Marine ecosystem active in West Bengal offshore including 'Sundarbans' exhibits an excellent breeding - nursing ground of uncountable marine species. With increasing demand for fish, commercial trawling is intensified very fast by modern bull trawlers specialy in Digha and Shankarpur offshore which is very likely to have destroyed undersea habitat of benthic species forming extensively broad baseline of marine food chain. Richness of benthic biodiversity is proved to be inversely related to the offshore distance because benthic nutrients deposition getting thinner with increasing offshore...