158 Marine Atlas of the Western Arabian Gulf

158 M a r i n e A t l a s o f t h e W e s t e r n A r a b i a n G u l f

Plate 6.1 Judaym Island.

CHAPTER 6__FINAL_12MAYL2011_jpk_VERONA.indd 158 23/07/12 13:26

Jeffrey D. Miller

University of Montana, USA

The Coastal and Offshore Island Ecosystems



Introduction

The Saudi Arabian islands of the Gulf represent two general categories of islands: Coastal Islands and Coral Islands. The Coastal Islands are essentially an extension of the coastal environment, being separated from the mainland by relatively shallow, narrow stretches of water; whereas, the Coral Islands are offshore, and are derived from coral reefs on which they are located.

The Saudi Arabian Gulf coastal area supports internationally important populations of breeding seabirds and wintering shorebirds; the offshore islands support breeding marine turtles and seabirds. Dugong, turtles, fish, and corals, as well as many other invertebrates, live in the intervening shallow waters (Abuzinada and Krupp, 1994). Floristically, the Gulf Coast supports a diverse assemblage of drought-adapted vegetation, including more than 200 species representing 54 families (Böer and Warnken, 1996), as well as scattered mangrove forests, extensive seagrass beds, and wide algal flats. Unfortunately, reclamation projects have altered or destroyed over 40% of intertidal areas.

Plate 6.2 Bridled Tern (Sterna anaethetus) resting on the back of basking sea turtle; turtles occasionally float at the surface for several hours to absorb warmth from the sun.

Plate 6.3 Spotted Eagle Rays (Aetobatus narinari) spend most of their time in deeper water but occasionally come into shallow water to feed. Map 6.1 Map showing location of offshore islands in the Arabian Gulf off Saudi Arabia.


161C h a p t e r 6 : T H E C O A S T A L A N D O F F S H O R E I S L A N D E C O S Y S T E M S

Plate 6.4 Osprey (Pandion haliaetus) Approaching Its Nest.

Plate 6.5 The sandy beaches change shape according to the prevaling winds and currents, particularly at the ends of the islands.

Plate 6.6 The coastal and offshore island ecosystem. (Drawing by Kym Wissemann)


162 163C h a p t e r 6 : T H E C O A S T A L A N D O F F S H O R E I S L A N D E C O S Y S T E M SM a r i n e A t l a s o f t h e W e s t e r n A r a b i a n G u l f

Plate 6.7 Karan Island and its surrounding coral reef.


Nearshore Islands The main coast line of Eastern Saudi Arabia extends in a northwesterly to southeasterly direction for about 1,900 km of coastline, including islands from Al-Khafji to Ras Abu Qamees. The coastal area is irregular and contains six large embayments.

Map 6.2 Gulf Coast of Saudi Arabia

Ras Al Khafji


Because the embayments contain the majority of the nearshore islands, the coast can be further subdivided by sections based on the occurrence of large embayments (Map 6.2); this artificial division is based on a location along the coast and convenience for mapping, rather than characteristics of the islands. A few islands are not associated with embayments. All of the coastal islands are low and flat; none has freshwater. A few islands have extensive development (e.g., Abu Ali, Tarut), while most do not. Beginning in the north, there are few large embayments along the northern coast and few nearshore islands (Map 6.3). The coastal beaches between Ras Al-Khafji and Ras Tanajib are exposed to the wind driven currents of the counter-clockwise circulation that dominates the Gulf. These beaches accumulate debris and are subject to storm inundation. Several areas of sabbka occur along this portion of the coast.

The first large embayment occurs south of Ras Tanajib where the coast is convoluted by long, southward projecting peninsulas (Map 6.4). The coastal environment is equally complex. The outer portion of the coast faces toward the northeast and east. The beaches are demarcated by a low crest that separates the tidal area from the sparsely vegetated area. The high tide line usually does not reach the low crest but storm driven waves may breach it.

