Identification and investigation of species diversity and richness of the Gastropoda in intertidal zone of Bushehr Port coastal area (the Persian Gulf waters)

This study aims to identify and determine species diversity and richness of the Gastropods of intertidal zone of Bushehr seaport coastal field and assess ecological status of the area using Welch index. Sampling was carried out at 6 stations in Bushehr seaport in winter and summer seasons during 2013-2014. Sampling bed sediments was done three times in each station and Gastropod samples were collected using Quadrate (25×25 cm) , then were preserved using 4 % buffered formalin. Then preserved samples were transported to the laboratory and were identified and counted by using valid identification keys. Furthermore, physicochemical properties of water including temperature, pH, Dissolved Oxygen (DO) and salinity were also measured in each station. According to the obtained results of this study, identified samples were totally 14 species from 12 families belonging to 7 orders. The most abundant identified species in studied stations belonged to Planaxis sulctus, Cerithidea cingulate, Anachis misera species. In this study species diversity was determined by using Shannon-weiner index, dominant species were investigated using Simpson index and species richness was calculated by using Margalof index. The results indicated that the most and the least Shannon and Margalof indexes were in cold and warm seasons respectively and Shannon and Margalof indexes showed significant differences between sampled stations and seasons (P˂0.05). Moreover, the results showed that the most and the least Simpson index was in cold and warm season respectively and Simpson index showed no significant differences between sampled stations and seasons (P˃0.05). Welch index was used in order to determine the ecological status of the regions in terms of the levels of pollution. Results of the status of water quality based on the mentioned indexes in sampled stations had average and rather low/weak pollution status.