Evaluation of multispecies marine fishery in West Bengal, India using diversity indices

Abstract

The effective management and conservation of ecosystems rely greatly on the understanding of spatial and temporal distributions of the fish community, ecological variables and fishing activity. The information on landings for all species by commercial fisheries can facilitate analysis of species diversity and distribution patterns. This paper attempts to assess the marine fishery in West Bengal, with emphasis on the diversity with special regard to the variation in quantity of fish caught during different seasons. During this period, a total of 154 different species of fish and shellfishes were landed along the West Bengal coast among which, demersal species were highest in number (65), followed by pelagic species (59). Only two or three groups were dominant in different seasons. During the first (January – March) and fourth (October – December) season, the dominant groups were Bombayduck, croakers and prawns. While, in the third (July – September) season, the dominant species were hilsa shad followed by Bombayduck and croakers. For assessing the diversity of fisheries in West Bengal, Simpson’s index and Shannon’s index were calculated from the season-wise estimated marine fish landings for the period 2007-2010. The values of Simpson’s index varied from 0.06 to 0.37, the lowest recorded in first season of 2009 and highest in third season of 2007. The highest value was mainly because of the landings of a single species, the hilsa shad.