Growth induction of common carp, Cyprinus carpio L., fry as a function of plankton density and improved water quality

Abstract. One hundred and ninety-eight fry of common carp, Cyprinus carpio L., were reared in outdoor tanks containing 9580 1 of water under five management schemes — separate live-food system (LF), intermediate system (I), static manured system (M), manured system with water exchange (EM) and supplementary food system (SF) — in triplicate for a growing period of 90 days. Examination of frequency distribution of different weight groups of fishes at the time of harvest showed a maximum proportion of larger and smaller fishes in the live-food and supplementary food system, respectively. Maximum growth and production of common carp in the LF treatment was the consequence of greater abundance of plankton food and improvement of water quality expressed in terms of higher values of pH and DO and lower values of COD and BOD.