The two-day survey of Qarnein Island was undertaken by members of the Emirates Natural History Group and friends at the request of His Highness Sheikh Hamdan bin Zayed al Nahyan. It is referred to henceforth in this Report as the Qarnein Expedition.
The purpose was to carry out a brief inspection of the whole area of the Island, to prepare a preliminary report on its natural history, including birds, mammals, fish, and other marine life, its surface geography, evidence of historical or archaeological sites, and its geology, and to assess the environmental impact of constructed work completed and planned by Sheikh Hamdan.
Recommendations were also sought on ways to minimize adverse environmental and ecological impact from the development programme.Members of the Survey Team
The team included the following persons, covering the topics indicated:
Several of the team were also engaged in taking still photographs and video-film.
The Report was compiled and edited by Peter Hellyer.
Material for section reports and species lists was contributed by J.N. ‘Bish’ Brown, Peter Hellyer, Colin Richardson and Maarten Verhage. Photographs were taken by J.N. ‘Bish’ Brown, Peter Hellyer, Philomena Henriksson and Maarten Verhage, while the accompanying video-film was shot and edited by Harry Barenbrug and Ingemar Henriksson.
Transport was supplied by Sheikh Hamdan bin Zayed.
Additional information on ornithological and other topics was provided by Ian Foxall, of the Decca Company, who was resident on Qarnein from 1982 to 1984, and was on special duty on the Island during the survey period. Physiological, geological and flora information owes much to previous work by R.A. Western, who made a brief survey of the Island in December 1982.Location and Physiographic Description
Qarnein Island is part of the Emirate of Abu Dhabi and lies in the southern Arabian Gulf, some 140 km northwest of Abu Dhabi and 27 km roughly southwest of Das Island at position 24’56’N and 52’51’ E. (It is the only land falling within Map Square SB26 of the Atlas of the Breeding Birds of Arabia, ABBA, project.) The Island is roughly 2.5 km long, from North to South, and one kilometer wide at its widest point, and is approximately rectangular in shape, on a northwest southeast axis, though narrowing to a sand spit at the southwestern end.
The northern third of the island is dominated by a group of low hills, the two highest of which, at the north east and north west points, have given the island its name, which means ‘The Two Horns’ in Arabic. The highest point is 58 m, with the second hill having a height of 53 m above sea level. The hills and the flat land between them are scored by a number of shallow and fairly broad gullies, caused by erosion.
The southern part of the Island is low, comprising carbonate sands that rise no more than a couple of meters above sea level. There is an outer low shelf of limestone around the whole coastline, with coral in some parts of the north and northeast. Qarnein has the rare characteristic among the islands of the Emirate of Abu Dhabi because of the mixture of sand, rocks and coral reefs around its shores, of providing all three types of typical shallow marine environment.
The Island consists of a core of pre-Cambrian Hormuz outcrop, which has pierced the surface as the highest point of a ‘salt dome’ formed by salt dispirism, which is now heavily eroded, plus a surrounding ‘plain’ of Pleistocene carbonates, including some coral reefs. There is a very thin covering of mixed carbonate and Aeolian sands. It is similar in geological terms to a number of other ‘salt dome’ islands in the territorial waters of the UAE, including Sir Bani Yas, Arzanah, Zirku and Sir Abu Nuair. The Hormuz series of rocks includes crystalline gypsum, red and brown haematites and black-speckled dolomite.Archaeology and History
Qarnein Island has no wells, very sparse vegetation (see Flora) and no permanent supplies of fresh water. Apart from the Decca Radio Station and the existing construction camp, there is no evidence of permanent occupation on the Island, whether of recent date or that might pre-date modern times. Well known to local Abu Dhabi fishermen, the island has long been a popular port of call during the breeding season of the Swift (Crested) Tern, around 250 of which were present during the survey (see Birds). In the past the eggs were, and still are, collected as food during the breeding season.Campsites and Graves
On the western side of the Island, about 10 m in from the beach and just north of the rough aircraft landing strip, there is a low mound of stones, of a roughly circular shape and about three meters in diameter, rising approximately one meter above the surrounding land surface and with a natural stone marker on top. On the surface of the mound there is a scattering of pottery, possibly of recent Islamic date. The site is probably that of a grave of a fisherman although the pottery would bear further examination. Among the low scrub immediately to the south of the grave are several other scatterings of surface pottery, some incised with markings. There are also some stones laid in straight lines that are visible on the surface. These sites are probably those of camps used by fishermen, and can be provisionally assigned to a recent Islamic date. However, some of the pottery shards show superficial similarities to shards found at archaeological sites elsewhere in the UAE, of a much earlier date, and an examination of the shards collected would be useful. These are being held in the collections of the Emirates Natural History Group.Mammals
At the time of the survey, the Island appeared to be suffering from an infestation of mice, probably the House Mouse Mus musculus. In and around the new Resthouse constructed for Sheikh Hamdan, a large number of mice were noted after nightfall among construction waste, and investigating food and other items brought by the Survey team. Sandy areas throughout the Island had a large number of small holes apparently dug by mice, many recently dug. Information from Ian Foxall suggested that there had been a recent explosion of the population following rainfall and subsequent growth of vegetation earlier in the year.
