Reef Fishes - UAE and Gulf of Oman

A r A b i A n H e r i t A g e g u i d e s

This fully illustrated book is primarily a guide to the

identification of the most frequently seen reef fishes

of the UAE and Gulf of Oman. The book will present

an opportunity for naturalists, divers and snorkellers

to identify an amazing variety of reef fishes and thus

enhance their snorkelling and diving experiences. Reef fishes

UAE and Gulf of Oman

Richard

F Field

A r A b i A n H e r i t A g e g u i d e s

Richard F Field

4 The first guide to the reef fishes of the UAE and Gulf of Oman.4 A comprehensive checklist of fishes of the region.4 Beautifully illustrated with colour photographs.4 A reference book for divers and snorkellers.


Reef fishesUAe And GUlf of omAn

Richard F Field


Published by Motivate Publishing

Dubai: Po Box 2331, dubai, UAeTel: (+971 4) 282 4060, fax: (+971 4) 282 0428e-mail: [email protected] www.booksarabia.com

office 508, Building no 8, dubai media City, dubai, UAeTel: (+971 4) 390 3550, fax: (+971 4) 390 4845

Abu Dhabi: Po Box 43072, Abu dhabi, UAeTel: (+971 2) 627 1666, fax: (+971 2) 627 1566

London: Acre house, 11/15 William Road, london nW1 3eRe-mail: [email protected]

directors: obaid humaid Al Tayer and ian fairservice

edited by david steele, assisted by Zelda Pinto

designed by Johnson machado and Andrea Willmore

first published 2005

front cover: A flag-tail triggerfishBack cover: A female Townsend’s anthias with big-eye snappershalf-title page: lined eel catfishes

Copyright © Richard f field 2005

All rights reserved. no part of this publication may be reproduced in any material form (including photocopying or storing in any medium by electronic means) without the written permission of the copyright holder. Applications for the copyright holder’s written permission to reproduce any part of this publication should be addressed to the publishers. in accordance with the international Copyright Act 1956 and the UAe federal Copyright law no 40 of 1992, any person acting in contravention of this copyright will be liable to criminal prosecution and civil claims for damages.

isBn: 1 86063 161 4

British library Cataloguing-in-Publication dataA catalogue record for this book is available from the British library

Printed and bound in the UAe by Rashid Printers, Ajman, UAe

Published with the support and encouragement of

Contents

Descriptions and photographs of species

sharks and rays 18moray eels and snake eels 26lizardfishes 30milkfish 31Catfishes 31needlefishes 32Pupfishes 33squirrelfishes and soldierfishes 33Cornetfishes 34shrimpfishes 34Pipefishes 35scorpionfishes and stonefishes 36flatheads 40Groupers and soapfishes 41dottybacks 45Big-eyes 46Cardinalfishes 47Remoras 52Jacks 53mojarras 56snappers 57fusiliers 61Grunts 62monocle breams 65emperors 66sea breams 68mullets 69Goatfishes 70monos 72

Introduction 6

Scope of this book 10

The naming of species 13

General sensory characteristics 16

Observing fishes 17

sweepers 72Chubs 74spadefishes 75Butterflyfishes 76Angelfishes 78damselfishes 80hawkfishes 86Barracudas 87Wrasses 89Parrotfishes 96Jawfish 99sandperches 99Blennies and triplefins 100Gobies and dartfishes 105surgeonfishes 112Rabbitfishes 114moorish idol 115mackerels and tunas 115flounders and soles 117Triggerfishes 118filefishes 120Trunkfishes 121Pufferfishes 122Porcupinefishes and burrfishes 124

Photograph origins 127Checklist of species 128Index of common and 139 scientific names

exomos/dpa ad

6 Reef fishes – UAe And GUlf of omAn 7Reef fishes – UAe And GUlf of omAn

introduction

The UAe and the sultanate of oman share both the east and west coasts of the musandam peninsula, bordering the Gulf of oman and the Arabian Gulf regions. The Gulf of oman extends southwards to Ras al hadd where it meets the Arabian sea region and oman's longest coastal exposure, down to dhofar.

The diversity of marine species of reef fishes is greatest along the Arabian sea coastline, and the number of species available declines as you go northwards. Consequently many species that are found in the southern regions are not found along the northern coastlines of oman and the UAe.

during one dive at the southern tip of masirah island (400 km south of muscat), the author positively identi fied 49 species, of which seven had not to date been seen by him in the Gulf of oman.

The characteristics of these different regions differ significantly. The Arabian Gulf is a shallow inhospitable sea with

relatively low faunal diversity, while the Gulf of oman is a deep sea with only a quarter of its area less than 1,000 m deep.The Arabian sea is fully exposed to the indian ocean cold upwelling with its water rich in nutrients (the upwelling is an effect of the summer monsoon, when south-wester ly winds drive surface water out to sea). These are not of course isolated regions, so fishes have no physical barriers to migra tion; nevertheless the cold upwelling along the Arabian sea coastline, and to some extent the Gulf of oman coast line, may prove disasterous to some species which are unable to tolerate large, and sudden, temperature changes. equally, the cold-water upwelling may be depleted of oxygen and in some instances may cause asphyxia tion on a large scale, particularly amongst shallow-water species. it has been suggested that the canny omani fishermen know that they should fish in certain areas during the cold up wel-ling – areas where oxygen levels are higher,

and fish numbers are therefore greater.The cold upwelling may present a barrier

to the migration of sensitive species; the region is very poorly researched and further discoveries and distributions can be expected, some of which may be surprising.

