthy hunting, some rely on camouflage or on hiding away in crevices and cracks, or both. Species such as gobies and blennies that hide away are often called ‘cryptic’ species. This following section covers benthic fishes which have a flattened body shape, well-suited to blending into low relief, open, featureless seabeds such as sand. It includes skates, rays and bony flatfishes. This is followed by a large section covering non-flattened benthic species, introduced on p. 148.

SD

A Topknot Zeugopterus punctatus

FLATTENED FISHES ON THE SEABED

Batoidea Skates and rays Skates and rays (batoid fishes) are one of two major groups of flattened, benthic (seabed-living) fishes that will be found living on sediment and occasionally on rock. The second group is the flatfishes (Pleuronectiformes), which are described from p. 122 onwards. The eight skate and two ray species most commonly seen by divers are described in the following pages, along with two other rarities. Like sharks (see pp. 34–43), skates and rays are cartilaginous fishes, with a pliable skeleton of cartilage rather than hard bone – indeed they are often thought of as squashed or flattened sharks. The body is vertically compressed, from the dorsal surface to the ventral surface (dorsoventrally). In contrast flatfishes are compressed from flank to flank (laterally) and lie on the seabed on one side or the other (see pp. 122–123). Both skates and rays have enlarged pectoral fins that form large ‘wings’, used to ‘fly’ through the water with a graceful flapping motion. In most species the tail is long and thin and may be used as a rudder, and in the case of stingrays, for protection. The eyes are placed high up on top of the head, and may initially be all that is visible of these fish, as they lie perfectly still after shuffling a covering of sediment over their back and wings. Other deepwater skates, particularly juveniles, may on occasion be found within diving depths and photographs of all species will help with later identification. snout eye spiracle snout mouth nasal opening

gill slits pectoral fin or wing pelvic fin

thorns

dorsal view

first dorsal fin second dorsal fin

caudal fin

The main skate features (using Thornback Skate Raja clavata

100

ventral view

What’s in a name? The terms ‘skate’ and ‘ray’ are often used interchangeably for different batoid species: ‘skate’ is frequently applied to species with long noses (such as Blue Skate) and ‘ray’ to short-nosed species (such as Cuckoo ‘Ray’). However, this is an artificial division without any morphological basis. Skates and rays are scientifically separated by their mode of reproduction, with skates laying eggs and rays producing live young. Almost all of the species found in British and Irish waters are skates and are so-called in this book (e.g. Cuckoo Skate Leucoraja naevus p. 112). Skates (Rajiformes) Have a tapering tail with rows of enlarged thorns and two small dorsal fins on it. All skates lay individual eggs with horny protective, oblong eggcases. These have projections at each corner and are colloquially known as ‘mermaid’s purses’. Any eggcases found underwater or intertidally can be identified to species level (see pp. 118–119. Stingrays (Myliobatiformes) Similar in general shape to skates, but the tail is slender and whip-like with one (sometimes two) serrated, venomous spines near the tail base and one or no dorsal fins. All rays, including stingrays, give birth to live young. Only the Common Stingray Dasyatis pastinaca (p. 116) is regularly found in British and Irish waters. The Pelagic Stingray Pteroplatytrygon violacea, and Common Eagle Ray Myliobatis aquila (p. 113) are very rare visitors. Electric rays (Torpediniformes) Have a rounded disc-like body and a short thick tail with two (usually) dorsal fins and ending in a large caudal fin. Like all other rays, they give birth to live young. Only two species are found in British and Irish waters (p. 117).

LB

A Spotted Skate Raja montagui

Skate and ray outlines (male)

Thornback Skate pp. 104–105

Spotted Skate p. 106

Blonde Skate p. 107

Small-eyed Skate p. 108

Undulate Skate p. 109

Cuckoo Skate p. 112

Blue Skate p. 114

102

Common Stingray p. 116

A juvenile skate almost completely buried in fine sand, leaving only the faintest trace of its outline visible. Jersey, Channel Islands.

A Small-eyed Skate Raja microocellata part-buried in fine sand. The wavy lines parallel to the edge of one of the pectoral fins allow it to be identified as this species. Gower, Glamorgan.

Marbled Electric Ray p. 117

LB

MG

Raja clavata Thornback Skate

Linnaeus, 1758

VC

A Thornback Skate showing the black and white bands on the tail, characteristic of this skate. Loch Alsh, Highland.

GENERAL DESCRIPTION Of all the short-snouted skates, the Thornback shows the greatest range of colour and pattern variants (see opposite). The background is usually greyish to brownish, often with small dark spots and larger cream to yellowish marks with dark edges. Some fish may be very pale and lack contrasting spots. However, the tail always has light and dark bands that usually stand out clearly, but can be faint especially in some of the paler colour variants. As the vernacular name suggests, this skate is particularly prickly on its dorsal surface, though this may be difficult to see underwater. Sexually mature skate have a row of large, broad-based thorns (called bucklers) running along the centre of the back and tail. This skate can grow up to 130cm in length but generally reaches 100cm or so. Adults and small juveniles of around 30cm in length are frequently seen by divers on mixed, often muddy, sediments in very shallow water, although the species is found down to over 1,000m. KEY FEATURES A skate with alternating dark and light bands on the tail and usually at least some large pale cream or white spots with dark margins on the dorsal surface. SIMILAR SPECIES Other skates may have dark and light bands on the tail, but these are generally much less obvious than those of the Thornback Skate. The most likely confusion is between Thornback variants that have rather small spots and which could be confused with Spotted (p. 106) or Blonde Skates (p. 107). Juvenile skates can be difficult to identify to species. ABUNDANCE AND DISTRIBUTION The Thornback Skate is widely distributed and common around Britain and Ireland, although there are fewer records from northeast England and the east coast of Scotland. This skate is the species most frequently seen by divers but records suggest it is not as common as previously thought. This is reflected in its classification as Near Threatened across its range, with steep population 10 m

25 m

104 FLATTENED FISHES ON THE SEABED –

Raja clavata Thornback Skate

(continued)

MM

Loch Hourn, Highland

RY

Loch Linnhe, Highland.

LB

Weymouth, Dorset.

LB

Juvenile. Mulroy Bay, County Donegal.

LKa

Loch Nevis, Highland.

Sark, Channel Islands.

LB

Loch Nevis, Highland.

SD

MM

Raja montagui Spotted Skate

Fowler, 1910

LB

Spotted Skate on hard ground. Kimmeridge, Dorset.

GENERAL DESCRIPTION This short-snouted skate has a pale yellowish to greyish brown background colour. It has large, more or less equally sized dark brown spots all over the dorsal surface and these do not extend right to the edge of the wings. On each wing there may be a small, dark ocellus in the centre of a pale yellowish diffuse circle. This circle may also be surrounded by either a few dark spots or a dark circle. This is a variable feature and may be absent or only appear as a vague cluster of slightly smaller dark spots. There may also be a number of small, circular, creamy coloured patches scattered over the surface, which lack spots. The pattern of spots is unique to each skate and can allow individuals to be recognised. Some skate may have a darker, steel blue snout. The Spotted Skate grows to a maximum of length 80cm, although is commonly seen at about 50cm. This skate occurs on sandy seabeds, from shallow water less than 10m deep to much deeper offshore waters (~800m). KEY FEATURES Covered in quite large, dark, similarly sized spots which do not extend to the extreme edges of the wings. SIMILAR SPECIES This short-snouted skate has the same pale yellowish to greyish brown background colour as the Blonde Skate (opposite) but the large, more or less equally sized dark brown spots all over the dorsal surface do not extend to the extreme edges of the wings. The Blonde Skate has proportionally smaller darks spots and these extend right to the edges of the wings. The Spotted Skate may have an ocellus on each wing while the Blonde does not. Thornback Skates (pp. 104–105) may have spots on their dorsal surface similar to those of the Spotted Skates, and occasionally have ocelli. Small juveniles may be especially difficult to distinguish from other skate species. ABUNDANCE AND DISTRIBUTION It is relatively common in southern and western parts of Britain, with scattered records as far east as East Anglia in England. It is also widely distributed around Ireland. 10 m

25 m

106 FLATTENED FISHES ON THE SEABED –

Raja brachyura Blonde Skate

Lafont, 1871

SD

The small, dark spots of the Blonde Skate extend to the extreme edges of the wings. Compare this with the fewer, larger spots of the Spotted Skate opposite. Sark, Channel Islands.

GENERAL DESCRIPTION This short-snouted skate is pale yellowish to greyish brown and has variably sized, small, dark spots which extend to the extreme edges of the wings. There are small, circular, cream-coloured patches which lack spots and are mirrored across the midline of the fish. This skate is typically found on sand banks which are subject to substantial water movement, with divers regularly recording it close inshore, in shallow water, at night, when these skates probably move in to feed. This is a large skate growing up to 120cm in length. KEY FEATURES Small, dark spots extending to the extreme edge of the wings. SIMILAR SPECIES The Spotted Skate (opposite) has larger dark spots in proportion to its body size, and these do not extend to the extreme edges of the wings. The Spotted Skate often has an ocellus on each wing. Small juveniles may be difficult to distinguish from other skate species. ABUNDANCE AND DISTRIBUTION This skate has a southern and western distribution in Britain and occurs all around Ireland and throughout the Irish Sea. It is rarely seen by divers, probably due to its preference for sandy seabeds subject to substantial water movement. This species is classified as Near Threatened across its range.

10 m 25 m

Raja microocellata Small-eyed Skate

Montagu, 1818

SD

The pale lines running parallel to the edges of the wings in both these images are characteristic of the Small-eyed Skate. Above Sark, Channel Islands. Right Jersey, Channel Islands.

KM

GENERAL DESCRIPTION As its name suggests, this short-snouted skate has distinctly smaller eyes than other skate species. The background colour is generally a sandy brown or greyish brown with paler whitish, wavy lines running parallel to the wing edges. There are also various pale spots and other faint, pale lines on the dorsal surface. It grows to a maximum length of 100cm though most individuals reach less than 60cm, and typically occurs on sandy sediments in water depths from less than 5m down to 100m. Small-eyed Skates often come close inshore at night where they may be seen by divers. This skate often lays its eggs in pairs in a rock crevice. KEY FEATURES Small eyes and pale lines running parallel to the wing edges. SIMILAR SPECIES None. ABUNDANCE AND DISTRIBUTION The Small-eyed Skate has a western and southern distribution around England and Wales, with a few records from southeast England and from the Irish Sea north to the border with Scotland. It occurs all around Ireland. This species is classified as Near Threatened across its range.

10 m 25 m

108 FLATTENED FISHES ON THE SEABED –

Raja undulata Undulate Skate

Lacepède, 1802

LB

Above The pattern of bold swirls and speckles shown by this female Undulate Skate is typical, but details are unique to each individual. Right Despite being partly covered in sediment, this large male can be confidently identified as an Undulate Skate. Both from Kimmeridge, Dorset.

GENERAL DESCRIPTION The Undulate Skate has a striking and distinctive pattern of dark, often chocolatecoloured, sinuous lines edged with small, pale white or creamy spots (absent in juveniles). There are also dark brown blotches on the pale brownish background and scattered whitish spots, larger than those edging the lines. There are two large, pale ovals, one on each wing towards the rear, which are usually prominent. The pattern of lines and spots is unique to each fish, allowing identification of individuals (see pp. 110–111 Undulate Ray Project). This skate grows to a maximum length of 120cm and occurs on mixed ground and sandy sediments from 5m to more than 100m. KEY FEATURES Dark sinuous lines edged with pale spots, and a large, pale, oval shape towards the rear of each wing. This skate swims differently from other skates, propelled by a series of waves rippling from end to end along each wing. In contrast, other skate species flap their wings up and down simultaneously and ‘fly’ through the water. SIMILAR SPECIES Provided that the distinctive markings on the dorsal surface of this skate are visible it can be identified with confidence. ABUNDANCE AND DISTRIBUTION The Undulate Skate is at the northern edge of its range in Europe, occurring commonly along the central southern coast of England and around the Channel Islands. It is also recorded from west and southeast Ireland. This species is Near Threatened across its range.

LB

10 m 25 m

The Undulate Ray Project The Undulate Ray Project (undulateray.uk) is a fascinating long-term study off the Dorset coast. Starting in 2012, it is focussed on populations and behaviour of Undulate Skates around Kimmeridge. The impetus for the project was the realisation that each fish has a unique pattern of spots and swirls on its dorsal surface allowing recognition of individuals on return visits. Using software originally developed for identifying individual giraffes from their hide patterns, photographs of rays were matched with previous images to discover if the fish had been photographed before. A total of 1,000 different Undulate Skates have now been identified (312 of these from the Kimmeridge site), of which 105 have been seen more than once. The ‘mark–recapture’ process of sequential sightings indicates an overall population of 300–500 different Undulate Skates using the site. In an extension of the study, samples of mucus were collected from a few Undulate Skates and genetically sequenced. The results confirmed the reliability of the mark–recapture technique for individual skates and indicated a genetically diverse population. The ability to recognise individuals has provided insight into the behaviour of these skates. Individual skates have been seen on the site multiple times, with one known as ‘Xerrys’ first recorded in August 2013, seen again in 2017, and then most recently in August © Martin Openshaw 2020, just a few days short of seven years after he was first observed. It seems these skates rarely move any great distance, with only two individuals from the whole dataset reported more than 30km from the point of first sighting. Results show that two sites on the Dorset coast separated by just 5km hold few shared individuals, suggesting the groups are very tight knit, which has implications for managing any fishery for this species. A surprising observation was that skates are not solitary fish but appear to have ‘friends’. The idea was first mooted when ‘Torvil’ and ‘Yveray’, two females recorded on the same day in August 2013, turned up again three years later on the same day in July 2016. Other Undulate Skates have also been seen on the site on the same day: four individuals together in June 2017 were all on the site again a year later, in 2018. Was this just coincidence? Statistical analysis demonstrated that the likelihood of this happening by chance was 1:700,000. Note The Undulate Ray Project observed the naming convention at the time it was created (thus Undulate Ray not Undulate Skate). Above Comparative images of the same skate photographed on different occasions showing unique, matching marks.

Left A mucus sample, taken from the skate in the foreground, being photographed in a labelled

110 FLATTENED FISHES ON THE SEABED –

MD

A montage of twelve different Undulate Skates showing the variation in patterns. Kimmeridge, Dorset.

FLATTENED FISHES ON THE SEABED

Leucoraja naevus Cuckoo Skate

(Müller & Henle, 1841)

CR

The distinctive dark ocelli with pale spots on the base of each wing, identify it as a Cuckoo Skate. Skye, Highland.

GENERAL DESCRIPTION This brownish skate is only likely to be seen on deeper dives. For example, deep wreck divers might spot one on the surrounding sediment. The outline shape is smooth, with a short snout and rounded wings. However, the most distinctive feature is a pair of large, round ocelli on the base of each wing (pectoral fin). These are black, often outlined with yellowish spots and filled with pale (white/yellow) spots. A double row of thorns starts with a triangular patch between the ocelli and runs to the end of the tail. KEY FEATURES A short-snouted, brown skate with a pair of very distinct round, black and pale-spotted ocelli. SIMILAR SPECIES Other skates such as Thornback Skate (pp. 104–105) may also have ocelli but these are less well defined, without the clear black and spotted markings. ABUNDANCE AND DISTRIBUTION Common all around Britain and Ireland, especially offshore, but less so in southern North Sea. Only occasionally seen by divers as it is most abundant below diving depths.

112 FLATTENED FISHES ON THE SEABED –

Skate and ray visitors A small number of other skates and rays may be found very occasionally around Britain and Ireland within diving depths. These are deepwater or rare visitors from the south or north. Common Eagle Ray Myliobatis aquila and Starry Skate Amblyraja radiata are described here but have very rarely, if ever, been seen by divers around Britain and Ireland. They are included here to highlight the possibility of an exciting sighting. Records of these exceptional rarities, whether by divers or anglers, will always require a photograph for verification. There are also deepwater skates within British and Irish waters that may occasionally wander within recreational diving depths (above about 40m), but are not further described here. These include the Critically Endangered White Skate Rostroraja alba (a southern species) and Shagreen Skate Leucoraja fullonica (the latter classified as Vulnerable throughout the northeast Atlantic).

Myliobatis aquila Common Eagle Ray

(Linnaeus, 1758)

Unmistakable (in British and Irish waters), uniformly brown ray, with a bulbous head and long pointed wings used to ‘fly’ through the water. It has a whip-like tail with a strong spine and small dorsal fin near the base. Most records are from the English Channel, but its range extends around Britain and Ireland except the northern North Sea. This species is classified as Vulnerable.

The unmistakable Common Eagle Ray. Canary Islands.

Amblyraja radiata Starry Skate

(Donovan, 1808)

JiG

A short-snouted skate with short, rounded wings. Also called Thorny Skate, it has a line of very prominent, thick-based thorns (13–17) along the midline and tail, plus other scattered thorns and thornlets over its dorsal surface. Colour is light brown with numerous light and dark spots and blotches. A Northern European cold­water skate whose distribution extends south into Britain and Ireland, but not as far as the English Channel or southern Ireland. Mostly found below 30m depth, but in colder Norwegian waters it is commonly seen by divers, even in water as shallow as 5m. Currently listed as Least Concern in European waters, but more recently

Dipturus batis Blue Skate

(Linnaeus, 1758)

OST

Above Attracted to a BRUV, this Blue Skate shows the pattern of pale swirls, spots and blotches and two darker ocelli on the wings. Mainland, Orkney. Right Eggcases of the Flapper Skate, right, and the much smaller Blue Skate, left. Mainland, Orkney. PM

GENERAL DESCRIPTION Also known as Common Skate. This is the smaller of the two Dipturus species in this guide, reaching around 150cm in total length. It has a long pointed snout and the front edges of the wings are distinctly concave in outline. Dorsal surface is a variable brownish grey with lighter, often indistinct streaks, swirls and blotches. A dark, oval-shaped ocellus with a pale yellowish outline is usually present on each wing and is definitive if clearly visible. Both this species and Flapper Skate (opposite) are patchily dark (completely in juveniles) on the ventral surface, but this is not usually visible to divers. Records without a photograph for verification should be recorded as ‘Dipturus sp.’ KEY FEATURES Large skate with pointed snout and concave front edge to wings. Dark, oval ocellus with light outline on each wing. SIMILAR SPECIES The Flapper Skate (opposite) is very similar but lacks the distinctive oval ocellus on each wing (but may have smaller ‘pseudo-ocelli’ of circular areas of pale spots). The Cuckoo Skate (p. 112) has distinct dark ocelli but head and wing shape are completely different. Two further Dipturus species, the Black Skate D. nidarosiensis and Longnosed Skate D. oxyrinchus (neither described separately here) occur offshore, below 70m depth. ABUNDANCE AND DISTRIBUTION Predominantly a southern species, extending around English, Welsh and southern Irish coastlines, and much more rarely into

114 FLATTENED FISHES ON THE SEABED –

Dipturus intermedius Flapper Skate

(Parnell, 1837)

CR

LB

Above The pattern of pale spots forming lines and curves distinguish this skate from the rather more intricately patterned Blue Skate. Summer Isles, Highland. Left Juvenile. Loch Sunart, Highland.

GENERAL DESCRIPTION The Flapper Skate is the largest of all European skates and rays and can potentially reach 250cm in total length (including the tail) and an age of 50 years. However, fish of this size and longevity are now extremely rare due to overexploitation. The outline shape is very similar to that of the Blue Skate (opposite) with a long, pointed snout and concave edges to the front of the wings. The dorsal surface is dark olive green or brownish grey, with scattered white spots in both, often forming graceful lines and curves. Juveniles have a concentrated patch of these spots on the wings either side of the midline. Records without a photograph for verification should be recorded as ‘Dipturus sp.’ KEY FEATURES Very large skate with pointed snout and concave front edge to wings. Patterned with scattered white spots. SIMILAR SPECIES Blue Skate (opposite) is very similar but only reaches 150cm in total length, has an oval-shaped ocellus on each wing and variable, lighter streaks, swirls and blotches. ABUNDANCE AND DISTRIBUTION In contrast to the Blue Skate, this species has a predominantly northerly distribution and is most likely to be seen by divers around Scotland, but also occurs all around Ireland and Wales. Sightings in the English Channel

Dasyatis pastinaca Common Stingray

(Linnaeus, 1758)

PBo

Above and right Despite its vernacular name this is an infrequent visitor to British and Irish waters. Off Bognor Regis, West Sussex. PBo

GENERAL DESCRIPTION BEWARE – THIS SPECIES CAN STING. The Common Stingray is somewhat similar in shape to many familiar skates, but with wide, rounded wings and a pronounced tip to its short snout. However, the giveaway identification feature is the long, tapered, whip-like tail up to 1.5 times the length of the body. This tail carries a serrated, venomous spine (sometimes two) about a third of the way along, but has no dorsal or caudal fins. The spine can be difficult to spot underwater if it is lying flat along the tail. Young are about 12cm from wingtip to wingtip, reaching about 40cm when adult. Unlike the skates described on previous pages, the Common Stingray has no distinctive markings on its greenish to greyish brown body. Stingray species are common in warm and tropical waters, but this is the only one likely to be seen by divers around Britain and Ireland. KEY FEATURES Plain-coloured ray (indistinct yellow around eyes) with whip-like, tapered tail bearing a single (occasionally two) long spine and no caudal fins. SIMILAR SPECIES None. Skates are similar in shape but lack a tail spine (sting) and have dorsal fins on the tail. ABUNDANCE AND DISTRIBUTION A relatively rare summer visitor. Records exist from Wales, Ireland and north to Scotland although the majority are from southern

116 FLATTENED FISHES ON THE SEABED

Torpedo marmorata Marbled Electric Ray

Risso, 1810

GrB

Above The marbled colouring distinguishes this ray from the more uniformly coloured Atlantic Torpedo Ray. Chesil Cove, Dorset.

SD

GENERAL DESCRIPTION BEWARE – THIS SPECIES CAN GIVE A STRONG ELECTRIC SHOCK IF TOUCHED. In outline, the Marbled Electric Ray has a very rounded shape in distinct contrast to the diamond-shape and pointed wings of other skates and rays described in this book. The front profile of the head is almost straight and flat, though there is a fringe of tentaculate papillae around the spiracles behind the eyes. The tail is short and thick with a large, paddle-shaped caudal fin at the end, preceded by two rounded dorsal fins. There are no spines either on the dorsal surface or tail. The dorsal surface background colour is cream to pale brown/grey, liberally sprinkled or marbled with darker and lighter brownish spots and blotches. KEY FEATURES A moderate-sized ray with a marbled brownish colour, a thick body, short tail and well-developed caudal fin. Fringed rather than smooth spiracles. SIMILAR SPECIES Atlantic Torpedo Ray Tetronarce nobiliana (previously Torpedo nobiliana) is very similar in shape, but is a fairly uniform dark brown to grey or almost black in colour. The spiracles in Atlantic Torpedo Ray are smooth and lack the fringing knobbly papillae of Marbled Electric Ray. It is not described separately in this book. ABUNDANCE AND DISTRIBUTION Marbled Electric Ray is only occasionally seen by divers, mostly along southern coasts, rarely extending further north than the English Channel and southwest England. The Atlantic Torpedo Ray seems to be reported even less frequently by divers but appears to be more widely distributed, with scattered records along the south coast of England, around Ireland, in the Irish Sea and as far north as the Hebrides. Above right Papillae round the spiracles. Sark, Channel Islands.

Juvenile about the size of a dinner plate. Les Écréhous,

Shark and skate eggcases The majority of the shark, skate and ray species described in this guide lay eggs with a tough outer casing, often known as ‘mermaid’s purses’ rather than giving birth to live young. Catshark (Scyliorhinidae) eggcases, slim with long anchoring tendrils at each end, are a relatively common sight underwater, often with developing embryos visible within. Skate eggcases, generally wider with long horns at the corners, are seldom sighted in situ so any underwater records are valuable. Fresh eggcases are easy to spot but older ones can be covered in debris and be well camouflaged.

DW

Smallspotted Catshark Scyliorhinus canicula (p. 42). Loch Creran, Highland.

KB

Smallspotted Catshark Scyliorhinus canicula (p. 42), embryo visible. Kinlochbervie, Highland.

JH

LB

Tagging Nursehound Scyliorhinus stellaris (p. 43) eggcases showed it takes about nine months for them to hatch. Wembury, Devon.

Nursehound Scyliorhinus stellaris (p. 43) eggcases tangled with a Pink Sea Fan Eunicella verrucosa. Lyme Bay, Dorset.

118 FLATTENED FISHES ON THE SEABED

A Spiny Starfish Marthasterias glacialis feeding on a Thornback Skate Raja clavata (pp. 104–105) eggcase. Loch Nevis, Highland.

LB

MM

Undulate Skate Raja undulata (p. 109). Purbeck, Dorset.

PBa

Flapper Skate Dipturus intermedius (p. 115). Loch Eribol, Highland.

MM

Thornback Skate Raja clavata (pp. 104–105). Loch Nevis, Highland.

LB

Small-eyed Skate Raja microocellata (p. 108), usually laid in

FLATTENED FISHES ON THE SEABED

Other flattened fishes Apart from the flatfishes (pp. 122–145), and skates and rays described previously, two other flattened benthic fishes are found in British and Irish waters; the Angelshark (family Squatinidae) and Angler (family Lophiidae, pp. 146–147). Both of these species are sometimes, rather confusingly, referred to as ‘monkfish’.

Squatina squatina Angelshark

(Linnaeus, 1758)

JD

An Angelshark showing how its freckled brown and white colouring blends well with the sandy seabed. Wales.

GENERAL DESCRIPTION Also known as Monkfish. While there are 26 known species of angelshark worldwide, only one is found in British and Irish waters. Superficially, the Angelshark may be thought to resemble a skate or ray. However, it is a true, albeit compressed, shark with both eyes on top of the broad, compressed head and gill slits on the sides of the head. The mouth is at the end of a squared-off snout. The body is rather thick and it looks as though it has two pairs of ‘wings’, as both the pectoral and pelvic fins are very wide, flat and spread out sideways. Two dorsal fins are set far back near the typically shark-like caudal fin. Background colour varies from pale to dark brown with freckle-like darker spots and scattered lighter ones. Young fish often have a roughly reticulate pattern of widely spaced light lines. KEY FEATURES Unmistakable flattened outline with extended flap-like pectoral and pelvic fins along the side of the body. Two dorsal fins set far back. SIMILAR SPECIES If you are lucky enough to see one, it should be unmistakable. ABUNDANCE AND DISTRIBUTION A very rare fish around Britain and Ireland, listed as ‘possibly’ extinct in the North Sea. There have been recent (2020 and 2021) sightings from Welsh waters (see ‘Angelsharks in Wales’ opposite). It is considered Critically Endangered in all European waters.

120 FLATTENED FISHES ON THE SEABED

10 m 25 m

Angelsharks in Wales Angelsharks Squatina squatina were once widespread in the northeast Atlantic and the Mediterranean, but today sightings around Britain and Ireland are extremely rare. Wales is one of only a very few places in the northeast Atlantic where they are regularly (though uncommonly) sighted, with the Canary Islands another Atlantic ‘hotspot’. However, in the last few years sightings have increased off the coast of Wales, including photographs of juveniles, indicating the area’s importance as a nursery ground. The ‘Angel Shark Project: Wales’ was launched by the Zoological Society of London and Natural Resources Wales in 2018, to collate current and past records and gain a better understanding of this Critically Endangered species. The ultimate aim is to restore the health and abundance of the Angelshark population in Welsh waters. The project provides a way for divers, or anyone else, to record sightings and, while focused on Wales, sightings from any location are of great interest (angelsharknetwork.com/#map or email angelsharks@ zsl.org). Angelsharks are fully protected in England, Wales and Northern Ireland and the species must not be ‘intentionally disturbed, targeted, injured or killed within 12nm of Welsh and English coastlines’. The species is prohibited from being landed in Scotland. However, records and photographs are important and an ‘Angelshark code of conduct for scuba and snorkel’ is provided on the project website (angelsharknetwork.com). The guidance is essentially to maintain a minimum distance of 1.5m and stay at the tail end of the fish. Historic records and photographs are also important and these can be reported in the same way. More information is provided in the project’s five-year action plan published in 2020. The Angel Shark Project is part of a wider initiative to encourage sightings of sharks, skates and rays off the coast of Wales, projectsiarc.com

JD

FLATTENED FISHES ON THE SEABED

Pleuronectiformes Flatfishes Flatfishes live up to their name with an extremely flattened body. This body shape, along with excellent camouflage coloration, means they are well adapted to live out in the open on the seabed, where they can hunt for invertebrate prey in relative safety. The majority occur on sediments and will mostly be seen lying still, often with a partial covering of sand. A notable exception are the topknots (pp. 142–145), the three species of which are often found on rocky substrata and mixed ground.