The adult mice seen were estimated to be between 100 and 125 mm in length from snout to tail, although accurate measurements were not possible as none were captured. In torchlight, the fur appeared to be uniform gray in color. There were also a large number of immature mice, indicating that the species breeds successfully. The mice were probably introduced several years ago, transported either in dhows or in stores for local residents, but have now spread across the whole of the island.
However, on the island of Sir Abu Nuair, there is believed to be a unique sub-species of mouse, with a shortened tail. Trapping of some Qarnein mice could ascertain whether or not the mice resident on the Island are the usual species or a local sub-species. There is limited food supply on the island, apart from around the living quarters of the Decca staff and the associated construction site.
There appear to be no land-based predators on the island.< However, three avian predators, two Kestrals Falco tinnunculus and one female Sparrowhawk Accipiter nisus were observed during the course of the survey. The mice probably form a part of their diet.
There was no evidence of rates, which might have been introduced by man. However, some larger holes, possibly made by or used by rats, were seen on a slope north of a Decca camp. No animals were seen. A careful watch or trapping might identify the occupants of the holes. No other mammals, like Arabian hares Capus lepensis, can survive naturally because of the sparseness of vegetation and the lack of water. If, however, more vegetation is introduced, such animals might survive.Birds
The island of Qarnein, an isolated spot of land in the middle of the Gulf, is known to be an important breeding site for a variety of seabirds. At the same time, it provides a resting point for passage migrants flying across the Gulf in both spring and autumn. The sparse vegetation and lack of water means that the island offers little to birds except as a stopping over point. Coinciding with a peak spring migration period, however, the Survey provided an important opportunity to study both migrants and nesting seabirds.
In total, 40 species of birds were recorded during the visit, including a number that appear to be new records for the island. An Interim List of the Birds of Qarnein Island is attached.
The 65+ pairs of Red-billed Tropicbirds present during the Survey confirmed that Qarnein Island is the most important breeding site for this species in the United Arab Emirates, and possibly in the whole of the Arabian Gulf. The tern colonies are also of great importance.
Passage migrants were scattered throughout the Island, although predominantly on the low scrub and in the immediate surroundings of the campsite. The single tree Prosopis juliflora, growing adjacent to the Decca hut, and watered by a small leak proved to be very attractive to small migrants, with several species being noted at very close quarters, including Yellow Wagtail, Rock Thrush, Red-throated Pipit, Redstart, Chiffchaff, Willow Warbler, Olivaceous Warbler and Booted Warbler. This underlined the fact that the introduction of more vegetation, and of water, is likely to increase the number of passage migrants making more than a single stopover on the Island.
The Survey of the Island gave rise to considerable concern about threats to the bird populations arising from three distinct areas. First, the recent expansion of human presence on the Island in the form of construction laborers and the garbage associated with their camp, has inevitably had an impact upon areas that were previously relatively undisturbed, such as the sandy scrub and rock slopes. These are important sites for breeding seabird colonies.
