知识与财富的链接
本文比较了太湖梅梁湾敞水区2004年秋季渔汛期刀鲚(Coilia ectenes)和间下鱵(Hyporhamphus intermedius)的食性,同时对不同食物的重要性、选择性以及两种鱼类食物的重叠进行了分析.结果表明,秋季刀鲚、间下鱵的食物主要由浮游甲壳动物、鱼和昆虫等组成.镖水蚤中的指状许水蚤(Schmackeria inopinus)是刀鲚最重要的食物,而间下鱵最重要的食物是裸腹溞(Moina sp.),而且摄食鱼和昆虫的比例远高于刀鲚.刀鲚和间下鱵对个体较大的指状许水蚤的选择性都比较高,对个体较小、而在太湖密度很高的象鼻溞(Bosmina spp.)都表现出主动回避.刀鲚与间下鱵的食物重叠系数较高,表明对竞争比较激烈,但要完全了解这两种鱼类的竞争关系,还要对它们在太湖的分布,不同发育阶段和不同季节的摄食情况进行详细的调查研究.
The feeding habits of Coilia ectenes and Hyporhamphus intermedius of Meiliang Bay of Lake Taihu were investigated in autumn,2004.The relative importance,selectivity of different food items and the diet overlap be- tween the two fish were also analyzed.The results showed that the man food of C.ectenes and H.intermedius in- cluded planktonic crustaceans,fish and insects.Calanoid copepod Schmackeria inopinus was the most important food for C.ectenes,while cladoceran Moina sp.played the most significant role in the food of H.intermedius,H. intermedius fed a much higher proportion of fish and insects than C.ectenes.Both C.ectenes and H.intermedius showed a high positive selection for S.inopinus,but negative selection for Bosmina spp.,the most numerous cla- doceran in Lake Taihu.Diet overlap between C.ectenes and H.intermedius was significant which indicates a strong competition existed.However,in order to have a complete understanding of the competition between C.ectenes and H.intermedius,it needs a further investigation on distribution,ontogenetic and seasonal characteristics of the feed- ing of both fish species in Lake Taihu.
