Species composition,trend of biodiversity variation and conservation of the fish in Lijiang River (in China)

In the present study, diversity investigations were conducted for fish species in Lijiang River main stream and its four tributaries for four times seasonally during the period from April 2013 to January 2015. Based upon the 19763 fish samples collected, a total of 91 species and subspecies belonging to five orders, 17 families and 65 genera, had been recorded. According to the method of inland water fishery natural resource investigation, by means of mathematics statistics and species diversity index to analyze data, studied the fish biodiversity characteristics and trend of biodiversity variation. On the basis, we found the reasons of exhaustion of fish resources and provided the scientific basis to protect and repair the aquatic ecosystem of Lijiang River. The research demonstrated that the diversity index of fish species in Lijiang River was at a high level, but due to the superposition of various risk factors, including overexploitation, water pollution, habitat alteration, etc., increasing exhaustion of fish stocks and decreasing significant of fish species diversity. It was urgent to take measures to protect and restore the aquatic ecosystem of Lijiang River.