Second, this enlarged human presence, coupled with the practice of driving vehicles anywhere, regardless of existing tracks, will disturb the colonies of Sooty Gulls which were found to be growing in numbers. Egg collection by laborers and fishermen is also a threat.
Third, the clearing and leveling of land at the south west and north west corners of the Island has put added pressure on the remaining areas of natural vegetation, which will further increase pressure on available sites for seabird breeding colonies. If an equilibrium is to be struck between the demands for development and the preservation of Qarnein as one of the most important ornithological sites in the lower Gulf and Arabia, firm action is a priority.An Interim List of the Birds of Qarnein Island
Compiled from records of the Emirates Natural History Group Qarnein Expedition (April 20-21 1989), of Maarten Verhage (April 8-10 1989) and Ian Foxall (Sept. 11-Nov. 6 1984).
Species seen during the April 1989 Qarnein Expedition are marked with an asterisk (*) in the column headed QE. Those seen by Ian Foxall in 1984 are marked with a plus sign (+) in the column IF.
Birds breeding or believed to bread on the Island are identified under NOTES. Numbers in this column refer to numbers seen during the April 1989 ENHG Qarnein Expedition.
The order and numbers follow those developed by Professor Voous and used by the Atlas of Breeding Birds of Arabia (ABBA).
|*||+||0064||Red-billed Tropic Bird||65+ pairs – April 1989|
|*||+||0081||Socotra Cormorant||900+, mainly juvenile|
|+||0019||Western Reef Heron|
|*||0121||Great White Egret||One|
|+||0262||Pallid Harrier (?)|
|*||+||0301||Osprey||Two. One recent nest.|
|*||+||0304||Kestrel||Two. Possibly breeder|
|+||0312||Sooty Falcon||Possibly breeder|
|+||0478||Lesser Sand Plover|
|*||+||0571||Sooty Gull||Breeding. 400+|
|*||0608||Swift (Crested) Tern||Breeds. 250+|
|*||+||0609||Lesser Crested Tern||Breeds. 1300+|
|*||0622||Bridled Tern||Breeds. 100’s|
|*||0690||Palm Dove||One. Possibly future breeder|
|*||1012||Red-throated Pipit||Approximately 20|
|*||+||1017||Yellow Wagtail||Two. Two races present|
|*||+||1122||Redstart||20+ (50-50 male/female)|
|+||1137||Whinchat||April 8-10 1989|
|*||+||1144||Isabelline Wheatear||One male, one female|
|*||1147||Pied Wheatear||One female|
|*||1162||Rock Thrush||One male, one female|
|+||1166||Blue Rock Thrush|
|*||1256||Booted Warbler||One plus; two possibly|
|+||1274B||Desert Lesser Whitethroat|
|+||1520||Great Grey Shrike|
|+||1591||House Sparrow||Possibly future breeder|
|*||1601||Pale Rock Sparrow||One|
|*||1866||Ortolan Bunting||Two male, three female|
|*||1881||Black-headed Bunting||One male|
Further recordings during the spring and autumn migration seasons should produce records of more species.
If the development programme includes planting (and watering) of more vegetation, more passage migrants can be expected to stay on the Island, while species breeding on the Abu Dhabi mainland, such as Palm Dove and House Sparrow, may extend their range to Qarnein.Lepidoptera (Butterflies and Moths) and other Insects
Despite a comprehensive search, only one species of Lepidoptera was discovered, a Crimson Speckled Footman moth Utetheisa pulchella, which was on the low scrub in the southern part of the Island, and may have been a migrant, since its usual food was not present. The only other species believed to occur on the Island is the Painted Lady butterfly Vanessa cardui. Suspected caterpillars of this species were observed ravaging the Malva parviflora plants during the survey of December 1982 (Western 1983).
