Ecology, Environment and Conservation Paper

STUDIES ON THE INFLUENCE OF PLANKTON ON FISH PRODUCTION OF CARP CULTURE PONDS OF KRISHNA DISTRICT, ANDHRA PRADESH, INDIA

P. Padmavathi and M.K. Durga Prasad

Abstract

Plankton forms the natural food for Indian major carps (Catla catla, Labe° rohita and Cirrhinus mrigala) and exotic carps (Ctenopharyngodon acidic? and Hypophthalmichthys molitrix). As a natural diet, plankton enhances fish growth and production. However, some members of plankton like cyanophycean and euglenoid genera are noxious, which lead to poor growth or even death of fishes. In culture practices, fertilizers are added to maintain rich plankton populations. Fertilization often results in the production of a diverse assemblage of both phyto- and zooplankton. In order to assess the effect of different plankters on fish production, a study was carried out in different carp culture ponds of Krishna district, Andhra Pradesh, India. In fish ponds under study, phytoplankton were mostly represented by Cyanophyceae, Chlorophyceae, Bacillariophyceae, Euglenineae and Dinophyceae, and zooplankton by Rotifera, Cladocera and Copepoda. The relationships among different groups of phyto- and zooplankton and their influence on fish production were discussed in the light of the existing literature.