The author was collecting specimens with scientist friends in south Africa near the mozambique border recently and collected what is now known to be Trimma omanensis, a small goby that had previously only been found in the Gulf of oman, after which it was named. dr Je Randall, the authority on indo-Pacific species, during three short stays in oman, recorded more than 100 previously unrecorded species, 52 of which were new to science. There are at least nine species which have been named omanensis (and two muscatensis), ranging from a shark to the small goby.

There are probably between 1,300 and 1,500 different species to be found in the coastal waters of oman and about half as many in the Arabian Gulf. most will also be present elsewhere in the indo-Pacific

region, but there are some that have restric ted distributions (as far as is current-ly known) and could be called ‘Arabian’ species – some of these are very common and snorkellers are guaran teed to see them – the Persian parrotfish (S persicus), spotted-tail hawkfish (C calliurus), pearly goatfish (P margaritatus) and black-spotted butterflyfish (C nigropunctatus) are all ‘local’ UAe/oman species.

To fully appreciate the faunal diversity of the waters of oman and the UAe it is of course necessary to don snorkelling or scuba gear. There are only a few coastal locations accessible or suitable for snorkelling or diving in a coral environment, so it is best to use a boat (there are several diving organisations which all offer services for snorkellers as well as divers).

A boat allows access to the islands, principally the daymanyat group and fahl island where corals and reef fishes are abundant. for the more adventurous, the coastline and offshore islands of the musandam peninsula offer splendid A live-aboard schooner anchored in the magnificent Musandam area.

The Musandam Peninsula offers splendid marine life for the advanced diver.


introduction

marine life and excellent diving. The very inaccessibility of the area protects it from human intrusion, and its strong currents can be hazardous for divers.

for visitors to muscat, the daymanyat islands provide an environment to rival the Red sea and, in terms of fish numbers, exceeds what you would expect in the Red sea. huge schools coexist with marauding jacks and large groupers. Zebra sharks are resident, as are the small black-tip sharks which can be seen in the shallow waters often behind a dividing mass of nervous sardines. With so much prey available the sharks are quite docile. Underwater photo-graphy can be difficult at the daymanyat islands simply because a fish may often cross unex pectedly in front of a photo-grapher’s lens.

it is clearly impractical to describe all the species you may see (the author invari-ably sees something new on each dive). so if we take a ‘virtual’ journey with snorkel, mask and fins seaward from a beach in oman, we are likely to see first, goatfishes stirring the sand with their sensory barbels looking for small crustaceans – the pearly goatfish is the most common. small silvery

fishes will also be hovering over sand watching for movement – these will be mojarras and breams. mullet, some times in large schools, will also be searching the sand. Approaching the rock or coral sides of the bay, fish life increases dramatically. in the shallower water, nervous epaulet groupers will be watching and Abudefduf damselfishes will be fussily protecting their eggs. in the sand at the base of the rocks, partner gobies warn their host shrimps of the presence of danger, and both dart back into their holes.

moving into deeper water, the diversity increases still further – an anemonefish rises from its host to inspect the intruder, small wrasses busily dart around and larger species, such as the beautifully coloured queen coris wrasse, continue feeding with-out alarm. Various damselfishes hide in coral, blennies on algae patches have their tails curled ready to dart away and a glori-ously coloured dottyback stares nervously, resenting our intrusion into its territory.

for the keen fishwatcher, a boat ride to the islands will pay dividends in terms of the number of different species to be seen. The islands are home to several

larger species; they are also visited by ocean-roaming species in search of an easy meal, or in a number of cases, to breed.

Groups of large-scale triggerfish are often present at fahl island, where they deposit eggs in pits in the sand. magnificent eagle rays can be seen glid ing over the reefs. As with most large species, it is always best to be still in the water when they approach – fishes are inquisitive, so a diver presents a curious object to investigate.

divers visiting fahl island or the daymanyats will always be impressed by the huge schools of snappers (black-spot, big-eye and Bengal) feeding in the current. The variable-lined fusilier (a close relative of the snappers) is one of the most abundant schooling species in the islands. Groupers are well represented amongst the smaller species; of the larger species the white-blotched is common at fahl island – others have probably been overfished.

There are few places in the world that boast so many moray eels – the sometimes immense laced (honeycomb) moray is abundant, and zebra, grey, yellow-mouth and undulate morays will always be seen amongst the coral.

The daymanyat islands are the first to be declared a national nature Reserve in oman, in line with the sultanate’s determination to protect and preserve its resources and to encourage tourism.

The islands serve as a breeding area for many species and, if left un disturbed,

or with controlled access, will provide a nursery for fish catches further afield – a number of species, particularly in the grouper family, have a breeding life of decades, so by protecting certain areas other areas benefit through migration.