A variety of small insects, including beetles, were noted although specimens were not collected. Two large dragonflies of the species Hemianax ephippiger were seen. Further investigation will almost certainly prove the existence, as residents or migrants, of other species of moths, butterflies and various insects.Flora
The lack of water on Qarnein means that natural vegetation is sparse. A number of specimens of plants were collected, however, while previous visits to the Island have yielded more species. This Section owes much to previous survey work. (See ‘Vegetation of Offshore Islands in the Gulf’, by A.R. Western, Bulletin 20 pp 15-23, 1983.)
The main vegetation is one the lower southern half of the Island and appears to comprise three salt-tolerant species, Suaeda vermiculata, (locally known as ‘Suwweid’) close to the shore line, even colonizing niches in the limestone shelf, with Salsola baryosma and Salsola tetrandra spreading inland to give a surface impression of dense vegetation. These plants are the main barrier preventing the removal of the sandy top-soil by the wind. It was noticeable during the Survey that in the areas in the south-west and north-west of the island where vegetation has been removed, sand particles were being blown away and off the island even though winds were only light. Substantial losses of sand can be expected during windy weather.
In the sandy areas of the shallow wadis around the base of the hills the following species have been recorded on earlier visits: Aizoon canariense (‘Safnah’), on deeper sand, along with Malva parviflora (‘Kobbeiyah’). Lotus schimperi, Argyrolobium roseum and Zygophyllum simplex have been collected from gravelly but more compact horizons, while Sperfula fallax, much less common, has been found in sheltered cracks and gullies at the foot of the hills. A few plants of Salsola vermiculata and Salsola baryosma also survive just above the high-tide mark and around the bases on the hills on the northeast and northwest of the island, while in sandy areas near the Decca station a few specimens of Zygophyllum simplex were in flower. It is important to realize that spring annual can appear at any time from early December through the following months, according to temperature levels and rainfall. In the Decca camp itself a very few introduced bushes were noted, including one specimen of Prosopis juliflora adjacent to the Decca hut, which was very attractive to birds on passage (see Birds). Mangroves Avicennia marina (‘Qura’ in Arabic) have not established themselves on the island and the beaches are possibly too sandy and too shelving for them to do so successfully. This species requires sheltered lagoons and smooth water conditions to survive.Reptiles
Reptile life on Qarnein is scarce, with only two lizards being seen during the survey.
Stone Gecko Bunopus tuberculatus: One was found in a hole under a stone in the sandy scrub. It grows up to five inches in length. The other lizard was in the foundations of the Decca hut. It was light in color, with a blue streak on its side. No identification was made.
Bose’s Sand Lizard Acanthodactylus boskianus
Short-nosed Desert Lizard Mesalina brevirostris
These species have been found on other islands and are almost certainly present on Qarnein.Snakes
No snakes were encountered and no visible traces were seen. A lack of suitable food, other than mice, is probably the reason for their absence. Three species of sea-snakes are known in the Arabian Gulf although none were encountered during the Expedition. The Yellow-bellied Sea Snake Pelanus platurus has previously been collected from the Island and is occasionally seen at sea around nearby Das Island.Marine Life Turtles
In the past, turtles were frequent nesters on Qarnein. Some may still do so, although a survey of the beaches of the southern part of the Island produced no evidence of females arriving to lay their eggs. Traditionally, local fishermen have collected the eggs whenever possible, although since adult turtles often return to the beaches on which they were born to lay their eggs, some may still use Qarnein.
In the Gulf in general, turtles usually lay eggs in batches of up to 100 at two-weekly intervals between April and July. In the absence of human disturbance, only five to 10 young per nest will grow to maturity. In recent years, the turtle population in the Gulf has been heavily reduced by pollution, hunting and accidental catching. Many more empty shells and killed carcasses are not being seen around Abu Dhabi than in previous years and the future of the four species known to inhabit the Gulf is precarious.
