二滩水电站水库形成后鱼类种类组成的演变

本文对二滩水库建成前后,雅砻江下游长约380km河段的鱼类种类结构、生态类群及相对资源量的变化进行了研究。结果表明水库建成后不同区段的鱼类种类结构发生了变化,喜栖静水和缓流环境的种类逐渐在库区占主导地位,适应急流环境的种类主要分布于库尾和支流等局部水域中,一些外来种已经定居并在某些水域形成了优势种群。在水库建成后的头几年,由于鱼类种群密度增加还导致了渔业捕捞量大幅度上升。针对上述变化,结合雅砻江梯级电站建设可能带来的进一步环境改变,作者提出了建立自然保护江段、开展人工繁殖放流、进行水库生态调度以及防止外来种入侵等措施和建议。

Changes of fish assemblages after construction of Ertan Reservoir in Yalongjiang River

The present paper investigated on changes of species composition, ecological pattern, and output of fish resources in the middle and lower Yalong River dealing with the construction of the Ertan Reservoir. Data collected by surveys on commercial fisheries and field sampling in different stages showed that the assemblages have been dominated by lentic species in stead of lotic species after the impoundment of the Ertan Reservoir. Moreover, some small invasive species have already settled down and became harmful to the native species. Habitats of native and endemic species which preferred to lotic environments have been narrowed and were restricted in upper reach of the reservoir and a few tributaries. In the first years, fishery output has obviously increased due to the impoundment of the reservoir. According to the above ecological consequences caused by the construction of the Ertan Hydropewer Plant, an integrated conservation plan including measures such as to establish river reserve, to restock artificially produced juveniles of native and endemic fish species, to make an ecological aimed operation schedule of dams, and to prevent invasion of Mien fish species should be undertaken in order to protect native fish specise from harms of the step-wise construction of dams in the Yalong River in the future.