Metamorphosis Unlike skates and rays (pp. 100–117) which are vertically compressed from the dorsal surface to the ventral surface (dorsoventrally), flatfishes are laterally compressed from flank to flank. They do not start out like this, but undergo a remarkable change, or metamorphosis, during their early juvenile stage. Like many other fishes, the eggs hatch in open water and each tiny larval fish forms part of the plankton. At this stage, the fish has a normal upright posture and shape, but as it grows, it swims nearer and nearer to the seabed, becoming more and more laterally compressed. Eventually the minute fish settles onto the seabed, lying either on its right or left side – this is predetermined for different species and can be an additional identification aid (see below). The eye on the underside moves round onto the upward-facing side through tissue growth and destruction, while the mouth also twists round. Most flatfishes have a white underside, as pigment is lost on this now ‘blind’ side during metamorphosis. In some species, such as European Plaice Pleuronectes platessa (p. 126) and European Flounder Platichthys flesus (p. 127), the occasional fish settles on the ‘wrong’ side. These reverse-sided individuals are known as ‘sports’.

Outline shape and fins All flatfishes have a single, long dorsal and anal fin, each of which run from head to tail, forming a peripheral fringe around the body. The rays making up the peripheral fins taper in length from the middle to each end. The relative length in the middle rays varies between species. While all flatfishes are flattened, they differ in their body shape, from oval to distinctly rounded. This shape, together with the peripheral fins and lateral line shape, gives an outline that can be a useful starting point for identification. For example, soles have a neat oval shape. Outlines for the species included in this book, are shown on pp. 124–125. dorsal fin

eyes

mouth

caudal fin

gill cover lateral line

pelvic fin anal fin

pectoral fin

The main flatfish features (using Sand Sole Pegusa lascaris as an example).

Colour Some flatfish species exhibit consistent, recognisable colour patterns that are useful for identification, for example the eye stripes of Topknot Zeugopterus punctatus (p. 143) and the bright orange spots of European plaice Pleuronectes platessa (p. 126). However, many species are able to change their background colour to match their habitat, providing excellent camouflage and potential identification confusion (pp. 24–27). Norwegian Topknot Zeugopterus norvegicus (p. 145), which live on rocks, are particular experts, as are Lemon Sole Microstomus kitt

122

Species Seventeen of the 25 or so species of flatfishes that live in British and Irish waters are regularly or occasionally seen by divers and are described in the following pages. These should be identifiable to species level, especially if sightings are backed up by photographs, but scaldfishes and soles may prove difficult. There are several other common species found in British and Irish waters that are only rarely encountered by divers as they live mostly in deeper water. These include Megrim Lepidorhombus whiffiagonis, Long Rough Dab Hippoglossoides platessoides and Atlantic Halibut Hippoglossus hippoglossus and are not described in this book.

Know your left and right As described already, a flatfish’s outline, plus peripheral fins and lateral line shape, are key to identifying flatfish groups and species (pp. 124–125). However, recognising whether the flatfish you are looking at is leftor right-eyed fish provides additional confirmation. While this may be difficult to see underwater, especially in well-camouflaged flatfish, it can be much clearer in photographs. To tell whether a flatfish is left- or right-eyed, first visually orientate your fish. To do this rotate the view of your fish such that the pectoral fin is positioned below the lateral line. Whichever way your fish is now facing indicates what ‘eyed’ it is. Head facing right: right-eyed. Head facing left: left-eyed. To confirm you have rotated your view of the fish correctly look at the mouth, which should have the opening sloping upwards towards the dorsal fin. European Plaice, European Flounder, Dab, Lemon Sole, Witch Flounder and all soles, described in the following pages, are right-eyed flatfishes. In contrast, Brill, Turbot, scaldfishes and all topknots included in this guide are left-eyed flatfishes.

dorsal fin

A right-eyed flatfish (Dab, Limanda limanda)

pectoral fin dorsal fin lateral line

A left-eyed flatfish (Brill, Scophthalmus rhombus)

pectoral fin

lateral line

Flatfish outlines Diamond outline shape

European Plaice p. 126

Dab p. 128

European Flounder p. 127

Rounded outline shape

Turbot p. 141

Brill p. 140

Elongate, rather narrow, oval outline shape

Common Sole p. 133

Sand Sole p. 132

Thickback Sole p. 134

124

Oval outline shape

Witch Flounder p. 130

Imperial Scaldfish p. 139

Scaldfish p. 137

Thor’s Scaldfish p. 138

Fat, broad, oval outline shape

Lemon Sole p. 129

Topknot p. 143

Eckström’s Topknot p. 144

Norwegian Topknot p. 145

CB

This European Flounder Platichthys flesus is a ‘sport’, being a left-eyed individual rather than the more usual

Pleuronectes platessa European Plaice

Linnaeus, 1758

SD

Above This top-down view clearly shows the diamond shape formed by body and peripheral fins. The large, rather bright orange spots are often striking. Sark, Channel Islands. Right A row of bony knobs just behind the eyes distinguish this European Plaice from European Flounder (opposite). Portland, Dorset. LB

GENERAL DESCRIPTION This large, well-known flatfish is one of three related righteyed flatfish, all with a body shape outline that forms a rough diamond. The other two are the European Flounder (opposite) and the Dab (p. 128). The head profile is distinctly concave above the eye nearest to the dorsal fin and a row, or ridge, of bony knobs runs the length of the head from between the eyes. A classic European Plaice has large, scattered, bright reddish orange spots on both upper body and fins, but these can sometimes be faint or even absent in juveniles. Background colour is a variable beige with both white and dark blotches. European Plaice over 100cm in length were once frequent, but 50cm is a large fish nowadays. KEY FEATURES Large flatfish with conspicuous orange spots. Bony ridge between the eyes (not always easily visible). SIMILAR SPECIES European Flounder are similar in body shape and size, but have a straight-edged caudal fin, taller dorsal and anal fins, and any orange spots are indistinct. Occasional hybrids of European Plaice and European Flounder may have intermediate features. The Dab (p. 128) may also have spots but these are small and yellow. ABUNDANCE AND DISTRIBUTION While still relatively common all around Britain and Ireland, and frequently recorded by divers, intense fishing has depleted some regional populations.

126 FLATTENED FISHES ON THE SEABED

10 m 25 m

Platichthys flesus European Flounder

(Linnaeus, 1758) The diamondshaped outline, absence of orange spots and squared-off tail identify this fish as a European Flounder. Assynt, Sutherland.

JaG

The greyishbrown coloration varies to match the background. Far left Portland, Dorset. CB

GL

Left Seaford, East Sussex.

GENERAL DESCRIPTION European Flounder have a similar diamond-shaped outline to European Plaice, but more exaggerated because the dorsal and anal fins are much taller in the middle. This is a result of each fin having very long central rays, tapering to short at both the head and tail. The head profile is almost straight behind the eye nearest to the dorsal fin, rather than concave (as in the European Plaice). Small, spiny knobs run the length of the peripheral fins at their base, and the lateral line can be rough. While these may be difficult for a diver to see in situ, they can show up clearly in a close-up photograph. The caudal fin ends in an almost straight, squared-off edge. European Flounder are right-eyed (see p. 123), but in some populations more than a quarter may be reversed left-eyed individuals. Colour is a good match to the seabed, often with grey, brown or greenish hues and there may be rather faint orange spots. Despite the vernacular name, Lemon Sole is not in the family Soleidae. KEY FEATURES Large, rather thick looking flatfish with tall dorsal and anal fins, a straight-edged caudal fin and prickly knobs at the bases of the peripheral fins. SIMILAR SPECIES European Plaice (opposite) are similar in body size and shape but usually have conspicuous orange spots. However, occasional hybrids with European Plaice may have intermediate features. Dab (p. 128) are smaller with a distinct curve in the lateral line, which is almost straight in European Flounder and European Plaice. ABUNDANCE AND DISTRIBUTION Common all around Britain and Ireland. Often found in shallow water and estuaries as they can tolerate brackish conditions where fresh and salt water meet and mix. 10 m

25 m

Limanda limanda Dab

(Linnaeus, 1758)

RY

LB

Top A Dab showing its diamond-shaped body and fins with scattered yellow and black speckles. Loch Nevis, Highland. Above Detail showing yellow and black speckles. Loch Sunart, Highland. Right Orange tinge to pectoral fin. Strangford Lough, County Down.

PW

GENERAL DESCRIPTION The Dab, a right-eyed flatfish, has a similar body shape to European Plaice (p. 126) and European Flounder (p. 127) but is a more lightly built and smaller fish than either of these two. The lateral line forms a pronounced D-shaped curve immediately above the pectoral fin. Dab may often have small yellow spots with black flecks around them, with the overall background colour ranging from brown to greyish hues and matching the sediment on which the fish is living. The pectoral fin, which is often held upright, is sometimes a dull orange colour. There may be irregularly distributed rays on the peripheral fins which are darker for part of their length. Dab can sometimes be seen raised up off the seabed, balanced on the edges of the peripheral fins. While this fish can reach a maximum size of about 40cm, it is rare to see one much longer than about 20cm. Dab tend to occur on muddy or slightly sandy, mixed sediments in shallow water from less than 5m to over 100m. KEY FEATURES D-shaped curve in the lateral line above the often orange pectoral fin. SIMILAR SPECIES The Dab has a similar outline shape to European Plaice and European Flounder but is more lightly built. The orange spots on the European Plaice are brighter and larger than those on Dab and lack the black flecks around them. The irregularly distributed darker peripheral fin rays of the Dab could cause confusion with the Solenette (p. 135), but the latter has dusky rays which are regularly spaced and dark for their entire length. The Solenette’s shape is an elongated, narrow oval compared with the diamond outline of the Dab. ABUNDANCE AND DISTRIBUTION Common all around Britain and Ireland and is often recorded by divers. 10 m

25 m

128 FLATTENED FISHES ON THE SEABED

Microstomus kitt Lemon Sole

(Walbaum, 1792)

MM

LM

DW

Top On typical rocky habitat showing the yellow-centered, teardrop-shaped mark behind the pectoral fin. Farne Islands, Northumberland. Above left Small head and thick, prominent lips. Isle of Man. Above right Sheringham, Norfolk.

GENERAL DESCRIPTION While also right-eyed, and similar in size and body shape to European Plaice and European Flounder, Lemon Sole has a less angular outline shape, because the peripheral fin rays are relatively even in length along the body. It has a noticeably small head and mouth with thick, prominent lips and the short caudal fin is rounded. The lateral line has a very gentle curve above the pectoral fin. This flatfish is a master of camouflage and therefore highly variable in colour and markings, the large tear-shaped, dark-edged, yellow-centred blotch below the lateral line, behind the pectoral fin, is distinctive. Other large circles and ovals are typically scattered over the body, often with darker margins and paler centres. This flatfish is frequently found in rocky habitats but also occurs on sediment, although it rarely buries itself. Lemon Sole have been recorded from depths of less than 10m to over 200m, and can reach at least 60cm in length, though most recorded are less than half this length. KEY FEATURES Small head and mouth with thick lips and a distinct tear-shaped mark below the pectoral fin. SIMILAR SPECIES European Plaice (p. 126), European Flounder (p. 127) and the smaller Dab (opposite) have a similar body shape, but a top-down view of those species shows a more angular outline. ABUNDANCE AND DISTRIBUTION The Lemon Sole is common and widely distributed around Britain and Ireland.

10 m 25 m

Glyptocephalus cynoglossus Witch Flounder (Linnaeus, 1758)

LB

Above A top-down view clearly shows the narrow oval body shape and distinct straight lateral line. Loch Fyne, Argyll & Bute. Right Large prominent eyes and the white tip to the dark pectoral fin are also obvious features. Loch Fyne, Argyll & Bute. LB

GENERAL DESCRIPTION This right-eyed flatfish has a relatively narrow, elongated, oval body outline and a small head with rather large eyes. The peripheral fin rays are relatively short. The lateral line shows as a distinct pale, very straight, line running the length of the body with only the slightest rising curve just above the pectoral fin. Colour is pale pinkish brown with very small dark speckles and larger, darker blotches on the body and peripheral fins. The caudal fin has a pale margin backed by a narrow, dark line and the dusky pectoral fin has a similar white tip with a black inner edge. Adult Witch Flounder can reach 40cm in size but juveniles reported by divers are not more than about 15cm in length. Seasearch divers have recorded this fish on soft, muddy sediments in Scottish sea lochs at depths of 10–15m. Adults are considered to be deepwater fish, occurring in water depths ranging from 40m to over 150m. KEY FEATURES Very prominent straight, pale lateral line on a narrow, oval body. SIMILAR SPECIES Dab (p. 128) is found in similar habitats but has dark rays on the peripheral fins and a D-shaped curve in the lateral line. ABUNDANCE AND DISTRIBUTION Generally considered to be a deepwater, offshore species with a western and northern distribution around Britain and Ireland; it also occurs off the south coast of the latter.

130 FLATTENED FISHES ON THE SEABED

10 m 25 m

Flatfish colour variants

DW

Dab Limanda limanda. Norfolk.

LB

Dab L. limanda. Loch Sunart, Highland.

LB

Dab L. limanda. Strangford Lough, County Down.

LB

Juvenile Dab L. limanda. Loch Fyne, Argyll & Bute.

LB

LB

European Plaice Pleuronectes platessa. Loch Sunart, Highland. European Flounder Platichthys flesus. Portland, Dorset.

KLe

Norwegian Topknot Zeugopterus norvegicus. Harris, Highland.

RY

Soleidae Soles Soles are right-eyed flatfishes and are relatively easy to recognise as a group due to their elongate, oval body shape and small, smoothly rounded head. The head has a small but distinctive, crescent-shaped mouth and is fringed with small filaments that extend a short way onto the underside. The dorsal and anal fins have rays that are rather uniform in height, which emphasises the oval body shape. Four species are found around Britain and Ireland, of which the Common Sole Solea solea and Solenette Buglossidium luteum are the two soles most commonly seen by divers. The two other species, Sand Sole Pegusa lascaris and Thickback Sole Microchirus variegatus, live mostly below normal diving depths, but are occasionally encountered on deeper sediment dives, especially in summer. See p. 134 for table summarising the differences between these four species. Small juveniles of all four species can be found in shallow water, in sheltered, sedimentdominated bays and estuaries that act as nursery areas. Sand Sole and Common Sole are the most difficult to tell apart. Record as ‘Soleidae’ if uncertain.

Pegusa lascaris Sand Sole

(Risso, 1810)

GENERAL DESCRIPTION Sand Sole has the same classic oval shape, crescent mouth, and ‘designer stubble’ of small filaments fringing its head, as other soles. Underwater, it is not at all easy to tell this species from the more commonly encountered Common Sole (opposite) and it is always worth taking photographs. This may allow a view of the pectoral fin which has an elongated dark spot surrounded by a pale border, placed in the middle of the fin. Look also at the dorsal and anal fins which often have regularly spaced pale brown (not black) rays interspersed along their length. Background colour is light brown with a salt and pepper appearance of small black spots and pale blotches. KEY FEATURES A mainly offshore, deeper water sole (except juveniles) with a dark spot in the middle of the pectoral fin. SIMILAR SPECIES Common Sole also have a dark mark on the pectoral fin. However, this is on the end of the fin, extending right to the edge, and does not have a pale margin. ABUNDANCE AND DISTRIBUTION Rarely encountered by divers, but worth looking out for juveniles in the shallows of bays and estuaries. It has a southerly, offshore distribution which rarely extends beyond northwest Ireland into the Irish Sea, or into the southern North Sea.

ST

10 m 25 m

132 FLATTENED FISHES ON THE SEABED

Solea solea Common Sole

(Linnaeus, 1758)

SS

The tapering oval body shape and filament fringe around the head identify this as a sole. It may not be possible to identify the species. Devon.

GENERAL DESCRIPTION The largest of the four soles described in this book, reaching about 70cm, though divers usually see smaller individuals no more than 40cm long. It exhibits all the typical sole characteristics described opposite. The background colour is a pale, variable brown, most commonly overlain with scattered dark, mottled patches. Other smaller dark and light spots are often present. The visible pectoral fin has a variably sized, dark blotch that extends to the edge of the pectoral fin. Common Sole are sometimes referred to as MM Dover Sole, particularly in a commercial fisheries context. KEY FEATURES Large sole lacking distinct stripes on the peripheral The pectoral fin with a black spot extending fins. Dark black mark on pectoral fin extends to the tip. Any sole right to the edge identifies this as a greater than about 45cm will be this species. Common Sole. Lyme Bay, Dorset. SIMILAR SPECIES Other soles, especially Sand Sole (opposite) which also has a dark spot on the pectoral fin, although this is situated in the centre and has a pale surround. Be careful as the fin spot is not always clear in either species. Solenette (p. 135) have distinct dark stripes on the peripheral fins. ABUNDANCE AND DISTRIBUTION This is the most common of the sole species described in this guide, and is found all around Britain and Ireland.

SD

Fringe of filaments characteristic of soles

10 m 25 m

Microchirus variegatus Thickback Sole

(Donovan, 1808)

SBo

The large scales and broad darker bands across the upperside identify the Thickback Sole. Isle of Man.

GENERAL DESCRIPTION This is the most distinctive of the soles found in British and Irish waters. It has the classic oval shape, crescent mouth and fringe of small filaments around its head found in all soles but, as its name suggests, it has a thick, chunky body. The background colour is chestnut brown with distinctive dark brown, broken bars across the width of the dorsal surface and extending onto the dorsal fin and anal fin bases. KEY FEATURES A small, deepwater sole with dark banding. SIMILAR SPECIES Other soles, but the colour is distinctive. ABUNDANCE AND DISTRIBUTION Living mostly below 40m, this is the least likely species of sole to be seen by divers, although juveniles may be netted in shallow bays and estuaries where they live and grow in relative safety. While this fish is comparatively uncommon, and is a warmwater species occurring in southern British and Irish waters, it is worth looking out for.

Colour

Pectoral fin

Dorsal and anal fins

Special features

Large, dark mottles and paler spots

Black blotch extends to fin tip

No dark rays

Can exceed 45cm in length

Fine, dark and light speckles

No mark

Dark or black rays spaced along length

Obvious dark fin streaks

Sand Sole Pegusa lascaris

‘Salt and pepper’ speckling

Central black blotch with pale margin

Brown (often faint) rays spaced along length

Rosetteshaped nostril on underside

Thickback Sole Microchirus variegatus

Dark broken bands

No mark

Large dark blotches

Distinct colour pattern

Common Sole Solea solea Solenette Buglossidium luteum

Comparison of sole features.

134 FLATTENED FISHES ON THE SEABED

Buglossidium luteum Solenette

(Risso, 1810)

SS

Above A Solenette on fine sand showing the distinctive, regularly spaced dark fin rays and rather coarse scales typical of this fish. Devon. Left A juvenile showing regular dark blotches. Loch Hourn, Highland.

LB

GENERAL DESCRIPTION Due to its small size, mostly less than 12cm long, and speckled, sandy colour, this sole can be difficult to spot. However, if it is not covered in sand then it is often given away by the distinct, contrasting black stripes on the dorsal and anal fins. This striped appearance is due to every 5th or 6th ray being black from almost base to tip. It exhibits all other typical sole characteristics described on p. 132. KEY FEATURES A small sole with distinct, evenly spaced black stripes on the peripheral fins. SIMILAR SPECIES Other soles. The distinct black fin stripes should distinguish the Solenette. Common Sole lacks these. Sand Sole may have similar, but much less obvious, paler, brown fin stripes. Dab (p. 128) often have irregularly spaced, darker fin rays on the peripheral fins but the colour does not extend the full length of the rays. ABUNDANCE AND DISTRIBUTION Locally common and found all around Britain and Ireland.

10 m 25 m

Bothidae Scaldfishes Scaldfishes are medium-sized, left-eyed flatfishes, with elongate-oval bodies around 15–20cm long including the short tail. The caudal fin has a rounded rear margin with a blunt point. They have large, loosely attached scales which are frequently lost when the fishes are caught, making them appear ‘scalded’, hence the vernacular name. They then appear as rather dull brown fish. However, they are true masters of disruptive camouflage, with an amazing ability to match their surroundings using a wide palette of different colours. On their preferred habitats of mixed, rather muddy sediments, this makes them extremely hard to pick out, especially as the colour blocks can match the size and shape of surrounding shells and stones. This is probably the main reason that they are rarely reported by divers. There are three species of scaldfishes recorded from around Britain and Ireland, though it is likely these have been confused in the past. Available database records indicate a wide offshore distribution for the Scaldfish Arnoglossus laterna and a southwesterly distribution for the Imperial Scaldfish A. imperialis. Sightings of Thor’s Scaldfish A. thori were originally entered into databases simply as ‘Arnoglossus’ indicating the lack of certainty on the identification. There appear to be no photographs of the Imperial Scaldfish, and only a very few of the other two species, taken by divers around Britain and Ireland. If it is uncertain which species is being observed, these fish should be recorded as ‘scaldfish Arnoglossus sp.’

RY

Thor’s Scaldfish

Imperial Scaldfish

Scaldfish

LKa

Above left Thor’s Scaldfish Arnoglossus thori. Killary, County Galway. Above right Thor’s Scaldfish A. thori. Killary, County Galway. Left Scaldfish Arnoglossus laterna. Loch Sunart,

136 FLATTENED FISHES ON THE SEABED

Arnoglossus laterna Scaldfish

(Walbaum, 1792)

LB

A Scaldfish on sediment showing a mosaic of blocks of colour and unclear scales. Note the dark smudge behind and below the pectoral fin. Loch Nevis, Highland.

GENERAL DESCRIPTION This scaldfish has the most elongate oval body shape of the three species described here. The body is very compressed between the upperside and underside, such that it hardly protrudes above the seabed. Even at close quarters it is often difficult to make out the individual scales on the body surface. The ends of the peripheral fin rays above the mouth are free (not connected by membrane – see illustration opposite) for about half their length and are not elongated. Colour is a mosaic of light and dark browns and greys. In live fish there is usually a dark smudge behind the pectoral fin, just above the midline, with other dark blotches sometimes visible. Colour, contrast and hue are adapted to match the seabed. Scaldfish can reach up to 20–25cm but most are about 10cm. Scaldfish are typically found on muddy sediments from 10m to over 200m depth. KEY FEATURES Narrower, elongated, oval body shape when compared with the other two scaldfishes. Greybrown coloration with indistinct scales. Fin rays above mouth are not elongated. SIMILAR SPECIES Other scaldfishes. Compare fin rays above the mouth in particular: Scaldfish – no extended rays; Thor’s Scaldfish – one extended ray; Imperial Scaldfish – four or five extended rays. ABUNDANCE AND DISTRIBUTION The Scaldfish is widely distributed around Britain and Ireland, especially offshore. There are shallow water reports by divers and reports from Scottish sea lochs. The Scaldfish is probably under-recorded because it is so inconspicuous.

LB

Detail of head showing absence of extended, free fin rays above the mouth.

Arnoglossus thori Thor’s Scaldfish

Kyle, 1913

ID

Above Thor’s Scaldfish showing large scales and blocks of contrasting colour including blue tints. Sound of Mull, Argyll & Bute. Right Detail of head showing a pale, broad free fin ray above the mouth. Sound of Mull, Argyll & Bute.

GENERAL DESCRIPTION Thor’s Scaldfish has a wider body than the Scaldfish (p. 137), with large scales that can be clearly seen. It can be distinguished from other scaldfishes by the single, conspicuous, elongated second peripheral fin ray above the mouth. This ray is wide and ribbonlike and often a pale creamy white, its length sometimes shorter in female fish. This scaldfish exhibits a remarkable mix of coarse, blocky colours, mainly pale fawn to darker browns, along with white and often scattered smudges of blue. There is a conspicuous darker blotch, sometimes with a blue centre, behind the pectoral fin, just above the midline. It occurs on a variety of seabeds including muddy, sandy and coarse sediments, in the open as well as amongst seagrass, at depths from as little as 10m, but more usually from 15–200m. KEY FEATURES Conspicuous, elongated, pale second fin ray just above the mouth. Conspicuous, large scales and coarse, blocky colours providing disruptive camouflage. SIMILAR SPECIES Other scaldfishes. Compare fin rays above the mouth in particular: Scaldfish – no extended rays; Thor’s Scaldfish – one extended ray; Imperial Scaldfish – four or five extended rays. ABUNDANCE AND DISTRIBUTION While there appear to be no British or Irish records for this species on available databases, divers have photographed this fish in Scottish sea lochs and in County Galway, Ireland. There are also records from Cornwall on England’s southwest coast.

138 FLATTENED FISHES ON THE SEABED

ID

Arnoglossus imperialis Imperial Scaldfish

(Rafinesque, 1810)

AS

The number of extended fin rays above the mouth identify this fish as Imperial Scaldfish. Portugal.

GENERAL DESCRIPTION While similar in overall body shape to Thor’s Scaldfish (opposite), the Imperial Scaldfish can be distinguished by its ‘crest’ of four (females) or five (males) elongated and thickened fin rays above the mouth. They are usually found on sand or mud as well as rather coarser sediments. It is considered to be a deepwater species, occurring at depths from 60m to over 350m and therefore rarely seen by divers, although it has been photographed in shallower water in the Mediterranean. KEY FEATURES Four or five conspicuous, elongated fin rays just above the mouth. SIMILAR SPECIES Other scaldfishes. Compare fin rays above the mouth in particular: Scaldfish – no extended rays; Thor’s Scaldfish – one extended ray; Imperial Scaldfish – four or five extended rays. ABUNDANCE AND DISTRIBUTION There are numerous records for this species, showing a western and southern distribution around Britain and Ireland, extending into the North Sea. Despite this apparently wide distribution, there are no photographs of this fish in the field from Britain or Ireland.

Scophthalmidae Brill and Turbot Brill and Turbot are superficially similar with very wide bodies and an overall circular body shape.

Scophthalmus rhombus Brill

(Linnaeus, 1758)

LB

Above This top-down view emphasises the rounded outline of Brill. Swanage, Dorset. Right The ‘frill’ of free fin rays above the mouth distinguishes Brill from Turbot. Lyme Bay, Dorset.

GENERAL DESCRIPTION This left-eyed flatfish has an almost circular body shape outline with a broad caudal fin that has a rounded rear edge. It is one of the largest flatfishes likely to be seen by divers and can grow to well over 50cm in length. The first three or four fin rays above the mouth are not attached to each other, and are branched. A careful look or close-up photograph is needed to see this ‘frill’. Colour is highly variable, being mainly speckles and darker smudges with the background adjusted to best match the seabed. However, there is usually a dark blotch (though sometimes inconspicuous) on the midline of the fish near the caudal fin and young fish may have yellowish spots with a partial, darker outline. Brill are sometimes recorded over rocky habitat and live at depths of at least 50m, with young fish mainly on sediment in shallower water. KEY FEATURES Large flatfish with a rounded body shape and branched dorsal fin rays just above the mouth. SIMILAR SPECIES Turbot (opposite) is a similar size and shape but does not have branched fin rays above the mouth. ABUNDANCE AND DISTRIBUTION Brill has a southern distribution around Britain and reaches its northern limit in Scotland. It is rare around Ireland, although there are numerous records from the Irish Sea.

140 FLATTENED FISHES ON THE SEABED –

CB

10 m 25 m

Scophthalmus maximus Turbot

(Linnaeus, 1758)

SD

Above Turbot have a rounded outline but are a thicker fish than Brill (opposite). Sark, Channel Islands. Left There is no ‘frill’ of free fin rays above the mouth. Loch Fyne, Argyll & Bute.