Another national nature Reserve is proposed for Barr al hikman-masirah island, and others suggested for Khawar Quway-Jazirat Um al Ghanam (musandam) and Raaha (dhofar). in the UAe the Al Yasat area has just been declared a marine sanctuary. marine Reserves have no value as simply a shaded area on a map. Awareness of the beauty of the creatures that they are designed to protect, and respect for their existence are important ingredients for successful conservation. i sincerely hope that this small book goes some way to engendering such respect and awareness.

Richard Fieldmuscat, 2005Splendid marine life – a colourful crinoid.

Fishermen at Fahl Island with a giant guitarfish and a shark.


scope of this book

This book is primarily a photographic reference guide to the identification of the most frequently seen reef fishes in the Gulf of oman (and round the musandam peninsula, including the UAe). it will be useful for divers and snorkellers anywhere in the Arabian Gulf – species which are known to be present there will be high-lighted in the descriptions. With one exception, all the photographs shown in this book were taken by the author or immediate family.

in some cases a photograph taken in the Red sea has been used where a Gulf of oman photograph was not available or of unsuitable quality. Red sea photographs are listed at the back of the book.

Readers should be aware that there are a few species that have different colour forms de pending on their location; only the Gulf of oman colour forms are shown in this particular book.

The various authors of books on the subject of reef fishes disagree on the distribution of some species – unfortunately the Gulf of oman is not exempt from these disagreements. it is bordered on the one side by the Arabian Gulf (which contains a low diversity of species) and on the other by the Arabian sea (with a high diversity).

overlaps in distribution can be expected. This may become permanent or merely a temporary phenomenon resulting from particular water conditions or circumstantial occurrences.

for example, the yellow-ear angelfish (Apolemichthys xanthotis), originally reported by Randall as Red sea and Gulf of Aden (Red Sea Reef Fishes, 1985) and extended to oman (Coastal Fishes of Oman, 1995), has an interesting distribu-tion. in the author’s experience, this species is common in the most northerly

part of the Red sea, absent in the central east coast of the Red sea, the most common angelfish in dhofar and fairly common in the daymanyat islands of oman.

This guide shows those species that have been personally observed and identified by the author, sometimes with the help of specific experts, as being present in the waters of the Gulf of oman.

many common indian ocean species are not included since they cannot strictly be called reef fishes. Amongst these are some cartilaginous species (sharks, rays) and the truly pelagic, such as tuna, jacks and the other ‘sport fishing’ species.

Although these species may be to a greater or lesser extent dependent on the reef fauna for their survival, they do not permanently inhabit the reef, but may visit to breed, rest or forage; however, a small number of photographs are included of very commonly seen species in this category – such as those of sharks, stingrays and the most common jacks, barracudas and mackerels.

some of the descriptions are somewhat anthropomorphic, and would therefore be considered unscientific by experts. This book is intended for divers and snorkellers who observe the fishes in the Gulf of oman and Arabian Gulf as a relaxing pastime, and who wish to identify what they see. A whimsical description of a species can often be a more useful aid to identification than details of scales, spines and teeth expressed in scientific language.

it is customary in scientific books to depict a fish (usually a dead specimen) with all its spines erect and tail spread but, in its natural habitat, it is seldom seen like this (with the exception perhaps of some nocturnal species). The recreational diver and snorkeller sees colours, shapes, patterns, swimming action and, often, eyes. These are the characteristics used in this book to assist

in the identification of species. A good picture is worth a thousand words, so only salient features of a fish are noted in the text. on the whole, the photo-graphs in this book are selected on the basis of showing the best lateral view of the animal.

every effort has been made to ensure that identifications are accurate, and that the latest accepted names are used. There is still much work to be done by the scientific community in agreeing classifications and naming of indo-Pacific species – the names used in this book, in some cases, may differ from those in others, which simply shows that taxonomic work is continuing.

Common names present a problem – they can be descriptive, but also misleading and sometimes quite obscure (a lionfish is a turkeyfish is a scorpionfish!). The author has, in the great majority of cases, adopted the names given by the iClARm fishBase database (fishbase.org on the internet).

The amateur photographer has a role to play in ichthyology. one well-known ichthyologist (and respected friend) when presented with a photograph of a fish which was most certainly one that had been described by the same scientist candidly confessed that scientists sometimes don’t know what the live animal looks like! often, specimens may be collected, slow cooked in a tub on a boat, and examined many hours later. The scientist may never see a live, naturally coloured, specimen.

The author has experienced considerable difficulty in identifying some juvenile forms – juvenile shapes and colours can vary considerably from the adults, but many have not been documented fully in scientific or popular publications. The only sure way to identify juveniles is to capture them (not an easy task) and have an expert examine them. in some cases, the author, in Fahl Island, a favourite dive site near Muscat.


The naming of speciesscope of this book

desperation, has captured a juvenile and resorted to observing its development into another, recognisable, stage within the confines of an aquarium (see the entry for 10404 Plectorhinchus gaterinus). This can be a lengthy process!

There are many small species, typically gobies and blenny-like creatures, that will be seen in the Gulf of oman if the observer is patient and curious enough to examine the contents of coral branches, sponges and gorgonions (or even sea cucumbers). information is scarce on these species but perhaps now that underwater macro photography is becoming more popular, these tiny creatures will receive closer attention. They are not adequately covered by this book and i hope that some day a book will be written describing these often beautiful little animals.

