Comparative on Fish Growth and Efficiency of Three Polyculture Models in Grass Carp Mainly Culture Pond

To further enhance the fish product quality,economic benefits and improve the ecological environment of Chinese vast number of ponds,fish growth and stocking efficiency of three different polyculture models were tested in nine land-based fish ponds in the 973 projects experimental base in Xinzhou district,Wuhan.In the model I,the stocking fish were included grass carp(Ctenopharyngodon idellus),silver carp(Hypophthalmichthys molitrix),bighead carp(Aristichthys nobilis) and high-back crucian carp(Carassius auratus).The grass carp,silver carp,bighead carp,high back crucian carp and paddlefish(Polyodon spathula) were stocked in the model II,while grass carp,silver carp,Paddlefish and high back crucian carp in the model III.Each mode was set up in three replications.Through 122 days culture trail,the results showed that the model II not only had the significantly higher growth rate of grass carp than that in the model I and model III(P0.05),but also its economic benefits higher than that in the model I and model III.