PBa

GENERAL DESCRIPTION This left-eyed flatfish has an almost circular body shape, and a very broad caudal fin with a rounded rear edge. The rays of the fin above the mouth are relatively short and unbranched. This can be a large flatfish growing up to 80cm in length. These fish are masters of camouflage; colour is highly variable with speckles and blotches and the background colour adjusted to match the seabed. Adults have been recorded on sediment down to depths of c. 70m, while juveniles prefer sandy seabeds in very shallow water. KEY FEATURES Rounded body shape and short, unbranched fin rays just above the mouth. SIMILAR SPECIES Brill (opposite), which has three or four branched fin rays above the mouth. ABUNDANCE AND DISTRIBUTION Turbot has a southern distribution around Britain,

10 m 25 m

Scophthalmidae Topknots Topknots are small left-eyed flatfishes with a wide-oval body shape. However, the peripheral (dorsal and anal) fin rays are longest near to the caudal fin, then shorten abruptly where they meet the caudal peduncle, giving them rather a square profile at the back. The colour and markings of the three species recorded from Britain and Ireland can closely match their background, which may be sediment or rock. When on rock, this can result in some very colourful individuals, especially where the surface is covered in red and pink coralline algae or orange encrusting bryozoans. In spite of their camouflage, topknots will often hide away between boulders and in crevices, clinging closely to the rock surface. By creating suction between the body and a hard surface, topknots are able to cling to vertical surfaces and even upside down beneath boulders.

MM

LB

LB

TM

Top left Topknot Zeugopterus punctatus wedged in a vertical crevice. Eigg, Small Isles. Top right Topknot Z. punctatus. Poole Bay, Dorset. Middle right Eckström’s Topknot Z. regius. Eigg, Small Isles. Bottom left Juvenile Eckström’s Topknot Z. regius. Torbay, Devon. Bottom right Norwegian Topknot Z. norvegicus. Copelands, County Down.

142 FLATTENED FISHES ON THE SEABED –

Zeugopterus punctatus Topknot

(Bloch, 1787)

CB

Above Dark bars running backwards from the eyes to the peripheral fins show this left-eyed fish to be a rather pale Topknot. Lyme Bay, Dorset. Right Mouth set almost at right angles to the longitudinal axis of the fish. Poole Bay, Dorset.

LB

GENERAL DESCRIPTION This is the largest of the three topknots found around Britain and Ireland, growing to over 25cm in length. It is a thick-bodied flatfish with a deep oval shape. The top side of the fish is covered in a dense felt of soft spines (papillae), giving the surface a rather spiky appearance when viewed from certain angles. These are less well developed in juveniles. The mouth is set almost at right angles to the longitudinal axis of the body of the fish. Colour is variable, generally rather drab colours of grey and dark brown speckles with five or six large circles of more-or-less contrasting colour on the front two-thirds of the fish. Most striking are the dark diagonal lines which run from each eye slightly backwards to the edges of the peripheral fins. The Topknot prefers rocky habitats and can sometimes be found attached to the underside of overhangs or squeezed into narrow crevices, at depths down to c. 30m. KEY FEATURES A thick-bodied, left-eyed flatfish with a dark diagonal stripe running backwards from each eye. SIMILAR SPECIES Other topknots are usually smaller and less thick-bodied. Ekström’s Topknot (p. 144) has a distinctive V-shaped pattern on the rear half of the body pointing towards the head. The Norwegian Topknot (p. 145) has large scales. Both of these species are smaller and lack the soft papillae which form a thick pile on the upperside of the Topknot. ABUNDANCE AND DISTRIBUTION Common and widely distributed all around Britain and Ireland, although there are fewer records from eastern England and southeast Ireland where suitable rocky habitat is rare. 10 m

25 m

Zeugopterus regius Eckström’s Topknot

(Bonnaterre, 1788)

LB

Above Showing the distinctive dark, inverted V-shape marking and the yellow-centred dark blotch near the tail. Loch Nevis, Highland. Below Elongated first fin ray. Mull, Argyll & Bute.

GENERAL DESCRIPTION This topknot grows up to about 20cm in length, but is usually seen at no more than 10cm. The overall body shape is a broad, symmetrical oval. The scales are small and sometimes have papillae developed from folds of skin. These spines are often black. The first ray of the dorsal fin, above the mouth, is elongated, often a pale creamy colour and may be split for part of its length. The mouth is angled at about 60° to the longitudinal axis of the body. Colour is highly variable and matches the surrounding seabed very well. However, there are several distinctive markings, including a V-shape on the rear half of the body pointing towards the head, with a wider circular blotch at each end. There is a circular mark just in front of the tail, often orange or yellow surrounded by pale blue, dark brown or black. These markings are lost very rapidly on death and old descriptions of Ekström’s Topknot do not mention them. This fish seems to prefer boulders with silty sediment in shallow water less than 5m deep, down to about 50m. KEY FEATURES V-shaped mark on the body with a pale or dark circle on the midline near the tail. Small, very spiky scales. SIMILAR SPECIES Other topknots, especially Norwegian Topknot (opposite), although this lacks the described markings. The Topknot (p. 143) grows to be a much larger, thicker-looking fish with the mouth aligned almost perpendicular to the main body axis. ABUNDANCE AND DISTRIBUTION This would seem to be an uncommon fish although, because of its excellent camouflage, it may be missed by divers and hence under-recorded. It has a western distribution around England, Wales and Scotland, with records from both sides of the Irish Sea, otherwise there are few reports from Ireland. It occurs offshore along England’s south coast with rare diver reports as far east LB 10 m

25 m

144 FLATTENED FISHES ON THE SEABED –

Zeugopterus norvegicus Norwegian Topknot (Günther, 1862)

MM

LKe

Top The narrow oval shape and prominent scales of this left-eyed fish indicate it is a Norwegian Topknot. Knoydart, Highland. Above Relatively large, clearly visible scales.

LB

Rock-dwelling Norwegian Topknots can take on startling colours. Isle of Man.

GENERAL DESCRIPTION This is the smallest of the three topknots which occur around Britain and Ireland, growing to a maximum length of about 12cm, but usually not more than 8cm. The body is a more elongated oval shape than the other two topknots. The scales are large in proportion to the size of the fish, easily seen and are smooth, lacking the skin papillae present in the other two species (with the exception of scattered papillae on some scales). The mouth is set at about a 45° angle in relation to the longitudinal body axis. Colouring is highly variable, the fish blending in with the seabed around, ranging from greyish freckles on plain, muddy sediments, to bright hues of pink and orange on maerl or bedrock encrusted with coralline algae and bryozoa. The pectoral fin is frequently held almost upright. This small fish occurs in a wide range of habitats including soft, silty sediment, maerl beds and rocky reefs from about 5m to over 50m. KEY FEATURES Large, smooth, easily visible scales. Mouth at 45° to longitudinal body axis. Often covered with large patches of bright colour. SIMILAR SPECIES Other topknots. Both the Topknot (p. 143) and Eckstöm’s Topknot (opposite) have specific markings absent in the Norwegian Topknot. ABUNDANCE AND DISTRIBUTION This appears to be a common topknot all around Britain and Ireland. However, there are few records from diving depths from southern England.

10 m 25 m

Lophius piscatorius Angler

Linnaeus, 1758

RY

A small Angler lurking on mixed shelly sediment with maerl. Eday Sound, Orkney.

GENERAL DESCRIPTION Also known as Anglerfish or Monkfish. The Angler is a flattened fish that relies on concealment to survive and is a master of deception. Highly variable and disruptive colour and markings, together with peripheral seaweed-like frills, break up its outline and allow it to blend into the seabed. When lying on sediment, it is further concealed by partially burying itself. This fish has a head which is very broad and flat, and which is followed by a thick, fleshy, tapering body and tail. Large pectoral fins fan out horizontally and trail backwards from just behind the head. A fringe of intricate, leaf-like skin tassels breaks up the outline of both head and body. Colour is a variable shade of very detailed blotchy brown, through to greenish grey depending on the habitat. The iconic feature of this, and other anglerfishes, is the first dorsal fin, which is broken up into a series of separate rays, the first of which is very mobile and is used as a ‘fishing lure’, called an illicium. A wide variety of unwary fish and other mobile prey are eaten, often enticed within reach by the lure. This ambush predator relies on its camouflage and lightning-quick reactions to engulf its prey with its wide, upwardfacing mouth in a fraction of a second. KEY FEATURES A fish with a wide, flattened head decorated with seaweed-like skin tassels, upward-facing mouth and tapering body, often motionless and partly buried in sediment. SIMILAR SPECIES If partially buried, this fish might at first glance be taken for a large skate or ray, though these have the mouth hidden on the underside. Black-bellied Angler Lophius budegassa is very similar, but usually occurs well below diving depths (not described separately here). ABUNDANCE AND DISTRIBUTION A common, but declining species found all around Britain and Ireland. The Angler is a Priority Species for conservation in the UK (including Northern Ireland). Female Angler do not mature until around eight years

146 FLATTENED FISHES ON THE SEABED

Lophius piscatorius Angler

(continued)

PBa

A rare sighting of a juvenile Angler swimming well up off the seabed. Scapa Flow, Orkney.

TM

LB

Jeffreys’s Goby Buenia jeffreysii. Loch Sunart, Highland.

148 NON-FLATTENED FISHES ON THE SEABED

Non-flattened fishes on the seabed As described on p. 99, a huge variety of fishes of many shapes and sizes spend the majority of their life down on the seabed, only swimming relatively short distances when necessary. Fish (and other animals) with this way of life are termed ‘benthic’ and are part of the ‘benthos’. Their body shapes reflect this lifestyle. The concept of benthic species is described, and flattened species are introduced, in the opener to the previous section on p. 99. This section covers the wide variety of other benthic fishes that retain a normal upright, non-flattened shape, but have various features that are adapted to their benthic environment. For example, blennies and gobies have bulging eyes near the top of their head to help them spot danger. Gobies, clingfishes and Lumpsucker Cyclopterus lumpus have pelvic fins shaped as suckers to give them a firm footing in currents and waves. Rocklings, pipefishes and eels have long, thin bodies for slipping between rocks and seaweeds and helping with camouflage. Learning the characteristic shapes and other features of these various groups is an important first step to their identification.

PBa

A Conger Eel Conger conger and the much smaller, browner Ling Molva molva swimming over wreckage. Scapa Flow, Orkney.

LB

A Couch’s Goby Gobius couchi

NON-FLATTENED FISHES ON THE SEABED

Lotidae Rocklings Rocklings are small to medium sized, elongate fishes, most being under 30cm long though some species can reach twice this length. These fishes are mostly brown in colour with variable darker and lighter markings in some species. Provided the head is visible, the most obvious feature identifying a fish as a rockling is the three to five head barbels (fleshy filaments), one on the chin and the others on the snout (see below). Rockling species differ in the number of barbels present and this is helpful in identifying the individual species. While other species in the same taxonomic order, Gadiformes, such as Ling Molva molva (p. 156) and codfishes Gadidae (pp. 60–69) may also have a single chin barbel, none has upper snout barbels (with the exception of the Pogge Agonus cataphractus (p. 259) which is a very different looking fish). Rocklings have two dorsal fins, though the first is not obvious as it consists of a single, long ray followed by a series of very short rays set within a groove along the dorsal surface. However, this feature is often visible in good underwater photographs. This fin is in constant, rippling motion, drawing water towards the fish, helping it to detect prey. The second dorsal fin and the anal fin are long, but are not continuous with the caudal fin. As adults, most rocklings live a largely hidden existence in holes and crevices and very often only the head is visible. When out in the open, they are always ready to retreat rapidly back under cover. In contrast, juvenile rocklings, known as mackerel midge, start life as open water, surface-dwelling, small, silvery, shoaling fish that were at one time thought to be a different species to the adults. There are five species of rockling likely to be seen by divers around Britain and Ireland, although they are difficult to spot and so are not often reported. If in doubt as to the species record as ‘rockling (Lotidae)’. Five-bearded Rockling Ciliata mustela (p. 152) and Northern Rockling Ciliata septentrionalis (p. 153) – five barbels.

Four-bearded Rockling Enchelyopus cimbrius (opposite) – four barbels.

Shore Rockling Gaidropsarus mediterraneus (p. 154) and Three-bearded Rockling Gaidropsarus vulgaris (p. 155) – three barbels. two dorsal fins

pectoral fin

eye barbels

eye nostril nostril

caudal fin

barbels gill cover

lateral line pelvic fin

anal fin

The main rockling features (using Five-bearded Rockling Ciliata mustela as an example).

The juvenile mackerel midge form of a rockling bears little resemblance

150

Enchelyopus cimbrius Four-bearded Rockling (Linnaeus, 1766)

The barbels, prominent first dorsal fin ray and black marks at the rear of the dorsal and (just visible) anal fins characterise this fish. Newfoundland, Canada.

GENERAL DESCRIPTION The main features that identify a fish as a rockling are described opposite. The Four-bearded Rockling grows to a maximum length of about 40cm but is more usually seen at about 25cm. It has four barbels: one either side of the nostrils, one centrally above the upper lip and one on the lower jaw. The first ray of the dorsal fin is greatly elongated and very prominent. Dorsal surface is an unremarkable dull brownish in colour and the ventral surface is paler. It is the only one of the five species described in this book to have a black blotch at the rear end of both the dorsal and anal fins. This fish occurs on muddy, offshore sediments moving inshore in the winter to spawn in water depths of about 20m, returning offshore to deeper, cooler waters up to ~500m for the rest of the year. It is very rarely recorded by divers. KEY FEATURES The only rockling with four barbels. Black blotch on rear of dorsal and anal fins. SIMILAR SPECIES Other rocklings, but distinctive if barbels and marks on dorsal and anal fins are clear. ABUNDANCE AND DISTRIBUTION The Four-bearded Rockling has a very wide offshore distribution around Britain and Ireland. There are no diver records for this species on available databases; inshore reports are largely of juvenile fish.

Ciliata mustela Five-bearded Rockling

(Linnaeus, 1758)

JL

DW

Above A mottled brown individual showing the paler ventral surface and a clear view of all five barbels. Loch Long, Highland. Left A close-up view of the head. Norfolk.

GENERAL DESCRIPTION The main features that identify a fish as a rockling are described on p. 150. The Five-bearded Rockling can reach at least 30cm in length, though is often seen much smaller at around 10cm. It has five barbels: one on each nostril, a pair above the upper lip and one centrally on the lower jaw. Colour is most commonly a plain dark brown and a lighter ventral surface, though some fish are so dark as to appear almost black. Some individuals are a mottled darker and lighter brown. This is a common intertidal species occurring in rockpools and subtidally down to about 60m. The Five-bearded Rockling is found on a wide range of seabed types, from rocky areas with crevices to mixed, muddy sediments. A rockling with five barbels found in intertidal rockpools will usually be this species, as will any rockling over about 25cm long. If uncertain of the distinction between this and Northern Rockling (opposite), then record as ‘Ciliata sp.’ as long as five barbels can be seen. Otherwise record as ‘rockling (Lotidae)’. KEY FEATURES A small, dark, usually plain coloured rockling with five barbels. SIMILAR SPECIES Other rocklings, especially the Northern Rockling which also has five barbels and, while usually a pale coppery pink colour, can be brown. Northern Rockling does not usually occur in rockpools (but has been found intertidally in northeast Britain) while Five-bearded Rockling is common on the shore. ABUNDANCE AND DISTRIBUTION This rockling is widely distributed in shallow

152

10 m 25 m

Ciliata septentrionalis Northern Rockling

(Collett, 1875)

LKe

Above A pale individual with a coppery pink hue. Strangford Lough, County Down. LKe

Left The skin lobes on the upper lip are visible as well as the barbels in this view. Strangford Lough, County Down.

GENERAL DESCRIPTION The main features that identify a fish as a rockling are described on p. 150. This is a small rockling reaching a maximum length of less than 20cm. It has five barbels: one on each nostril, a pair above the upper lip and one centrally on the lower jaw. There is a frill of small skin lobes along the upper lip, but this may not always be visible in the field or in photographs. Colour is a fairly light brown (sometimes mottled) with a coppery pink hue that fades on death. This species occurs on a range of seabed types, from rocky areas to muddy sediments, mostly below 10m down to nearly 100m. It occasionally found in rockpools in the northeast of Britain. If uncertain of the distinction between this and the Five-bearded Rockling, then record as ‘Ciliata sp.’, as long as five barbels can be seen. KEY FEATURES A small, medium brown to coppery pink rockling with five barbels. SIMILAR SPECIES Other rocklings especially the Five-bearded Rockling (opposite). The Five-bearded Rockling is never coppery pink in colour (normally chestnut to dark brown) and does not have skin lobes on the upper lip. ABUNDANCE AND DISTRIBUTION The Northern Rockling is considered an offshore species, rarely reported by divers. There are numerous (mostly non-diver) offshore records from the Celtic Sea and Western Approaches. Otherwise, there are scattered inshore records from around Britain and Ireland. Its small size and possible confusion with the Five-bearded Rockling may mean it has been under-recorded in the past.

Gaidropsarus mediterraneus Shore Rockling (Linnaeus, 1758)

ST

Above This Shore Rockling has been caught out by the falling tide. Kimmeridge, Dorset. CR

Left Only the head needs to be seen on this red-brown fish to identify it as a Shore Rockling. Rosehearty, Aberdeenshire.

GENERAL DESCRIPTION The main features that identify a fish as a rockling are described on p. 150. Shore Rockling can grow up to at least 40cm in length but is more usually found at 20–30cm. It has three barbels: one just below each nostril and one centrally on the lower jaw. Dorsal surface is a uniform dull brown or reddish brown in colour, paler on the ventral surface. Sometimes with pale speckles on the flanks, especially along the lateral line. Some larger individuals have pale spots on the head. The Shore Rockling, as its name implies, is a shallow water species occurring on rocky seabeds to depths of about 20m, exceptionally down to 60m. KEY FEATURES A plain brownish coloured rockling with three barbels. SIMILAR SPECIES Other rocklings, especially the Three-bearded Rockling (opposite) which also has three barbels. The Three-bearded Rockling has distinctive dark spots or blotches over the paler dorsal surface and flanks and is not usually found in rockpools. ABUNDANCE AND DISTRIBUTION This rockling is patchily recorded from all coasts around Britain and Ireland, particularly from southwest. There are fewer records from southeast England and Ireland, where suitable habitat is lacking. Some databases show the Shore Rockling having a wide offshore distribution, especially in the Celtic Sea. However, it may have been confused with the Three-bearded Rockling, which has a much wider depth range and distribution.

154

10 m 25 m

Gaidropsarus vulgaris Three-bearded Rockling (Cloquet, 1824)

ST

Above Out in the open, the bold markings make this large rockling unmistakeable. Chesil Cove, Dorset. Left A small fish hiding within a wreck can still be confidently identified. Whitsand Bay, Cornwall.

TM

GENERAL DESCRIPTION The main features that identify a fish as a rockling are described on p. 150. This rockling, the largest of the five species described here, grows up to 60cm in length, though is more usually seen at 25–30cm. It has three head barbels: one just below each nostril and one centrally on the lower jaw. Unlike the other rocklings, it has a distinctive colour pattern of bold, dark blotches, sometimes in the form of rings, on a pale fawn or pinkish background. KEY FEATURES A rockling with three barbels and bold dark markings on a pale, fawn background. SIMILAR SPECIES Other rocklings, especially the Shore Rockling (opposite) which also has three barbels. However, the Shore Rockling does not have the dark markings on a paler background that are characteristic of the Three-bearded. ABUNDANCE AND DISTRIBUTION This rockling is widely distributed around Britain and Ireland, from the shallow subtidal to offshore depths of over 120m. There are few records from eastern England and Scotland.

Molva molva Ling

(Linnaeus, 1758)

CW

Above Ling showing its mottled brown-green dorsal surface and dark margins on all fins. Hand Deeps, Cornwall. ID

Right A rather greyer fish in wreckage. Unst, Shetland.

GENERAL DESCRIPTION Ling can grow to be a large fish up to 2m in length, although 1–1.5m is more usual. This fish has an elongated body and a large, rather pointed head with a conspicuous, long, white barbel on the lower jaw. There are two dorsal fins, the first short and the second long. These, along with the caudal fin and the long anal fin, have black edges often with a narrow, pale margin. There is frequently a dark blotch on the rear of the first dorsal fin. Adults are usually uniform steely grey to dark greenish brown. In contrast, young fish are predominantly a lighter brown, usually with mottled paler marbling and a whitish ventral surface. This fish can be found in deep rock crevices, under overhangs and among wreckage, occasionally it can be seen out in the open. Ling is considered to be a deepwater species, occurring down to 400m but there are diver reports (among others) from inshore waters less than 5m deep. KEY FEATURES A large grey or mottled brown fish with a large pointed head and a long white barbel on the lower jaw. SIMILAR SPECIES If the whole fish is not visible, a Ling could be mistaken for a small Conger Eel (p. 260) but the Conger lacks the conspicuous long barbel. Rocklings are mostly dark brown, have more than one barbel and never get as large as even a small Ling. There are two other species of ling found around Britain and Ireland: the Blue Ling Molva dypterygia, a deepwater northern species reaching its southern limit off northern Scotland and Ireland; and the Spanish Ling Molva macrophthalma which reaches its northern limit of its range off Scotland and the north of Ireland. These species are not described further here. ABUNDANCE AND DISTRIBUTION Ling is fairly common and widely distributed around Britain and Ireland, with inshore records from all regions apart from the

156

Raniceps raninus Tadpole Fish

(Linnaeus, 1758)

ST

JaG

JBr

Top Seen from above, the resemblance in shape to a large tadpole is clear. Kimmeridge, Dorset. Above left Loch Carron, Highland. Above right Kilkee, County Clare.

GENERAL DESCRIPTION This elongate fish resembles a giant tadpole in shape. The broad head has large eyes and a large mouth, with a very small, pale chin barbel. The head tapers to a rather short, stout body and a rounded caudal fin. At a glance, the fish appears to have only one long dorsal and one anal fin, sometimes with pale or white edges that show up against the fish’s dark purple-brown to almost black colour. There is also a minute first dorsal fin that might be visible on a really close look (or photograph). Tadpole Fish can be seen out in the open during the day, but spend much of their time hiding in the safety of rock crevices. However, it is worth keeping an eye out for a protruding, broad head, sometimes with ghostly white lips, when recording animals and seaweeds close-up in rocky areas. Divers sometimes see individuals in the open in poor condition, with mouth damage and abrasions on the skin. Tadpole Fish seem to inhabit shallower water, up to the low tide mark, in northern areas and deeper water in the south. KEY FEATURES An elusive, elongate, tadpole-shaped, dark fish with white or partly white lips, a small chin barbel and sometimes pale edges to the dorsal, anal and caudal fins. SIMILAR SPECIES Rocklings (pp. 150–155) and Ling (opposite) are similar in shape and also have the habit of hiding away with only the head visible. Rocklings have between three to five chin barbels. Ling has a single, long, white barbel but a much flatter, grey-brown head. Of these, only the Tadpole Fish has white or partly white lips. ABUNDANCE AND DISTRIBUTION Occurs all around Britain and Ireland in inshore waters, but is rarely recorded due to its reclusive nature.

Anarhichas lupus Wolf Fish

Linnaeus, 1758

SS

A pair of Wolf Fish in a large crevice. This head-on view shows the large, peg-like teeth so characteristic of this species. St Abbs, Berwickshire.

GENERAL DESCRIPTION The Wolf Fish is a large, grey, crevice-dwelling fish. Usually only the large head of an adult fish will be visible, but this is craggy and has very obvious peg-like teeth often set rather crookedly in its mouth. This feature makes an adult Wolf Fish easily identifiable even if the whole body cannot be seen. A fully grown Wolf Fish can be over 100cm in length and its smooth, pale grey flanks have narrow, vertical, dark bars. Juveniles are brownish or greyish with cream marbling on the head and flanks and relatively wide vertical bars, and are more commonly seen out in the open. Despite a rather aggressive appearance, Wolf Fish are generally docile but may be inquisitive and some have even become habituated to divers. Wolf Fish usually live as solitary individuals at depths of around 20m to over 150m. KEY FEATURES The large, crooked teeth are unlike those of any other fish found around British or Irish coasts. SIMILAR SPECIES None. With their thick lips and elongated shape, very small juvenile Wolf Fish could possibly be confused with a blenny, particularly the Shanny (p. 165) which lacks the distinctive head tentacles present in most blennies. Wolf Fish occur much deeper than Shanny. ABUNDANCE AND DISTRIBUTION While records suggest a northeasterly distri­ bution, with reports from Scottish coasts including Orkney and Shetland, there have

158

Anarhichas lupus Wolf Fish

(continued)

PBa

A Wolf Fish feeding on a crab, showing the dark vertical bars on its flank. St Abbs, Berwickshire.

PBa

Mullus surmuletus Red Mullet

Linnaeus, 1758

PNa

A Red Mullet foraging on the seabed showing the long, white barbels which it uses to search for food in the sediment. Plymouth Sound, Devon.

GENERAL DESCRIPTION This slender fish has a blunt, steeply sloping head with two characteristic long, white barbels extending from the lower jaw. It has two separate dorsal fins, a clearly forked caudal fin and obvious large scales on the body. The Red Mullet belongs to the same family as tropical goatfish (Mullidae) and, like them, probes into sediment with its barbels searching for edible items before digging them out using its mouth. This results in a cloud of disturbed sediment – often the first indication that a Red Mullet is present. Colour is variable, depending on age, mood, depth and time of day, but is based on red, orange and yellow. A common daytime pattern is of longitudinal stripes, often overlain with red blotches. At night and at depth, red predominates. The first dorsal fin is horizontally banded with black or brown and white. Very young fish swim in small shoals just above the seabed. At this stage they are have a green dorsal surface with white flanks and a single brown horizontal band running the length of the body. As they grow, juveniles develop red patches and a red band and move down onto the seabed. KEY FEATURES A slim, reddish fish with a steep head profile, constantly probing the sediment with a pair of long, white chin barbels. First dorsal fin banded. SIMILAR SPECIES None within diving depths. The similar Bearded Mullet Mullus barbatus barbatus (not described separately here) is usually found offshore in deeper water. ABUNDANCE AND DISTRIBUTION A southern species with regular diver records from southern and western England, along with scattered ones from all around Britain and Ireland, except the far north of Scotland. The majority of records are from late summer.

160

Mullus surmuletus Red Mullet

(continued)

SD

A shoal of adult Red Mullet investigating the seabed. Sark, Channel Islands. A juvenile Red Mullet showing the bright green and black dorsal surface and mottled red flanks as it adapts its life style from the water column to the seabed. Cley, Norfolk.

DW

A juvenile fish not long adapted to benthic life showing no bright red colour. Portland, Dorset.

LB

Blenniidae Blennies Blennies are elongate, tapering fishes with a blunt head, high-set, bulbous eyes and thick lips. Almost all species have tentacles high up on the head, just behind the eyes; the exception in British and Irish species being the Shanny Lipophrys pholis (p. 165). The shape of the head tentacles is a useful identification feature and close-up photographs are shown on pp. 163–164. Blennies have large pectoral fins but the pelvic fins are reduced to two stout rays (see below). These are strong enough to support the fish and they will often prop themselves up using these modified fin rays in order to have a good look round. This is typical blenny behaviour. There is a single, long dorsal fin that may dip down halfway along the body. The size range of British and Irish species is from about 8–16cm. The majority of blenny species live in rocky habitats and generally hide away in rock crevices and amongst seaweeds, where they can be difficult to spot. They are found mostly from the intertidal down to a depth of about 15m. In a global context, this is a very large family of fish with over 400 species, though only five species are regularly found in British and Irish waters. Some species, particularly Tompot Blennies Parablennius gattorugine (p. 168), appear to be curious and are often quite approachable by divers, but will dart back under cover if they feel threatened. During spring and summer, males may be seen in, or peering out of, crevices where they are guarding and looking after their eggs. head tentacles

bulbous eye

long single dorsal fin

mouth with thick lips

caudal fin gill cover

pectoral fin

anal fin

pelvic fin

The main blenny features (using Tompot Blenny Parablennius gattorugine as an example).