The prevailing wind and water currents deposit waterborne debris, at least seasonally, along the outer beaches. Storms both bury the debris by mixing it into the sand and re-float some that is subsequently deposited on beaches further southward. In comparison to the dynamic nature of the outer beaches, the coast of the inner bays is low and often backed by sabbka. There is little waterborne debris. The substrate within the embayment is shallow mud flats and sand flats that host cyanobacterial mats, algae, and seagrass; the zonation

results from the interplay among salinity, temperature, and type of substrate.The second large embayment is situated just to the north of Abu Ali Island (near Jubail) and extends from Ras az-Zaur through Dauhat al-Musallamiya and Dauhat ad-Dafi to the northern shore of Abu Ali (Map 6.5). This area contains five large (over 5 km in length) and many small coastal islands, as well as several peninsulas. A wide variety of substrates: dunes, sand sheets, sabkha, and rocky outcrops define the landward margin; extensive intertidal mud flats, some rocky shores and sandy beaches occur in the embayment. The wide north-eastward facing opening to the bay allows wind and storm driven currents to enter, increasing the circulation in the middle portion of the bay.

The northern portion (Dauhat al-Musallamiya) of the bay is more protected and circulation is reduced. Circulation is also reduced in the southern portion (Dauhat ad-Dafi) because it forms a cul-de-sac. The islands of the embayment are separated from the mainland by relatively narrow waterways and are essentially extensions of the mainland environment. The intertidal mud and sand flats are often covered with blue-green algal mats. Seagrass beds are relatively extensive in some subtidal areas; the distribution of coral reefs and rocky reefs is more restricted.

The coastal margin contains some beaches and areas of sabbka; in a few areas there is a relatively stable beach that has sabbka just inland. Several extensive areas of mangroves (Avicennia marina) grow along the margins of the islands and coast. This is one of the most studied embayments along the coast as a result of the Jubail protected areas proposal (Krupp, et al., 1996). The area was heavily polluted during the 1991 Gulf War. Many salt marsh and mangrove areas appeared dead after the oil contamination; however, many are now showing signs of recovery.

Plate 6.8 Karan Island showing the ends of the beach rock ridges that extend under the sand and along the

sides of the island.

Map 6.3 Ras Al-Mish’ab and Safaniya Coast. Map 6.4 Ras Tanajib and Khawr Al-Musharrah Bay Area. Map 6.5 Dawhat Al-Musallamiya. Map 6.6 Dawhat Abu Ali.

Ras Al Khafji

Ras Tanajib



The northward facing shore of Abu Ali is exposed to storm action and accumulates considerable debris. Some of the exposed coastal margin has been altered by the addition of concrete armament; whereas, less exposed areas (to the west and south, including part of Batinah Island) are open beaches. The northern and western coasts were impacted severely by the 1991 Gulf oil spill. Because of the wind and wave action over offshore seagrass beds, the beaches regularly have accumulations of decaying seagrass and algae. Seaward of the sandy beaches there are some fringing reefs.

The third major embayment occurs to the south of Batinah and Abu Ali Islands and extends to the vicinity of Jubali (Map 6.6); it is defined and protected by the curve of the two long, flat islands. Because of the oil extraction from the bay, the substrate has been extensively studied. The terrestrial habitats are primarily sand and sabkha. The sandy central areas of the islands are vegetated with grasses and herbs, especially following winter rains. Salt marshes boarder the intertidal mud and sandflats along the sheltered southern shore. Mangroves (Avicennia marina) grow along some of the tidal drainage canals. The middle portion of the bay is bisected by causeways and contains several oil rigs. Seagrass meadows, principally Halodule uninervis, cover most of the bottom from low water mark down to 3 m.

