江湖阻隔对涨渡湖区鱼类资源的生态影响

长江中游两岸绝大多数通江湖泊自20世纪50年代以来因水利工程阻隔先后失去与长江的联系而产生一系列的生态问题。我们以涨渡湖为例开展江湖阻隔后对单个湖泊鱼类资源所产生的生态影响进行研究，结果表明：江湖阻隔导致湖泊生产经营方式改变，使得野生渔业产量的比例由1949年的95%，降低到2002年的不足5%；江湖阻隔后湖泊鱼类种类由50年代约80种下降到现在的52种，其中，洄游性和流水型鱼类比重由50%下降至不足30%；迷魂阵渔获物在单位产量、个体大小上极显著(p < 0.01)地高于通江湖泊，但在物种数和多样性指数上则要低得多(p < 0.01)。因此，江湖阻隔对湖泊渔业具明显影响，且正导致野生鱼类资源的进一步衰退。

ECOLOGICAL IMPACTS OF DISCONNECTION FROM THE YANGTZE ON FISH RESOURCES IN ZHANGDU LAKE

Most of lakes along the Yangzte River were disconnected from the river because of hydrautic projects, which caused many ecological problems. Here, we took demonstration study of the ecological impacts of disconnection from the river on fish recources in Zhangdu Lake. Our results showed that: (1) Fishery mode changed and the rate of wild fishery production changed from 95% in 1949 to less than 5% in 2002. (2) Fish species have decreased from 80 in 1950s to 52 at present, and the rate of migrant and potamic species decreased from 50% in 1950s to 30% at present. (3) Comparing with the linking lake, Zhangdu Lake had higher fishing production, larger individual size, fewer species number and lower diversity index of “mihunzheng” fishery, a universal fishing tool in Yangtze. Therefore, disconnecting lake from Yangtze had significant negative impacts on lake fish resources, which resulted in the decrease of the wild fish diversity in the lake. 〖