SD

162

A pair of Butterfly Blennies Blennius ocellaris in a gastropod shell. Sark, Channel

Guide to blenny (and blenny-like) fishes heads and head tentacles Some fish which look blenny-like, or include ‘Blenny’ in the vernacular name, actually belong to other families. Although they are not in the family Blenniidae, these have been included in the illustrations of the heads below. They are Viviparous Blenny (Zoarcidae, eelpouts), Yarrell’s Blenny and Snake Blenny (Stichaeidae, pricklebacks), and Black-faced Blenny (Tripterygiidae, triple-fin blennies).

No head tentacles

LB

Shanny Lipophrys pholis p. 165

DW

Viviparous Blenny Zoarces viviparus p. 178

Single central ‘crest’ with small filaments behind

LB

LB

Snake Blenny Lumpenus lampretaeformis p. 177

Single, unbranched, pale filament above each eye

LB

LB

Montagu’s Blenny Coryphoblennius galerita p. 166

Black-faced Blenny Tripterygion delaisi p. 179

Multi-branched tentacles forming a prominent tuft on the head

LB

Yarrell’s Blenny

LB

Multibranched filaments White or pale filaments branched on one side only

SD

SD

Butterfly Blenny Blennius ocellaris p. 167

Multibranched filaments Sparse, fine filaments in one plane

PNa

MM

Variable Blenny Parablennius pilicornis p. 171

Multibranched filaments in a three-dimensional arrangement

LB

MM

Tompot Blenny Parablennius gattorugine p. 168

164

KA

Red Blenny Parablennius ruber p. 170

MM

Lipophrys pholis Shanny

(Linnaeus, 1758)

LB

Above Disruptive camouflage among pale barnacles on dark rock. Knoydart, Highland. Right Juvenile about 15mm long. Weybourne, Norfolk. Below Pale lips of male fish guarding eggs. Swanage, Dorset.

GENERAL DESCRIPTION Once it has been recognised as a blenny (pp. 162–164), the Shanny is a very easy species to identify, as it is the only European blenny that lacks head tentacles. The colour consists of shades of brown and green, sometimes mottled, with patterning highly variable depending on habitat. There is a dark, irregular patch behind the eye, which is often eye-shaped and obvious. The rear parts of the thick upper lips are unpatterned and pale. Nestguarding males take on white lips and are very dark brown to black in colour. This species will be seen by both divers and snorkellers as it lives in rockpools and in very shallow water. KEY FEATURES A blenny found mostly in rockpools and in very shallow water (deeper in winter). Without head tentacles and usually a distinct dark patch behind the eye. SIMILAR SPECIES All other true blennies have head tentacles. ABUNDANCE AND DISTRIBUTION Common in shallow water all around Britain and Ireland but not often reLB

MSo

Coryphoblennius galerita Montagu’s Blenny (Linnaeus, 1758)

LB

GENERAL DESCRIPTION This small blenny (c. 8cm) is distinctive with a single, pointed head tentacle (or crest), sometimes fringed in gold, in the middle of the top of its head. There are four or five filaments directly behind this. Overall colour is determined largely by its habitat so that it blends almost perfectly with its surroundings e.g. black, brown and white among barnacles, duller and darker among mussels. Montagu’s Blenny has a series of dark saddles across its dorsal surface with small, white spots along the flanks, while the head is typically spotted with white and iridescent blue. Fins rays may be yellowish. Some fish have red/orange coloration on a generally greenish background under the chin. Montagu’s Blenny lives in the intertidal zone, moving up and down the shore with the tide or taking refuge in rockpools during low water, typically in areas with a reasonable amount of wave action. KEY FEATURES A small blenny in intertidal pools and the subtidal fringe on exposed to moderately exposed rocky shores. Single, centrally placed head tentacle, or crest, and several similarly positioned filaments immediately behind this. SIMILAR SPECIES None, provided you have a good view of the head tentacle (crest). Montagu’s Blenny could be confused with a small Shanny (p. 165) as this species shares the same habitat, though Shanny have no head tentacles. Small Rock Goby (pp. 192–193) might also be seen in the same habitat but these have two separate dorsal fins, whereas blennies have a single, long dorsal fin. ABUNDANCE AND DISTRIBUTION Montagu’s Blenny has very much a western and southern distribution in Britain and Ireland with large gaps in its recorded range. It is probably under-recorded.

166

A fish amongst intertidal barnacles. The single head tentacle is clearly visible. Eskigeen, County Kerry.

Blennius ocellaris Butterfly Blenny

Linnaeus, 1758

CL

Above A Butterfly Blenny with the characteristic dorsal fin raised. Porthkerris, Cornwall. Right A male guarding bright orange eggs in a mussel shell. Swanage, Dorset.

RY

GENERAL DESCRIPTION This is a stout, deep-bodied blenny which is quite distinctive if the very large dorsal fin is raised. This fin has an elongated first ray with a dark spot edged in cream one-third the way along the fin. There is a pair of forward-drooping tentacles set rather far forward on the head and a second pair of very small skin flaps behind these. Colour is usually mottled chocolate brown and white, though they can be almost black with contrasting white tentacles. Males can be seen guarding eggs, often in large Common Whelk Buccinum undatum shells, though they will use other items such as empty paired mussel shells, the folds of colonies of the Potato Crisp Bryozoan Pentapora foliacea and bottles. Because of their preference for Common Whelk shells it is increasingly difficult for the Butterfly Blenny to find suitable sites, as in some areas commercial Common Whelk fisheries have removed all large shells. In England the minimum landing size for whelks can be as low as 45mm, which is a very small shell for this robust blenny to squeeze into. Often, just the mottled brown and white head can be seen poking out of the fish’s retreat, as the male guards the eggs which are a rich red or orange colour. They prefer shell-rich, gravelly sediments and mixed ground, often including maerl, in water depths from 5m to over 100m. KEY FEATURES Large, extended dorsal fin with a dark spot edged in cream, set well back on the fin. Has habit of males guarding eggs, often in Common Whelk shells. SIMILAR SPECIES None if dorsal fin can be seen. Otherwise check head colour and tentacles (pp. 163–164). ABUNDANCE AND DISTRIBUTION This blenny has a southern and western

Parablennius gattorugine Tompot Blenny

(Linnaeus, 1758)

ID

Above Adult Tompot Blenny. Portland, Dorset. Far right A Tompot (foreground) and Variable Blenny (behind). Torbay, Devon. Right Juvenile with dark blue spot on front of dorsal fin. Swanage, Dorset.

LB

TM

GENERAL DESCRIPTION This large, solid blenny is an underwater photographer’s ideal fish, appearing to pose for the camera. The bushy head tentacles distinguish the Tompot from other blennies, though detailed shape is inconsistent (p. 164). Colour is variable, ranging from rich red-browns to more decidedly brownish hues; colour and pattern in part dictated by habitat. The head and body are marbled with blocks of colour appearing as interrupted dark and light broad, vertical bars down the flanks. The head pattern of each fish is unique (see Tompot Blenny project opposite). Juveniles have a dark blue spot on the front of the dorsal fin which fades gradually as they mature. The Tompot Blenny is relatively easy to watch going about its business underwater: guarding crevices containing its eggs, defending territory from intruders and hunting for food. This blenny occurs in rocky habitats and on wrecks with many nooks and crannies, from very shallow water to depths of over 30m. KEY FEATURES A crevice-dwelling blenny. Shape of the head tentacles (p. 164). SIMILAR SPECIES Very colourful, largely red versions of the Tompot Blenny could be confused with the Red Blenny (p. 170). A careful comparison of the head tentacles, the double pale bars radiating from the eyes and the body shape of the Red Blenny should prevent confusion. Tompot Blenny could also be confused with the recently arrived Variable Blenny (p. 171) which has a fine honeycomb pattern on the head and different head tentacles; juveniles have a prominent dark, longitudinal stripe absent in the Tompot. Nest-guarding male Variable Blennies are very dark, almost black, unlike Tompot Blennies which retain their normal colours. ABUNDANCE AND DISTRIBUTION This blenny is common in rocky habitats and among wreckage with a wide range of wave exposure in the Channel Islands, on southern and western coasts of England and Wales and all around Ireland. There are scattered records from around Scotland and England’s east coast wherever there is suitable rocky habitat. 10 m

25 m

168

Parablennius gattorugine Tompot Blenny

(continued) Far left A very brightly coloured Tompot Blenny which could be mistaken for a Red Blenny. Aran Islands, County Galway. Left A rather dull coloured Tompot Blenny. Lyme Bay, Dorset.

LB

RG

Tompot Blenny social structure and territories A long-term study of individually identifiable Tompot Blennies in Wembury Bay, South Devon, has provided information about territory retention and other aspects of their biology. Over a ten-year period, more than 50 individuals in two areas of shallow rocky reef have been identified from underwater photographs by their distinctive and unique head markings (see below). Observations show that males stay in their breeding territory throughout the year, although they may retreat deep into the rocky fissure in winter, and typically retain the territory for two to three years. One particularly tenacious, caring male guarded eggs in the same crevice for eight consecutive breeding seasons. Consistent with the typically complex breeding habits of blennies, males were found to host several different egg-laying females while a female would visit several male territory-holders, all during one breeding season. A new finding was that younger male Tompot Blennies can exhibit ‘sneaker’ behaviour, entering the home of a caring, territory-holding male during a female’s visit and apparently fertilising some of the eggs, without contributing to their subsequent care (see also Careful fathers pp. 198–199). All the observed ‘sneaker’ males became territoryholders in later years – another finding demonstrating the value of recognising individual animals. Tompot Blennies were seen to visit established territory-holders outside the breeding season and exhibit rolling, apparently submissive, behaviour. These and other observations of interactions within and between the genders indicate the presence of a fascinating social structure (marinephoto.co.uk/research/).

PNa

PNa

Three male Tompots, each showing their unique head markings. Wembury, Devon.

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Parablennius ruber Red Blenny

(Valenciennes, 1836)

PBa

Above A Red Blenny showing the two white bars beneath the eyes, the front one extending onto the lip. Tory Island, County Donegal. Right First record of a Red Blenny in Welsh waters (2016). The Smalls, Pembrokeshire. KLe

GENERAL DESCRIPTION Also known as the Portuguese Blenny, this is a solid-looking blenny reaching up to about 8cm. It is often brightly coloured with bright red or reddish brown blocks of colour, some of which may be edged in blue. Males defending territories are predominantly red, and brightest when breeding. There is often a blue spot on the front edge of the dorsal fin between the first and second fin rays, possibly indicating breeding fish. Juveniles may look brownish. Two pale bars radiate out from each eye, separated by a narrow band of darker brown or red, sometimes with blue margins. The front bar reaches to the lip. The head tentacles have two lobes and look two dimensional (p. 164). This fish prefers exposed locations where its habitat can overlap with that of the Tompot Blenny. It can generally be found by scanning likely looking rock clefts and ledges at potentially suitable, exposed rocky sites. It has been recorded in water depths from 5m to over 30m. KEY FEATURES Rich red colouring of males. Habitat typically in deep crevices on exposed, high-energy, rocky sites. SIMILAR SPECIES The Red Blenny can be confused with the Tompot Blenny (pp. 168– 169), especially at sites where both species are present. The Tompot Blenny has much bushier head tentacles (p. 164) and a finer chequer pattern on the cheeks. Juvenile Tompot Blennies up to about 5cm long have a blue spot on the dorsal fin between the third and fifth rays, a feature not seen in adults. ABUNDANCE AND DISTRIBUTION This blenny is never common at a site but records, many from Seasearch divers, show this fish to be widespread on exposed west and north coasts. Reports from the south and west of Ireland; the Isles of Scilly, Cornwall and south Devon in England; south Wales; and at exposed sites on the west coast of Scotland out to St Kilda.

170

Southern blennies The Mediterranean and adjacent coastlines are inhabited by a wide range of blennies and blenny-like fishes. There are at least 17 species of Mediterranean true blennies (Blenniidae), including three of the five (pp. 165–170) found around Britain and Ireland. With global warming, southern fish species are extending their ranges northward (see pp. 266–268). A recent addition to British and Irish waters is the Variable Blenny described here. Others may follow.

Parablennius pilicornis Variable Blenny

(Cuvier, 1829)

HS

PNa

Above left Typical (‘striped’) colouring. Lyme Bay, Dorset. Above ‘Standard’ pattern, including dark chin bands. Plymouth, Devon. PNa

Left Dark, mature male guarding eggs. Plymouth, Devon.

GENERAL DESCRIPTION In the Mediterranean this species is common and more usually called Ringneck Blenny due to two complete or partial dark bands under the chin. This typical, stout blenny shows all the usual blenny features, including a pair of head tentacles above the eyes, each with a short stalk topped by fine, thread-like divisions (p. 164). Colour varies with age and maturity: a ‘standard’ pattern of dark reddish-brown blotches forming smudged H-shapes along the flanks; a ‘striped’ pattern with a continuous dark band starting from behind the eye; and an almost black coloration in breeding males. In all, there is typically a honeycomb pattern over the head and cheeks. A uniform orangeyellow variation has not yet been recorded in British and Irish waters. KEY FEATURES Typical blenny with fine head tentacles, honeycomb head pattern, chin strap markings (not always distinct) and, in apparently younger/smaller fish, a dark band along the flanks (not all individuals). SIMILAR SPECIES Individuals with the ‘standard’ pattern are easily confused with the Tompot Blenny (p. 168), however the Tompot has large, tufted head tentacles and no chin straps. Individuals with the ‘striped’ pattern are distinctive. ABUNDANCE AND DISTRIBUTION Currently, in Britain and Ireland, records are restricted to the Channel Islands (Sark) and the south coast of England (Cornwall, Devon and Dorset). It was first recorded in Bigbury Bay, South Devon in 2007 (albeit as Parablennius rouxi) and by 2020 was documented just east of Portland Bill (see Changing fish distributions pp. 266–268). The distribution may well change further; more sightings and records should provide information on whether its range is expanding northwards. 10 m

25 m

Unrecognised flamboyance – discovery of the Red-mouthed Goby and Red Blenny Both of these colourful and flamboyant fishes have western distributions in Britain and Ireland but were only documented here comparatively recently. The Red-mouthed Goby Gobius cruentatus (p. 197) has the more restricted distribution, with records only from southern and western Ireland, including Lough Hyne in County Cork, several sites in County Kerry and in County Galway. The Red Blenny Parablennius ruber (p. 170), on the other hand, has now been recorded on very exposed rocky reefs from western Ireland, to Cornwall and the Isles of Scilly, north to Orkney.

LB

A male Red-mouthed Goby clearly showing why it has been given this vernacular name. Kenmare Bay, County Kerry.

The Red-mouthed Goby long went unrecognised as a member of the fish fauna in southwest Ireland until 1970, when the ichthyologist Alwyne Wheeler established the presence of this fish in the area. He had studied three museum specimens identified as the Black Goby Gobius niger. Two specimens had been collected in the 1930s, one from just outside Lough Hyne, County Cork, and another by Professor Renouf in Bantry Bay who had queried its identity with J.R. Norman at the Natural History Museum saying ‘…it is nearest to the black goby, but its colouring was all wrong, including, especially in the head region, a lot of bright red’. Norman ignored this observation and identified it as a Black Goby, remarking that this species was highly variable in colour. In 1960, a Redmouthed Goby was again reported from Lough Hyne, but once again recorded as a Black Goby. All three specimens were later identified as the Red-mouthed Goby by Wheeler, who also noted a report from Galway Bay of the capture of a ‘large goby with a reddish head…’ which he considered very likely to be a Red-mouthed Goby. There are recent records from the entrance to Killary Harbour in County Galway. JC A large, well-established population of the Red-mouthed Goby was confirmed in Lough Hyne in 1978 and on numerous Most northerly record to date (2022). Killary

172

side of Kenmare Bay. Two further locations in Kenmare Bay were discovered in 2009 and, at least at one of these, the population was still extant in 2022, with gobies consistently found in one particular overhanging, silty crevice during the intervening years. The Redmouthed Goby’s wider distribution extends from northwest Spain southwards to Senegal, as well as throughout the Mediterranean and into the Black Sea, meaning the Irish populations are very much outliers. The discovery of the Red (or Portuguese) Blenny on exposed western coasts of Britain and Ireland was first reported from Sherkin Island in 2003. A later (2007) study of historic underwater photographs showed that the species had in fact been photographed in 1982 on Skerd Rocks in Galway Bay but had not been recognised at the time. This colourful blenny has now been widely recorded on very exposed rocky reefs all around Ireland (excluding the southeast and east coasts); western Scotland north to Orkney (2000), including St Kilda (1998); the Isles of Scilly (2002); Cornwall (2012); and The Smalls off southwest Wales. Rather than using evidence from dead specimens, these reports were all derived from photographs, the great majority taken by Seasearch divers. The Red Blenny appears to have a more restricted distribution than the Red-mouthed Goby. First described from the west coast of France in 1836, the Red Blenny was only subsequently reported from the west coast of Portugal, Madeira and the Azores until its discovery in Ireland in 1982. It is also recorded from the north coast of Spain and off Finistère, Brittany. The lack of records for this colourful blenny could be in part due to its typical habitat: overhangs and crevices on very exposed rocky reefs which cannot be adequately sampled using remote methods. It was not until the advent of diver surveys that the wider distribution of the species was recognised.

MM

Above A male Red Blenny guarding eggs in a crevice. Small Isles, Highland.

RY

Right A fish peering out from its crevice with Jewel Anemones Corynactis viridis and Plumose Anemones Metridium dianthus, typical of its high energy habitat.

Other blenny-like fishes There are a number of small fishes that resemble true blennies (Blenniidae, see pp. 162–171) but which have long, eel-like bodies. Like blennies, they have stout heads with their eyes set high up, and thick lips. All have a single long, dorsal and anal fin and may or may not have head tentacles. Although distantly related to blennies, they belong to various different families: Pholidae (gunnels), Stichaeidae (pricklebacks), Zoarcidae (eelpouts) and Tripterygiidae (triple-fin blennies). The five species that divers or snorkellers are likely to see are described in the following pages.

Pholis gunnellus Butterfish

(Linnaeus, 1758)

MM

Above A typically marked fish with characteristic, large dark spots outlined in white on its dorsal surface. Loch Hourn, Highland. Left Showing ‘tear stain’ eye-stripe. Loch Carron, Highland.

GENERAL DESCRIPTION Also known as Rock Gunnel. This bottom-hugging fish of the gunnel family Pholidae, has a long sinuous body, slightly laterally compressed. Normally found hiding amongst seaweed or under and between rocks, this little fish slides away with sinuous eel-like movements when disturbed. Typically, a Butterfish can be easily recognised from the row of about 12 (9–15) evenly spaced black ocelli outlined in white that run along the length of the dorsal surface, at the base of the single continuous dorsal fin. However, colour varies with habitat and location (see opposite). A down-turned, oblique mouth with fleshy lips and a vertical ‘tear-stain’ eye-stripe give it a mournful expression. Minute pelvic fins, tiny embedded scales and copious mucus make this a slippery customer for predators. Butterfish are an important food for Black Guillemot Cepphus grylle. KEY FEATURES Small eel-shaped fish characterised (usually) by large, evenly spaced black ocelli along the dorsal surface. SIMILAR SPECIES If the classic patterning is present, confusion is unlikely. Individuals with unclear ocelli might be confused with Yarrell’s Blenny (p. 176), but that species has prominent head tentacles. ABUNDANCE AND DISTRIBUTION Common in shallow water all around Britain and Ireland. Also found intertidally.

174

LB

10 m 25 m

Pholis gunnellus Butterfish

(continued)

Colour variants

LB

Loch Nevis, Highland.

MM

Loch Nevis, Highland.

LB

Loch Creran, Argyll & Bute.

Portaferry, County Down.

RY

Loch Sunart, Highland.

LKe

LKa

Chirolophis ascanii Yarrell’s Blenny

(Walbaum, 1792)

MM

Above The eye-stripe and large, frilly tentacles help distinguish this large, blenny-like fish. Loch Hourn, Highland. Right In southern parts of Britain and Ireland, this fish only occurs in deeper water, at 45m in this case. HMS Warrior II, Dorset.

HW

GENERAL DESCRIPTION Yarrell’s Blenny (not a true blenny) has a long, thin body with a single, long, spiny dorsal fin, hence the name of the family it belongs to – pricklebacks (Stichaeidae). The first few spines are separate and have divided tips. The head is adorned with a pair of large, frilly tentacles (p. 163), sometimes preceded by another smaller pair as well as various skin filaments on the back of the head. The basic colour is a pinkish or yellowish brown with numerous vertical, darker brown markings and a series of pale and dark saddles running along the length of the dorsal surface. The obvious bulbous eyes are ringed with brown and a vertical stripe runs beneath each eye. KEY FEATURES A long, thin, crevice-dwelling fish with conspicuous, tufted head tentacles and a dark, vertical eye-stripe. SIMILAR SPECIES None if the whole fish is visible. Check carefully if only the head is visible, as the Butterfish (pp. 174–175) has a similar head shape and a dark eye stripe, but has no head tentacles. ABUNDANCE AND DISTRIBUTION Found all around British and Irish coasts, with the exception of parts of the southeast English and Irish coastlines where suitable habitat is lacking. Another name for pricklebacks is Arctic blennies because most are northerly coldwater fishes – probably the reason Yarrell’s Blenny is less abundant in

176

Lumpenus lampretaeformis Snake Blenny

(Walbaum, 1792)

LB

LB

Top The long dorsal fin and blotchy patterning are clearly visible on this adult fish. Elswick, Shetland. Above Juveniles are less strongly marked and the long dorsal fin is almost invisible. Elswick, Shetland.

GENERAL DESCRIPTION Living up to its name, this is a long, slender, snake-like fish with a pattern of dark brown blotches on a blue-grey to pale brown background. It belongs to the same family as Yarrell’s Blenny – the pricklebacks (Stichaeidae), and has a similar long, spiny dorsal fin running the length of the dorsal surface. The caudal fin is wide and has a pointed tip, though this might be difficult to see. The head is small, topped by protruding, high-set eyes. It can reach up to 50cm in length. The Snake Blenny burrows into muddy sediments (see Fish in burrows p. 263). KEY FEATURES A long, thin fish marked with large, sometimes rectangular brown blotches, living predominantly on sediments below 40m. SIMILAR SPECIES None. ABUNDANCE AND DISTRIBUTION A northern species, found mainly around Scotland and in the northern Irish Sea. There are some records from southeast England but these are of young fish in the plankton, adults may not extend so far south. While most records are from depths below 40m, on occasion it can be found much shallower.

Zoarces viviparus Viviparous Blenny

(Linnaeus, 1758)

DW

Above This fish appears to pose showing off the thick lips and large pectoral fins. Weybourne, Norfolk. Left In northern areas, this long eel-like fish can be found in the intertidal zone as well as on deep muddy sediments. Runswick Bay, Yorkshire.

PLi

GENERAL DESCRIPTION Also known as Eelpout. This fish is long and eel-like in shape (hence the name for the Zoarcidae family: eelpouts) and is slimy. It appears to have a single continuous fin running from just behind the head (above the pectoral fin base), around the pointed tail and along two-thirds of the ventral surface. Where the fin runs along the dorsal surface, it has a characteristic dip just before the tail, but this is difficult to see underwater. Colour is variable, mostly grey to brown with mottling and spots, with darker bars along the dorsal fin. Unusually, it produces live young which is uncommon in ray-finned (bony) fishes, hence the vernacular name and specific part of the scientific name. Diver sightings are most likely in soft sediment (mud) habitats such as sea lochs and they also occur on rocky shores in the intertidal. Viviparous Blennies are only occasionally recorded underwater, possibly due to preference for habitats not often frequented by divers; eagle-eyed snorkellers may be favoured here. KEY FEATURES Eel-like with thick lips, large pectoral fins and continuous dorsal, caudal and anal fins running around the body from the dorsal to ventral surface. SIMILAR SPECIES Superficially similar to small Conger Eel (p. 260) and European Eel (p. 261), but in both of these species the dorsal fin starts further back, behind the base of the pectoral fin. ABUNDANCE AND DISTRIBUTION The great majority of records are from northern and eastern areas of Britain, including intertidal and estuarine habitats. There are records from west coast Scottish sealochs, from the Clyde northwards, and Viviparous Blenny are common in Shetland where they are important prey for Otters Lutra lutra. There are rare records from Ireland’s east coast. 10 m

25 m

178

Tripterygion delaisi Black-faced Blenny

Cadenat & Blache, 1970

LB

TM

Top Juvenile. Portland, Dorset. Above The pale first dorsal fin. Falmouth, Cornwall.

MM

A bright yellow male fish displaying to a duller female. Swanage, Dorset.

GENERAL DESCRIPTION This moderate-sized blenny (more correctly a triple-fin) grows to c. 10cm and has three dorsal fins. Males in breeding colours have a startlingly bright yellow body which contrasts with a dark blue-black head (hence the name) and an electric blue margin to the dorsal, caudal and anal fins. Brightly coloured males can be seen in spring and early summer with the black head sometimes retained late into the year. Females and juveniles are an overall mottled brown colour, flecked with small white spots and several broad, paler saddles across the dorsal surface, blending in well with the general background. There are often rosy and copper coloured tints around the head, while dorsal and anal fins may be flushed maroon. Behaviour is distinctive, the fish often posing head-down on slightly overhanging surfaces, while flicking the pale, opaque, three-spined first dorsal fin. When absorbed in courtship and egg-laying, these fish can be approached closely without causing any apparent concern. Adult Black-faced Blennies can be found among boulders and on wreckage, especially overhanging surfaces clear of any silt. Juveniles typically occur among short seaweed growths where their mottled colouring makes them breeding male almost invisible until they dart for cover. Found in water depths from 1–20m. KEY FEATURES Dark blue-black head and brilliant yellow body of breeding males. Three dorsal fins, the first pale with three spines which the fish tend to flick. female/ SIMILAR SPECIES Males in breeding colours cannot be mistaken for any other fish in non-breeding male Britain or Ireland. At first glance, juveniles, and females and males outside the breeding season, might be mistaken for a goby, but the three dorsal fins are a unique feature. ABUNDANCE AND DISTRIBUTION This blenny is not common, occurring along England’s south coast, from Dorset to the Lizard in Cornwall, and in the Channel Islands. There are as yet no Irish records. 10 m

25 m

Gobiidae Gobies Gobies found around Britain and Ireland are mostly small fishes from around 2.5cm to 10cm in length, although a few are larger, with the Giant Goby Gobius cobitis (p. 195) reaching up to 30cm. The smallest fish on the British and Irish lists is Guillet’s Goby Lebetus guilleti (p. 200) with a maximum length of 2.5cm. Gobies have a broad, rounded head with a large mouth and prominent lips. Their body is cylindrical and gradually tapers to the tail. They have two dorsal fins, with the colour and shape of the first dorsal fin, in particular, helpful in identification. The detail of scale distribution over the dorsal surface and flanks of gobies is another useful characteristic for identification. In some species the scales are easily seen, on others high quality photographs are needed in order to make them out. Underneath the body is a sucker formed from highly modified, fused pelvic fins, which the fishes use to secure themselves in turbulent conditions. Gobies are a difficult group of fishes to differentiate, but with experience it is possible to identify many species underwater. Most gobies are benthic fish and can be found in a wide range of habitats including intertidal rockpools, rocky reefs, mixed sediments and soft muddy seabeds, from the intertidal down to water depths of 80m. Male gobies may construct a nest or adopt a crevice or shell and then attract females to lay eggs (see Careful fathers pp. 198–199). Goby interactions are known to be highly complex with studies demonstrating intricate courtship and territorial behaviours using sound as well as visual cues. There are 19 species of goby found around Britain and Ireland at present, however it is possible climate change may support the arrival of additional species. Worldwide, there are about 2,000 species of goby comprising over 10% of all known marine fishes. There are two main genera of goby in Britain and Ireland: Gobius and Pomatoschistus, each with six species. Details of how to differentiate species in these two groups are provided in tables on pp. 184–185. The main distinctions in the field between these two are size (any goby over 8cm in length is likely to be Gobius) and head shape (Gobius species have a rather steep, rounded head profile, while Pomatoschistus species (and Buenia) tend to have flatter heads with the eyes set towards the top). Once experienced at identifying adult gobies, it is often possible to distinguish the species of very small juveniles from good photographs. If in doubt about identity, record as ‘goby (Gobiidae)’.