There are no coastal islands between Jubail and Tarut Bay. The coastal beaches are backed by areas of low dune and sabkahs. Seagrass occurs offshore in locally dense patches. Tarut Bay is the fourth largest embayment along the coast (Map 6.7); it is formed by the southeasterly directed peninsula that terminates at Ras Tanura, which shelters it from storms. The bay contains the large Tarut Island, Za’l Island and several smaller islands; many sand banks are exposed during low tide. The substrate is primarily

sandy flats with areas of mud. Tarut Island has been inhabited for several hundred years and is connected to the mainland by a causeway that limits circulation. The island has large areas of palm groves and gardens. The bay receives sewage effluent and agricultural run-off from the Qatif oasis. The bay supports extensive areas of seagrass; there are also a few rocky outcrops near the outer margin of the bay. The rich waters support an important shrimp and fishing industry. Dawhat Zalum (Half Moon Bay) is located to the south of al-Khobar and opens southeasterly into the Gulf of Bahrain (Map 6.8); it contains no nearshore islands but does have extensive sabbkah along the coastal margins and contains extensive areas of seagrass. The substrate is currently defined as mud flats and sand; however, survey work is ongoing along the Gulf of Bahrain and Gulf of Salwa. The intertidal area in the Gulf of Salwa is mainly sand flats and sand rock close to the shore. The most notable islands are Judhaim, Samamik and Zakhnuniyah. One island, Unaibir, to the south of the bay, is composed of fossil coral rock. The embayment located to the northwest of Al Uqair is formed by a southeasterly extending peninsula (Map 6.9); the bay contains no islands and is bounded by large areas of sabbka. A short distance to the south is an embayment that opens to the northwest. It is formed by a long, relatively narrow island that is situated at the end of a northwestward projecting peninsula. The mainland beach is interrupted by sections of sabbka; whereas, the island beaches are low crested and not backed by sabbka. The outer beaches of the island accumulate debris. The substrate of the bay is tidal mudflats with areas of muddy-sand that supports seagrass.Jazirat as-Samamik is located on the Gulf of Salwa side of the peninsula. The axis of its long, narrow shape extends roughly parallel to the coast; it is separated from the coast by a relatively narrow strait. It is a low, sparsely vegetated and without freshwater. The northerly facing beaches accumulate wind and current driven debris. The substrate of the bay is tidal mud flats and muddy sand that supports seagrass.

Map 6.7 Tarut Bay. Map 6.8 Dawhat az Zulum. Map 6.9 Al Uqair and Jazirat as-Samamik embayment in the Gulf of Salwa.

Map 6.10 Lower portion of the Gulf of Salwa.

Plate 6.9 Kurayn Island is situated on the same reef that supports Karan Island; Kurayn is circular in shape and smaller than Karan.



The coast from the vicinity of Jazirat as-Samamik and southward to Salwa is mostly unbroken by bays with the exception of one small bay that opens to the north and is bordered to the south by sabbka (Map 6.10). The majority of the coastline is continuous low dune backed by vegetation that is occasionally interrupted by areas of sabbka. As occurs along the entire coast, the shallow nearshore area is exposed at low tide.

The Ras Abu Qamees area forms a corner in the coastline between Qatar and the United Arab Emirates facing the southern Gulf (Map 6.11). A large bay sits on the eastern side of the main peninsula; the Saudi Arabian territory stops at the base of the peninsula. One large island and several small islands extend from the eastern peninsula. The substrate of the bay is subtidal and tidal mud flats and sand that support algae and seagrass; large areas are exposed during low tides as a result of the gentle slope of the bottom. Sandy beaches extend along the southern portion of the bay and the eastward facing side of the major peninsula, sometimes backed by extensive sabbka; the beaches have a low crest and are backed by salt tolerant vegetation, similar to beaches in the northern Gulf. The outer part of the major peninsula is highly convoluted by raised headlands. Crescent-shaped, sandy beaches have formed at the back of shallow bays between the headlands. The raised headlands provide a vertical component (2-4 m) to the habitat that does not occur along the northern Gulf beaches. Most of the crescent beaches have large accumulations of debris. The northwestern side of the major peninsula is separated from Qatar by a narrow strait that leads into a shallow embayment (known as the Inland Sea). In this area some of the rocky material has become detached from the mainland to form small rocky islands, at least at high tide.

