太湖鱼类区系变化和渔获物分析

20世纪80年代之前,太湖有鱼类107种、25科,属4个生态类型:洄游型、江湖洄游型、河流型和湖沼型.自2002年9月至2006年1月进行了太湖鱼类采集,共采得鱼类60种、18科.其中,除放流的鱼类外,都能在封闭的湖泊环境中完成生命周期(湖沼生态型);团头鲂、鲮、银鲫和尼罗罗非鱼属移植种类.团头鲂、鳙、鲢、草鱼和青鱼是从20世纪60年代起每年向湖中放流的鱼类;鳗鲡则是自1976年起放流从长江采捕的鳗苗.20世纪50年末至1985年,长江和太湖之间人为隔断,不能在静水中繁殖的鱼类在湖中消失,自然鱼类资源下降;加上过度捕捞和对繁殖群体缺少保护,导致鱼类群体小型化.最后,对太湖渔业资源的优化进行了讨论,并进一步提出对策.

Changes of the fish fauna and fish yield analysis in Lake Taihu

Before 1980s,there were over 107 species belong to 25 families of fish in Lake Taihu,which can be di- vided into 4 ecological group,i.e.,migratory,fiver-lake migratory,potamophilus and limnocolous.A total of 60 species of fish belong to 18 families were collected in the lake from Sep.2002 to Jan.2006.Among them,4 species (Megalobrama amblycephala,Cirrhinus molitorella,Carassius auratus gibelio and Oreochromis niloticus)were transplanted into the lake.From 1960s to now,grass carp,black carp,silver carp,bighead carp and blunt snout bream were stocked mainly with the artificial cultural fingerlings.From 1978 to now,the stocking object of eel (AnguiUajaponica)were natural fry collected from the Yangtze River.During the end of 1950s to 1985,duo to"river-lake blocking"caused by artificial interruptions between the Yangtze River and Lake Taihu,the recruitment of those fish species that can not spawn in standing water were disappeared and natural fish resources of the lake had steadily declined.Moreover,reckless overfishing and inadequate protection of the spawners caused the diminu- tion both in the size of fish species and of individual fishes,resulting the lake being dominated by species of small size as well as by populations of stunted growth.The optimization of fishery strategy for the lake has been put for- ward in view of the above results and environmental effect.