The results obtained on the biomass and composition of zooplankton from fortnightly collections at two fixed stations, one at Fairway buoy and another at Aroor during the period January to December 1968 are presented in this paper. The results deal with the zooplankton biomass and the quantitative abundance of major zooplankton taxa of the area investigated.

The results show that zooplankton at Aroor is richer in biomass and diversity than that at Fairway buoy. A major peak of zooplankton was observed at Fairway buoy during August-September, while Aroor recorded the highest value during December-January. Three groups viz. copepods, decapod larvae and cladocerans controlled the total zooplankton composition. It was found that no single group continued to dominate the community though copepods were the major component of the community for most part of the year. Cladoceran abundance was noted at Fairway buoy during the low salinity period.