Biodiversity of Demersal Species from Trawl Surveys in the Iranian Waters of the Persian Gulf

Data from trawl survey was used for estimate of biodiversity indices and abundance of demersal resources in the Iranian waters of the Persian Gulf. Sampling was done by R/V Ferdos 1 from 49 00E to 57 00E during January-March 2013. In this study, 130 stations within the 10-20 m, 20-30 m and 30-50 m depths were sampled. Abundance and biodiversity of demersal fish communities at different depth strata were evaluated by various indices. In summary, of 113 taxa identified, only 91 fish species were found typically demersal, 6 were pelagic and 16 were other marine organism groups. The results showed that 4.4% of 113 species have critically imperiled status, 5.3% are imperiled and 9.7% appear to be rare but not immediately imperiled. The indices value of Shannon for entire investigated area (10-50 m depths) were 3.14, Simpson 0.04 (D) and 0.96 (1-D), Pielou 0.72, Margalef 8.45 and Menhinick 0.15. Sorenson's coefficient between depths was 0.97 that shows high similarity in the depth strata. In general, the results of abundance and biodiversity indices indicate that, the health score is fair but this region is under stress.