KLe

Leopard-spotted Goby Thorogobius ephippiatus

180

MD

Guillet’s Goby Lebetus guilleti, the smallest adult fish in British and Irish waters, beside a large sea squirt. Kimmeridge, Dorset.

JF

Rock Goby Gobius paganellus, sucker formed by highly modified, fused pelvic fins. New Quay, County Clare.

MD

Two male Black Goby Gobius niger displaying. Poole Bay, Dorset.

CL

Displaying Painted Goby Pomatoschistus pictus illustrating the social interactions of these fish.

Which goby have you got? Before proceeding to work through the identification tables on pp. 184–185, you must decide which genus your goby belongs to. There are two main genera of goby in Britain and Ireland: Gobius with six species and Pomatoschistus also with six species (and possibly one more on the way). There are two main physical distinctions in the field between these two groups: size – Gobius species tend to grow larger; and the presence (in Gobius) and absence (in Pomatoschistus and all other goby species in Britain and Ireland) of separated free rays (i.e. no joining membrane between rays) on the upper edge of the pectoral fins (see p. 186). Obviously all fish grow, but once familiar with adults of the two genera, it is possible to distinguish even very small juveniles using good field photographs. The tables to distinguish the species of Gobius and Pomatoschistus require some experience to use and need to be referred to in combination with good field photographs. The characteristic which best distinguishes each species is highlighted in bold text in the table. If you are unable to identify the species, record as ‘Gobiidae sp.’, ‘Gobius sp.’ or ‘Pomatoschistus sp.’ according to your confidence level. There are several species pairs which cause particular problems: among Gobius this includes Black and Rock Goby, Rock and Giant Goby, Black and Couch’s Goby. It is impossible to distinguish the two sand gobies (Sand Goby and Lozanoi’s Goby) in the field and these, in turn, are hard, but not impossible, to tell apart from the Common Goby. This leaves seven goby species on the British and Irish list which are rather more distinctive. The best approach is to check out the descriptions and images of these first to confirm that you are not looking at one of them. If you do not get a good match then try to decide whether you might have Gobius or Pomatoschistus and proceed to the appropriate table. Leopard-spotted Goby Thorogobius ephippiatus (p. 188) – a blue-grey goby with large, dark brown to orange spots living in deep overhangs and clefts on rocky reefs. Old fish may be almost black. Fries’s Goby Lesueurigobius friesii (p. 189) – a grey and gold-spotted goby with particularly large pronounced scales on the dorsal surface, living in sheltered sites on soft, muddy sediments especially in western Scotland and Ireland. Diminutive Goby Lebetus scorpioides (p. 201) and Guillet’s Goby L. guilleti (p. 200) – extremely small (12cm.

Mature male

Female/ immature male

6–16cm.

1–10cm.

More or less bright blue scribbles with dark margins on brownish yellow background.

Brownish, red, speckled, depending on habitat.

Head colours

Bold, bright blue scribbles with dark margins on orange/brownish background. Brightest during breeding, fades later.

First dorsal fin shape

Pointed, very much higher than second dorsal.

Curved and tapering to a point (falcate). Higher than second dorsal.

Triangular, similar height to second dorsal.

Broad-based, tapering to a point (falcate). Held forward over head in display.

Triangular, similar height to second dorsal.

Near vertical blue lines on translucent background.

Gradually losing dark colour on rear section, becoming translucent.

Pale, opaque leading edge. Variable more or less dark colouring to rear.

Horizontal bright blue lines with dark margins on yellowish green background. Dark (black) mark on rear and along leading edge.

Variably coloured from entirely to partly grey/black, with the pale elements variably placed.

First dorsal fin colours

Second dorsal fin ray count (see below)

9 (rarely 8 or 10) (caution: double 9th ray with bifurcating ends could appear to be 10 rays).

Second dorsal fin colours

Horizontal blue lines on translucent background.

Second dorsal fin height

Less than a third the height of first dorsal.

Ratio of eye to head height (see below) 1

2 3

Brownish, red or speckled, depending on habitat.

2 3

More or less conspicuous, darker, horizontal banding on a translucent membrane; may appear as very subtle shading.

Steeply curved rows of dark-edged blue flecks and lines with dark smudges on yellowish green background.

Oblique rows of darker spots on a translucent background.

Less than half the height of first dorsal.

Slightly higher than first dorsal, depends on the way the fin is held at the time.

Similar height to first dorsal.

Similar height to first dorsal.

A less than B

4

5

6

7

8 9

1

10

4

5

6

7

8

Bifurcated final fin ray clearly showing, but ray count is 9, not 10

9 Bifurcated final fin ray folded and as such is barely visible

Second dorsal fin ray count, note bifurcation (see table above).

A equals B

A B

Callionymus lyra Common Dragonet

Linnaeus, 1758

PNa

Above A brightly coloured female showing second dorsal fin with nine rays. Note also the approximately equal height of the first dorsal fin, with pale leading edge. Fal Estuary, Cornwall. SBo

Left Fish showing the electric blue markings characteristic of adult males. Loch Long, Argyll & Bute.

GENERAL DESCRIPTION This wide-bodied dragonet is the largest of the three species described here, reaching 30cm, though 15–20cm is more usual. The eyes are set high on the head in comparison to those of the other two species, and are relatively smaller (see diagram p. 223: A less than B). Mature males have bright splashes and scribbles of electric blue on the head and flanks extending onto the pectoral fins. The dorsal fins, the first greatly elongated, have vertical (first dorsal) or horizontal (second dorsal) lines of bright blue. As noted in the introduction to dragonets, these brightly marked dorsal fins are rarely seen in the field, although there are rare occasions where displaying fish have been photographed by divers. Females and immature males lack the blue and orange colours. The first dorsal fin in females is triangular and the same height as the second, generally with a pale leading edge and dark behind. In immature males, this fin elongates and gradually becomes translucent without any distinctive marks. The second dorsal fin ray count is generally nine for this species (see diagram p. 223). Body coloration is extremely variable depending on the background habitat and is not a useful identifier (see range pp. 226–227). Compare other distinctive characteristics in table (p. 223). Common Dragonet occur on sediments and in areas of mixed ground among rocky reefs, to over 50m depth. KEY FEATURES Any female dragonet of 12cm or more in length is most likely this species. Mature males have electric blue flashes on an orange background on head and fins. With experience, and in conjunction with other characteristics (p. 223), the large size of mature males and females may permit a confident identification to species. SIMILAR SPECIES This fish is generally difficult to distinguish from the Reticulated Dragonet (opposite) though with experience, it may be possible to separate the two species in the field. For distinctions, see Reticulated Dragonet. If in doubt, record as ‘dragonet Callionymus sp.’ ABUNDANCE AND DISTRIBUTION This dragonet is widely distributed and common inshore around all coasts of Britain and Ireland, as well as offshore to depths of well over 50m.

Second dorsal fin with nine rays (see table p. 223). Loch

224

10 m 25 m

Callionymus reticulatus Reticulated Dragonet Valenciennes, 1837

CL

Above A brightly coloured male with huge dorsal fins displaying to a female. Loch Carron, Highland. Right A camouflaged female with erect first dorsal fin showing predominantly dark colouration. Loch Carron, Highland.

CL

GENERAL DESCRIPTION A small dragonet, reaching only around 16cm in length, more usually 12cm. A topdown view of this fish shows a narrower, slimmer body compared with the Common Dragonet (opposite). The eyes are set high on the head, and are intermediate in proportion to the head height compared with the other two species (see diagram p. 223: A equals B). Mature males have enlarged greenish yellow dorsal fins with curved, vertical rows of electric blue flecks and lines with darker black smudges, which can sometimes be observed even when the fin is folded down. The blue lines extend onto the sides and the other fins. In females and immature males, the first dorsal fin is short (extending later in maturing males) and variably dark in colour, sometimes with variably placed pale marks. The second dorsal fin has oblique rows of darker spots with ten rays. Contrasting shieldshaped patterns are visible on the dorsal surface. However, body coloration is highly variable depending on the background habitat, and is not a useful identifier (see range pp. 226–227). Compare other distinctive characteristics provided in table (p. 223). Reticulated Dragonet occurs on sediment habitats and in areas of mixed ground among rocky reefs, from shallow water to over 50m. KEY FEATURES Mature male fish have dorsal fins with vertical rows of electric blue flecks and darker black smudges. Second dorsal fin has ten rays. Eye proportion intermediate (A equals B). SIMILAR SPECIES Other dragonets. This fish is very difficult to distinguish from the Common Dragonet, though with experience it may be possible to separate the two species in the field. The Common Dragonet grows larger, up to 30cm. It may be impossible to separate small females and immature males of these two species, in which case record as ‘dragonet Callionymus sp.’ ABUNDANCE AND DISTRIBUTION Reticulated Dragonet were not recognised in the fish fauna of Britain and Ireland until 1949, when a population was studied near Plymouth. The first Irish record was made in 1967 from Mweenish Bay, County Galway. It appears to be distributed on southern and western coasts of Britain and Ireland and there are increasingly frequent reports of this fish from the North Sea. Since distinguishing the Reticulated from the Common Dragonet in the field is difficult, the true distribution is uncertain. Quantitative surveys report the Reticulated Dragonet to 10 m

25 m

Common and Reticulated Dragonet variants Common Dragonet Callionymus lyra female. Loch Carron, Highland.

LB

Common Dragonet C. lyra. Loch Fyne, Argyll & Bute.

PBa

Common Dragonet C. lyra immature male. Swanage, Dorset.

NO

Common Dragonet C. lyra female. Swanage, Dorset.

LB

Common Dragonet C. lyra female. Poole Bay, Dorset.

MM

Common Dragonet C. lyra juvenile (c. 2cm). Kenmare Bay, County Kerry.

226

Common Dragonet C. lyra female. Portland, Dorset.

LB

Common Dragonet C. lyra. Kenmare Bay, County Kerry.

LB

Reticulated Dragonet Callionymus reticulatus male. Loch Sunart, Highland.

LB

Reticulated Dragonet C. reticulatus male. Weybourne, Norfolk.

CB

Reticulated Dragonet C. reticulatus female. Loch Sunart, Highland.

LB

Reticulated Dragonet C. reticulatus female (note almost entirely dark first dorsal fin). Loch Teacuis, Highland.

Callionymus maculatus Spotted Dragonet Rafinesque, 1810

RY

Above Mature male with blue spots on head and pelvic fins. Loch Duich, Highland. Left End of season emaciated, mature male. Loch Duich, Highland.

LB

GENERAL DESCRIPTION Females and immature males of this dragonet grow to c. 12cm, though generally less than 10cm, while mature males can reach up to c. 16cm. Spotted Dragonet lack the clearly defined, shield-shaped marks seen on the dorsal surface of the other two species, and have fine brown/maroon speckles instead. Mature males are slender, looking almost emaciated at the end of the breeding season. They are flecked with white and electric blue spots on the dorsal surface and, particularly, on the translucent pelvic fins – the last, a feature probably shared by immature males. The head of the mature male has bright yellow and electric blue flecks, while the enlarged dorsal fins have yellow and blue flecks with large black spots which are absent in females. Females and immature males are shorter, much stouter-looking fish and typically have a slight pinkish tinge. Both sexes have diffuse chocolate brown spots and larger blue/white pearly circles on the flanks. The eyes are large in proportion to the head height (see diagram p. 223: A greater than B) and are set high on the head. The top half of each eye is often bright white and it is this which can give the fish away when buried in its typically muddy habitat. This dragonet is found on soft, muddy sediments, from less than 10m to much deeper. KEY FEATURES Spotted Dragonet usually live in soft, muddy sediments, often in deeper water. There is a bright white top half to the prominent eyes, which are proportionally larger than the other dragonets and set very high on the head. Mature males give an impression of a slim, rather glittery fish. Females and immature males have a pinkish tinge. SIMILAR SPECIES The three dragonet species described here are difficult to distinguish unless you are lucky enough to find a male fish displaying in breeding colours. Females, immature males and juveniles less than c. 5cm can be particularly difficult to separate. Habitat and colour detail should help distinguish the Spotted Dragonet from the other two species. If in doubt, record as ‘dragonet Callionymus sp.’ ABUNDANCE AND DISTRIBUTION Occurs all around the south and west of Britain, and all around Ireland, with many records from the northern Irish Sea. There are Seasearch records, among others, from Scottish sea lochs and from Strangford Lough in Ireland.

228

Callionymus maculatus Spotted Dragonet

(continued)

LB

LB

Top Female showing a pinkish tinge and pale tops to the eyes, but without blue spots on pelvic fins. Loch Hourn, Highland. Above Immature male lacking the bright blue head markings, but showing the bright blue spots on the pelvic fins. Loch Sunart, Highland. SBo

Left First dorsal fin of female showing pale leading edge. Loch Duich, Highland.

Left Male with white and electric blue spots and lines on the head and pelvic fins. Loch Duich,

Triglidae Gurnards The gurnards are a group of seabed-dwelling fishes with about 175 species worldwide, of which only four are likely to be seen around Britain and Ireland, with three more being rare. Gurnards have a large, bony head and a tapering body. There are two dorsal fins, the first triangular, while the pectoral fins are relatively large, often with striking colours which may act as a deterrent to predators when they are displayed suddenly. Gurnards, as a group, are easy to identify since the three lowest rays of the pectoral fins are modified into finger-like feelers, which move independently as the fish appears to walk over the seabed. These feelers are used to search the sediment for prey such as small crustaceans and fishes. In addition to the four species described here, the three other, much rarer, gurnards which might be seen in British and Irish waters are the Long-finned Gurnard Chelidonichthys obscurus, the Piper Trigla lyra and the Flying Gurnard Dactylopterus volitans (not a true gurnard). While these might be spotted by divers, such a sighting would be unusual. If a gurnard is seen which does not fit any of the four species described here, a photograph and expert opinion would be needed to confirm the record. Gurnards can be difficult to identify to species level; colour is not a good characteristic and all species can show rich red hues. If uncertain, then record as ‘gurnard (Triglidae)’. The following features will help to tell the different gurnard species apart: Red Gurnard Chelidonichthys cuculus p. 233

Tub Gurnard Chelidonichthys lucerna p. 234

Streaked Gurnard Chelidonichthys lastoviza p. 235

Grey Gurnard Eutrigla gurnardus pp. 236–237

Head profile detail

Steep (45°).

Almost straight profile.

Very steep (60–70°), short, straight, profile head.

Juveniles with concave profile, adults straighter.

Lateral line

Vertical elongated scales.

A prominent raised ridge.

Vertical skin folds above and below.

With backwardpointing spines.

Characteristics

Overall red to grey-brown shades. May have more or less contrasting patches of paler hue.

Body colour

Dorsal fin markings

Larger fish with marbled brown head and dorsal surface. Silvery white lower third. Juveniles highly variable. Black spot on rear of first dorsal fin

Pectoral fin markings

Match general body colour

Adult yellowish with blue edge; ocellus more or less prominent.

Adults may have blue flecks, lines and margin but lack prominent ocellus of juveniles.

Unpatterned; may be dark; may have paler blue margin.

Pectoral fin length

Reaches start of anal fin.

Reach well past start of anal fin.

Reach past start of anal fin.

Do not reach start of anal fin.

eye

two dorsal fins

gill cover

lateral line

Finger-like ‘feelers’ modified from lower rays of pectoral fin

caudal fin

pectoral fin

pelvic fin

The main gurnard family features (using Red Gurnard

230

anal fin

Gurnard head profile detail Red Gurnard Chelidonichthys cuculus Steep profile (45°) to head.

CB

Tub Gurnard C. lucerna Almost straight profile to head.

LB

Streaked Gurnard C. lastoviza Steeply sloping profile (60–70°), short head.

LB

Juvenile Grey Gurnard Eutrigla gurnardus Adult (right) has straighter head profile.

LB

Gurnard lateral line detail Red Gurnard Chelidonichthys cuculus No spines on lateral line, but a vertically elongated scale covers each pore. SD

1mm

Tub Gurnard C. lucerna Lateral line with no spines, but appears as a smooth, rounded, raised ridge.

SD

1mm

Streaked Gurnard C. lastoviza Lateral line has spines, along with distinctive striations and folds on the flanks. LB

1mm

Grey Gurnard Eutrigla gurnardus Lateral line is a sharp-edged, raised ridge, but look closely for short, backward-pointing spines, often most conspicuous towards the tail.

232

LB

Chelidonichthys cuculus Red Gurnard

(Linnaeus, 1758)

CB

MM

Top A common colour variant with contrasting red and white pattern. Beachy Head, East Sussex. Above A rather darker-coloured fish. Swanage, Dorset.

GENERAL DESCRIPTION A relatively large gurnard growing up to 50cm. The head profile has an overall slope of around 45° and is distinctly concave. The straight lateral line is more or less clearly delineated by a series of elongated, narrow, vertical scales. As the name indicates, the overall colour is generally a red hue although this can be variable, with grey or brown colours present. The pectoral fins, which do not extend further back than the start of the anal fin, match the general coloration of the fish. Red Gurnards occur in a wide range of habitats from gravelly, muddy sediment to rocky areas in water depths from 5–200m. KEY FEATURES Usually with red coloration and concave, 45° profile to the head. Vertically elongated scales on lateral line. SIMILAR SPECIES Other gurnards. Streaked Gurnard (p. 235) and Tub Gurnard (p. 234) may also show predominantly red colouring. The Streaked Gurnard has a much steeper profile to the head (60–70°), while the Tub Gurnard also has a 45° profile but with a subtle change in angle about two-thirds of the way down. The lateral line of the Red Gurnard is made up of vertical plates, while the Tub Gurnard has a distinct, narrow, raised ridge. ABUNDANCE AND DISTRIBUTION Red Gurnard is widely distributed around Irish Sea coasts and along the south coast of England. It appears to be rare off the west coast of Ireland and there are only scattered records from western Scotland and the North Sea.

Chelidonichthys lucerna Tub Gurnard

(Linnaeus, 1758)

LM

LM

Top and above Fish showing bright colours of the pectoral fins. Isle of Man.

GENERAL DESCRIPTION This is the largest of the gurnards at up to 75cm, more usually c. 25cm, with divers mostly seeing even smaller juveniles. The profile of the head is less steeply angled than in the other gurnards and the snout is longer. The large pectoral fins extend beyond the start of the anal fin and the straight lateral line is a distinct, slightly raised ridge running along the body. The Tub Gurnard is greybrown, especially juveniles, with adult fish often showing red coloration. There may be more or less contrasting blocks and bars of brown and white along the dorsal surface in juveniles. Adult pectoral fins, if displayed, are yellowish with a blue edge and have a more or less prominent ocellus. Tub Gurnards are typically found over sediment to depths of up to 150m. KEY FEATURES Less steeply angled profile to the head compared with other gurnards. Lateral line a prominent raised ridge. SIMILAR SPECIES Other gurnards. Streaked Gurnards (opposite) and Red Gurnards (p. 233) may also show red colouring. The Streaked Gurnard has a much steeper profile to the head (60–70°), while the Red Gurnard has a lateral line with vertically elongated scales. ABUNDANCE AND DISTRIBUTION Tub Gurnard is common and widely distributed, though adults are infrequently reported by divers. It occurs on coasts around the Irish Sea with sparse records from the southern and eastern coasts (to East Anglia) of England, with range seemingly extending in the North Sea. The species appears to be rare off western Ireland and there are only scattered records from western Scotland. Divers are most likely to see juveniles.

234

SD

A more grey-browncoloured fish. Sark, Channel Islands.

Chelidonichthys lastoviza Streaked Gurnard (Bonnaterre, 1788)

MM

Above A Streaked Gurnard displaying bright blue edge to the pectoral fins. Portland, Dorset. Left A darker fish among red algae and maerl. Fal Estuary, Cornwall.

LB

GENERAL DESCRIPTION Streaked Gurnard can reach up to 40cm, but is usually about 25–30cm in length. There are vertical ridges over the dorsal surface and down the flanks, although these and the straight lateral line, delineated by very small spines and appearing as a raised ridge, are not always conspicuous. The short head is steeply angled (60–70°) and straight. The body is deeper and broader than that of other gurnards described here, giving the fish a solid look. The Streaked Gurnard varies in colour from red to brown, and is usually variably mottled with darker and paler blotches and saddles. In adults, pectoral fins may be edged with bright blue and have blue-dashed concentric patterns, while juveniles display a prominent ocellus. It is usually found on sediment, but sometimes among boulders and seaweed, in depths from 10–100m. KEY FEATURES A steeply angled profile to the head. Delicate vertical ridges of skin on the flanks extending above and below the lateral line. SIMILAR SPECIES Other gurnards. Tub Gurnards (opposite) and Red Gurnards (p. 233) may also show red colouring and both have a more moderate profile to the head of c. 45°. ABUNDANCE AND DISTRIBUTION Streaked Gurnard has a southern and western distribution around Britain and Ireland, and may be relatively common in shallow inshore waters. Diver records are concentrated along the south coast of England and in the Channel Islands.

Eutrigla gurnardus Grey Gurnard

(Linnaeus, 1758)

PBa

Above A juvenile fish clearly showing the distinctive black spot on the trailing edge of the first dorsal fin. Loch Fyne, Argyll & Bute. RS

Left Showing marbled brown colouring on the dorsal surface and pale ventral surface. Loch Creran, Argyll & Bute.

GENERAL DESCRIPTION Grey Gurnard reach up to 60cm but are usually seen at c. 35cm in length. In adults, the head profile is fairly straight, coming to a point just above the mouth, while juveniles have a more concave profile. The straight lateral line is defined by a series of sharp, backward-pointing, bony spines. These are very small in juvenile fish but may be discernible in a good photograph especially towards the tail. Pectoral fins are short, not reaching back as far as the anal fin. The colour of this gurnard varies greatly, ranging from pale grey, through brown to red. Larger fish have a marbled brown head and dorsal surface, extending to the caudal fin, with a silvery white ventral surface. The pectoral fins may show blue or yellow hues and often have pale, almost electric blue, margins. There is a characteristic dark or blackish spot on the central trailing edge of the first dorsal fin, usually obvious on small, juvenile fish but may be less so on older, darker fish. Very small juveniles may be almost pure black (opposite). This fish occurs in shallow water over sediment, down to depths of c. 150m. KEY FEATURES Black spot on the central trailing edge of the first dorsal fin, particularly prominent in juveniles. Lateral line with sharp, backward pointing spines. SIMILAR SPECIES Other gurnards. The spiny lateral line is characteristic of this species. ABUNDANCE AND DISTRIBUTION Grey Gurnard are a common inshore fish very widely distributed around Britain and Ireland. However, there are few diver reports for this species and these are mostly of juveniles. It is the only gurnard regularly recorded in the North Sea, very few of which are from divers.

236

10 m 25 m

Eutrigla gurnardus Grey Gurnard

(continued)

Juvenile gallery

PW

Groomsport, County Down.

LB

Loch Nevis, Highland.

DW

Cley, Norfolk.

GeB

Loch Sunart, Highland.

MG

Gower, West Glamorgan.

RS

Weybourne, Norfolk.

Loch Nevis, Highland.

Trachinidae Weevers Weevers are small, venomous fishes that bury themselves in sand with only their eyes showing. Two of the nine species found worldwide occur around Britain and Ireland and of those two, only the Lesser Weever Echiichthys vipera is likely to be encountered by divers.

Echiichthys vipera Lesser Weever

(Cuvier, 1829)

ST

A young fish in typical mobile, fine sand habitat, showing the spiny, black dorsal fin with pale rays. Portland, Dorset.

GENERAL DESCRIPTION WARNING: VENOMOUS FISH. Lesser Weever have a short, snub face with an oblique, upturned mouth and small eyes set high up near the top of the head. This is followed by a rather rotund body that tapers down to a thinner rear half. This is an efficient shape for burial in sand, while still being able to maintain vision above the sand. The fairly straight lateral line usually shows up clearly in photographs. The first dorsal fin is short, consisting of sharp, pale spines and is fairly obvious as the membrane is almost entirely black. In colour, this fish is a relatively dull silver with overlying yellowish brown or greyish mottling and golden markings. Divers may encounter Lesser Weever if they look in the right habitat: shallow sand, especially on sunny summer days, and are prepared to look carefully for them. The fish spend much of their time buried in sand, often with only the eyes, and sometimes the first dorsal fin, showing. KEY FEATURES A short-headed fish with an upturned face. Short, spiny, black, first dorsal fin. Usually buried in sand. SIMILAR SPECIES Greater Weever Trachinus draco (not described separately), however this has diagonal striations, blue lines and an only partially black first dorsal fin, and is primarily a southern and deeper water fish. While the Lesser Weever can reach 15cm, the Greater Weever grows much larger, up to around 50cm. ABUNDANCE AND DISTRIBUTION Common all around Britain and Ireland. Found within diving depths and up into the intertidal (including estuaries), mainly in the summer. Fewer records from Scotland and western Ireland.

238

Greater Weever Trachinus draco showing the blue and brown striations on the flank. Gran Canaria, Canary Islands.

LB

LB

An unidentified weeverfish with only the eyes peering out of the sand. Poole Bay, Dorset.

DW

Lesser Weever Echiichthys vipera showing the darker colouring of adult fish. Norfolk.

Weever stings The first dorsal fin and spines on the gill cover can inflict an extremely painful sting if the fish is trodden on or handled carelessly. The venom is protein-based and stings can be treated by placing the stung area (usually a foot or hand) into very hot, but bearable, water and replenishing this until the pain subsides. The hot water breaks down and deactivates the venom.

RS

Syngnathidae Pipefishes and seahorses Pipefishes and seahorses are closely related and while different in shape, they share many features. As their name implies, the bodies of pipefishes are long and very thin relative to their length. Seahorses can be thought of as pipefishes swimming head-up, but with the head bent over at an acute angle (see pp. 248–249), resulting in an unmistakable overall shape. Both groups have relatively stiff bodies because they are encased in a rigid bony armour of interlocking plates that form rings around the body, clearly visible in the larger species. There are two species of seahorses and six pipefishes found in British and Irish waters. Some photographs suggest that an additional southern species, Black-striped Pipefish Syngnathus abaster, may well be present, but there are as yet no confirmed records. Recognising a pipefish should be relatively straightforward, as all are long, thin and have a distinctive tubular snout with a small mouth at the end. The cross-sectional shape of the bony rings is polygonal in some species, giving an angular look, while others are smoothly rounded. Telling the species apart underwater is a bit more difficult but perfectly possible, particularly if photographs are taken. The head and snout shape are important for identification, as is the snout length compared to the total head length and to the body length. Note that head length is measured from the end of the snout to behind the gill cover, while snout length is to the rear edge of the eye (see diagram opposite). An identification can often be made even if only the head is visible – frequently the case. Other identifiers include certain markings, the cross-sectional shape and whether pectoral, anal and caudal fins are present or absent. However, if a definitive identification is not possible, but the fish is recognised as a pipefish, then record as ‘pipefish Syngnathidae’. Pipefishes are inconspicuous and readily blend into their background. They are often found amongst seaweed and seagrass and frequently lie with the body aligned along the vegetation, swaying as it does with any wave motion. Because of their protective armouring, pipefishes are relatively ungainly and stiff swimmers, but can move surprisingly fast when they need to. Female seahorses and pipefishes lay their eggs in pouches or grooves on the male’s belly and the male protects them until they hatch and the young are released. Therefore, although counterintuitive, if eggs are visible, this indicates you are looking at a male fish. dorsal fin long snout

mouth

long snout

pectoral fin

eye

bony plates (no scales) pectoral fin

gill cover

anal fin bony plates (no scales)

caudal fin

mouth

Syngnathus pipefish dorsal fin

anal fin dorsal fin

gill cover

Nerophis pipefish

240

no other fins no caudal fin

seahorse

Pipefish head and snout detail head length

snout length

Greater Pipefish Syngnathus acus Snout Over half total head length. Head Well-developed hump behind eyes.

