MACROBENTHOS OFF MAHIM (BOMBAY), WEST COAST OF INDIA IN RELATION TO COASTAL POLLUTION AND AQUACULTURE

Abstract

Deterioration of water quality clearly indicated a moderate to severe
coastal pollution around Mahim whereas a relatively healthy marine
environment towards offshore was noticed. Foraminiferans, polychaetes,
crustaceans and pelecypods were the dominant macrofauna! groups
encountered in the area. The occassional inhabitants lil{e pennatularians,
nemertines, sipunculids, ophiuroids and fish larvae were mostly restricted
to offshore regions. Biomass and population density of macrofauna were
moderate and showed fluctuating trend. Similarity coefficients of
foraminiferans (0.89) and polychaetes (0.81) were high for offshore
unpolluted stations (3 and 4) as compared to nE1arshore coastal stations
(1 and 2). Faunal diversity was relatively more in unpolluted zone. The
I diversity Index (H ) was more at station 3 for polychaetes (1.39) and at
station 4 for foraminiferans (0.54). In general, biomass was high during
postmonsoon excepting station 1 which was invariably under severe
pollution stress throughout the study period. Foraminiferans were
abundant at sandy bottom while polychaetes preferred muddy (clayeysilt)
bottom. A noticeable ecological modification associated with faunal
abundance and diversity were related to deteriorating marine water
quality due to anthropogenic waste disposals. The prevailing water quality
around Mahim is unsuitable for any kind of culture practices and also
for harvesting economically important marine species.