25 Dec 2011

Saudi Arabian Gulf Coral Islands

All six Saudi Arabian, Arabian Gulf Coral islands were formed when sand, produced by wave action, boring of some worm species and grazing by Parrot Fish as well as other factors builds up on a submerged coral reef and finally breaks through the water surface. The islands are thus surrounded by extensive, shallow coral reefs which are excellent for diving and snorkelling as well as supporting local fisheries. The islands have grown in size but all still have elevations of less than three metres above the high tide line. They are all aligned along the edge of where the Gulf increases in depth to 35 metres with the exception of Arabiyah which is located in deeper water. The islands are located 35 – 90 kilometres offshore Jubail Industrial City (excluding Arabiyah) and to visit the islands you need permission from the National Commission for Wildlife Conservation, and the Coast Guards, which is not easy to get unless you have a contact in the ministry. The nesting Hawksbill Turtles (Eretmochelys imbricate) arrive to lay eggs in mid-May and the larger and commoner Green Turtle (Chelonia mydas) in mid-June and start leaving the islands in September. They lay their eggs on the wide sand beach platforms of each island. Apart from the large breeding populations of terns on these islands they are also important for breeding larks including Crested Lark, Lesser Short-toed Lark and occasionally Bimaculated Lark. Birds, mainly passerines, often stop on the islands during migration and they are listed as an important bird area by BirdLife International
Karan Island



Kurain Island
The descriptions of the islands below are listed with the southern-most first and the northern-most last.

Juraid
(27°11’N, 49°52’E) is the third largest island measuring 20 hectares in size (732 x 282m) and is vegetated primarily with suaeda vermiculata and Salsola baryosma bushes. The vegetation is quite dense in places reaching a height of up to one metre and is mainly located in the central area of the island. There is a narrow bare beach platform and this island holds the largest breeding population of Bridled Terns in Saudi Arabia, with good numbers of breeding Lesser Crested Terns and White-cheeked Terns. The seabird nesting density is 65 birds per hectare. After Jana and Karan this is the next best nesting island for Hawksbill Turtle and Green Turtle and is probably less favourable then the two other islands due to its steeper sloping beach which the turtles find hard to climb.

Jana (27°22’N, 49°54’E) is the second largest island being 33 hectares in size (1105m x 300m) and is vegetated primarily with Suaeda vermiculata and Salsola baryosma bushes. The vegetation is quite dense in places, reaches one metre in height and is located mainly in the center of the island. Beach rock occurs on the northern side in the lower portion of the beach and the upper inter-tidal zone. There is a narrow bare beach platform and the largest colony of White-cheeked terns on the coral islands occurs on this island. Large numbers of Bridled tern and small numbers of Lesser Crested Terns and Swift Terns also nest here. The seabird nesting density is 28 birds per hectare. Hawksbill Turtle and Green Turtle nest on the island in preference to all other islands excepting Karan, probably as it has a gently sloping beach with good substrate to lay eggs in.

Kurain (27°39’N, 49°50’E) is the second smallest island with a size of 8 hectares (312m x 251m), has a narrow beach platform and is vegetated primarily with Suaeda vermiculata and Salsola baryosma bushes with the annual Mesembryanthemum nudiflorum also present. The vegetation is quite dense in places, can reach one metre in height and is located mainly in the center of the island. Large numbers of Lesser Crested Terns along with good numbers of Bridled Terns and White-cheeked Terns nest on this island along with 30 pairs of winter nesting Socotra Cormorant. The seabird nesting density is 404 birds per hectare and small numbers of Hawksbill Turtle and Green Turtle also nest on the island.

Karan (27°44’N, 49°50’E) is the largest of the six coral islands measuring 128 hectares in size (2025m x 625m) and it has a bare beach platform. It is vegetated primarily with Suaeda vermiculata and Salsola baryosma bushes with the annual Mesembryanthemum nudiflorum also present. The vegetation is much the same as on the other islands, being quite dense in places, up to one metre in height and located primarily in the center of the island. Beach rock occurs on the northern side in the lower portion of the beach and upper inter-tidal zone. This island has the largest breeding population of Lesser Crested terns in Saudi Arabia as well as good numbers of Bridled Terns and White-cheeked terns and a small number of Swift Terns. The seabird nesting density is 42 birds per hectare. The island is the main breeding location for Hawksbill Turtle and Green Turtle due to its gently sloping beach and suitable substrate for egg laying.

 Arabiyah is quite a small island being just over 13 hectares in size (488m x 267m), with a narrow bare beach platform. It is now a coast guard station, which occupies almost the entire surface area and as a result has been abandoned by breeding seabirds. It is located about 125 kilometres from the Saudi Arabian coast and previously had vegetation cover all of which has been destroyed.

Harqus (27°56’N, 49°41’E) is the smallest of the six coral islands being only two hectares in size (259m x 76m) and has a narrow bare beach platform. It is very low lying and has no vegetation due to the fact that during severe storms, waves wash over the entire island. The largest breeding colony of Swift Terns nest on this island with Lesser Crested terns also breeding. Very small numbers of both Hawksbill Turtle and Green Turtle also breed.

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