Map 6.11 Ras Abu Qamees.

Plate 6.10 Lesser Crested Terns (Sterna bengalensis) resting on the beach of Kurayn Island.

Ras Abu Qamees

Saudi Arabia

Ras Qamees

Khor Dweihin



Offshore Islands The six offshore islands are low and flat (Map 6.12; Table 6.1); none has fresh water. Each of the islands sits on the southern margin of an extensive, shallow reef flat (Basson, et al., 1977; IUCN 1987b, 1987). Each island has wide, sand beach platforms. The larger islands have dense vegetation, principally of Salsola and Suaeda, however, Mesembryanthemum is also present following rainfall.

Karan is the largest of the offshore coral cay islands (Plate 6.12). Exposed beach rock extends along the northern side, as well along about half of the southern side. Two long, parallel, spines of rock extend under the island from one end to the other. The exposed ends form small bays that change in size through out the year as the wind blown currents move the sand. Because the northern side of the island is exposed to the prevailing winds and waves, it has accumulated a heavy load of debris on the strand line above the beach rock; the southern side has less debris. Tar (from the Gulf War oil spill) has accumulated on the beach rock around the island. The middle portion of the island is covered by low shrubs (Suaeda sp., Salsola sp.); the outer margin of the island, where turtles nest, is not vegetated. The unvegetated area varies in width from a few meters wide on the eastern side to about 50 meters wide on the southwestern portion.

Jana Island is the second largest of the coral islands (Plate 6.13). Like Karan Island, the northern side of Jana is bounded by beach rock, accumulates a heavy load of debris and tar blown in by the wind. The middle portion of the island is covered by low shrubs (Suaeda sp., Salsola sp.). Jana Island is similar to Karan because it is supported by two spines of underlying beach rock. Turtle nesting keeps the outer margin of the island free of vegetation.

Jurayd Island is the third largest of the Saudi Arabian Gulf territory islands (Plate6.15). It is similar to the two largest islands but no exposed beach rock surrounds it. The central portion of the island is covered with shrubs (Suaeda sp., Salsola sp.). As the seasonal currents change, the southern arm of sand accretes back and forth, sometimes creating a bay. There is a large abandoned navigation beacon standing near the middle of the island.

Kurayn Island is the second smallest of the coral islands and is located on the same reef complex as Karan Island (Plate 6.14). Although there is no exposed beach rock around the island, the island looks very much like a miniature version of Karan Island. It hosts both turtle and bird nesting.

Harqus Island is the smallest of the coral islands (Map 6.12). It is a small, unvegetated cay that is washed over by storm tides. Birds often stop to rest on Harqus and, occasionally, they remain to nest. Turtles, too, may attempt to nest on Harqus but for both groups, the island is not typically suitable for nesting.

Al Arabiyah Island is located the furthest offshore and supports a technical installation (Map 6.12). The island is roughly circular and has limited sandy beach along the southern side; the remainder of the island has raised beach rock cliffs and a rocky rough shoreline. The constant presence of people and the movement of supplies over the years have reduced the presence of wildlife on the island. The coral reefs around Al Arabiyah Island however are the most pristine in the region, because the island is remote, and the presence of the Coast Guard means that the island is little visited by fisherman and divers.

Map 6.12 Coral Islands of the Saudi Arabian portion ofthe Northern Arabian Gulf.

Harqus Island

Plate 6.11 Jurayd Island is ‘tear-drop’ shaped and has an abadonded communications tower that is visable for many kilometers. The shape of the long sand spit changes with the seasons.



Plate 6.12 Early aerial photograph (1965) of Karan Island. Plate 6.13 Early aerial photograph (1965) of Jana Island.

