Environmental influences on the species diversity, biomass and population density of soft bottom macrofauna in the estuarine system of Goa, west coast of India

A total of 58 species were recorded belonging to polychaetes, molluses, crustaceans and other minor groups in order of species abundance. eighteen species are new to the local fauna that were not reported earlier. The maximum mean species diversity index (Shannon-Wiener), total biomass (wet) and total population density recorded were 2.3 (Z1), 6.7 g/m(2) (M1) and 703 no./m(2) (M2) respectively. Significantly higher species diversity was observed at high salinity, fine sand and high sedimentary biochemical parameters of total organic carbon (TOC), total organic nitrogen (TON) and carbon of biopolymeric fraction (C-BPF) sites, Medium grain size sites supported significant high biomass whereas population density showed no significant difference among the sites. The best multiple linear regression model revealed that all the 13 parameters studied were significant influencing parameters on species diversity, biomass and population density with exception of temperature. Among these salinity and TON were the main significant parameters. The combination of significant influencing environmental parameters, % variation and Mallows' C-p values varied from sites to biotic parameters. This explained 32-72% of the total variance. The regression model derived from this data helps in detection of these biotic parameters and detection of pollution-induced effects.