Long-term (1991–1995) monitoring of the intertidal biota of Saudi Arabia after the 1991 gulf war oil spill

Quantitative surveys of the intertidal macrobiota were conducted between 1991 and 1995 in the Saudi Arabian Gulf along permanent transect lines (PTLs). These were established within the area impacted between Ras az-Zaur and Abu Ali as a result of the 1991 Gulf War, which now forms the Jubail Wildlife Sanctuary, and at control unpolluted sites to the south of the region. Oil moved rapidly off the lower shore and became impacted along the top of all shores within the study region. During the study period this oil weathered and has largely disappeared from rocky shores and decreased in extent on soft sediment shores. By December 1991 between 50 and 100% mortality of biota had occurred on the upper shore as a result of pollution, but by 1995 on the lower shore species diversity was similar to that found on unpolluted shores, and in the upper eulittoral ranged from normal to 71% of that found on control shores. At the top of the shore, numbers of individual species (diversity) ranged from normal to 83% of that found on control shores. Abundances of individual species also increased during the survey period and reached or exceeded levels found at lower shore levels on control shores, but at higher shore levels densities remained lower than normal at some sites. Recovery rates for Saudi Arabian shores, although tentative for upper shore marshes, are within the time scale for shores worldwide, but longer than for subtropical shores elsewhere.