Swarming of Creseis acicula Rang (Pteropoda) in the coastal waters of Goa

Abstract

Swarms of Creseis acicula Rang (Pteropoda) were observed in the coastal waters of Goa regularly in October, from 1976 to 1980. The highest biomass value obtained for this species was 494 ml/100 m@u3@@, forming 96% of zooplankton population. The value is higher than the highest biomass value recorded for C. acicula from the Indian waters. The low temperature (24.8 to 25.3 degrees C), low oxygen (0.6 to 1.2 ml/l) and high nutrient values (2.8 to 3.8 mu g at/l PO sub(4)-P and 1.5 to 1.9 mu g at/l NO@d3@@-N) of bottom waters obtained during peak swarming period (October) appear to be the optimum hydrographic conditions facilitating rapid multiplication and proliferation of this pteropod species