滇池红鳍原鲌生物学及对太湖新银鱼渔业的影响

THE BIOLOGY OF Cultrichthys erythropterus IN DIANCHI LAKE WITH EVALUATION ON ITS INFLUENCE ON Neosalanx taihuensis

太湖新银鱼是云南出口创汇的主要鱼产品。近几年来,种群数量呈上升趋势的红鳍原鮊,普遍被视为是导致太湖新银鱼产量大幅度下降的主要原因。研究结果表明,滇池中的红鳍原鮊当体长小子100mm时,食物以枝角类为主;体长100—130mm时,枝角类和虾各半;体长大于130mm时,以虾为主食,兼食水生昆虫和鱼类,其中太湖新银鱼在食物中仅出现2次,出现频率为0.45％。可见红鳍原鮊对太湖新银鱼的直接危害极小,而间接影响则在于食物的部分重叠。这一新的研究结果,已成为滇池渔业科学管理的依据之一。

The salangid fish Neosalanx taihuensis has become into a major export fish product in Yunnan. In recent years, the accretion of Cultrichthys erythropterus population was supposed to be the major factor that had caused the salangid fish yield to drop down. The present investigation has revealed that the individuals of C. erythropterus smaller than 100 mm SL feed mainly on Cladocera; individuals of 100-130 mm SL feed mainly on Cladocera and shrimps (each accounting for about half of the food amount); individuals over 130 mm SL feed mainly on shrimps as well as aquatic insects and little fishes (the salangid fish has occurred only for 2 times, occurring frequency being 0.45%). Based on these results, it is concluded that C. erythropterus shows meager direct interference, and little indirect interference, on the salangid fish. These discoveries from the investigation have been included into the fishery management of Dianchi Lake.