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Abstract:
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Cochin backwaters, a tropical barbuilt estuary is well known for its prawn,
molluscan and demersal fisheries. Also it formed the dumping area for sewage,235
retting of husks and discharge of effluents from industries located on either side
of it. As a result the fishery is being gradually dwindled year after year due to
the lowering of the water quality. The effect of industrial polution on the benthic
community of this tropical estuary was worked out. An area extending over 21
km from the mouth of the estuary to upstream of industrial belt was selected.
Temporal and spatial variations of 16 environmental parameters at 9 stations
along the area were monitored monthly during 1981. Benthic fauna of these 9
stations consisted of amphipods , polychaetes, isopods, tanaidaceans, molluscs
and other crustaceans (Decapods, Acetes, Alpheids, Balanus, insect larvae,
chironomid larvae, cumacea and some fresh water forms ). Apart from these, sea
anemone, flat worms, nematodes, sipunculoids, echinoderms and fishes were
also encountered. 75 species belonging to 31 faunal groups were identified. Of
these 31 groups, amphipods, polychaedes, isopods, tanaidaceans and molluscs
were numerically abundant. Rest of the 26 groups (including 13 riverine forms)
were found less significant due to their rare occurrence/low numerical abundance.
Polychaetes and molluscs were the only major groups present at all the stations. |