Plate 6.14 Early aerial photograph of Kurayn Island. Plate 6.15 Early aerial photograph of Jurayd Island.

Name Location Size (m)

2025 x 632(5.3 km cir)1105 x 300(2.6 km cir)732 x 282(1.8 km cir)488 x 267(>1 km cir)312 x 251(<1 km cir)259 x x76(<0.6 km cir)

Biological FeaturesVegetated; major turtle and birdbreeding siteVegetated; major turtle and birdbreeding siteVegetated; major turtle and birdbreeding siteScattered bushes; minor turtleand bird breeding site

No vegetation; minor turtle andbird breeding site

Karan 27° 42’ N;49° 49’ E27° 21’ N;49° 54’ E27° 11’ N;49° 59’ E

27° 38’ N;49° 49’ E27° 56’ N;49° 41’ E

27° 46’ N;49° 59’ E

Jana

Juyard

Al Arabiyah

Kurayn

Harqus

Table 6.1 Size and location of the six offshore islands.

Scattered bushes: major turtle and bird breeding side

2024 x 632



Plate 6.16 A dhow fishing near a patch of coral with other patches in the distance. Dhows fish the waters of the Gulf using fish traps and nets.

Plate 6.18 Ghost crab (Ocypode rotundata) forage along the beach in search of a range of food, including dead fish

and occasionally baby turtles.

Plate 6.19 Ghost crabs (Ocypode rotundata) build a cone (about 30 cm tall) to show their presence to other crabs and advertise to potential mates.

Plate 6.17 Osprey (Pandion haliaetus) leaving its nest. Osprey feed on fish.


Island Vegetation

The coastal vegetation communities of the Western Arabian Gulf from Kuwait to Qatar, including Bahrain have been described (Halwagy and Halwagy, 1977; Batanouny, 1981; Abbas, et al., 1991; Abbas and El-Oqlah, 1992; Böer and Warnken, 1996; Basson, et al., 1977). Coastal species can be identified using the keys, illustrations and descriptions provided by El-Ghonemy (1985), Collenette (1985), Phillips (1988), Cornes and Cornes (1989), Western (1989), and Mandaville (1990). Böer and Warnken (1996) described the vegetation assemblages found in the proposed Jubail Marine Wildlife Sanctuary (Table 6.2); although the study area is small, it is reasonably representative of the Gulf coastline. For example, the salt marsh vegetation recorded in the study area was similar to that found elsewhere on the Arabian Gulf Coast (Zahran, 1977).

There are important differences in vegetation among the mainland, nearshore islands and offshore islands (Böer and Warnken, 1996). Based on their study, the mainland coast had 97 species (56.7%) that were not shared with the nearshore or offshore islands, and only shared 12 species (7.0%) with both the in-shore and offshore islands.

The nearshore islands hosted four species (2.3%) that were not found on either the mainland or the offshore islands; however, shared 56 species (32.7%) with the coastal mainland. In contrast, the offshore islands had no species that were not found in the other two areas, and only two species (1.1%) occurred on both the mainland and offshore islands but not on the nearshore islands. This provides insight into the reduction in floral diversity from the mainland to the nearshore islands and then further out to the offshore islands.

Plate 6.20 Only a few salt tolerant plants (such as this Mesembryanthemum nodiflorum)live on the Offshore Islands.

Plate 6.21 The vegetation is almost identical on the offshore islands, which have fewer species than the mainland.

Plate 6.22 Senecio sp.



Plate 6.22 Senecio sp. is one of the plants on Jana Island.

Plate 6.23 Suaeda sp.

Plate 6.24 Salsola sp. Plate 6.25 Zygophyllum sp.

