菜子湖鱼类区系变动及其驱动力分析

2007～2008年对菜子湖鱼类多样性和渔业方式进行了调查,采集到鱼类8目18科68种,包括3种新记录.历史记录的13种洄游性鱼类本次仅见2种野生群,湖区野生洄游性鱼类经济绝灭.养殖鱼类产量占渔业总产的91.4%,成为渔业主体.杂食性鱼类物种丰富但产量甚微,相反人工放流的鲢、鳙等滤食性鱼类产量达鱼类总产的68.6%,为绝对优势种.湖区鱼类区系组成的特征变化与江湖阻隔和渔业养殖模式变革密切相关,因此江湖关系变动及渔业养殖当为菜子湖鱼类区系变动的关键驱动因子.

Dynamics of Fish Community Structure in Lake Caizi and its Driving Factors

We conducted a specific survey on fish diversity and fishery modes in Lake Caizi during 2007~2008.We identified 68 fish species,including three new species records,from our samples,which belonged to eight orders and 18 families.Compared with historical data,we found that only two out of the 13 historically recorded migratory fishes existed in the lake area in 2008 and the others disappeared with wild populations.As result,migratory fishes lost economic production from Lake Caizi.Further analysis on the composition of commercial fishery collections,we found that the cultured fishes took the predominant status with more than 91.4% fishery yield.And similarly,filter-feeding fishes,such as bighead carp and silver carp,took some 68.6% of the total fishery yield in Lake Caizi.Based on the dynamics of the species composition of the fish community and their relationships with the ecological processes of river-lake disconnection and modern culturing fishery in Lake Caizi,we discussed that the changed river-lake linkage and the bulk introduction of artificially reproduced larvae and juveniles of few species must be the key driving factors which have affected the species diversity and led to the longtime degradation of fish community structure in the lake area.