There are many species which are not recorded in this book, despite being present in the Gulf of oman. Those shown can be considered those most likely to be seen; it would take many years to photograph and document all the species known in the region and it would require a very large handbook indeed to describe them all.

A checklist of Gulf of oman species, compiled by the author using data from various publications, and from his own

observation, is included at the back of this guide. This checklist contains some 1,000 species, and species are numbered according to the author’s own convention.

These numbers appear with the fish descriptions. The last two digits of the 3–5 digit number define the species (01–99); the preceding digits (1–168) define the family to which the species belongs. Thus Scarus persicus (12714) is the 14th species of the scaridae family (127).

The goby family unfortunately is too large for this system, so has therefore been split into Gobiidae and the sub-family Gobiinae (141 and 142 respectively). Gobies in the Gobiinae sub-family are commonly called ‘shrimp gobies’ since they cohabit with shrimps in burrows.

The Gulf of oman checklist contains species that have been recorded in the Gulf of oman, and the presence of species in adjacent regions is recorded in adjacent columns. new records for the Gulf of oman can be expected as species known in the more species-rich south are discovered in the Gulf. The list does not include the deep-water species, of which there is very little known.

This system has been adopted to allow additions within the families, as new species are discovered, or names changed. species will therefore not be in any particular order, alphabetically or otherwise.

scientific names are made up of two parts. The first part is the name of the Genus (generic name) and the second the species (specific name). The generic name always begins with an upper case letter, the specific name with lower case; both names should be in italics.

A genus contains animals that are very closely related in terms of outward appearance (morphology), internal structure (anatomy) and reproductive habits. members of the same genus are usually very similar, in shape and size but they will differ in colour and small details such as the shape of the tail, number of teeth and so on.

A genus may contain many species within it – eg the genus Chaetodon, the major genus of butterflyfish in the Chaetodontidae family, contains more than 60 species world wide. on the other end of the scale the family Zanclidae contains only one species, Zanclus cornutus, the moorish idol.

The strict biological definition of a species is a group of organisms that reproduce sexually to produce fertile offspring. different species within a genus may be able to interbreed but the offspring will be sterile.

The genus and species together define a unique animal. At times a third name is added to specify a local variant of a species.

The scientific naming, or nomenclature, of animals is consistent throughout the world. Whatever variations there are result from disagreements amongst taxonomists as to which group certain animals belong. The characteristics used in classification overlap to a great degree and it is not always easy to decide at what point the differences become great enough to warrant the introduction of a new genus or species. Confusion also arises as a result of the same animal having been found and named by different people in different parts of the world. in some cases,

different names have arisen for species that have a juvenile phase that looks very different from the adult. Reference books usually quote the name of the first describer and the date after the scientific name. The rule is that the oldest published name should prevail. it is interesting to specu late what effect dnA sampling will have on the grouping, and naming, of species.

scientific names are mostly derived from latin or sometimes Greek words that describe a particular feature of a fish. A turkeyfish is in the genus Pterois from the Greek word for ‘wing’ (to be doubly sure, the Western Australian form of P miles is Pterois volitans which has both latin and Greek origins!). The pectoral fins of a lionfish and a turkeyfish are indeed remi-niscent of wings as the fish gently glides through the water. The genus Chaetodon of the butterflyfish family is named after the brush-like teeth of its members.

specific names are more varied in origin, being derived from appearance (eg Cheilodipterus quinquelineatus – five-line cardinalfish); the name of the discoverer (Paracheilinus mccoskeri – mcCosker’s wrasse); or the local common name (Acanthurus sohal from the Arabic name of this surgeonfish).

Related genera are grouped together in families. in the animal kingdom the names of families always end with ‘idae’, eg Blen-nii dae (blennies) or labridae (wrasses).

members of a family share a number of characteristics of appearance, anatomy and behaviour but they are not as obvious-ly similar as members of the same genus.

There is no mistaking, even upon casual observation, the family relationship amongst the parrotfishes. The wrasses are much more diverse in appearance but have similarities such as tooth structure and methods of reproduction.

dr John Randall’s work Coastal Fishes of Oman is still the only recent authoritative


The naming of species

systematic investigation of species of the oman coast and his work has played a substantial contribution in the prepara-tion of this book.

it should be noted, however, that since publication of his work, Randall has changed the scientific names of some species, and endorsed changes suggested by others. There have been a number of changes, and the author has included as many as are known to him.

Common names are much more con-fusing and vary throughout the world.

some are a direct trans lation of the scientific name. This is often true of a fish whose scientific name stems from an obvious physical feature. some are named after their discoverer. many common names are derived from names used by the local population of the area where the fish is found. for common names, the author has adopted those used by iClARm in its fishBase website, in the absence of a standard list of names. Arabic names are not included, since no standard list of names is available.