Table 6.2 General habitats and associated vegetation of the coastal mainland, and islands. s



Reptiles and Amphibians The Arabian herpetological fauna includes amphisbaenas, turtles, lizards, and snakes that use the terrestrial, freshwater, and/or marine habitats of the coast and islands (Arnold, 1986; 1987; Gasperetti, 1998; Gasperetti, et al., 1993; Al-Merghani, et al., 1996; Martens, 1996), as well as a few anurans that avoid the dry conditions (Balletto, et al., 1985). One anuran, the marsh frog (Rana ridibunda), inhabits irrigation channels at Al Qatif and the wetlands of the oasis at Al Ahsa (Balletto, et al., 1985). The distribution of the marsh frog along the Coast of the Eastern Province is restricted to areas that provide access to freshwater. Similarly, amphisbaenas exhibit restrictions on their distribution, at least locally, because their preference for high substrate moisture habitat that does not generally occur on the islands. Terrestrial lizards and snakes are the common reptiles found along the coast and on the islands. Martens (1996) reported 14 species of lizards representing five families (Agamidae, Gekkonidae, Lacertidae, Scincidae, Varanidae) and four species of snakes from three families (Boidae, Colubridae, Viperidae) from the proposed Jubail Wildlife Marine Sanctuary. Because these species are able to cross short distances of salt water, their distribution is not limited to the coastal mainland and several species may occur on the nearshore islands. However, because systematic surveys of the coastal islands of the Saudi Arabian Gulf coast have not been done, their occurrence on nearshore islands is poorly documented; there is probably a reduced number of species on the nearshore islands resulting from the reduced vegetation and habitat diversity. Only two species of lizards have extended their range to include the offshore islands.

Turtles can be divided into three groups based on their habitat preferences: terrestrial, freshwater, and marine. No terrestrial turtles have been recorded along the coast of the Eastern Province and only one species of freshwater turtle (Mauremys caspica) has been reported in the oases of Al Qatif, Al Ahsa and Al Uqair (Gasperetti, et al., 1993). Although the Caspian turtle may occasionally be found in brackish, estuarine water, its populations do better in freshwater habitats. Because only Tarut Island of all the nearshore and offshore islands has fresh water, it is the only island that this turtle can inhabit.

Two species of marine turtles breed on the offshore islands (Gasperetti, et al., 1993; Al-Merghani, et al., 1996). The green turtle (Chelonia mydas) breeds in June through August where as the hawksbill turtle (Eretmochelys imbricata) breeds in May and June. Each species has resident populations that live around the reefs of the Gulf islands. These species (especially the green turtle) also use the habitats in the coastal embayments where seagrass meadows and coral or rocky habitats occur. No marine turtle nesting has been recorded on the mainland for several decades.

A loose assemblage of several species of sea snakes inhabits the northern portion in the Arabian Gulf (Pelamis platura, Hydrophis cyanocinctus, Hydrophis lapemoides, Hydrophis spiralis, Hydrophis (Microcephalophis) gracilis, Lapemis curtus; Gasperetti, 1988; Martens, 1996). The occurrence of sea snakes in the northern Gulf is based on museum records and beach washed specimens found along the mainland and island beaches during the colder months (Gasperetti, 1988; Martens, 1996). Systematic surveys to determine the occurrence and distribution of all species of sea snakes in the Arabian Gulf need to be conducted.

Plate 6.26 Several hundred green turtles (Chelonia mydas)

come to the Offshore Islands to lay their eggs each year.

Plate 6.27 This agamid lizard (Trapelus persicus) lives along the mainland coast but does not occur on the Offshore Islands. (Photograph by Michael R. Reilly)

Plate 6.28 The toad headed lizard (Phrynocephalus

arabicus) lives in the sparsely vegetated sandy areas along the coast. (Photograph by Michael R. Reilly)

Plate 6.29 Sea turtle courtship takes place over the reef flats that surround the Offshore Islands in April and May.



