知识与财富的链接
通过分析和比较太湖鲚鱼、鲢、鳙鱼的食物组成,研究了它们间的食物关系;并结合太湖历年鱼类渔获量资料,对渔获量变化间可能存在的相互影响进行了相关分析.结果表明:在9-12月份期间,鲢鱼、鳙鱼食物中微囊藻约占体积比的90%以上、浮游动物不足10%;用Pianka提出的公式计算鲢鱼和鳙鱼间的食物重叠系数为＞0.99,相同食物组成比例为95.40%.而同期调查0 鲚鱼食物中微囊藻约占体积的15%-35%;如不计算微囊藻仅计算浮游动物的个数组成比则为:枝角类占89.77%±13 69%,桡足类占7.84%±11.53%,轮虫占2.39%±4.95%.而简单相关、偏相关分析表明:鲚鱼和鲢、鳙鱼数量变化间的负相关关系均达到显著水平.分析认为:在富营养化条件下,太湖的鲢鱼和鳙鱼以微囊藻为主要食物;而鲚鱼和鲢、鳙鱼食物中浮游动物的种类基本相同,可能存在对浮游动物资源的激烈竞争;它们种群数量变化间的相互影响是负向的,可能存在互相抑制.
From September to December in 2004, based on the food content investigation, the food relationship and the mutual effects between Coilia ectenes taihuensis Yen et Lin and Hypophthalmichthys molitrix (Cuvier et Valenciennes) and Aristichthys nobilos(Richardson) were studied in Lake Taihu. Results showed that:Cyanobacteria occupied over 90% of food volume in alimentary canal of Hypophthalmichthys molitrix(Cuvier et Valenciennes) and Aristichthys nobilos(Richardson), about 15%-35% of food volume in alimentary canal of Coilia ectenes taihuensis Yen et Lin; Hypophthalmichthys molitrix(Cuvier et Valenciennes) and Aristichthys nobilos(Richardson) basicly fed on the same food. Except Cyanobacteria, Coilia ectenes taihuensis Yen et Lin mainly fed on Cladocera accounting for 89.77% ± 13.69%, Copepoda accounting for 7.84% ± 11.53% and Rotifera accounting for 2.39% ± 4.95%. Hypophthalmichthys molitrix (Cuvier et Valenciennes) and Aristichthys nobilos (Richardson) nearly fed on the same species of Cladocera as that of Coilia ectenes taihuensis Yen et Lin. The partial correlative analysis showed that:there was negative correlation between the catches of Coilia ectenes taihuensis Yen et Linand the catches of Hypophthalmichthys molitrix (Cuvier et Valenciennes) and Aristichthys nobilos (Richardson) at the significant lever of p<0.05.