Some commonly used Latin and Greek stems

acanth (Gr) thorn Acanthurus – surgeonfish (caudal spines)acumin (l) taper-pointed Heniochus acuminatus – long-fin butterflyfishaetos (Gr) eagle Aetobatus narinari – eagle ray argentum (l) silver Monodactylus argenteus – silver moonyaxilla (l) armpit Chromis flavaxilla – Arabian chromis (yellow pectoral base)cauda (l) tail Sphyraena flavicauda – yellow-tail barracudachaet (l) bristle Chaetodon – butterflyfish (bristle-like teeth)chrysos (Gr) gold Pterocaesio chrysozona – gold-band fusilierdimidiatus (l) halved Labroides dimidiatus – cleaner wrasse (half blue, half black)fascia (l) band Acanthopagrus bifasciatus – two-bar sea breamferruginus (l) rusty coloured Scarus ferrugineus – rusty parrotfishfuscus (l) brown, dusky Scarus fuscopurpureus – purple-brown parrotfishflavus (l) yellow Sphyraena flavicauda – yellow-tail barracuda fuco (l) to paint Archaemia fucata – orange-lined cardinalfishgibbus (l) humped Lutjanus gibbus – hump-back red snappergramma (Gr) mark, line Diagramma pictum – painted sweetlipsleptos (Gr) slender Pomacentrus leptus – slender damselfishlunatus (l) crescent shaped Thalassoma lunare – moon wrassemacula (l) spot or mark Parapercis maculata – harlequin sandperch (spotted)marga (Gr) pearl Parupeneus margaritatus – pearly goatfishmargo (l) edge Gymnothorax flavimarginatus – yellow-edged moraymitra (Gr) head dress Petroscirtes mitratus – floral blennymugilis (l) sea fish, mullet mugilidae – mulletsniger (l) dark, black Odonus niger – red-tooth triggerfish (dark teeth)notatus (l) marked Epinephelus multinotatus – white-blotched grouperodontos (Gr) tooth Cheilodipterus macrodon – large-tooth cardinalfishpara (Gr) related to Paracheilinus mccoskeri – closely related to genus Cheilinuspinnula (l) small plume Cirrhitus pinnulatus – stocky hawkfish (plumed fin spines)pleura (Gr) ribs, sides Leptojulis cyanopleura – wrasse (blue spots on sides)pter (Gr) wing, fin Pterois scorpionfish – wing-like pectoral rayspunctatus (l) spotted Chaetodon nigropunctatus – black-spotted butterflyfish purpur (l) purple Scarus fuscopurpureus – purple-brown parrotfishrubescens (l) becoming red Parupeneus rubescens – rosy goatfishscaros (Gr) parrotfish scaridae – parrotfishsinus (l) a curve Torpedo sinuspersici – curved markings on backsordidus (l) dirty Abudefduf sordidus – dull markingstigma (Gr) point, mark Lutjanus monostigma – one-spot snappertaeniatus (l) striped Scolopsis taeniatus – black-streaked breamthalassa (Gr) sea, marine Thalassoma lunare – moon wrassetorpedius (l) to make numb Torpedinidae – electric raysxanthos (Gr) yellow Chromis xanthopterygia – yellow-fin chromis

(source: A Source Book of Biological Names, edmund C Jaeger)

A tiny ghost goby on soft coral in the Daymanyat Islands.


observing fishesGeneral sensory characteristics

The fishes are believed to be the oldest group of vertebrates (animals with back-bones) and it is thought that all other vertebrates evolved from them. There are more than 20,000 species known – about 40 per cent of all living vertebrate species.

They ‘breathe’ by means of their gills. Water is sucked in through the mouth – then with the mouth closed the water is forced over the gills and out through the opening of the operculum. As the water passes over the feathery surface of the gill filaments, oxygen is absorbed from the water into the bloodstream and waste carbon dioxide is passed into the water. According to lieske & myers (Coral Reef Fishes), they can effectively remove about 74 per cent of available oxygen.

fishes have a well-developed nervous system. of the senses, that of smell is especially keen, so that very small concentrations of substances can be detected. sharks, as an example, can detect minute quantities of blood in the water, and salmon are thought to find

their home waters guided by their sense of smell.

The lateral line (usually clearly visible as a curved line from operculum to caudal peduncle) detects vibrations and pressure changes in the water. in some species, changes of water temperature are also detected.

Research scientists have recently concluded that the lateral line also assists shoaling species to synchronise their movement. This is achieved by subtle changes in light refraction, and hence colour, and thus serves as an optical communication system.

fishes are the only animals that can generate and discharge electricity and electric eels, rays and catfish produce a voltage strong enough to stun prey.

most species have well-developed vision. focusing is however limited and is usually achieved by moving the lens towards, or away, from the retina. some species have a double lens (see the entry for 12657 Paracheilinus mccoskeri).

for snorkellers and divers alike, the first early morning venture into the sea can be the most rewarding moment of the day. To be first in the water is to be the first to see the larger species that rule and feed during the night. once disturbed, they will quickly disappear and not be seen again during the day. it is well worthwhile to enter the water gently, or approach a reef cautiously, to catch a glimpse of life in the sea as it is without the presence of humans.

A diver starting to descend should look around – before the rays, turtles and other larger creatures decide to escape this intrusion into their world. When entering from a boat, a clumsy entry can frighten away the very animals you want to see!

