Benthic studies in Goa estuaries. I. Standing crop and faunal composition in relation to bottom salinity distribution characteristics in the estuary of Mandovi River

Abstract

Macrobenthos in Mandovi, Cumbarjua canal and Zuari estuaries, a physically interconnected tropical estuarine system which undergoes large seasonal changes in salinity distribution due to heavy monsoonal precipitation, is very rich (111 species) and varied. Fauna is most continuously distributed showing high degree of aggregation, less affinity, lowest degree of association and high diversity. Six faunal assemblages based on dominant species and faunal associates are identified. Polychaetes and bivalves together contribute 70% of the macrofauna, by number and weight. Biomass production, inspite of large temporal and spatial variations, is high (54.17 g m-2) with proportionately high organic matter production of 4.08 g C m-2 y-1. Estimated annual benthic production, based on standing stock measurements, is 49.95 g m-2 or 5 tonnes km-2