A Study on Zooplankton of a Grass Carp Nursing Pond

This study was conducted in an earthen pond having an area of 0.61 ha and a depth of 1 meter. Fiveday-old grass carp larvae were stocked at a rate of 1/ha in the pond. Zooplankton samples were taken every week from July to September. Zooplankton community was dominated by various rotifer species apart from the week 7 and 8; the mean abundance ratio was 74%. It changed to small cladocerans in 7 rn and 8 th weeks. The mean abundance ratio for Cladocera was 24%. Cladocera was represented by small cladocerans such as Bosmina longirostris, Daphnia hyalina, D. pulex, Diaphanosoma sp. and Alana sp. Large cladocerans, D. longispina and D.magna were rarely found. Planktonic crustacean population in this nursing pond consisted primarily of Calanoid and Cyclopoid species nauplii and copepodits.The ratio of Copepoda abundance was 2%.During the study, the biomass of Cladocera was the highest in the zooplankton community.