LB

Nilsson’s Pipefish Syngnathus rostellatus Snout Less than half total head length. Head No hump behind eyes. LB

Broad-nosed Pipefish Syngnathus typhle Snout Laterally compressed, nearly two-thirds total head length. Head No hump behind eyes.

SM

Snake Pipefish Entelurus aequoreus Snout About half total head length. Head Dark reddish stripe through eye.

SD

Worm Pipefish Nerophis lumbriciformis Snout Very short, about a third total head length, with upward tilt. Head Very short in relation to body length.

ST

Straight-nosed Pipefish Nerophis ophidion Snout Straight, about half total head length. Head Very short in relation to body length. TM

The eye of each species is aligned to show the difference in snout length relative to total head length (measured to the rear of the gill cover). Not to scale.

Syngnathus acus Greater Pipefish

Linnaeus, 1758 CB

LB

SBo

Top Typical greyish banding. Portland, Dorset. Above left Well-developed caudal fin. Portland, Dorset. Above right The long snout and distinctive hump of the head. Isle of Bute, Argyll & Bute. Left Showing the polygonal shape of the body. Devon. SS

GENERAL DESCRIPTION The Greater Pipefish, as its name suggests, is one of the larger pipefish species found in British and Irish waters and can reach lengths of at least 45cm, although 30–35cm is more usual. The bony plates/ rings give the body a distinctly segmented appearance, polygonal on the trunk and four-sided on the tail, the latter ending in a well-developed caudal fin. The snout is long, comprising over half the total length of the head, and there is a distinctive hump on the top of the head just behind the eyes. Colour is usually a greyish brown, but there may also be green or yellow hues and lighter and darker bands. This fish occurs in a variety of shallow water habitats including seagrass beds, amongst algae in rocky areas and over sediment, to a depth of about 20m. KEY FEATURES A large pipefish with an angular body, humped head and long snout. For certainty, check comparative snout lengths (see p. 241). SIMILAR SPECIES Nilsson’s Pipefish (opposite) never grows as large, has a shorter snout (less than half the length of the head) and lacks the hump behind the eyes. The Greater Pipefish could also be confused with the Black-striped Pipefish Syngnathus abaster (not described separately), for which there are as yet no confirmed records in British or Irish waters. ABUNDANCE AND DISTRIBUTION The Greater Pipefish is the pipefish most frequently recorded by divers and is quite common around all British and Irish coasts, apart from the northeast English coast. 10 m

25 m

242

Syngnathus rostellatus Nilsson’s Pipefish

Nilsson, 1855

LB

Above Shorter snout, no hump behind the head and rather plain colour are characteristic. Cley, Norfolk. Left A darker fish with markings superficially similar to the Greater Pipefish. Essex.

DW

GENERAL DESCRIPTION Also known as the Lesser Pipefish, this species grows to a little more than 15cm long and has a moderately thin body compared to Greater Pipefish (opposite) and Broad-nosed Pipefish (p. 244). Like the two latter species, the body has distinct polygonal sections, four-sided on the tail, with a well-developed caudal fin. However, it has a short snout, less than half the total head length, and there is no hump on the top of the head behind the eyes. The colour is often plain brownish or greenish with more or less conspicuous paler rings around the body. Nilsson’s Pipefish is common on sandy seabeds and among seaweeds. Usually found in water depths of less than 10m, but exceptionally to 20m. KEY FEATURES A slim pipefish with a clearly segmented appearance. Snout short, less than half the total head length, and no hump behind the eyes. SIMILAR SPECIES Greater Pipefish juveniles (opposite), in which the distinctive head hump is less well developed. Check comparative snout lengths (see p. 241). ABUNDANCE AND DISTRIBUTION Nilsson’s Pipefish is a common coastal and estuarine species, with particularly numerous records from the east of England where suitable sediment habitat abounds. It appears to have been sparsely recorded from shallow waters around the rest of Britain and Ireland, but may be greatly underreported due to confusion with the Greater Pipefish.

10 m 25 m

Syngnathus typhle Broad-nosed Pipefish

Linnaeus, 1758

TM

JF

Top The broad laterally compressed snout and polygonal body shape are characteristic. Torbay, Devon. Above New Quay, County Clare.

GENERAL DESCRIPTION Also known as Deep-snouted Pipefish. The vernacular names of this large pipefish, which may reach 35cm in length, reflect its key feature: a very deep, long, laterally compressed snout, making up nearly two-thirds the total length of the head and almost the same depth. Like the Greater Pipefish (p. 242), the body has fairly distinct segments, polygonal on the trunk and four-sided on the tail, the latter ending in a welldeveloped caudal fin. Colour is usually mottled greenish or brownish, depending on habitat. Broad-nosed Pipefish are most often found amongst seagrass, but also live among seaweeds in rocky areas down to about 20m depth. They can sometimes be seen hovering head-up in the water column among seagrass and seaweeds. KEY FEATURES Deep, long, laterally compressed snout. For certainty, check comparative snout lengths (see p. 241). SIMILAR SPECIES While similar in size and body shape to the Greater Pipefish, there should be no confusion with the Broad-snouted Pipefish due to its distinctive long and deep snout. ABUNDANCE AND DISTRIBUTION Broad-nosed Pipefish are not frequently recorded by divers and appear to be scarce, with a mainly southern and western distribution in Britain and Ireland. Although not confined to seagrass beds, this distribution may partly reflect their preference for this habitat.

KN

244

A dark coloured fish mimicking dead seagrass leaves. Cawsand,

10 m 25 m

Entelurus aequoreus Snake Pipefish

(Linnaeus, 1758)

ST

ST

Top Showing the typical golden colour with pale, vertical stripes on the flank. Portland, Dorset. Above The distinct dark horizontal stripe through the eye. Portland, Dorset.

GENERAL DESCRIPTION This is the largest pipefish found around Britain and Ireland with the larger females reaching nearly 60cm in length, though 40cm is more usual. The body is rounded in cross-section and appears smooth without the angular look of the three Syngnathus species. Unlike the latter, it lacks pectoral and anal fins and has a very small, almost indistinguishable caudal fin. The snout is about half the total length of the head. Typically, the fish is a dull yellow to orange brown, lighter or darker depending on conditions. It has a conspicuous dark reddish horizontal stripe running along the head, through the eye and onto the snout. There are light, often pale blue, vertical stripes on the flanks, each sometimes with a darker, reddish margin. This pattern may continue onto the dorsal surface as a loose series of pale spots and squiggles. These markings may be inconspicuous in very dark or very pale fish. Juveniles may be more uniformly coloured. Occurs among algae and in seagrass beds, usually to a depth of 20m, but has been recorded at 100m. KEY FEATURES A slender, rounded pipefish with an extremely small caudal fin, dark line through the eye and pale, vertical stripes. SIMILAR SPECIES Unlikely to be confused with any other pipefishes. ABUNDANCE AND DISTRIBUTION Snake Pipefish occur around all coasts of Britain and Ireland, but are not particularly common. There have been periods when this pipefish was highly abundant for a year or two, only to decline again. Records indicate that there was a population boom between 2000 and 2010; since then, reports have declined.

10 m 25 m

Nerophis lumbriciformis Worm Pipefish

(Jenyns, 1835)

ST

Above A fish entwined in seaweed, showing its short, upturned snout. Portland, Dorset. Right A dark individual on a rocky shore. Swanage, Dorset. Below A pale coloured fish showing mottling on the head. Falmouth, Cornwall.

LB

GENERAL DESCRIPTION This is the smallest of the pipefishes found around Britain and Ireland, usually reaching no more than 12–15cm. It is one of two, very slender pipefishes, with a smooth body, rounded in cross-section, in which the bony rings are barely visible. The other is the Straight-nosed Pipefish (opposite). The Worm Pipefish has a very short snout with a distinct upward tilt. The only fin present is a small dorsal fin and the tail simply ends in a point. The colour is most often a dark, rather uniform greenish brown to black, but can be overall reddish to pale or mottled. Pale markings may be present around the head. Commonly found on rocky shores and rocky areas down to about 5m depth. KEY FEATURES Small, very slim, smooth pipefish with a very small head compared to total body length. Short, distinctly upturned snout. No caudal fin. SIMILAR SPECIES Straight-nosed Pipefish (opposite), however that species has a straight, or only slightly curved snout. ABUNDANCE AND DISTRIBUTION Common and sometimes abundant around Britain and Ireland, but less so on eastern coasts which generally lack extensive suitable rocky habitat. Not often seen by divers as it most abundant in rockpools and in very shallow water. MSl

10 m 25 m

246

Nerophis ophidion Straight-nosed Pipefish

(Linnaeus, 1758)

Above The bright blue swirls and flecks on the head of this fish show that it a female. The overall greenish colour provides good camouflage among seagrass. Tenerife, Canary Islands. Right Torbay, Devon.

GENERAL DESCRIPTION The Straight-nosed Pipefish is very slender, if anything even more so than the Worm Pipefish (opposite), while reaching up to 30cm, nearly twice the length of the latter. The body is rounded in cross-section and there are no pectoral, anal or caudal fins. The head and straight snout are of about equal length and short in relation to the total body length. The basic colour is a greenish brown, or sometimes reddish, but variously marked with pale lines and spots, especially towards the head. Mature females can be particularly colourful with bright blue lines and spots on the head, flanks and even the ventral surface. KEY FEATURES Small, slim, smooth pipefish with a short head compared to total body length. Short, straight snout. No caudal fin. SIMILAR SPECIES Worm Pipefish (opposite) have an even shorter snout which is distinctively upturned. In colour, the Straight-nosed Pipefish may resemble the Broadnosed Pipefish (p. 244), though that species has a much longer, deeper snout and is angular in cross-section. ABUNDANCE AND DISTRIBUTION Straight-nosed Pipefish are rarely recorded, but widely distributed, in coastal waters around Britain and Ireland. Unlike the Worm Pipefish, it is seldom found in rockpools.

TM

10 m 25 m

Hippocampus guttulatus Long-snouted Seahorse Cuvier, 1829

MSl

Above A male Long-snouted Seahorse in typical seagrass habitat. Falmouth, Cornwall. Left Perfectly camouflaged among brown seaweed. Portland, Dorset.

LB

GENERAL DESCRIPTION Seahorses are virtually unmistakable. The Long-snouted Seahorse, also known as the Spiny Seahorse, is the most frequently recorded of the two species found around Britain and Ireland. As its vernacular name suggests, it has the longer and straighter snout of the two, more than one-third of the total head length. A more obvious characteristic, reflected in its other name, is the presence of numerous skin tassels over the dorsal surface and head. Be careful to look at the head and snout of any seahorse without tassels, as they will be not present on every Longsnouted Seahorse. This species is protected by law and must not be disturbed intentionally without a license – that includes photography with a flash. KEY FEATURES Seahorse with a relatively long, straight snout more than one-third of the head length. Usually has skin tassels and numerous white spots. SIMILAR SPECIES Short-snouted Seahorse (opposite), however that species has a short snout with a concave profile and lacks skin tassels. ABUNDANCE AND DISTRIBUTION Most records are from southern Britain and Ireland. Older records suggest a more extensive range around the western coasts of Britain and Ireland as far north as Orkney and Shetland.

248

10 m 25 m

Hippocampus hippocampus Short-snouted Seahorse (Linnaeus, 1758)

MM

A male Short-snouted Seahorse over sand close to a seagrass bed. Studland, Dorset.

GENERAL DESCRIPTION Seahorses have an unusual and characteristic body shape and are virtually unmistakable. The Short-snouted Seahorse is the less frequently recorded of the two species found around Britain and Ireland. It has a short snout, onethird or less of the total head length, with a concave upper profile. The head is topped with a distinct, wedge-shaped ridge. Most individuals lack skin tassels but some do develop them, always check the snout shape and length. As with the Long-snouted Seahorse, the colour is highly variable but often a yellowish to very dark brown. The Short-snouted Seahorse is found in a wider variety of vegetated sediment habitats than the Long-snouted Seahorse, and has been recorded in the outer reaches of estuaries. This species is protected by law and must not be disturbed intentionally without a license – that includes photography with a flash. KEY FEATURES Seahorse with short, curved snout, one-third or less than the total head length. A ridge on top of the head and (usually) no skin tassels. SIMILAR SPECIES The Long-snouted Seahorse (opposite), however that species has a longer, straighter snout and (usually) numerous skin tassels. ABUNDANCE AND DISTRIBUTION Most records are from southwest coasts of Britain and Ireland. Older records suggest a more extensive range around the western

Gasterosteidae Sticklebacks Sticklebacks are familiar small fishes, best known for the sharp spines that run along the back. ‘Sticel’ is an old AngloSaxon word for a thorn or sting. These fishes are not easy to see but can certainly be felt if picking the fish out of a net. Rows of bony plates along the flanks provide protection. Males build elaborate nests of seaweed and algae, and guard both eggs and young. Two species are found around Britain and Ireland with a third, the Nine-spined Stickleback Pungitius pungitius, confined to freshwater.

Spinachia spinachia Sea Stickleback

(Linnaeus, 1758)

RG

DW

Top A strongly patterened fish in seagrass. Portland, Dorset. Above Showing the wide, fan-shaped caudal fin. Loch Creran, Argyll & Bute. Right Nest of seaweed bound by silvery threads. Kenmare Bay, County Kerry.

LB

GENERAL DESCRIPTION This is an elongated fish with a slim rather rigid body that is fatter in the middle and tapers to a long, slender caudal peduncle, ending in a wide, fan-shaped caudal fin. The head, too, is drawn out into a long snout. Fifteen sharp spines on the dorsal surface precede a short, but high dorsal fin. A similar shaped anal fin lies directly below on the ventral surface. This species is also called the Fifteen-spined Stickleback, but the exact number of back spines varies from 14–17. Spines are not easy to see underwater, but body shape alone is sufficient for identification. A brown stripe runs from the mouth through the eye. The Sea Stickleback prefers seaweed and seagrass habitats in which it will swim slowly and very inconspicuously. Doing so, makes it difficult to pick out as it blends in with the material in which it hides and is easily overlooked. The nests of this stickleback are made of seaweed bound together in a tight bundle by opaque, tough threads which resemble monofilament fishing line, but are secreted from the kidneys of the male. KEY FEATURES An elongate fish, slightly fatter in the middle, tapering from the rear of the dorsal and anal fins to a fan-shaped caudal fin. Sharp spines along the dorsal surface and, short but high dorsal and anal fins. SIMILAR SPECIES Provided both head and body can be seen, then none. However, a projecting head could, at first glance, be confused with a Snake Pipefish (p. 245) which has a similar brown eye stripe. ABUNDANCE AND DISTRIBUTION Found in shallow coastal waters all around Britain and Ireland amongst seaweed and seagrass, including lower shore rockpools.

250

Gasterosteus aculeatus Three-spined Stickleback

Linnaeus, 1758

KB

Above Typical greenish and silver mottling of this fish in marine habitats. Mainland, Orkney. Left Breeding male fish showing reddish tinge to the throat. The Fleet, Dorset.

LB

GENERAL DESCRIPTION Three-spined Stickleback are a small, greenish brown fish, laterally compressed and with silvery, reflective bony plates along the flanks. Two large spines and one tiny spine on its dorsal surface, are followed by a dorsal fin. On the ventral surface, in place of paired pelvic fins are strong paired spines. The spines may be difficult to see underwater but, with patience, these fish can be approached closely. Breeding males develop a red throat and ventral surface, but a diver would be lucky to observe this as the fish usually build their nests in freshwater, estuarine and rockpool habitats. This stickleback is best-known from freshwater streams and ponds, but to a lesser extent can also be found in estuaries and coastal waters. KEY FEATURES Small fish with silvery, reflective plates along the flanks and three separated spines on the dorsal surface. SIMILAR SPECIES Difficult to separate from other small silvery fishes at a distance, but distinctive close up, and does not swim in shoals. ABUNDANCE AND DISTRIBUTION Apparently found in all coastal and freshwater habitats in Britain and Ireland. Despite this, there are few underwater, marine records

Cottidae Sea Scorpions The sea scorpions are moderate-sized fishes, some growing to c. 30cm. They have a large, bony-looking head, notably spiny in some species, with a thick-set body tapering to a broad tail. There are two dorsal fins, and the pectoral fins are large in proportion to the length of the fish. The spines do not carry a venom but can inflict a painful wound nonetheless. These fishes inhabit rocky reefs and areas of mixed sediment and are very loath to move when encountered underwater. There are four species recorded in British and Irish waters, which may be seen at diving depths and intertidally. Scorpionfishes (Scorpaenidae), with a long, continuous, single dorsal fin, are related to sea scorpions, but are warmwater species with only very rare records from Britain and Ireland. Two species are infrequently reported from Cornwall, west Wales and southwest Ireland: the Red Scorpionfish Scorpaena scrofa and the Black Scorpionfish Scorpaena porcus. In contrast to sea scorpions, scorpionfishes can inject toxins if handled carelessly, inflicting extremely painful wounds. These fishes are not described further here.

Taurulus bubalis Long-Spined Sea Scorpion (Euphrasen, 1786)

PW

A common colour variant of this fish, showing the large spine on the gill cover and long, white barbel at the corner of the mouth. Glenarm, County Antrim.

GENERAL DESCRIPTION This is a moderate-sized fish growing up to 20cm, but more usually found at c. 15cm. It has a strong, backward-pointing spine extending beyond the gill cover and there is a white barbel at the corner of the mouth. Colour is extremely variable, generally matching the background habitat (see colour variants opposite). There is a common bright red form which, at least to divers, stands out startlingly. The fish lays balls of bright yellow, spiny looking eggs, hidden under rocks and in kelp holdfasts in early spring. Long-Spined Sea Scorpions occupy rocky habitats from relatively shallow, seaweed dominated sites, including maerl beds, to rocky reefs in water depths of up to c. 30m. KEY FEATURES White barbel at corner of the mouth. Strong, backward-pointing spine extending beyond the gill cover. SIMILAR SPECIES The Norway Bullhead (pp. 256–257) is generally a smaller fish (to 8cm), with a row of robust spines above the lateral line and smaller, evenly spaced spines below. The larger Short-spined Sea Scorpion (pp. 254–255) lacks the white barbel at the corner of the mouth, and, overall the head appears less spiky. ABUNDANCE AND DISTRIBUTION The Long-Spined Sea Scorpion is common and widely distributed around all coasts of Britain and Ireland.

252

10 m 25 m

Taurulus bubalis Long-Spined Sea Scorpion

(continued)

MM

Above Mass of eggs. Swanage, Dorset. PW

Left Spiny head. Rathlin O’Birne, County Donegal.

LB

Loch Nevis, Highland.

MM

Sound of Sleat, Highland.

MM

Portland, Dorset.

LB

Portland, Dorset.

KLo

Pembrokeshire. Some colour variants of the Long-spined Sea Scorpion. Note

DW

Norfolk.

Myoxocephalus scorpius Short-spined Sea Scorpion (Linnaeus, 1758)

MM

Above A large fish among cobbles, with pink and grey hues matching the habitat. Note, no barbel at corner of mouth. Loch Nevis, Highland. Right The less spiny appearance of the Short-spined Sea Scorpion. Loch Slapin, Skye. LB

GENERAL DESCRIPTION Also known as Father Lasher or Bull Rout. This is the largest of the three sea scorpions to be seen by divers, reaching up to 30cm, though more usually c. 20cm. It has a large, broad, bulbous head with several short spines on the cheek, none of which extends beyond the edge of the gill cover. There is no barbel at the corner of the mouth. Overall, it appears much less spiny than the other two sea scorpions. Colour is highly variable, matching well with the surrounding habitat. It is often found among stones of a similar size and colour to the fish, further enhancing its camouflage. Juveniles are small, stout fish with bands of strongly contrasting colour. Short-spined Sea Scorpions occurs on mixed ground and sediment habitats, to depths of c. 30m. KEY FEATURES Large, bulbous head tapering to a small tail. SIMILAR SPECIES The Long-spined Sea Scorpion (pp. 252–253) has a short, white barbel at the corner of the mouth and is also a more spiky-looking fish. ABUNDANCE AND DISTRIBUTION The Short-spined Sea Scorpion is common and widely distributed around all British and Irish coasts but appears to be much less frequent along England’s south coast.

254

10 m 25 m

Myoxocephalus scorpius Short-spined Sea Scorpion (continued)

RY

Great Orme, Conwy.

KB

Juvenile. Loch Linnhe, Argyll & Bute.

RY

Loch Hourn, Highland.

RY

Eday Sound, Orkney.

PW

Strangford Lough, County Down.

LB

Loch Duich, Highland.

MM

Rathlin, County Antrim. Some colour variants of the Short-spined Sea Scorpion.

LB

Weybourne, Norfolk.

Micrenophrys lilljeborgii Norway Bullhead

(Collett, 1875)

DW

A Norway Bullhead showing the evenly spaced spines below the lateral line. The bright red coloration behind the head may indicate a breeding male. Loch Creran, Argyll & Bute.

GENERAL DESCRIPTION This small sea scorpion, which grows to less than 8cm, has a single strong spine on the cheek which does not extend beyond the edge of the gill cover. It has a small, white barbel at the corner of the mouth which may be difficult to see. The head and body are scattered with pointed spines of varying length. These spines are longest on the head and dorsal surface. There is a more or less clear row of slightly larger spines running above and parallel to the spiky lateral line. Shorter spines are evenly distributed on the flanks below the lateral line. The overall effect is to give the fish a prickly look. Colour is highly variable, sometimes blending in well with the surrounding habitat. There are usually four vertical, darker bars of variable colour (they can be bright red or orange), with paler bands between them on the body behind the head. The back of the head is often a contrasting, usually duller colour, but sometimes it is bright magenta or orange, possibly indicating a breeding male. Many descriptions state that the eyes reflect green. Norway Bullhead seems to prefer rocky reefs and wrecks in high energy situations down to 100m. KEY FEATURES A row of large spines above the spiky lateral line; evenly scattered, slightly smaller spines on the flanks below this. SIMILAR SPECIES Any sea scorpion longer than c. 8cm will not be this species. The Long-spined Sea Scorpion (pp. 252–253) has a conspicuous longer, white barbel at the corner of the mouth and lacks the evenly spaced, scattered spines on the flanks. These two fishes can be easily confused, so careful examination is needed to distinguish Norway Bullhead from small specimens of the Long-spined Sea Scorpion. ABUNDANCE AND DISTRIBUTION The Norway Bullhead appears to be an uncommon fish, but the true picture of its distribution may be confused by misidentification with the much more common Long-spined Sea Scorpion. There are occasional, very scattered records from south, east and northeast England, southwest Wales, all around Scotland, southwest Ireland and the Channel Islands.

10 m 25 m

256

Micrenophrys lilljeborgii Norway Bullhead

(continued)

LB

Jersey, Channel Islands.

CB

Christchurch Bay, Hampshire.

DW

Sheringham, Norfolk.

LKe

Portaferry, County Down. Norway Bullhead variants from around Britain and Ireland.

PNe

Martin’s Haven, Pembrokeshire.

Triglops murrayi Moustache Sculpin

Günther, 1888

LB

LB

Top Showing the characteristic vertical folds on the flank and alternating dark and light bands of colour. Eday Sound, Orkney. Above Detail of vertical folds on the flank. Eday Sound, Orkney. Right Stippled texture of the skin on the head. Eday Sound, Orkney.

GENERAL DESCRIPTION This is a fairly small fish (8–15cm) with a large head and a body which rapidly tapers to the tail. Colours are alternating, with more or less equally wide bands of white, flecked with gold and dark brown faintly mottled with blue along the entire dorsal surface. Oblique, vertical folds of skin show up along the flanks, below the lateral line, and are characteristic of this genus. The skin has a stippled texture particularly evident on the dorsal surface, above the lateral line, and on the head. Moustache Sculpin have been recorded on shelly ground and maerl beds at 25m off Orkney. This is a coldwater species, the type specimen of which was collected from muddy, deepwater sediments off the Mull of Kintyre. KEY FEATURES A small fish with brown and white bands across the dorsal surface and oblique folds of skin along the flanks. SIMILAR SPECIES Could be confused with a juvenile Short-spined Sea Scorpion (pp. 254–255), though that lacks the skin folds and is a much more robust-looking fish. ABUNDANCE AND DISTRIBUTION Moustache Sculpin are considered a rare, deepwater species, but may have been overlooked or misidentified by divers in the past because of its small size and cryptic behaviour. There are Scottish records from the Mull of Kintyre and Orkney.

