Biological characteristics of the Vashishti estuary, Maharashtra (west coast of India)

Abstract

The estuary and coastal nearshore regions sustained fairly high concentration of chlorophyll <i>a</i> (av. 3.1 mg/m³) and primary productivity (av. 89.9 mgC/m³/h). High rate of primary productivity was observed in the estuarine segments especially along the lower reaches. However, the standing stocks of zooplankton (av. 3 ml/100 m³) and macrobenthos (av. 2.1 g/m²) of the estuarine system were low compared to the nearshore coastal system off Vashishti, Maharashtra, India. A gradual increase in zooplankton faunal group diversity from inner estuary to the coastal waters was evident. There was no marked change in faunal group diversity of macrobenthos between estuarine and coastal system. Selected water quality parameters were correlated with chlorophyll-<i>a</i>, phaeophytin, primary productivity, zooplankton and benthos. Fishery resources of the coastal area in terms of catch per unit effort (CPU) was fairly good during premonsoon (33 kg/h) than postmonsoon (3.4 kg/h) period. The observed biological characteristics of the Vashishti River indicated good production only at primary level and the overall potential could be rated as moderate.