Threats and Conservation of Fish Biodiversity in the Lancang River, China

Abstract: Lancang River originates from an alpine springs on the slopes of the Tanggula Mountain in Qinghai-Tibet Plateau, and the species and distribution of fish are very special. To master the present composition and distribution of fish in this water system, the authors carried out a comprehensive survey on the Lancang River and affiliated lake, Erhai Lake, from 2009 to 2011. The researchers set up 65 sampling sites based on the different elevation and multiplex habitatform. A total of 174freshwater species and subspecies belonging to 10 orders, 28 families and 99 genus have been recorded. Among these are 70 species and subspecies endemic to Lancang River Valley and 22 species of exotic species. The fish composition varies greatly from headwater to downstream. It is observed that species richness increased from upstream to downstream. The differences in horizontal and vertical distribution of aboriginal fish are obvious. The horizontal distribution shows an obvious diversity and regional variety. The distribution of fish in Lancang River is influenced by altitude and climate. Many groups have a certain distribution range. Compared with the historical data, the current species number of aboriginal fish in some sections of Lancang River has decreased obviously. Environmental stress caused by river construction, over-fishing, pollution and exotic fish are external effect factors to fishes in Lancang River. These effect factors were the most significant threats to fish diversity and ecosystem functioning in the Lancang River. It was recommended that relevant departments should adopt various measures such as establishing nature reserves, artificial enhancement and release, seting up eco-environment monitoring system, improving aquatic living resources and entironment administrative systems, to tackle the problem.

Key words: biodiversity, threat, conservation, freshwater fish, Lancang River