Diversity and biomass distribution of intertidal fauna in sonmiani bay (Miani Hor), balochistan (pakistan)

Abstract

A year long study of seasonal variations in community structure and biomass of sandy intertidal zone was carried out in SonmianiBay (Miani Hor), Balochistan. The samples were collected, by using a small beach seine and experimentally designed small beam trawl to collect the pelagic, demersal and benthic intertidal organisms. The sampling was carried out from January 2002 to December 2002 during the low tides duration. A total of 84 species were recorded mainly comprised of three major faunal groups e.g. fishes, crustaceans and mollusca. The mollusca were the most diverse and abundant group of animals that formed 39.37% of total faunal assemblage, where as crustaceans and fishes contributed 32.2% and 27.6% ,respectively. Of these, Mugilidae and Sillaginidae were dominating families from fishes. Portunidae, Penaeidae, Diogenidae, Nassariidae and Dentaliidae families also showed their presence obviously as the prominent community groups. The beam trawl collected more number (58.71%) of benthic individuals from the benthic area than beach seine that sampled the pelagic and free swimming fauna (41.28%). A significant seasonal variation (P=0.047) in the biomass distribution indicated the utilization of shallow intertidal zone adjacent to mangroves, as nursery and refuge of many juveniles of resident and visiting fauna