Mammals

Terrestrial mammalsDetailed studies of the terrestrial of the coastal mainland and adjacent islands are few (Kock and Nader, 1996). Fourteen species of mammals, ranging from the common mouse (Mus musculus) to the Arabian fox (Vulpes v. arabica) and including one bat (Asellia t. tridens), were recorded in a four week study period on the mainland in the proposed Jubail Marine Wildlife Sanctuary area (Kock and Nader, 1996). As expected, given the size range and ecological trophic role of the species, more species, particularly the larger predators, were found on the mainland where they can maintain larger home ranges than on near-shore islands. At least three small species of rodents (Gerbillus sp., Meriones sp., Mus musculus) inhabited nearshore Jana Island. Only one species (Mus musculus) was found on the offshore islands. Mice probably arrived on Karan, Jana, Kurayn, and Jurayd islands with fishermen and traders many decades ago. Normally mice are vegetarian but on the offshore islands their diet includes plants and their seeds, beetles, as well as sea bird and marine turtle eggs and hatchlings.

Kock and Nader (1996) speculate that the 14 species recorded represent a reduced diversity from previous times. At least one species (Gazella subgutturosa) of gazelle have been exterminated from the area through hunting and habitat modification; reintroduction of the sand gazelle is considered feasible (Kock and Nader, 1996). The presence of feral cats (Felis catus) may also cause a reduction in smaller species.

Marine mammalsAerial surveys and stranded carcasses indicate that six species of marine mammals (dugong, porpoises,dolphins, and whales) inhabit the Northern Arabian Gulf (Robineau and Fiquet, 1996). The dugong (Dugong dugong) is more common along the coast where it feeds on seagrass in summer than in winter when large herds congregate in the area between Bahrain and Qatar (Preen, 1989). The common dolphin(Delphinus delphis) is widely distributed in the region as is the bottlenose dolphin (Tursiops truncatus) and the humpback dolphin (Sousa chinensis). These species use the inshore and offshore habitats. The small, finless porpoise (Neophocaena phocoenoides) is represented by a few specimens (Robineau and Fiquet, 1996). Bryde’s whale (Balaenoptera edeni) has been recorded several times near the offshore islands; the sightings and carcasses indicate that the Bryde’s whale is able to find enough food in the Northern Gulf to be considered a resident (Robineau and Fiquet, 1996).

Plate 6.230 Bottlenose dolphins (Tursiops truncatus) live in small groups and for-age over the reef areas at high tide.

Plate 6.31 House mice (Mus musculus) Probably arrived on the Offshore Islands by dhows; primarily they eat seeds and

vegetation but they may also eat baby terns and turtles.

Plate 6.32 Dugong (Dugong dugon) forage for seagrass along the shallow coastal zone but may occasionally venture

to the reef flats of the Offshore Islands.



Birds More than 75% of the bird species (n= 275 of 360) recorded in the Eastern Province occur along the coast, in the coastal embayments, and on the nearshore and offshore islands, including resident, migratory, and over-wintering passerines and nonpasserines (Symens and Alsuhaibany, 1996a). The shallow coastal embayments provide food for waterfowl; the surrounding environment provides essential habitat for other species. The coastal region supports species that (1) are globally endangered (n= 5), (2) threatened or declining (n= 5), and/or (3) have restricted ranges (n= 15) (Symens and Alsuhaibany, 1996a). The offshore islands provide nesting sites for thousands of pairs of the Socotra Cormorant (Phalacrocorax nigrogularis); whereas the mainland coast does not (Symens and Werner, 1996). The six species of terns that nest in the Northwestern Gulf region use both the mainland and nearshore islands as well as the offshore islands for nesting; however, most nesting is on the offshore islands (Table 6.3). The offshore and nearshore islands of the Northern Arabian Gulf to the nesting cormorants and terns are very important to maintaining the wide ranging populations. The offshore and nearshore islands of the Northern Arabian Gulf are very important for nesting cormorants and tern populations.

