Management induced changes in food selection, growthandsurvivalofkoicarp,Cyprinuscarpiovar.koi l.,Intropicalponds

Abstract

The effects of different management regimes on the feeding habits and food selection of koi carp (Cyprinus carpio var. koi L.) larvae were examined. Weight gain, fish deformities, and survival were compared in an 11-week growth trial conducted in tropical ponds maintained according to four culture regimes: (1) live food system; (2) poultry manure treated system; (3) cow dung treat- ed system; and (4) a control. The Ivlev’s Electivity Index showed that koi larvae avoided phyto- plankton and preferred cladocerans, an important source of natural food in all the regimes. In the poultry and cow manured ponds, the larvae were negatively elective towards copepods although they were more abundant than cladocerans. Weight gain and survival was significantly higher in the live-feed system (p<0.05) than in the other systems. Fish deformities were significantly high- er (p<0.05) in the control.