Distribution and seasonal abundance of macrobenthos of the Cochin Backwaters

Abstract

Macrobenthos was studied at fortnight1y intervals during March 1974 to March 1975 at S. stations spread over a distance of about 12 km in the eochin Backwaters. Environmental parameters such as temperature, salinity, dissolved oxygen and grain size were also studied and correlated with distribution and abundance of macrofauna. Pattern of distribution and seasonal abundance of important benthic groups were studied. Among the various animal groups studied. Polychaetes constituted the bulk of the fauna at all stations throughout the year. Distribution of bottom fauna in different stations from month to month showed maximum bentbic population during December to April and minimum during south-west monsoon period (July to September). It was also seen that thick clay supported poor fauna while sand, silt and clay in more or less equal proportions supported dense and varied populations.