Zooplankton ecology in the Mandovi-Zuari estuarine system of Goa, west coast of India

Seasonal variability in the physico-chemical features, zooplankton standing stock (biomass) and faunal composition in the Mandovi-Zuari estuarine system of Goa during January to December 1990 were studied. Hydrobiological characteristics were influenced by the southwest monsoon. Salinity fluctuations were drastic (0.1 to 36.6 x 10(-3)). This appeared to cause variations in plankton production and heterogeneity of various taxa. Zooplankton biomass and total numerical counts varied significantly between seasons and estuaries. Highest biomass values (1.9 ml/m(3)) were recorded in the Zuari estuary but the maximum counts (25700/m(3)) were obtained in the Mandovi estuary. Crustaceans particularly copepods predominated (54.9 to 70.6%). Invertebrate larvae, luciferid shrimps, cladocerans and chaetognaths were the other common zooplankton groups. Diustribution and abundance of majority of constituent groups and species were influenced by various hydrographical characteristics of the environment.