258

LB

Agonus cataphractus Pogge

(Linnaeus, 1758)

RY

Above A Pogge showing the rigid, angular body and fringe of barbels around the mouth. Sound of Mull, Argyll & Bute. Right Showing the upturned, hooked nose. Scapa Flow, Orkney. MD

GENERAL DESCRIPTION Also known as the Hooknose. This moderate-sized (c. 15cm) fish has a small head, a rounded, barrel-like body and a long, tapered tail. It has a rather extraordinary appearance, with a strange upturned nose and a series of coarse barbels forming a fringe around the mouth and under the chin (these have been shown to contain taste buds). There are two, almost equal-sized dorsal fins set well back, which are rarely seen erect. The spiny head and body are very rigid as they are encased in hard, bony plates. Colour is generally grey-brown-black with pale bands and saddles of varying extent to match the surrounding habitat. Young Pogge just a few centimetres long can be found in shallow water on sand. As they grow, the fish move onto mixed sediment, stony and shelly ground, often in estuaries. They appear to move to deeper, cooler water along the south coast of England during the summer. This fish has been recorded at depths of over 200m. KEY FEATURES Angular body, hooked nose and the obvious fringe of barbels around the mouth and under the chin are distinctive. It is unlikely to be confused with any other fish. SIMILAR SPECIES None, though at first glance the body shape and rather spiny head might be thought to resemble that of a sea scorpion. ABUNDANCE AND DISTRIBUTION Pogge are widely distributed all around Britain and Ireland, though there are fewer records from southwest England. However, its

10 m 25 m

Conger conger Conger Eel

(Linnaeus, 1758)

SS

Above Head of a Conger Eel emerging from wreckage, showing the equallength jaws. Whitsand Bay, Cornwall. Right When free-swimming in the open, the Conger Eel’s single long fin can clearly be seen. Scapa Flow, Orkney. PBa

GENERAL DESCRIPTION In common with many other species of eel, the Conger Eel has a long, snake-like body that is cylindrical in cross-section. It is the largest eel in British and Irish waters, reaching 300cm in length. Conger Eels have a large mouth which reaches back as far as the eyes, and jaws of either equal length or a slightly overhanging upper jaw. A single, long fin (dorsal and anal fins are confluent with caudal fin), edged in black, starts a short distance behind the head (from the point the pectoral fin reaches if flattened back) and runs along the dorsal surface, round the tail and onto the ventral surface. Usually dark grey with a paler ventral surface, but can be brownish and fins sometimes black-edged. Most individuals spend daylight hours tucked away in a refuge amongst rocks or wreckage, with just the head sticking out, and emerge to hunt at dusk. However, this eel can sometimes be seen free-swimming during daylight hours. Mature adults migrate to specific areas in the deep Atlantic and Mediterranean to spawn and then die. The resultant leaf-shaped larvae (called leptocephalus larvae) eventually drift back inshore. KEY FEATURES Large eel generally seen as a greyish head sticking out of a hole or crevice in wrecks and amongst rocks. SIMILAR SPECIES None if large. Small individuals may be similar to the European Eel (opposite), though that species is distinguished by a protruding lower jaw, dorsal fin origin well behind the head, and generally greenish brown colour. Ling (p. 156) have two distinct dorsal fins and a chin barbel. ABUNDANCE AND DISTRIBUTION Common all around Britain and Ireland especially in rocky areas, wrecks and other artificial structures and sometimes intertidally. 10 m

25 m

260

Anguilla anguilla European Eel

(Linnaeus, 1758)

DW

Above A European Eel showing the protuberant lower jaw. Sheringham, Norfolk. Right An eel out in the open. Sheringham, Norfolk. MSo

GENERAL DESCRIPTION Compared to a Conger Eel (opposite), this is a much smaller and slimmer eel, slightly laterally compressed and only reaching about 100cm in length. A single, long fin (dorsal and anal fins are confluent with caudal fin) runs along the dorsal surface, around the tail and onto the ventral surface. This fin starts further back from the head compared to the Conger Eel (opposite), covering approximately two-thirds of the dorsal surface. If only the head is visible, look at the lower jaw which sticks out beyond the upper jaw, and distinguishes it from the Conger Eel. Colour varies according to maturity, but those seen by divers are usually a greenish brown on the dorsal surface, with a pale to white ventral surface. Individuals are not easy to spot as this fish generally remains well hidden amongst seaweed and rocks. The European Eel has an extraordinary life history involving several colour, size and habitat changes. Adults live primarily in fresh water, but some remain in shallow coastal habitats (where divers may encounter them). At maturity, they migrate out into the deep Atlantic, around the Sargasso Sea, to spawn. Their leaf-shaped larvae (called leptocephalus larvae) drift back to European shores and become transparent elvers, which enter fresh water via river systems. KEY FEATURES A greenish to yellowish brown eel with its lower jaw longer than upper jaw, with a dorsal fin that starts about one-third of the way along the body. SIMILAR SPECIES Small Conger Eel (opposite), though these are dark grey, often with a black edge to the dorsal fin, an upper jaw equal in length or slightly longer than the lower jaw, and the dorsal fin begins close behind the head. Ling (p. 156) have two distinct dorsal fins and a chin barbel. ABUNDANCE AND DISTRIBUTION This species spends most of its life in fresh water but can be seen in coastal waters, estuaries and intertidally. Once abundant it is now Critically Endangered throughout its range. 10 m

25 m

Cepola macrophthalama Red Bandfish

(Linnaeus, 1758)

KH

Above A fish fully emerged from its burrow in soft mud. Plymouth, Devon. Left A more usual diver’s view of a fish lurking in its burrow. Small Isles, Highland. MM

GENERAL DESCRIPTION This elongate fish is easy to identify, with its orange-red, eel-like body that is laterally compressed and tapers down to a small, pointed caudal fin. It has long, ribbon-like dorsal and anal fins that run most of the length of the body; in males, these are edged with blue or violet. The mouth is angled obliquely upwards and so is ideal for catching any plankton passing above the vertical mud burrow in which this fish lives, and into which it will withdraw rapidly if anything approaches. Red Bandfish usually live in colonies and each burrow is about 5cm across and runs vertically into the sediment. Imprints of the pectoral fins may be visible where a fish has propped itself up while peering out of its burrow. It is unusual to see one in the field, as most colonies are in deep water, but there some colonies and individuals established within diving depths. KEY FEATURES Orange-red, eel-like fish living in a mud burrow. Long dorsal and anal fins, oblique mouth and large eyes. SIMILAR SPECIES None in British and Irish waters. ABUNDANCE AND DISTRIBUTION In deeper offshore, soft sediments, the Red Bandfish is moderately common around Britain and Ireland, though rare in the shallow North Sea. Colonies within diving depths are known from several locations, especially along the south coast of England including Lundy Island (Bristol Channel), Brixham (Devon), Portland Harbour, Plymouth Sound and the Fal Estuary. There are

262

Fish in burrows Many British and Irish fishes live within the crevices, holes and other similar hiding places found in rocky habitats. However, a very few excavate and live in sediment burrows. Those that can be found within diving depths are the Red Bandfish Cepola macrophthalama (opposite), Snake Blenny Lumpenus lampretaeformis (p. 177) and Fries’s Goby Lesuerigobius friesii (p. 189). Holes that are obviously burrow entrances can often be seen when diving over soft sediments, but many will belong to invertebrates, especially decapod crustaceans, some of which construct quite complex mud burrows. Red Bandfish (opposite) This fish puts considerable effort into excavating its burrow, carrying material in its mouth and piling it in a spoil heap by the burrow entrance. It very rarely leaves the burrow completely. The simple vertical shaft with an expanded base can extend to a metre deep, and is often intersected by the tunnels and burrows of other species such as the Angular Crab Goneplax rhomboides. The various residents of the resulting burrow complexes may benefit from these associations. Fries’s Goby This small goby excavates shallow burrows about 10cm into the sediment and uses them as a safe retreat if danger threatens. Very little else is known about the burrows, though one early study suggests each may have two entrances. In the 1970s, divers observed gobies occupying small burrows amongst the larger burrows of Norway Lobster Nephrops norvegicus in some soft muddy areas. Whether this species ever associates with Nephrops and shares burrows, as is often stated, remains uncertain. It also occurs on sediments where there are no Nephrops and may not always have a burrow. More diver observations are needed. Black Goby and Tompot Blenny will use burrows in soft sediment as a refuge. It is not known whether or not the fish dig the burrow themselves, or take advantage of a ready-made home.

PNa

LB

Above left Fries’s Goby Lesueurigobius friesii around entrance to Nephrops burrow. Loch Duich, Highland. Above right Fries’s Goby L. friesii. Loch Linnhe, Highland. Left Black Goby Gobius niger. Portland, Dorset.

NON-FLATTENED FISHES ON THE SEABED

Hagfishes and lampreys Hagfishes and lampreys are an ancient group of eel-like fishes that have no biting jaws with teeth, and only a flexible rod of cartilage as a supporting skeleton. This means they are extremely flexible, with hagfishes able to wrap their body into a knot. Hagfishes live exclusively in the ocean, while lampreys live either entirely in fresh water or migrate from the sea into rivers to spawn. There are three species of lampreys in British and Irish waters and one species of hagfish.

Myxine glutinosa Hagfish

Linnaeus, 1758

Hagfish out of its burrow showing fleshy barbels on the head and skin flap on the ventral surface. Norway.

GENERAL DESCRIPTION With its long, cylindrical body, the Hagfish resembles a pinkish brown eel, but with no snout or jaws and tiny, barely visible eyes. It can grow to about 60–70cm in length. The slit-shaped mouth at the head end is surrounded by numerous fleshy barbels. The Hagfish has no fins apart from a single long skin flap extending from the mid ventral surface to the tail, and no gill cover. This fish lives buried in mud with just the head showing, only emerging to feed on crustaceans and dead animals, usually at night. Found from depths of 20m, to much deeper water. KEY FEATURES Eel-like, mud-dwelling fish. Fleshy tentacles surround a slit-shaped mouth. Eyes almost invisible. SIMILAR SPECIES Superficially similar to the European Eel (p. 261), though European Eels have jaws and well-developed eyes, and lack barbels. Both the Hagfish and Sea Lamprey (opposite) lack jaws, however the latter has no mouth barbels and has a series of rounded gill openings behind the head. ABUNDANCE AND DISTRIBUTION Rarely recorded by divers but there is a Seasearch record, accompanied by video, off Sunderland, northeast England. Hagfish are found all around Britain and Ireland. Shallow water occurrences are most common in northern waters.

264

Petromyzon marinus Sea Lamprey

Linnaeus, 1758

An adult Sea Lamprey nestbuilding in a river; they return to freshwater to spawn. This one uses its sucker-like mouth to move a cobble. Note the round gill openings behind the eye.

GENERAL DESCRIPTION The Sea Lamprey has a long, eel-like body and can reach up to 100cm long, but is more usually around half this length. There is an obvious row of seven, round gill openings behind each eye. The mouth lies just beneath the head and has no jaw, consisting instead of a round sucker-disc edged with a frill of tiny skin flaps and lined with concentric rows of rasping teeth. There are two low dorsal fins near the tail, but no other fins. The colour is an overall pale greyish brown, but heavily mottled with darker speckles and blotches. Adults live in coastal waters down to about 20m depth where they feed mainly by attaching to larger fishes or mammals using the sucker-disc, and rasp off flesh and blood. They move into rivers to spawn. KEY FEATURES Eel-like fish with a round,sucker-disc, a row of round gill openings on either flank and two dorsal fins. Usually seen feeding, attached to other fishes. SIMILAR SPECIES Adult River Lampreys Lampetra fluviatilis (not described here) also live in coastal waters, but are smaller (30–50cm) and a uniform dark greenish brown on the back. The European Eel (p. 261) has a jawed mouth, gills covered by a gill flap, pectoral fins, and a single, long dorsal fin. ABUNDANCE AND DISTRIBUTION Occasionally seen by divers, may be attached to larger fishes. Found all around Britain and Ireland.

10 m 25 m

Changing fish distributions The geographical distribution of fish species depends on a variety of factors, particularly water temperature. However, fish distributions can alter over time in response to other causes such as climate change and consequent warmer seas, as well as habitat destruction, chronic pollution and the introduction of non-native species. Seasearch volunteers and other divers are helping to document the northward spread into British and Irish waters of some warmer water, southern fish species. Two such species added to the British and Irish lists over the years, and recorded by divers, are the Black-faced Blenny Tripterygion delaisi (p. 179) and the Variable Blenny (or Ringneck Blenny) Parablennius pilicornis (p. 171), and their spread is detailed below. Similarly, the Red Blenny Parablennius ruber (p. 170) and the Leopard-spotted Goby Thorogobius ephippiatus (p. 188) have been added to British and Irish fish lists in recent times, however these two species were discovered through changes in recording and reporting methods, and are not thought to have altered their distribution. They were only recognised in Britain and Ireland when divers began survey work in the rocky reef habitats they prefer, which could not be sampled using traditional trawling methods. Details of the Red Blenny discovery are provided on pp. 172–173. The Leopard-spotted Goby was collected from rocky reefs off Plymouth by divers in the 1950s when it was described as a new species, before being synonymised with Thorogobius ephippiatus – a species previously known only from Madeira and the Mediterranean.

PW

Leopard-spotted Goby Thorogobius ephippiatus in its favoured rocky reef habitat, close to a crevice for safety. Strangford Lough, County Down.

Range expansions The Black-faced Blenny was first recorded from Portland Harbour, Dorset in 1973 and for many years this location and Swanage Pier were the only known English sites. However, its distribution has expanded westward, with reports from 2006 onwards in Cornwall (Rame Head, Falmouth, Helford, Porthkerris and The Lizard) and Devon (Plymouth Sound and Torbay). There are fewer records from east of Dorset than in Devon and Cornwall, and advances in this direction appear to be taking longer than to the west. There are possible outlier reports from East Sussex and the South Llyn Peninsula in North Wales. Although there are as yet no Irish records, this is clearly a species on the move. The first reports of the Variable Blenny were from Bigbury Bay in 2007 and nearby Wembury Bay in 2010; it has now been recorded at locations from Cornwall to Dorset. Breeding was confirmed east of Portland Bill in Dorset in 2020. Portland Bill, projecting nine miles out from the Dorset coast, can act as a physical barrier to marine species moving along the coast, however exceptional weather conditions combined with favourable

266 CHANGING FISH DISTRIBUTIONS

CB

The Comber Serranus cabrilla is a relatively recent arrival to the Channel Islands but now appears to be resident year-round. Guernsey, Channel Islands.

Grey Triggerfish Balistes capriscus (p. 79) sightings in British and Irish waters date back to the nineteenth century, with the first record in 1827 off the coast of Sussex and from County Kerry, Ireland in 1845. However, it appears to fluctuate in abundance over the decades. Considered rare before the 1960s, it seems to have increased its range in the 1960s and 1970s. There were frequent reports in the early 1990s from southwest Ireland, and from the English south coast in the 2000s, where abundance appeared to decline again in 2019. Breeding in British and Irish waters has not been confirmed, though a specimen close to spawning was captured in 1989 off Slea Head in County Kerry; occasional small specimens are reported from time to time as far north as the west coast of Scotland. Species from other groups of fishes such as the seabreams (pp. 70–71) and southern wrasses such as the Rainbow Wrasse Coris julis (p. 92) have long been known from around the coasts of Britain and Ireland, with occasional records from at least the early 19th century. It would now seem that some of these species with typically southern European and Mediterranean distributions are appearing more frequently in the records off the southwest coasts of Britain and Ireland. Some, such as the Gilthead Seabream Sparus aurata (p. 77) and Couch’s Seabream Pagrus pagrus (p. 76), have established breeding populations which may be related to ocean warming. The Comber Serranus cabrilla has been very rarely recorded from the Channel Islands since 1905 but, has recently become a more regular visitor. There were many reports in summer 2022 from southwest England and the Channel Islands by both scuba divers and anglers.

Depth distributions Some small fishes found in British and Irish waters were previously thought to be exclusively deepwater, offshore species, including Steven’s Goby Gobius gasteveni (p. 196), Jeffreys’s Goby Buenia jeffreysii (p. 202), Norway Goby Pomatoschistus norvegicus (p. 208), Spotted Dragonet Callionymus maculatus (pp. 228–229) and Moustache Sculpin Triglops murrayi

RY

Male Jeffreys’s Goby Buenia jeffreysii. Loch Nevis, Highland.

have shown that these all occur well within diving depths, very often on sheltered, muddy habitats in Scottish lochs and Irish loughs. Steven’s Goby was first reported from deepwater offshore habitats around Plymouth in 1974. Since then, it has been recorded from as shallow as 12m in south Devon in 2008, Lyme Bay in 2009, and Plymouth Sound in 2011 – where breeding was confirmed in 2022. The expansion in records continues, with the first recorded sighting east of Portland Bill in 2021, and numerous diver reports from the Fal Estuary and the south Cornish coast in recent years. Couch’s Goby Gobius couchi (p. 194) was considered very rare, confined to the Helford Estuary in Cornwall, but subsequent reporting has shown it is often common and widely distributed on southern English and southern and western Irish coasts.

PNa

Steven’s Goby Gobius gasteveni

268 CHANGING FISH DISTRIBUTIONS

Parasites of fish A wide variety of parasites infect marine fishes. This section describes some of the few visible parasites that can be seen by divers in situ on fish. The most conspicuous are crustaceans, especially the isopods Anilocra and gnathids (Gnathiidae), as well as copepods in the family Caligidae. There are also leeches, and a flatworm which causes clearly visible ‘black-spot’.

Crustaceans Anilocra spp. There are two species recorded from fishes in British and Irish waters, which are indistinguishable underwater or from photographs. These are large, woodlouse-like isopods and observations suggest that they may have become increasingly common on fishes in recent decades. Once rarely seen, they are now frequently encountered on a wide variety of fish: Goldsinny Wrasse Ctenolabrus rupestris, Cuckoo Wrasse Labrus mixtus, Corkwing Wrasse Symphodus melops, Rock Cook Centrolabrus exoletus, Ballan Wrasse Labrus bergylta, Two-spotted Goby Pomatoschistus flavescens, sand gobies Pomatoschistus sp., Painted Goby Pomatoschistus pictus, Rock Goby Gobius paganellus, Sand Smelt Atherina presbyter, Black Seabream Spondyliosoma cantharus, Bib Trisopterus luscus, Pollack Pollachius pollachius, Sea Stickleback Spinachia spinachia and Red Mullet Mullus surmuletus. Scarborough, on England’s east coast, is the most northerly record to date for this isopod. Often, pairs of Anilocra attach just behind the eye, slightly to one side on large fish such as wrasse, or behind the pectoral fin on small species such as gobies. Divers may see free-swimming Anilocra at night when there is the best chance for the parasite to find a stationary fish to attach to. The presence of Anilocra may well change the behaviour of the host, with the fish becoming much more skittish and secretive. Below A pair of Anilocra isopods on a Rock Cook Centrolabrus exoletus. Jersey, Channel Islands. Right Free-swimming in search of a host.

ST

RY

NO

LB

Above left Gnathid isopods attached just below the eye on a Common Dragonet Callionymus lyra. Mulroy Bay, County Donegal. Above right Gnathid isopod on a Long-spined Sea Scorpion Taurulus bubalis. Lough Hyne, County Cork. ST

Left A free-swimming Gnathia maxillaris.

Gnathiidae Larvae of this isopod family are called praniza and are temporary parasites on the body of fishes. The praniza needs three separate blood meals: first, it feeds for a few hours before dropping onto the seabed to moult. Next, it needs to find another fish for another feed: these isopods are good swimmers and are often collected in plankton samples. A third feed completes this stage of their lifecycle. These larvae occur on a wide range of fish species, including dragonets, gobies, blennies, sea scorpions and Lumpsucker Cyclopterus lumpus. The swollen body of the larva may be an eye-catching colour, for example duck egg green or lurid pink. Caligidae Copepods in this family are parasitic on farmed salmon, causing considerable commercial losses. The life stage which divers see most often on fishes are the adult females with long egg strings, and males which lack these. These parasites have been reported on a wide range of fishes in the wild, including gobies, gurnards, salmonids, gadoids, wrasses, John Dory Zeus faber, Lumpsucker and some flatfishes.

LB

A Two-spotted Goby Pomatoschistus flavescens

270 PARASITES OF FISH

PW

A small Atlantic Cod Gadus morhua with black-spot disease. Strangford Lough, County Down.

Black-spot diseases Black-spot diseases are caused by the cysts of several species of parasitic flatworms (Digenea) which develop in the skin of the fish. The fish secretes dark material (melanin) around the cyst and it is this which produces the characteristic black spot. This parasite has been seen on a wide range of species, including Bib, Haddock Melanogrammus aeglefinus and other members of the cod family, as well as Sand Smelt and Red Bandfish Cepola macrophthalma. Often, photographs of fishes on the seabed, Haddock in particular, show heavy infestations of black-spot, particularly late in the year. This suggests the parasite has a debilitating effect on the fish, causing them not to swim as actively away from a diver as might be expected.

Leeches Leeches are another common parasite, and again, some can infest a wide range of fishes. One common species is the large, spiky-looking Pontobdella muricata, while another, Hemibdella soleae, occurs only on species of sole. There are many other marine leeches, with at least 29 listed from the waters around Britain and Ireland. Heavy infestations of leeches can seriously weaken the host fish.

LB

Pontobdella muricata on a Thornback Skate Raja clavata.

SD

Associations with other species Divers are in a unique position to watch and record the activities of fish in their natural environment. Some interesting associations between different fish species, and between fish and invertebrates, have been documented in this way and three are described here.

Rock Cook and Ballan Wrasse Groups of Rock Cook Centrolabrus exoletus (p. 91) are often seen swimming with large Ballan Wrasse Labrus bergylta (pp. 86–87), and will sometimes follow closely behind and around individual fish. Their apparent intent is to feed on any small crustaceans and other food items that the larger Ballan Wrasse disturbs during its own feeding activities. Such associations between two different species are better known amongst tropical reef fishes. Ballan Wrasse have been photographed carrying loose kelp up off the seabed and then releasing it, whereupon attendant Rock Cooks quickly home in to eat any dislodged amphipods or other invertebrates that had been feeding on the decomposing kelp (see Great British Marine Animals in Where to find out more pp. 276–277). Given the opportunity, Rock Cooks consistently act as ‘cleaner fish’, removing parasites from larger fishes. Large Ballan Wrasse benefit from this, adopting a particular position in the water with the head up and tail down to encourage cleaner activity. To a lesser extent, young Ballan Wrasse themselves, as well as Goldsinny Wrasse Ctenolabrus rupestris (p. 90) and Corkwing Wrasse Symphodus melops (pp. 82–83) also act as cleaners.

PNa

A group of Rock Cook Centrolabrus exoletus surround the larger

272 ASSOCIATIONS WITH OTHER SPECIES

PNa

Common Prawns Palaemon serratus possibly hoping for food scraps from the concealed Conger Eel Conger conger. Devon.

Conger Eel and Common Prawn Conger Eels Conger conger (p. 260) spend a lot of their time hidden away in holes and crevices, with just the head showing. They are generally not the only inhabitants: Common Prawns Palaemon serratus can often be seen on the ceiling, floor and at the entrance of these hideaways. Lobsters Homarus gammarus have also been observed sharing space with Conger Eels. This in spite of the fact that a large Conger can easily catch and dismember crabs and lobsters. The prawns may well benefit from food scraps in the Conger’s lair, though Conger Eels mostly hunt at night out in the open. Prawns and shrimps are well known for their mutually beneficial associations with other invertebrates, such as anemones, and many tropical species act as cleaners of fish.

Other associations Several species of tropical gobies are known to live only in the burrows of alpheid (Alpheus spp.) shrimps. The shrimp maintains the burrow while the goby acts as a lookout. No British or Irish goby has yet been shown to do this, but Fries’s Goby Lesueurigobius friesii (p. 189), while it can and does build its own burrow, will also use Norway Lobster Nephrops norvegicus burrows as a temporary refuge from danger (see p. 263). It is also possible their own burrows may intersect with Nephrops burrows, as is certainly the case with Red Bandfish Cepola macrophthalama (p. 262) and several species of crustacean.

Protected species and conservation status Legal protection and conservation priority Seasearch currently operates in a number of separate jurisdictions around Britain and Ireland, all of which enact their own legislation. This can make for a very confusing picture when trying to ascertain whether a particular species is protected or not. The list provided here is not intended to be exhaustive but will provide a starting point for interested readers. There are numerous articles of legislation in Britain, Ireland, the Isle of Man and the Channel Islands bailiwicks that confer protection on marine species, including fishes. The primary legislation in the United Kingdom is the Wildlife and Countryside Act 1981 (legislation.gov.uk/ukpga/1981/69), which originally applied across the UK but has been subsequently supplemented and amended by the devolved governments. The most important legislation underpinning biodiversity and nature conservation in Ireland comprises the Wildlife Acts 1976 to 2021 and the European Communities (Birds and Natural Habitats) Regulations 2011–2021 (see npws.ie/legislation for further information). In the Isle of Man, the Wildlife Act 1990 is the overarching instrument and includes a list of protected animals in Schedule 5 (gov.im/media/59710/waschedule5jul04order.pdf ). In its original incarnation, the Conservation of Wildlife (Jersey) Law 2000 only included marine mammals and turtles. A project to review and update this legislation published a number of recommendations in 2016, including addressing the lack of statutory protection for marine species. These have not yet (as of autumn 2022) been formally adopted (see gov.je/Government/Pages/StatesReports.aspx?ReportID=2468 for details). At the time of writing, Guernsey has limited legislation with the specific aim of protecting and conserving wildlife, a situation which is under review as part of the current Biodiversity Strategy (gov.gg/CHttpHandler. ashx?id=123295&p=0). As signatories to the Blue Island Charter in 2019 (alderney.gov.gg/article/176960/Blue-Island-Charter), the States of Alderney is in the process of drafting and consulting upon the Wildlife (Alderney) Law 2020. This will repeal existing narrow legislation and replace it with an ordinance containing requirements for general conservation of biodiversity, as well as protection for specific habitats and species. Some of the above legislation confers legal protection upon a species, such that it becomes a prosecutable offence to interfere with, kill, damage or possess a specimen (or damage its habitat). Other legislation highlights those species deemed of importance to conservation (priority species), whose presence may have to be taken into consideration, or require an environmental impact assessment, as part of the planning process. The Joint Nature Conservation Committee has published a list of designations for UK species (both marine and terrestrial) – it can be downloaded from jncc.gov.uk/our-work/conservation-designations-for-uktaxa/

Marine licencing Some activities undertaken by divers and others, for example, recovering items from wrecks, may require a licence from a regulatory body. Collecting marine life, including while using scuba gear, may be restricted or forbidden, or require registration or a permit of some kind (this applies to recreational as well as commercial collection in some localities). Intentionally seeking out and photographing some species of fish also falls into this area. The links below provide a starting point to check whether your activities might require a licence: • gov.uk/guidance/wildlife-licences (applies to England with links to Wales, Scotland and Northern Ireland) • gov.uk/guidance/do-i-need-a-marine-licence (applies to England and Northern Ireland) • npws.ie/licencesandconsents (information covering all marine activities in Ireland)

274

Conservation status The European Red List summarises the conservation status of a species using guidelines developed by the International Union for Conservation of Nature (IUCN). The European Red List for fishes can be downloaded from iucnredlist.org/resources/nieto2015 At the time of writing (autumn 2022), the IUCN deemed 7.5% of all European marine fish species as threatened in European waters and nearly 10% to have declining populations. The main threats to these species are overfishing, coastal development, energy generation, mining and pollution. Searching the IUCN website by species name will indicate whether the population trend is stable, increasing or decreasing, as assessed on a regional basis. In this field guide we have highlighted those species that are currently placed by the IUCN in one of the following categories: Critically Endangered A species is Critically Endangered when the best available evidence indicates that it is facing an extremely high risk of extinction in the wild. Endangered A species is Endangered when the best available evidence indicates that it is facing a very high risk of extinction in the wild. Vulnerable A species is Vulnerable when the best available evidence indicates it is at high risk of extinction in the wild. Near Threatened A species is Near Threatened when the best available evidence indicates that it is close to qualifying in the near future for one of the three threat categories listed above. The criteria used to evaluate a species’ Red List status are rigorously defined and full details can be down­ loaded from iucnredlist.org/resources/categories-and-criteria

Where to find out more We hope that this guide will help you to identify most, if not all, of the fishes you are likely to see underwater around Britain and Ireland. However, distributions change, as we have highlighted, and you may want to consult other sources of information. The following list of books, websites and other resources should help as a starting point.

BOOKS – FISH-SPECIFIC Field Guide to Sharks, Rays and Chimaeras of Europe and the Mediterranean (2021). Ebert, D.A. and Dando, M. Wild Nature Press/Princeton University Press. Marine Fish of the Channel Islands (2018). Plaster, A. and Chambers, P. Charonia Media. Europe and Mediterranean Marine Fish Identification Guide (2015). Louisy, P. Les Éditions Eugen Ulmer. Identification Guide to the Inshore Fish of the British Isles (2014). Henderson, P. Pisces Conservation Ltd. A Field Guide to the Marine Fishes of Wales and Adjacent Waters (2009). Kay, P. and Dipper, F. Marine Wildlife. Key to the Marine and Freshwater Fishes of Britain and Ireland (2009). Maitland, P.S. and Herdson, D. Environment Agency. This is a lightly revised edition of Key to the Fishes of Northern Europe (1978). Wheeler, A. Fredrick Warne. British Sea Fishes (2001). Dipper, F. Underwater World Publications Ltd.

BOOKS – GENERAL Great British Marine Animals 4th Ed. (2021). Naylor, P. Sound Diving Publications. The Essential Guide to Rockpooling (2019). Hatcher, J. and Trewhella, S. Wild Nature Press/Princeton University Press. Marine Life of the Channel Islands (2018). Daly, S. Small Island Publishing. Handbook of the Marine Fauna of North-West Europe 2nd Ed. (2017). Hayward, P.J. and Ryland, J.S. Oxford University Press. Collins Complete Guide to British Coastal Wildlife (2012). Sterry, P. and Cleave, A. HarperCollins. Marine Fish and Invertebrates of Northern Europe (2004). Moen, F.E. and Svensen, E. Aquapress.

ONLINE RESOURCES Fishbase – fishbase.se A global species database of information about finfishes. There are local mirrors of the database, multiple search tools and an app available for mobile devices. MarLIN, The Marine Life Information Network – marlin.ac.uk Based at the Marine Biological Association in Plymouth, the site provides much information about species, with photographs for most, and habitats. It also contains information about biodiversity and conservation for key species. Habitas, Encyclopaedia of Marine Life of Britain and Ireland – habitas.org.uk/marinelife Based in the Ulster Museum and maintained by Bernard Picton and Christine Morrow, this photographic guide covers a selection of the larger animals which live around the coasts of Britain and Ireland. It is intended for divers and marine biologists who need to be able to recognise species in situ and is illustrated with underwater pictures. The Shark Trust – sharktrust.org Great Eggcase Hunt – sharktrust.org/great-eggcase-hunt A wealth of information about shark-related issues, including citizen science recording schemes (e.g. the Great Eggcase Hunt and the Basking Shark Project).