The commonest species is the Green Turtle Chelonia mydas. The Loggerhead Caretta caretta, and the Hawksbill Turtle Eretmochelya umbricata may breed but there is no evidence that the Leatherhead Turtle Dermochelys coriacea has done so.Fish and Coral
The Island of Qarnein lies at the northern end of a shallow and narrow sandy bank that extends for nearly double the Island’s north-south length away to the south. The southern half of the Island is bounded by mainly sandy beaches that slope gentle away from the limestone shelf that surrounds the whole Island. The northern half, in contrast, is rockier, with small reefs visible to the northeast and northwest, and just off the landing point adjacent to the Decca station accommodation.
The more varied environment off the northern shores, with coral and rocks, was examined at several points by scuba divers taking part in the expeditions. The divers investigated and photographed the fish and other marine life visible. An interim list of all the species seen and identified follows.
Only one record of fish was made from elsewhere off the island – three Black-tipped Reef Sharks Melanopterus species, which were observed swimming close to the shores on the west side.
Evidence of earlier oil pollution was observed on the rocky shores of the northeast of the Island. Team members were advised that this pollution was over a year old and there was evidence on the oil-covered rocks that the oil that had come ashore was drying out and beginning to disintegrate. However, substantial damage to the local marine life, and to the sea birds, must have been caused when the oil slick hit the Island in the period immediately after this. Evidence from Das Island suggests that some oil slicks on coastal rocks last for years.
Along the north coast of the Island, it was also noticed that serious erosion of the shoreline was taking place, with substantial areas having apparently been undermined. Cracks in the land were visible and further slippage of soil is probably.
The beaches were heavily strewn with waste wood, presumably dumped overboard by passing ships, while there were also plastic bottles and other jetsam, evidence of the degree to which the waters of the Gulf are now affected by such rubbish. Occasional clearance of this waste could be undertaken but it will continue to arrive from offshore.
In the area on the northeast of the Island, where topsoil had been bulldozed into the sea, some of the coral had been covered and killed by the sand. This area will take some time to recover while the erosion of the sandy surface into the sea will further affect marine life. As far as possible, further bulldozing of soil and topsoil into these parts of the island surround by rocks and coral should be prevented.
A local fishing boat, using a ‘gargour’, was observed off the north coast of the Island during the survey although members of the survey team had been advised that such fishing had been forbidden. The ‘gargour’ form of fishing traps many fish that are either inedible or too small to eat, and these are thrown back but generally die as a result.
The rocky shorelines off Qarnein are inhabited by the usual plentiful variety of fish to be found in the Arabian Gulf and, for those who use snorkels or scuba-diving equipment, add substantially to the attractiveness of the Island.
|English Name||Latin Name|
|Grouper (Hamour)||Epinophilus tauvina|
|Butterfly Fish||Chaetodon melapterus|
|Butterfly Fish||Chaetodon obscurus/nigropunctatus|
|Black-tipped Reef Shark||Melanopterus sp|
|Angel Fish||Pomacanthus muculosus|
|Sergeant Major||Abudefduf saxatilis|
|Blue Surgeon Fish||Zebrasoma xanthurus|
|Moon Wrasse||Thalassoma lunare|
|Parrot Fish||Scarus ghobban|
|Blue Parrot Fish||Scarus sp|
|Striped Surgeon Fish||Acanthurus sohal|
|Box Fish||Ostracion sp|
|Spotted Gaterin||Plectorhynchus gaterinus|
|Golden Trevally||Caranx speciosus|
|Yellow-tailed Jack||Caranx sp|
|Amber Jack||Seriola sp|
|Six-banded Angel Fish||Euxiphipops sextriatus|
|Angel Fish||Theniochus accuminatus|
|Grey Grunt (skin)||Spilotichthys pictus|
|Captain’s Daughter||Acanthopagrus bifasciatus|
|Sea-slug (shell-less)||Onchidium peronil|
|Sea cucumber (black)||Holothuria sp|
|Sea cucumber (beige)||Stichopus sp|
|Long-spined Sea Urchin||Diadema setosum|
|Short-spined Sea Urchin||Echinometra mathaei|
|Limpet-like Shell||Siphonaria tenuirostrilata|
|Brain Coral||Platygypsa sp|
|Honeycomb Coral||Goniastrea sp|