Zooplankton Diversity in the Nearshore Waters of Bay of Bengal, Off Rushikulya Estuary

Abstract

The study was carried out in the coastal waters of Bay of Bengal off Rushikulya estuary, to evaluate the diversity of zooplankton and its distribution with respect to hydrographical parameters. A gradual increase in salinity from 27.12-34.78‰ and water temperature from 25.8-31.9 oC was noticed. The zooplankton volume ranged from 0.1-3.8 mL per 10 m3. The density of zooplankton varied from 0.34-6.55 x 104 individuals 10 m3, out of which copepods were found to be the dominant group contributing 53.4-67.9% of the total zooplankton standing stock. In total, 93 species of zooplankters belonging to 46 genera and 33 families of six different phyla were identified. Copepods were represented by 49 species of 21 genera, belonging to 15 families and three orders. The lowest and highest contribution of copepods was recorded during January and June respectively. Chaetognaths appeared as the second dominant group and their contribution ranged from 9.0-10.7% of the total density. The share of meroplankton components accounted for about 9.4-15.7% of the bulk zooplankton density. A gradual increase in zooplankton volume and density from post-winter to summer showed a significant influence of salinity and temperature on zooplankton community at this locality.

Keywords: Zooplankton, Nearshore waters, Bay of Bengal, Rushikulya estuary