Plate 6.33 Common kestrels (Falco tinnunculus) hunt along the coast of the mainland and nearshore islands but seldom venture to the Offshore Islands. They feed on small rodents and birds.

Plate 6.34 Bridled tern (Sterna anaethetus) are common on the Offshore Islands where they breed in large numbers.

Plate 6.35 Greater sand plover (Charadrius leschenaultii) is a visitor that stops to rest and forage on the islands during its migration to and from its breeding areas.

Plate 6.37 Lesser crested tern (Sterna bengalensis) nest in their thousands on Karan Island.

Plate 6.36 Thousands of lesser crested terns (Sterna bengalensis) nest and raise their young on Kurayn Island each year.

u


There are various types of fishing practices used in the Northwestern Gulf (Essen, 1996) and these are described in the following chapter. There are also secondary activities associated with fishing that impact on the island ecosystems. One is the illegal collection of bird and turtle eggs from the offshore islands, another is that nets and gargors continue to catch target and non target species after being lost. Nets and gargor ropes can entangle marine mammals and turtles, causing them to drown. Anchor damage to coral reefs by fishing vessels is a major concern. The use of buoys at the offshore islands by fishing dhows and small boats will help reduce anchor damage to the corals growing around the reef base. Saudi Aramco initiated a buoy mooring program in recent years, and this is helping to protect the coral reefs around the islands.

Coastal and offshore development alters habitats, and construction brings more people into the coastal and marine areas. Such development has impact during initial construction, as well as on going impact through the presence of lights, boating activity, and other human activities which can often impact indirectly on marine habitats and wildlife, including those of nearby islands. On the offshore islands in particular, nesting birds and nesting turtles are easily disturbed by human approach and activities. Activities on the offshore islands during the breeding season (spring and summer) of birds and turtles can cause these species to abandon their nesting efforts.

Beach washed debris (litter) is a significant problem along the shoreline and on offshore islands; even remote beaches have some accumulation of debris. Although terns will occasionally nest under debris at the top of the beach, surface and buried debris may disrupt marine turtle nesting by blocking nest construction. The floating debris that washes up on the beaches comes from ships transiting the Gulf as well as local dhows and small boats. Some debris is blown from the land into the water and eventually washes onto the beaches, this is particularly the case during coastal development projects.

Major oil spills impact marine habitats and wildlife, and the greatest regional spill occurred during the 1991 Gulf war. Large areas of the coast, coastal embayments, and islands were contaminated. Coastal plant communities and animals were also impacted despite containment and clean up efforts. Literally thousands of birds became oiled and died; marine mammals, turtles, and fishes were also killed. Even benthic communities were damaged.

One indirect impact of oil extraction infrastructure in offshore areas is the lights that are used on offshore oil platforms. The baby turtles swim toward the lights and remain in the vicinity where predatory fish and sharks consume them. This extra, concentrated predation is beyond that found offshore of nesting beaches without visible lights.

Conservation of Coastal and Offshore Island Ecosystems

Plate 6.40 Oil that washes ashore on rocky areas becomes tar and will remain for many years. Plate 6.38 This navigation bouy broke loose from its mooring and drifted on to the reef at Kurayn Island.

Plate 6.39 Careless anchoring casues damage to the living coral of the reef; occasionally the anchorline becomes entangled in coral and is left on the bottom.

Plate 6.41 Lesser crested terns (Sterna bengalensis) nest in groups on the Offshore Islands; the birds space themselves so there is just enough room to

land, sit on the egg, and take off.

0 1 2 km0.5

Plate 6.42 Jana Island and it’s Coral Reef.


Plate 6.43 Karan Island and it’s Coral Reef.

0 0,5 1 2 km

0

scale: 12,500



Plate 6.44 Marine scientist monitoring coral reefs on the Offshore Islands.


Map 6.13 Map of Western Arabian Gulf Islands.


Documents

158 Marine Atlas of the Western Arabian Gulf