Ichthyoplankton Community Spectrum in Coastal West Bengal : Threats and Conservation

Abstract

The juvenile stage of finfish, commonly referred to as ichthyoplankton, constitutes an important component of the planktonic community in estuaries, seas and oceans. The pelagic and demersal fishery resources of coastal waters are intricately related to ichthyoplankton standing stock and community structure. Although many ichthyoplankton may not have direct edible food value from the point of view of human consumption, but their role in maintaining and stabilizing the brackish water food chain cannot be ignored. However this vital component of marine and estuarine biodiversity is presently under threat due to wild han/est of tiger prawn seeds from the coastal waters of West Bengal.

The seeds of tiger prawn have high demand in the coastal aquacultural farms and hence the brackish water systems are screened at regular intervals by thousands of seed catchers in search of the target species (PLj^ of Penaeus monodon). This practice is, however, associated with a huge quantum of finfish juvenile loss, which has great ecologic and economic valuation. The present paper attempts to highlight the quantum of finfish juvenile loss at three important zones of coastal West Bengal (selected on the basis of salinity profile: low, medium and high saline waters) since the last 10 years in terms of H. Although the sampling stations showed significant spatial variation in terms of physico-chemical variables, but the oscillation of ichthyoplankton community exhibited a common trend irrespective of space. The 10 years data bank reveals the ichthyoplankton diversity to be maximum in premonsoon and minimum in monsoon during the entire period of investigation, which may be related to the life cycle pattern of coastal and estuarine fishes in the study area.