Abstract
► A unique physico-chemical conditions, particularly hyper salinity of the inner bays resulted distinct benthic communities compared to other parts of the bay. ► The assessment on the polychaetes indicated a healthy condition. ► BOPA index probably indicates the residual effect of the 1991 oil spill and the oil sensitive amphipods were not completely re-colonized at certain locations in the bay even 15years after the spill.
Shallow water bays located in the western Arabian Gulf experience harsh environmental conditions. Some of these bays, including Manifa–Tanajib Bay System (MTBS), were also exposed to the 1991 oil pollution event. This study investigates the status of the macrobenthos in MTBS during 2006. This bay system is characterized by very shallow inner bays with elevated salinity and temperature compared to the rest of the bay area. As a result mainly of the hyper salinity, the inner bay communities are distinct from the outer bay communities. Overall, fairly high species richness with several rare species was observed. High Shannon–Wiener diversity values and ABC plots indicated the healthy status of the polychaete communities, while BOPA index indicated slightly polluted status in 20% of the stations. The oil sensitive amphipods were not completely re-colonized in 20% of the stations, even after 15years of recovery from the 1991 oil spill.