草鱼对不同种类沉水植物的摄食研究

THE FEEDING BEHAVIOR OF GRASS CARP(CTENOPHARYNGODEN IDELLVS) ON DIFFERENT TYPES OF SUBMERGED PLANTS

文章研究了草鱼对轮叶黑藻、苦草、菹草、金鱼藻和穗花狐尾藻等不同种类沉水植物的摄食作用,探讨了不同规格(35,45,55,65,75和85 g)和密度(1.20,2.40,3.60和4.80 g/L)的草鱼对沉水植物的摄食选择性及摄食率。结果表明:草鱼对沉水植物摄食优先选择次序为:轮叶黑藻>苦草>菹草>金鱼藻>穗花狐尾藻;对不同规格的草鱼而言,在有轮叶黑藻的情况下,草鱼会对轮叶黑藻优先摄食,且摄食率大于苦草、穗花狐尾藻和金鱼藻,同时小规格草鱼的日均摄食率大于大规格草鱼;对不同放养密度的草鱼而言,在有轮叶黑藻的情况下,草鱼对食物的摄食竞争作用明显,当水质恶化时,草鱼的摄食率随着密度的增大而减小。

Here we studied the feeding behaviors of grass carp on different types of submerged plants including Hydrilla verticillata, Vallisneria natans, Potamogeton crispus, Ceratophyllum demersum and Myriophyllum spicatum, and we examined the feeding selectivity and feeding rate of grass carp with different weights （35, 45, 55, 65, 75 and 85 g） and community densities （1.2, 2.4, 3.6 and 4.8 g/L）. We found that the order of feeding preference of grass carp was： H. verticillata〉 V. natans〉P, crispus〉C, demersum〉M, spicatum. Regardless of the fish weight grass carp preferred feeding on H. verticillata, followed by E natans, C. demersum and M. spicatum. We also found that the daily feeding rate of small grass carp was higher than that of big individuals. The competition on submerged plants was obvious in the pre- sence of H. verticillata, and the feeding rate decreased along with the increase in community density when the water quality deteriorated.