Reef Fishes - UAE and Gulf of Oman
Reef Fishes - UAE and Gulf of Oman
Reef Fishes - UAE and Gulf of Oman
Published by Motivate Publishing Dubai: PO Box 2331, Dubai, UAE Tel: (+971 4) 282 4060, fax: (+971 4) 282 0428 e-mail: books@motivate.ae www.booksarabia.com Office 508, Building No 8, Dubai Media City, Dubai, UAE Tel: (+971 4) 390 3550, fax: (+971 4) 390 4845 Abu Dhabi: PO Box 43072, Abu Dhabi, UAE Tel: (+971 2) 627 1666, fax: (+971 2) 627 1566 London: Acre House, 11/15 William Road, London NW1 3ER e-mail: motivateuk@motivate.ae 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 triggerfish Back cover: A female Townsends anthias with big-eye snappers Half-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 holders 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 Data A catalogue record for this book is available from the British Library Printed and bound in the UAE by Rashid Printers, Ajman, UAE
Contents
Introduction Scope of this book The naming of species General sensory characteristics Observing fishes Descriptions and photographs of species Sharks and rays Moray eels and snake eels Lizardfishes Milkfish Catfishes Needlefishes Pupfishes Squirrelfishes and soldierfishes Cornetfishes Shrimpfishes Pipefishes Scorpionfishes and stonefishes Flatheads Groupers and soapfishes Dottybacks Big-eyes Cardinalfishes Remoras Jacks Mojarras Snappers Fusiliers Grunts Monocle breams Emperors Sea breams Mullets Goatfishes Monos 18 26 30 31 31 32 33 33 34 34 35 36 40 41 45 46 47 52 53 56 57 61 62 65 66 68 69 70 72 Sweepers Chubs Spadefishes Butterflyfishes Angelfishes Damselfishes Hawkfishes Barracudas Wrasses Parrotfishes Jawfish Sandperches Blennies and triplefins Gobies and dartfishes Surgeonfishes Rabbitfishes Moorish idol Mackerels and tunas Flounders and soles Triggerfishes Filefishes Trunkfishes Pufferfishes Porcupinefishes and burrfishes Photograph origins Checklist of species Index of common and scientific names 72 74 75 76 78 80 86 87 89 96 99 99 100 105 112 114 115 115 117 118 120 121 122 124 127 128 139 6 10 13 16 17
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 identified 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-westerly winds drive surface water out to sea). These are not of course isolated regions, so fishes have no physical barriers to migration; nevertheless the cold upwelling along the Arabian Sea coastline, and to some extent the Gulf of Oman coastline, 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 asphyxiation 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 upwelling areas where oxygen levels are higher,
The Musandam Peninsula offers splendid marine life for the advanced diver. 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 restricted distributions (as far as is currently known) and could be called Arabian species some of these are very common and snorkellers are guaranteed 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
REEF FISHES UAE AND GULF OF OMAN
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 photography can be difficult at the Daymanyat Islands simply because a fish may often cross unexpectedly in front of a photographers lens. It is clearly impractical to describe all the species you may see (the author invariably 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, sometimes 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 without alarm. Various damselfishes hide in coral, blennies on algae patches have their tails curled ready to dart away and a gloriously 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 gliding 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.
Fishermen at Fahl Island with a giant guitarfish and a shark. Divers visiting Fahl Island or the Daymanyats will always be impressed by the huge schools of snappers (blackspot, 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 Sultanates determination to protect and preserve its resources and to encourage tourism. The Islands serve as a breeding area for many species and, if left undisturbed, 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 Field Muscat, 2005
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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 photographs 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 dont 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
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Operculum
Pectoral fin
Pelvic fin
Anal fin
Caudal fin
The fishes are believed to be the oldest group of vertebrates (animals with backbones) 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).
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Observing fishes
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 investigating 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 sometimes acceptable and necessary when approaching 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 spectrum cannot be seen at depth. Perhaps the best example of a fish that demonstrates 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 missing colours. The colour red is quite a dominant colour in fishes, which may help them to hide at depth, although I have often wondered whether the colour perception 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 bottomdwelling species very difficult to see.
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Zebra shark
Zebra shark The widely distributed, but uncommon zebra shark is the only member 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 yellowish/grey background, somewhat resembling the markings of leopards. 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.