At the beginning of a dive, slowly descend, without excessive movement to a good vantage point, and then keep quite still for a few minutes – by doing this, a large fish may approach to investigate. Also, when swimming, a diver naturally tends to look downwards and may miss a large fish alongside.

divers should always move carefully in the water, and particularly when inves ti-gating the contents of a coral head or other hiding place. Although it is contrary to good diving practice to hold your breath, as long as you are relaxed and maintaining good buoyancy, it is some-times acceptable and necessary when approach ing a fish – particularly when taking photographs. Bubbles can frighten it, not only because they can be seen, but because they have noisy origins! The sea is already a noisy place, but to introduce an unfamiliar sound may make an interesting subject quickly dart for cover.

At night many species sleep, and can be observed closely. When using a torch, project the beam to one side of the fish, and use a narrow beam torch. light will confuse and frighten them. A fish frightened out of its hiding place at night becomes an easy target for predators.

divers should be aware that the colours they see underwater may not be the same as those in photos. The sea acts as a blue filter, so that colours at the red end of the spec trum cannot be seen at depth. Perhaps the best example of a fish that demon-strates this effect is a soldierfish which in daylight near the surface is bright red in colour, but at depths below 10 m appears to be a drab, dark brown. A photo taken at depth with flash restores most of the mis-sing colours. The colour red is quite a domi -nant colour in fishes, which may help them to hide at depth, although i have often won dered whether the colour per cep tion of man can be compared with that of a fish.

Judging the size of a fish in the water is not easy, since the observer sees refracted images that make a subject appear closer than it actually is – so what may appear to be a 2 m-long shark will actually be 1.6 m.

A number of authors of guides have attempted to compile checklists of physical characteristics for identification; these are of limited use in identifying a fish, unless the observer notes particular physical features such as the shape of the mouth, the position of fins, shape of tail, size of the eyes and so on; furthermore, he must remember them. After much practice these characteristics become easier to note, but by the time this stage is reached he would probably recognise the family to which the fish belongs from the way it behaves, its swimming ‘style’ and the habitat in which it was seen.

While a diver observes, he can be sure that many eyes observe him. A fish below a diver is able to clearly see shapes against the sunlit background, while remaining unseen in the gloomy depths. it should not go unnoticed that most of the non-pelagic species are dark on top of their body and, usually, silver or white on the underside. This is of course effective camouflage, and makes some of those large bottom-dwelling species very difficult to see.

EXTERNAL CHARACTERISTICS

lateral line spinous part of dorsal fin soft part of dorsal fin Caudal peduncle

operculum Pectoral fin Pelvic fin Anal fin Caudal fin

18 reef fishes – uae and gulf of oman 19reef fishes – uae and gulf of oman

Carcharhinidae requiem sharksstegostomidae Zebra shark

701 Stegostoma fasciatum, seba, 1758 Zebra shark

stegostomidae Zebra shark

1015 Carcharhinus amblyrhynchos, Bleeker, 1856 Grey reef shark

although the black-tip may be the most abundant reef shark of the shallow coastal areas, the grey reef shark is the most likely to be seen around offshore reefs, particularly in the musandam area. it is recognised by the dark trailing edge to its tail fin. This species in the indian ocean area has a white tip to the rear edge of its first dorsal – this mark is absent in specimens from the Pacific area. The grey reef shark can be aggressive, particularly

1023 Triaenodon obesus, rüppell, 1837 White-tip reef shark

and may allow divers to approach. The specimen shown is probably near maximum size. This species has not been reliably reported from the arabian gulf. maximum recorded length: 213 cm.

The white fin tips of this species, and its blunt snout, are characteristic. during daytime white-tip reef sharks may be found resting on sand in open areas, or in sandy caves. it is not aggressive

1012 Carcharhinus melanopterus, Quoy & gaimard, 1824 Black-tip reef shark

Carcharhinidae requiem sharks

The black-tip reef shark is the most likely shark to be seen along oman’s coastline; it is common in localised areas of shallow water, but is very shy and extremely wary of divers. The black tips to the fins and the white band around the first dorsal fin are distinctive. maximum recorded length: 200 cm.

The requiem sharks (whoever named them so was surely of a fearful disposition) comprise a family of 50 described species, 23 of which have been reliably reported as present in Omani waters. Re liable Arabian Gulf records are scarce.

Requiem sharks are difficult to differen tiate to species level when seen

under water, and they are also difficult to approach, unless baited. The position, size and marking of the first dorsal fin provide the best clues for identification. All requiem sharks are potentially dangerous, but in local waters the bull and tiger sharks, though rare and not likely to be seen by divers, may pose the greatest threat to man.

The widely distributed, but uncommon zebra shark is the only mem-ber of the stegostomidae family. it is closely related to the nurse sharks, but differs in having a very long tail, large rounded pectoral fins and, as an adult, longitudinal ridges of skin along its body. as a juvenile it is black and white banded (hence the name zebra) and on gaining maturity the bands break up into dark spots on a yello w-ish/grey back ground, somewhat resembling the markings of leo-pards. The zebra shark is passive, usually resting by day; at night it hunts in the reef feeding chiefly on molluscs. maximum recorded length: 235 cm.

when in groups, and should be approached with caution. maximum recorded length: 200 cm.


