Abstract:

The Chishui River,a firstorder right tributary of the upstream of the Yangtze River,is an important part of the national nature reserve for rare and endemic fishes in the upper Yangtze River basin.A survey on fish resources of early life was carried out in Chishui City located in the middle reaches of the Chishui River from March to July in 2007 and 2008.The results showed that there were at least 34 species spawned in Chishui section from March to July，which included eight species with pelagic eggs and four endemic species of the upper Yangtze River.In 2007 and 2008,the density of ichthyoplankton reached their peak for seven and five times,respectively.From April to July,the quantities of pelagic eggs were estimated to be 326×108 ind.and 526×108 ind. in 2007 and 2008,respectively.Three important spawning sites of fishes in the middle reaches of the Chishui River located in the towns of Bing’an,Fuxing and Taiping.The appropriate water temperature for fish reproduction varied from 21℃ to 24.5℃.The ichthyoplankton resource with pelagic eggs was promoted by increased water discharge.〖