三角帆蚌对综合养殖水体水质及鱼蚌生长的影响

在草鱼(Ctenopharyngodon idellus)养殖池中进行鱼蚌综合养殖试验,以探究三角帆蚌(Hyriopsis cumingii)吊养密度和深度对水质、鱼和蚌生长的影响。试验共分4个处理组,三角帆蚌放养模式分别为对照组0只/m^3(C)、水下40 cm处单层吊养9只/m^ 3(D-6)、水下40 cm处单层吊养18只/m^3(D-12)、水下40 cm和80 cm处双层吊养18只/m^ 3(S-12)。结果显示:试验期间,各组透明度和溶氧均随时间的延长呈现下降趋势。吊养组(D-6、D-12、S-12)TN、NH+4-N和COD的平均含量均低于C组。各组TP平均含量无显著差异。吊养三角帆蚌后草鱼的成活率和增重率显著提高,其中D-12组鱼和蚌的存活率和增重率最高。同等三角帆蚌密度下,单层吊养(D-12)的水质化学指标、鱼和蚌的存活率和增重率均优于双层吊养(S-12)。从改善水质、鱼蚌生长情况等指标考虑,在草鱼养殖池中,三角帆蚌最佳吊养密度和深度分别为18只/m^3和40 cm。

Effects of Hyriopsis cumingii on water quality and growth of other mussel and fish in the integrated culture

A pond-based experiment was conducted to evaluate the effects of freshwater mussel Hyriopsis cumingii on water quality and mussel and fish survival and growth performance in the ponds of grass carp Ctenopharyngodon idellus.Four different mussels densities and hanging depth were set up,including control ponds(0 ind./m^3)(Group C),hanging at 40cm underwater surface with 6 boxes(9 ind./m^3)(Group D-6),hanging at 40cm underwater surface with 12 boxes(18 ind./m^3)(Group D-12)and hanging at 40cm and 80cm double layers underwater surface with 12 boxes(18 ind./m^3)(Group S-12),with the same amount of grass carp in each pond.The results revealed that the water transparency and dissolved oxygen of each group decreased with time.Total nitrogen,ammonia nitrogen and COD in different hanging culture ponds(D-6,D-12 and S-12)were significantly lower than those in the control group(C).No significant difference was found among total phosphorous among the four groups.The grass carp survival rates and weight gain rates were significantly higher in hanging groups than those in the control group.The values of survival rate and weight gain rate of mussel and fish were the highest in Group D-12.The chemical index of water quality,survival and growth performance of mussel and fish were better in single layer group(D-12)than those in double layers group(S-12)at the same mussel density.This study indicated that integrated culture could effectively improve the water quality and survival and growth performance of mussel and fish.As a conclusion,this study demonstrated that the optimal culture density of freshwater mussel in the ponds of grass carp was 18 ind./m^3 hanging at 40cm underwater surface.