Carcharhinidae
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. Reliable Arabian Gulf records are scarce. Requiem sharks are difficult to differentiate to species level when seen
Requiem sharks
underwater, 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.
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when in groups, and should be approached with caution. Maximum recorded length: 200 cm. 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.
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Electric rays
side of the head. These organs, which can produce an electrical shock of up to 200 volts, are used primarily to stun prey (a fish), but can also be employed to deter predators. Panther electric ray This is an Arabian peninsular species with a known range from the northern Red Sea to the Arabian Gulf. Its body is tan in colour and marked with white spots or blotches and it is usually found in sandy patches in reef areas. It is not common anywhere within its range. Maximum length: 100 cm.
Marbled electric ray The marbled electric ray is more widespread than T panthera, ranging from the Red Sea to Sri Lanka and South Africa. It is common in the Gulf of Oman and will typically be found in sand under ledges. Electric rays swim using their tails, not their discs. Maximum length: 130 cm.
1903 Torpedo sp This species may be unnamed and as yet undescribed. The position and shape of the dorsal fins, and the markings and colour on the back, do not conform to the two other species described. It has been observed on occasions by the author, which suggests that it is not uncommon in Oman waters. Length approximately 60 cm.
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Stingrays
defensively. Should a half-buried ray be trodden on, the ray will raise its tail over its body, with the spine erect, and pierce the offending foot. It is therefore clearly advisable not to attempt to ride these rays. Identification of rays can be difficult. Many may be seen damaged severed tails are common and shark attacks leave many discs misshapen. Honeycomb stingray Characterised by a rhomboid disc, pointed snout and very long black-and-white banded tail usually with one sting. It has dark spots on a tan back, sometimes forming broken rings. Found throughout the Indo-West Pacific region. Rests in sand, sometimes completely covered. A benthic feeder, but will also eat small fishes and jellyfishes. Usually solitary, it can be approached. Maximum disc size, 200 cm.
Cow-tail stingray This species may be identified by its rhomboid disc, blunt snout and short tail bearing a distinctive lower finfold, with stings near the end. It is plain dark brown in colour, with a white underside. Found in lagoons and reef flats, its distributed throughout the Indo-West Pacific, including the Arabian Gulf. It is very common in the Gulf of Oman but difficult to approach. Feeds on small fishes and crustaceans. Maximum disc size, 180 cm.
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Dasyatidae Stingrays
2007 Himantura jenkinsii, Annadale, 1909 The identification of this species is based on its short tail (just longer than disc width) which is cylindrical, thin and without folds. It also has small projections (tubercles) from between the eyes along its spine. It is white underneath, with a distinct white margin round the disc. Maximum recorded disc size, 104 cm. 2010 Taeniura meyeni, Bleeker, 1853 Disc almost circular, tail slightly longer than disc diameter, and a prominent ventral finfold extending to the tip of the tail. Back greyish with black blotches. Widespread throughout the Indo-West Pacific region, but not very common in the Gulf of Oman. Feeds on bottom fishes, molluscs and crustaceans. Sometimes seen with jacks in attendance. Maximum recorded disc size: 180 cm. Blotched fan-tail stingray Pointed-nose stingray
Mobulidae
2302 Manta birostris, Donndorff, 1798 The manta is the largest-known ray in the world and is widespread throughout tropical and sub-tropical seas, including the Arabian Gulf. It feeds on plankton and sometimes performs loops when feeding something divers would be wise to watch from a distance. Theyre found near reefs, and may enter very shallow lagoon areas. When not feeding, the head flaps are curled into a spiral as shown. The greatest disc span reported is 8 m.
REEF FISHES UAE AND GULF OF OMAN
Manta ray
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Eagle rays
Spotted eagle ray characterised by large heads. This species has two to five venomous stings at the base of its very long tail. Like many of its cousins amongst the cartilaginous species, the courtship process of eagle rays can be very violent, and can involve more than one male with a female this photo shows two rays (a female followed by a male) which nearly collided with the author in the excitement of their chase. Interestingly, the pilot fish (Naucrates ductor) has taken refuge under the sharksucker (Echeneis naucrates), which in turn has become detached from its host in the mayhem of the courtship. Eagle rays feed on molluscs and small invertebrates (they use their snouts to shovel sand), as well as octopuses and squid, while larger individuals will feed on fishes.
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