2807 Gymnomuraena zebra, shaw & nodder, 1797 Zebra moray

a large, docile, secretive though apparently social, moray which feeds on crabs and molluscs, and has short stubby teeth that assist in crushing shells. it has a dark-brown body with thin yellow or white bands and its fins are undeveloped. it is widely distri-buted in the indo-Pacific region including the arabian gulf. reported length to 150 cm.

2811 Gymnothorax flavimarginatus, rüppell, 1830 Yellow-edged moray

a large, thick-bodied moray with a varied habitat, which has not previously been reported in the gulf of oman (but known from southern oman). distinctly yellowish compared to other large morays, with a yellow/brown body with dense brown spots. it has a dark gill opening, similar to the giant moray (G javanicus, which does not appear to occur in the gulf of oman). feeds on fishes and crustaceans. maximum length: 120 cm.

muraenidae moray eels

2819 Gymnothorax nudivomer, Playfair & günther, 1867 Starry moray

The starry (or yellow-mouth) moray is brown with many bluish-white connected speckles on the forebody – these speckles enlarge to spots towards the tail as the fish matures. small individuals are bluish-brown with speckles. its mucus is toxic but the purpose of the toxin is not known. The inside of the mouth is a brilliant yellow. maximum length: 100 cm.

2801 Echidna nebulosa, ahl, 1789 Snowflake moray

a small shallow-water species which usually hides amongst rocks, but is sometimes found in seagrass. identified by its white snout (with yellow nostrils) and white body marked with black blotches containing yellow spots. feeds primarily on crustaceans. a nocturnal species that sometimes cohabits with other species. maximum length: 80 cm.

muraenidae moray eelsthreatening – in fact morays are docile, although they may not appear so when they exhibit their impressive teeth.

Species in three other eel families may be encountered by divers – snake eels, in shallow waters (one such species resembles the banded sea snake), conger eels (the most likely to be seen are the garden eels) and reef eels.

Moray eels are characterised by their lack of pelvic and pectoral fins. There are at least 15 species known in the Gulf of Oman, but it appears there may be many more, some undescribed. Morays have very small gill openings, so they tend to ‘breathe’ heavily, opening and closing their mouths continuously; new divers may perceive this action as


2805 Gymnothorax favagineus, Bloch & schneider, 1801 Laced moray

Perhaps the most common and largest species found in the gulf of oman, sometimes referred to as the honeycomb moray, reflecting the pattern of black spots of large individuals. smaller specimens have many black spots with either white or pale yellow surrounds. individuals found in non-reef areas may be much darker overall. large adults are said to be aggressive. attains a maximum length of at least 180 cm.


2825 Gymnothorax pictus, ahl, 1789 Peppered moray

a creature of the shallows, found in sandy or silty areas with coral outcrops, hiding in the coral. like species of the genus Siderea the snout is blunt and rounded. This species is said to sometimes jump out of the water in pursuit of small prey; it feeds on fishes and small crustaceans. maximum length: 120 cm.

specimens have been observed in shallow coastal water near muscat. it has a passing resem-blance to G pictus but has large eyes. The dentition suggests it is of the genus Gymno thorax. This is one of a number of species yet to be described from the area. length estimated at 80 cm.


2830 Gymnothorax sp

3114 Myrichthys colubrinus, Boddaert, 1781 Harlequin snake eel

a long, thin, round-bodied eel much resembling a snake. like a snake it may be found ‘wriggling’ in the shallow water (typically in a sandy sea-grass area)

ophichthidae snake eels

searching for food. despite the presence of a dorsal fin, it is often mistaken for the venomous sea snake, Laticauda colubrina. reported to 97 cm.

2822 Gymnothorax undulatus, lacepède, 1803 Undulated moray

The markings on this moray are highly variable. The base body colour is a dull yellow/green. The body is covered in brown blotches, which on some speci-mens are expanded to give the appearance of greenish/yellow lines and spots. The head is usually more yellow overall and the lower jaw and snout are invari-ably brown. its snout is pointed and its eyes large. This species is said to be aggressive and may bite. reported from the arabian gulf. maximum length: 100 cm.

2823 Scuticaria tigrina, lesson, 1829 Tiger reef eel

also known as the leopard moray, the tiger reef eel is secretive and uncommon, seldom leaving the security of the reef. all that is usually seen of this moray is a patch of skin between the rocks. The fins are almost absent, giving it a snake-like appearance. maximum length: 120 cm.


2824 Siderea grisea, lacepède, 1803 Geometric moray

a common, narrow-bodied moray with distinctive markings on the head. The forward part of the body is white, with in-line brown spots, while the body becomes yellowish with brown speckles towards the tail. The head is slightly darker than the forward body. a Western indian ocean/red sea species, that is fairly common in the gulf of oman. geometric morays are frequently seen with groupers and are often paired. maximum length: 65 cm.


syngnathidae Pipefishes

syngnathidae Pipefishes

rarely seen in the Gulf of Oman, but close examination of sea-grass beds may be rewarding. They may be seen at tached to abandoned lines and cables, feeding in the current. Pipefishes feed on minute ani-mals that they find on sand, coral or algae.