276 WHERE TO FIND OUT MORE

National Biodiversity Network Atlas – www.nbnatlas.org and separate atlases for Isle of Man isleofman. nbnatlas.org, Northern Ireland northernireland.nbnatlas.org, Scotland scotland.nbnatlas.org and Wales wales.nbnatlas.org The main resource for distribution and mapping of British and Irish species, this site allows you to view distribution maps and download data using a variety of interactive tools. This is the public repository for all Seasearch information and allows you to search for marine data from a number of sources in a single location. National Biodiversity Data Centre of Ireland – biodiversityireland.ie An online portal bringing together biodiversity data and recording schemes from across Ireland, including distribution maps. Artsdatabanken (Knowledge Bank for Natural Diversity) – artsdatabanken.no Available in English as well as Norwegian, useful for northern species. Mer et Littoral (European Marine Life) – european-marine-life.org/index.php Available in French and English, useful for southern species. Biodiversity Heritage Library – biodiversitylibrary.org Many older books and original species descriptions are now out of print, however a large number which are out of copyright are available here.

MD A Seasearch diver recording a rocky reef in the Farne Islands, Northumberland.

278 SEASEARCH

Seasearch surveying and recording Seasearch is a volunteer underwater survey project for divers and snorkellers throughout Britain and Ireland to record observations of marine habitats and the life they support. This guide has been produced to help volunteers identify the fishes seen on their surveys. We have included a ‘confidence guide’ to indicate the most robust and accurate level of recording – what you need to be able to see to identify the subject to a particular taxonomic level. Seasearch data is a trustworthy resource due to the multiple levels of quality assurance it undergoes. Seasearch hopes that this guide will encourage even more people to complete recording forms after any of their sea surveys. You can download the forms from our website or obtain them from any of the coordinators. The information gathered is used to increase our knowledge of the marine environment and contribute towards its conservation. Seasearch data have helped to define the boundaries of areas for conservation, recorded the presence of rare and unusual species, and provided information underpinning campaigns for protection of marine life and habitats. The data are held both by local record centres and centrally, and are available under a Creative Commons licence (CC-BY) through the National Biodiversity Network (NBN). Go to registry.nbnatlas.org/public/show/dp119 to see all the Seasearch datasets (these are separated by country, plus seafans and crawfish). Note that species records deemed ‘sensitive’ are only available at high resolution (less than 10km squares) on application, and with a valid reason. Volunteers can participate in Seasearch training courses at different levels suitable to their knowledge and experience. The Observer course provides an introduction to marine habitat and species identification and survey methods. The Surveyor course is for more experienced recorders, and there are also Specialist courses which provide participants with more information on specific groups of marine life or additional survey techniques. In addition to a national coordinator for the project, there is a network of regional coordinators in most coastal areas and countries, who organise Seasearch surveys and training. Training and talks in other areas can be arranged on request. For further information see the Seasearch website at www.seasearch.org.uk

Seasearch is a partnership between the Marine Conservation Society (MCS), The Wildlife Trusts, statutory nature conservation bodies and others. It is organised overall by MCS and coordinated and delivered locally by Wildlife Trust staff and individuals under contract to MCS.

Biosecurity and non-native species Scuba divers and snorkellers, along with other water users, have a part to play in preventing the spread of non-native species. Some of these may be nuisance or invasive species (INNS, invasive non-native species). If you suspect that you have been diving or snorkelling in water containing an INNS then, WHEREVER POSSIBLE, the Check-Clean-Dry guidelines at nonnativespecies.org/checkcleandry (in Ireland see invasives.ie) should be followed. Photographs of the possible INNS should be taken in situ, taking care not to disturb or dislodge it. A report should be made of the sighting: email [email protected] or submit online via the National Biodiversity Data Centre in Ireland records.biodiversityireland.ie/record/invasives

Taxonomic list of fishes included in this guide The classification followed here is from the World Register of Marine Species or WoRMS (marinespecies.org). Within each class the orders are arranged alphabetically, as are the families within each order. The order Perciformes is under revision and within this order, families marked with a double asterisk** are under review and may be assigned to different orders in the near future as research progresses. Class

Order

Family

Genus

Species

Vernacular name Page

Myxinidae

Myxine

Myxine glutinosa

Hagfish

264

PETROMYZONTI (lampreys) Petromyzontiformes Petromyzontidae Petromyzon

Petromyzon marinus

Sea Lamprey

265

ELASMOBRANCHII (sharks, skates & rays) Carcharhiniformes (ground sharks) Carcharhinidae Prionace Triakidae Galeorhinus Mustelus Scyliorhinidae Scyliorhinus

Prionace glauca Galeorhinus galeus Mustelus asterias Scyliorhinus canicula Scyliorhinus stellaris

Blue Shark Tope Starry Smoothhound Smallspotted Catshark Nursehound

38 40 41 42 43

Lamniformes (mackerel sharks) Cetorhinidae Cetorhinus

Cetorhinus maximus

Basking Shark

36

Myliobatiformis (eagle rays) Myliobatidae Dasyatidae

Myliobatis aquila Dasyatis pastinaca

Common Eagle Ray Common Stingray

113 116

Rajiformes (skates) Rajidae Amblyraja Dipturus Leucoraja Raja

Amblyraja radiata Dipturus batis Dipturus intermedius Leucoraja naevus Raja clavata Raja brachyura Raja montagui Raja microocellata Raja undulata

Starry Skate Blue Skate Flapper Skate Cuckoo Skate Thornback Skate Blonde Skate Spotted Skate Small-eyed Skate Undulate Skate

113 114 115 112 104 107 106 108 109

Squaliformes (dogfish sharks) Squalidae

Squalus

Squalus acanthias

Spurdog

Squatiniformes (angelsharks) Squatinidae

Squatina

MYXINI (hagfishes) Myxiniformes

Myliobatis Dasyatis

39

Squatina squatina

Angelshark

120

Torpediniformes (electric rays) Torpedinidae Torpedo

Torpedo marmorata

Marbled Electric Ray

117

ACTINOPTERI (bony fishes) Acanthuriformes (surgeonfishes & relatives) Caproidae Capros

Capros aper

Boarfish

Anguilla anguilla

European Eel

Anguilliformes (eels) Anguillidae Congridae

280

Anguilla Conger

97 261

Class

Order

Family

Genus

Species

Vernacular name Page

Atherina

Atherina presbyter

Sand Smelt

52

Belone belone Scomberesox saurus

Garfish Atlantic Saury

56 56

Blennius ocellaris Coryphoblennius galerita Lipophrys pholis Parablennius gattorugine Parablennius pilicornis Parablennius ruber Tripterygion delaisi

Butterfly Blenny Montagu’s Blenny Shanny Tompot Blenny Variable Blenny Red Blenny Black-faced Blenny

167 166 165 168 171 170 179

Callionymiformes (dragonets) Callionymidae Callionymus

Callionymus lyra Callionymus maculatus Callionymus reticulatus

Common Dragonet Spotted Dragonet Reticulated Dragonet

224 228 225

Carangiformes (jacks) Carangidae

Trachurus

Trachurus trachurus

Atlantic Horse Mackerel

51

Clupeiformes (herrings) Clupeidae Engraulidae

Clupea Sardina Sprattus Engraulis

Clupea harengus Sardina pilchardus Sprattus sprattus Engraulis encrasicolus

Atlantic Herring European Pilchard Atlantic Sprat European Anchovy

46 47 47 47

Gadiformes (codfishes) Gadidae Lotidae

Gadus Melanogrammus Merlangius Pollachius Raniceps Trisopterus Ciliata Enchelyopus Gaidropsarus Molva

Gadus morhua Melanogrammus aeglefinus Merlangius merlangus Pollachius pollachius Pollachius virens Raniceps raninus Trisopterus luscus Trisopterus minutus Ciliata mustela Ciliata septentrionalis Enchelyopus cimbrius Gaidropsarus mediterraneus Gaidropsarus vulgaris Molva molva

Atlantic Cod Haddock Whiting Pollack Saithe Tadpole Fish Bib Poor Cod Five-bearded Rockling Northern Rockling Four-bearded Rockling Shore Rockling Three-bearded Rockling Ling

62 63 68 64 65 157 66 67 152 153 151 154 155 156

Gobiesociformes (clingfishes) Gobiesocidae

Apletodon Diplecogaster Lepadogaster

Apletodon dentatus Diplecogaster bimaculata Lepadogaster candolii Lepadogaster purpurea

Small-headed Clingfish Two-spotted Clingfish Connemara Clingfish Shore Clingfish

215 214 213 212

Gobiiformes (gobies) Gobiidae

Aphia Buenia Crystallogobius Gobius

Aphia minuta Buenia jeffreysii Crystallogobius linearis Gobius cobitis

Transparent Goby Jefrreys’s Goby Crystal Goby Giant Goby

210 202 211 195

Atheriniformes (silversides) Atherinidae

Beloniformes (needlefishes) Belonidae Belone Scomberesocidae Scomberesox Blenniiformes (blennies) Blenniidae Blennius Coryphoblennius Lipophrys Parablennius Trypterygiidae Tripterygion

Class

Genus

Species

Vernacular name Page



Lebetus Lesuerigobius Pomatoschistus Thorogobius

Gobius cruentatus Gobius gasteveni Gobius niger Gobius paganellus Lebetus guilleti Lebetus scorpioides Lesuerigobius friesii Pomatoschistus flavescens Pomatoschistus lozanoi Pomatoschistus microps Pomatoschistus minutus Pomatoschistus norvegicus Pomatoschistus pictus Thorogobius ephippiatus

Red-mouthed Goby Steven’s Goby Black Goby Rock Goby Guillet’s Goby Diminutive Goby Fries’s Goby Two-spotted Goby Lozano’s Goby Common Goby Sand Goby Norway Goby Painted Goby Leopard-spotted Goby

197 196 190 192 200 201 189 209 207 206 207 208 204 188

Lophiiformes (anglerfishes) Lophiidae

Lophius

Lophius piscatorius

Angler

146

Mugiliformes (grey mullets) Mugilidae

Chelon

Chelon aurata Chelon labrosus Chelon ramada

Golden Grey Mullet Thicklip Grey Mullet Thinlip Grey Mullet

Mulliformes (goatfishes) Mullidae

Mullus

Mullus surmuletus

Red Mullet

Perciformes (perch-like fishes) Agonidae Ammodytidae Anarhichadidae Cepolidae** Cottidae Cyclopteridae Gasterosteidae Labridae** Liparidae Moronidae** Pholidae Sparidae**

Agonus Agonus cataphractus Ammodytes Ammodytes marinus Ammodytes tobianus Gymnammodytes Gymnammodytes semisquamatus Hyperoplus Hyperoplus immaculatus Hyperoplus lanceolatus Anarhichas Anarhichas lupus Cepola Cepola macrophthalma Micrenophrys Micrenophrys lilljeborgii Myoxocephalus Myoxocephalus scorpius Taurulus Taurulus bubalis Triglops Triglops murrayi Cyclopterus Cyclopterus lumpus Gasterosteus Gasterosteus aculeatus Spinachia Spinachia spinachia Acantholabrus Acantholabrus palloni Centrolabrus Centrolabrus exoletus Coris Coris julis Ctenolabrus Ctenolabrus rupestris Labrus Labrus bergylta Labrus mixtus Symphodus Symphodus bailloni Symphodus melops Liparis Liparis liparis Liparis montagui Dicentrarchus Dicentrarchus labrax Pholis Pholis gunnellus Boops

282

Order

Family

54 54 54 160

Pogge 259 Raitt’s Sandeel 48 Lesser Sandeel 48 Smooth Sandeel 48 Corbin’s Sandeel 48 Greater Sandeel 48 Wolf Fish 158 Red Bandfish 262 Norway Bullhead 256 Short-spined Sea Scorpion 254 Long-spined Sea Scorpion 252 Moustache Sculpin 258 Lumpsucker 218 Three-spined Stickleback 251 Sea Stickleback 250 Scale-rayed Wrasse 93 Rock Cook 91 Rainbow Wrasse 92 Goldsinny Wrasse 90 Ballan Wrasse 86 Cuckoo Wrasse 88 Baillon’s Wrasse 84 Corkwing Wrasse 82 Striped Seasnail 220 Montagu’s Seasnail 220 European Seabass 53 Butterfish 174

Class

Order

Family

Genus

Species

Vernacular name Page

Diplodus Diplodus sargus Diplodus vulgaris Pagellus Pagellus bogaraveo Pagellus erythrinus Pagrus Pagrus pagrus Sparus Sparus aurata Spondyliosoma Spondyliosoma cantharus Stichaeidae Chirolophis Chirolophis ascanii Lumpenus Lumpenus lampretaeformis Trachinidae Echiichthys Echiichthys vipera Triglidae Chelidonichthys Chelidonichthys cuculus Chelidonichthys lastoviza Chelidonichthys lucerna Eutrigla Eutrigla gurnardus Zoarcidae Zoarces Zoarces viviparus

White Seabream Common Two-banded Seabream Blackspot Seabream Common Pandora Couch’s Seabream Gilthead Seabream Black Seabream Yarrell’s Blenny Snake Blenny Lesser Weever Red Gurnard Streaked Gurnard Tub Gurnard Grey Gurnard Viviparous Blenny

78 71 70 76 77 72 176 177 238 233 235 234 236 178

Pleuronectiformes (flatfishes) Bothidae Arnoglossus Pleuronectidae Glyptocephalus Limanda Microstomus Platichthys Pleuronectes Scophthalmidae Scophthalmus Zeugopterus Soleidae Buglossidium Microchirus Pegusa Solea

Arnoglossus imperialis Arnoglossus laterna Arnoglossus thori Glyptocephalus cynoglossus Limanda limanda Microstomus kitt Platichthys flesus Pleuronectes platessa Scophthalmus maximus Scophthalmus rhombus Zeugopterus norvegicus Zeugopterus punctatus Zeugopterus regius Buglossidium luteum Microchirus variegatus Pegusa lascaris Solea solea

Imperial Scaldfish Scaldfish Thor’s Scaldfish Witch Flounder Dab Lemon Sole European Flounder European Plaice Turbot Brill Norwegian Topknot Topknot Eckström’s Topknot Solenette Thickback Sole Sand Sole Common Sole

139 137 138 130 128 129 127 126 141 140 145 143 144 135 134 132 133

Scombriformes (mackerels & tunas) Scombridae Scomber

Scomber scombrus

Atlantic Mackerel

Syngnathiformes (seahorses & pipefishes) Syngnathidae Entelurus Hippocampus Nerophis Syngnathus

Entelurus aequoreus Hippocampus guttulatus Hippocampus hippocampus Nerophis lumbriciformis Nerophis ophidion Syngnathus acus Syngnathus rostellatus Syngnathus typhle

Snake Pipefish Long-snouted Seahorse Short-snouted Seahorse Worm Pipefish Straight-nosed Pipefish Greater Pipefish Nilsson’s Pipefish Broad-nosed Pipefish

Tetraodontiformes (triggerfishes & relatives) Balistidae Balistes Molidae Mola

Balistes capriscus Mola mola

Grey Triggerfish Ocean Sunfish

79 57

Zeiformes (dories) Zeidae

Zeus faber

John Dory

96

Zeus

70

50 245 248 249 246 247 242 243 244

Index Page numbers in italic refer to the main species entry

A Acantholabrus pailloni 93 Agonus cataphractus 259 Amblyraja radiata 113 Ammodytes marinus 48 tobianus 48 AMMODYTIDAE 48 Anarhichas lupus 158 Anchovy, Blue 47 European 47 Angelshark 120, 121 Angler 98, 146 Black-bellied 146 Anglerfish 146 Anguilla anguilla 261 Anilocra spp. 269 Aphia minuta 183, 210 Apletodon dentatus 215, 217 Arnoglossus imperialis 139 laterna 137 thori 138 Atherina presbyter 52

B Balistes capriscus 79 Bandfish, Red 262, 263 Bass 53 BATOIDEA 100 Belone belone 56 svetovidovi 56 Bib 58, 59, 61, 66 Black-spot disease 271 Blennies 162 BLENNIIDAE 162 Blennius ocellaris 162, 167 Blenny, Black-faced 179 Butterfly 162, 167 Montagu’s 166 Portuguese 170, 173 Red 170, 173 Ringneck 171 Snake 177 Tompot 28, 168, 169 Variable 171

284 INDEX

Viviparous 178 Yarrell’s 176 Boarfish 97 Bogue 70 Boops boops 70 BOTHIDAE 136 Brill 140 Buenia jeffreysii 148, 183, 185, 187, 202, 203, 268 Buglossidium luteum 135 Bullhead, Norway 256 Butterfish 174

C CALIGIDAE 270 CALLIONYMIDAE 222 Callionymus lyra 223, 224, 226, 270 maculatus 228 reticulatus 223, 225, 227 Capros aper 97 Catshark, Greaterspotted 43 Smallspotted 34, 42, 118 Centrolabrus exoletus 24, 80, 91, 269, 272 Cepola macrophthalama 262, 263 Cetorhinus maximus 36, 37 Chelidonichthys cuculus 230, 231, 232, 233 lastoviza 230, 231, 232, 235 lucerna 230, 231, 232, 234 obscurus 230 Chelon auratus 54 labrosus 54 ramada 54 Chirolophis ascanii 176 Ciliata mustela 25, 152 septentrionalis 25, 153 Clingfish, Connemara 213 Shore 212 Small-headed 215, 217 Two-spotted 214, 216 Clupea harengus 46 Coalfish 65 Cod, Atlantic 61, 62, 271 Poor 22, 61, 67 Codfish 60 Coley 65

Comber 267 Conger conger 149, 260, 273 Cook, Rock 24, 80, 91, 269, 272 Coris julis 92 Coryphoblennius galerita 166 COTTIDAE 252 Crystallogobius linearis 211 Ctenolabrus rupestris 10, 29, 90 Cyclopterus lumpus 218

D Dab 22, 27, 128, 131 Long Rough 123 Dactylopterus volitans 230 Dasyatis pastinaca 116 Dentex, Common 71 Dentex dentex 71 Dicentrarchus labrax 23, 53 Diplecogaster bimaculata 214, 216 Diplodus sargus 70 vulgaris 78 Dipturus batis 114 intermedius 115, 119 nidarosiensis 114 oxyrinchus 114 Dogfish, Lesserspotted 42 Dory, John 96 Dragonet, Common 223, 224, 226, 270 Reticulated 223, 225, 227 Spotted 228

E Echiichthys vipera 238 Eel, Conger 149, 260, 273 European 261 Eelpout 178 eggcases 118 ELASMOBRANCHII 35 Enchelyopus cimbrius 151 Engraulis encrasicolus 47 Entelurus aequoreus 230, 241, 245 Eutrigla gurnardus 231, 232, 236

F Fish, Tadpole 157 Wolf 158

Flatfishes 122 Flounder, European 125, 127, 131 Witch 130

G GADIDAE 60 Gadus morhua 61, 62, 271 Gaidropsarus mediterraneus 154 vulgaris 155 Galeorhinus galeus 40 Garfish 56 Short-beaked 56 GASTEROSTEIDAE 250 Gasterosteus aculeatus 251 Glyptocephalus cynoglossus 130 Gnathia maxillaris 270 GNATHIIDAE 270 GOBIESOCIDAE 212 GOBIIDAE 180 Gobius cobitis 184, 186, 195 couchi 149, 184, 186, 194, 203 cruentatus 172, 184, 197 gasteveni 184, 196, 268 niger 181, 184, 186, 190, 198, 199, 203, 263 paganellus 181, 184, 186, 192, 203 Gobiusculus flavescens 209 Goby, Black 181, 184, 186, 190, 198, 199, 203, 263 Common 183, 185, 187, 199, 206 Couch’s 149, 184, 186, 194, 203 Crystal 211 Diminutive 183, 199, 201 Fries’s 189, 203, 263 Giant 186, 195, 184 Guillet’s 181, 183, 198, 200, 203 Jeffreys’s 148, 183, 185, 187, 202, 203, 268 Leopard-spotted 21, 180, 183, 188, 203, 266 Lozano’s 185, 187, 207 Norway 183, 185, 187, 208 Marbled 182 Painted 30, 181, 183, 185, 187, 199, 204 Red-mouthed 172, 184, 197 Rock 181, 184, 186, 192, 203

Sand 185, 187, 207 Steven’s 184, 196, 268 Transparent 183, 210 Two-spotted 183, 209, 270 Gunnel, Rock 174 Gurnard, Flying 230 Grey 230, 231, 232, 236 Long-finned 230 Red 230, 231, 232, 233 Streaked 230, 231, 232, 235 Tub 230, 231, 232, 234 Gymnammodytes semisquamatus 48

H Haddock 61, 63 Hagfish 264 Halibut, Atlantic 123 Hemibdella soleae 271 Herring, Atlantic 46 Hippocampus guttulatus 248 hippocampus 249 Hippoglossoides platessoides 123 Hippoglossus hippoglossus 123 Hooknose 259 Huss, Bull 43 Hyperoplus immaculatus 48 lanceolatus 48

I Isurus oxyrinchus 38

L LABRIDAE 81 Labrus bergylta 86, 94, 272 mixtus 88, 94 Lamna nasus 38 Lampetra fluviatilis 265 Lamprey, River 265 Sea 265 Lasher, Father 254 Lebetus guilleti 181, 183, 198, 200, 203 scorpioides 183, 199, 201 Leeches 271 Lepadogaster candolii 213 purpurea 212 Lepidorhombus whiffiagonis 123

Leucoraja fullonica 113 naevus 112 Limanda limanda 22, 27, 128 Ling 13, 149, 156 Blue 156 Spanish 156 Liparis liparis 220 montagui 220 Lipophrys pholis 165 Lophius piscatorius 98, 146 budegassa 146 LOTIDAE 150 Lumpenus lampretaeformis 177 Lumpsucker 218

M Mackerel, Atlantic 50 Atlantic Chub 50 Atlantic Horse 44, 45, 51 Mediterranean Horse 51 Mako, Shortfin 38 Masturus lanceolatus 57 Megrim 123 Melanogrammus aeglefinus 61, 63 Merlangius merlangus 61, 68 Micrenophrys lilljeborgii 256 Microchirus variegatus 134 Micromesistius poutassou 60 Microstomus kitt 27, 129 Mola alexandrini 57 mola 33, 57 tecta 57 Molva dypterygia 156 macrophthalma 156 molva 13, 149, 156 Monkfish 120, 146 MUGILIDAE 54 Mullet, Bearded 160 Golden Grey 54 Red 24, 160 Thicklip Grey 54 Thinlip Grey 54 Mullus barbatus barbatus 160 surmuletus 24, 160 Mustelus asterias 41 mustelus 41 MYLIOBATIFORMES 101 Myliobatis aquila 113

Myxine glutinosa 264

N Nerophis lumbriciformis 241, 246 ophidion 241, 247 Nursehound 43, 118

O Oblada melanura 71

P Pagellus acarne 71 bogaraveo 71 erythrinus 70 Pagrus pagrus 76 Pandora, Common 70 Parablennius gattorugine 28, 168, 169 pilicornis 171 ruber 170 Parasites 269 Pegusa lascaris 132 Petromyzon marinus 265 Pholis gunnellus 174 Pilchard, European 47 Pipefish, Black-striped 240, 242 Broad-nosed 241, 244 Deep-snouted 244 Greater 241, 242 Lesser 243 Nilsson’s 241, 243 Snake 241, 245 Straight-nosed 241, 247 Worm 241, 246 Piper 230 Plaice, European 126, 131 Platichthys flesus 125, 127, 131 Pleuronectes platessa 126, 131 PLEURONECTIFORMES 122 Pogge 259 Pollachius pollachius 61, 64 virens 61, 65 Pollack 61, 64 Pomatoschistus flavescens 183, 209, 270 lozanoi 185, 187, 207 marmoratus 182 microps 183, 185, 187, 199, 206 minutus 185, 187, 207 norvegicus 183, 185, 187, 208

286 INDEX

pictus 30, 181, 183, 185, 187, 199, 204 spp. 183, 186 Pontobdella muricata 271 Porbeagle 38 Pout, Norway 60 Pouting 66 Prionace glauca 38 Pteroplatytrygon violacea 101 Pungitius pungitius 250

R Raja brachyura 107 clavata 104, 119, 271 microocellata 103, 108, 119 montagui 101, 106 undulata 11, 109, 110, 119 RAJIFORMES 101 Raniceps raninus 157 Ranzania laevis 57 Ray, Atlantic Torpedo 117 Common Eagle 113 Marbled Electric 117 Rays, electric 101 Rockling, Five-bearded 25, 152 Four-bearded 151 Northern 25, 153 Shore 154 Three-bearded 155 Rostroraja alba 113 Rout, Bull 254

S Saithe 61, 65 Salema 71 Sandeel, Corbin’s 48 Raitt’s 48 Sandeel, Greater 48 Lesser 48 Smooth 48 Sardina pilchardus 47 Sarpa salpa 71 Saury, Atlantic 56 Scaldfish 137 Imperial 139 Thor’s 138 Scomber colias 50 scombrus 50 Scomberesox saurus 56 SCOPHTHALMIDAE

Scophthalmus maximus 141 rhombus 140 Scorpaena scrofa 252 porcus 252 Scorpionfish, Black 252 Red 252 Scorpion, Long-spined Sea 252, 270 Short-spined Sea 254 Sculpin, Moustache 258 SCYLIORHINIDAE 42 Scyliorhinus canicula 42, 34 stellaris 43, 118 Seabass, European 23, 53 Seabream, Axillary 71 Black 72, 74, 94 Blackspot 71 Common Two-banded 78 Couch’s 76 Gilthead 77, 94 Red 71 Saddled 71 White 70 Seahorse, Long-snouted 248 Short-snouted 249 Spiny 248 Sea scorpions 252 Seasnail, Common 220 Montagu’s 220 Striped 220 Serranus cabrilla 267 Shanny 165 Shark, Basking 36, 37 Blue 38 eggcases 118 School 40 Skate, Black 114 Blonde 107 Blue 114 Common 114 Cuckoo 112 eggcases 118 Flapper 115, 119 Longnosed 114 Shagreen 113 Small-eyed 103, 108, 119 Spotted 101, 106 Starry 113

Thorny 113 Undulate 11, 109, 110, 119 White 113 Skates 100 Smelt, Sand 52 Smoothhound 41 Starry 41 Solea solea 133 Sole, Common 133 Dover 133 Lemon 27, 129 SOLEIDAE 132 Solenette 135 Sole, Sand 132 Thickback 134 SPARIDAE 70 Sparus aurata 77, 94 Spinachia spinachia 250 Spondyliosoma cantharus 72, 74, 94 Sprat, Atlantic 47, 49 Sprattus sprattus 47, 49 Spurdog 39 Squalus acanthias 39 Squatina squatina 120, 121 Stickleback, Fifteen-spined 250 Nine-spined 250 Sea 250 Three-spined 251 Stingray, Common 116 Pelagic 101

Stingrays 101 Sucker, Cornish 212 Sunfish, Bumphead 57 Hoodwinker Ocean 57 Ocean 33, 57 Sharptail 57 Slender 57 Symphodus bailloni 84 melops 82 SYNGNATHIDAE 240 Syngnathus abaster 240, 242 acus 241, 242 rostellatus 241, 243 typhle 241, 244

T Taurulus bubalis 252, 270 Tetronarce nobiliana 117 Thorogobius ephippiatus 21, 180, 183, 188, 203, 266 Tope 40 Topknot 99, 143 Eckström’s 25, 144 Norwegian 12, 26, 131, 145 TORPEDINIFORMES 101 Torpedo marmorata 117 TRACHINIDAE 238 Trachinus draco 238 Trachurus mediterraneus 51 trachurus 44, 45, 51 Triggerfish, Grey 79

Trigla lyra 230 TRIGLIDAE 230 Triglops murrayi 258 Tripterygion delaisi 179 Trisopterus esmarkii 60 luscus 58, 59, 61, 66 minutus 22, 61, 67 Turbot 141

W Weever, Greater 238 Lesser 238 stings 239 Whiting 61, 68 Blue 60 Wrasse, Baillon’s 84 Ballan 86, 94, 272 Corkwing 82 Cuckoo 88, 94 Goldsinny 10, 29, 90 Rainbow 92 Scale-rayed 93

Z Zeugopterus norvegicus 12, 26, 131, 145 punctatus 99, 143 regius 25, 144 Zeus faber 96 Zoarces viviparus 178

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