配养滤食性鱼对投饵网箱养鱼负荷力的影响

THE IMPACT OF FILTER-FEEDING FISH ON THE CARRYING CAPACITY OF RESERVOIRS FOR FEEDING-CAGE-CULTURE OF FISH

本文用现场围隔实验的方法研究了养鱼水库中配养鲢对投饵网箱养鲤负荷力的影响。共用围隔30个,每个围隔水深5m,容积14.3m^3。实验中观测了理化指标8项、生物指标5项。实验结果表明配养鲢不仅在溶氧(DO)、化学需氧量(COD),总磷(TP)等方面明显改善了水质,而且还降低了浮游植物、浮游动物和浮游细菌的数量。配养鲢对投饵网箱养鲤的净产量,生长率,饲料效率都有显著地提高;使鲤、鲢的总负荷力和总鱼产量各自都提高了35％。并已查明,投饵网箱养鲤与水库配养鲢的适宜现存量比例3:1优于2:1。

This paper deals with the impact of stocking silver carps into fish farming reservoirs on the carrying capacity of the reservoirs for feeding-cage-culture of common carps. 30 enclosures were used in the experiment. Every enclosure was 5 m in deep and 14.3 m^3 in capacity. 8 physical and chemical factors and 5 biological factors were examined periodically during the experiment, and results of fish rearing of every ericlosure were analysed in the end. Results indicated that stocking of silver carps improved water quality obviously in respects of DO, COD and TP, and remarkably diminished phytoplankton, zooplankton and planktonic bacteria in the water. Thereby it improved the results of carp rearing distinctly in terms of net production, growth rate, and food efficiency, and increased the totel fish production and total carrying capacity by 35％. As for the optimum stocking ratio (by weight) of common carp to silver carp, it was found out in the experiment that 3:1 is superior to 2:1.