This family includes pipefishes and sea-horses. There are at least 41 species known from the Indian Ocean region. The females deposit their eggs into the pouch of the male, where the eggs are fertilised and incubated. Seahorses are

7105 Corythoichthys flavofasciatus, rüppell, 1838 Network pipefish

mottled bands, containing splashes of light blue. it has a relatively short, red-dish, snout. distributed throughout the indo-Pacific. maximum length: 12 cm.

Probably the most frequently seen pipe-fish in the gulf of oman. found in shallow, algal areas and also seaward reefs. it has a tan-coloured body with reddish

7138 Trachyrhamphus bicoarctatus, Bleeker, 1857 Double-ended pipefish

The double-ended pipefish, one of the longest pipefishes, favours sand or mud substrates and strong currents. usually dark brown in appearance, but may also be much paler than shown here. since this pipefish anchors itself in the current with its tail, the caudal fin is often missing, or damaged, hence the common name. When approached it may sway from side to side, perhaps imitating the motion of seaweed in a current. maximum length: 40 cm.

6902 Centriscus scutatus, linnaeus, 1758 Grooved shrimpfish

although reported to range from shallow water to 100 m in depth, this species has been observed by the author only in shallow, sandy areas and typically in sheltered bays. Juveniles settle in long spine sea urchins for protection and their dark stripe helps disguise them. They will also harbour in crinoids. The maximum reported length is 15 cm.

fistulariidae Cornetfishes

6810 Fistularia commersonii, rüppell, 1838 Blue-spotted cornetfish

fistulariidae Cornetfishes

bars along their bodies. The usual colour is blue-green dorsally, with either blue dots or stripes along its body. This species has been frequently observed ‘shadowing’ large non-carnivorous parrotfishes and appears to use them as cover. it has also been seen ‘shadowing’ stingrays. maximum length: 160 cm.

Common in the gulf of oman, cornet-fishes are usually observed in groups off the island reefs, but a cornetfish may also be seen hunting alone. They feed primarily on small fishes and are often found motionless just above the bottom waiting for opportunities. in this mode, they adopt a camouflage of broad dark

Centriscidae shrimpfishesTheir fins are bunched together where the tail should be; what appears to be the tail is in fact the dorsal fin. The only species in the family that is likely to be seen is Centriscus scutatus, although the widely distributed Aeoliscus strigatus can be expected to be present in the region.

The peculiar fishes of the Centriscidae family are not only oddly shaped – they also have strange ways. They are schooling fishes and move as a group with their bodies vertical, heads down, sucking in small crustaceans in the water above the sand into their tubular mouths.


scorpaenidae scorpionfishes & stonefishes

7220 Pterois miles, Bennett, 1828 Devil firefish

a red sea/indian ocean form of P volitans of the Western Pacific region. it would seem that no two specimens of this species are identical in colour, shape of pectoral fins, or the shape and position of the various tassles and appendages they bear. it is perhaps fortunate that only one other common species (P antennata) resembles this species. unlike many of the scorpionfishes which are lie-and-wait predators of small fishes (particularly

7219 Pterois antennata, Bloch, 1787 Broad-barred firefish

a common species in the gulf of oman and also present in the arabian gulf, usually seen hiding by day in caves or crevices, sometimes upside down. distinguished from the similar Pterois radiata (which has not been observed by

the author in the gulf of oman) by the lack of horizontal white lines along the caudal peduncle. The second photo shows a group of juveniles disguising themselves on an abandoned steel cable. maximum size reported: 20 cm.

cardinalfishes) and crustaceans, a group of this species may be seen ‘herding’ a school of small fish, with the intention of surrounding it to pick out individual fishes. They are particularly active at night and divers should take care not to inadvertently collide with them, since their spines can inflict very painful stings. The devil firefish is widely distributed and is present in the arabian gulf. maximum length: 31 cm.

scorpaenidae scorpionfishes & stonefishes

distinctive. The specimen shown below appears to have larger than usual tentacles above the eyes. maximum length: 18.6 cm.

a similar species to P antennata opposite. however, the dorsal rays are much shorter and the pectoral fin markings are

7218 Pterois mombasae, smith, 1957 Mombasa turkeyfish

scorpaenidae scorpionfishes and stonefishes

colour patterns on the inside of their pectoral rays when disturbed. In view of the close similarity of species of Scorpaenopsis, only the most common in the Gulf of Oman and the Arabian Gulf are detailed below – pictures of other ‘variants’ are included, which may be the same or different species.

The more spectacular scorpionfish species are called by a multitude of common names, depending on where you may be: stingfish, firefish, lionfish, chickenfish, waspfish, turkeyfish, etc, so there’s often confusion among divers.

There are more than 50 scorpionfish species in the Indian Ocean – some, particularly of the Scorpaenopsis genus, are extremely difficult to identify, which makes their number questionable. There are 24 species of Scorpaenopsis so far known in the Indo-Pacific region, eight of which have been described only recently (2001). Typically, they are bottom-dwelling, carnivorous and dangerous, in that their dorsal, anal and pectoral fins are venomous. They are masters of camouflage, but some reveal their true identity through individual

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Reef Fishes - UAE and Gulf of Oman

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