Evaluation of Production Potentiality of Silver Carp and Bighead Carp in Yuehai Lake and Its Verification by Enclosure Experiment

The actual productivity potentiality of silver carp and bighead carp were verified using the approaches of partitioning enclosure and gradient culture.The result shows that the theoretical evaluation of the potential yield of silver carp and bighead carp in Yuehai Lake was 363.83 kg/hm2 The result of verification of enclosure experiment shows that the growth of silver carp and bighead carp was good under the throw-in density of 140 kg/hm2 and the experimental yield was 236.5 kg/hm2.Considering the comprehensive water environment of Yuehai Lake and the limitation of the experiment,the average yield of silver carp and bighead carp in Yuehai Lake should be decided appropriately as 280~300 kg/hm2 and it is lower than that of theoretical evaluation.The highest potential output of silver carp and bighead carp of the whole lake is 336-360 ton.All together 110 million fingerling of silver carp and bighead carp longer than 13 cm should be thrown in and the throw-in proportion should be that silver carp︰bighead carp =1.4︰1.