Investigation on fishery resources in the upper reaches of Hanjiang River,Shaanxi Province

Based on the data of collation and induction of the fishery resources in the main stream and partial tributary of the upper reaches of Hanjiang River, 80 species of fishes belong to 15 families and 5 orders were collected in the past ten years.The Cyprinidae had 51 species is the main variety, and the national and provincial protected fish had 15 species in this region.Taking the Sanhuashi as the boundary, the fish community structure in the upstream and downstream of the main stream had few differences, and more than 30 mainly economic varieties were concentrated in the reservoir area.Seasonal analysis of the catch showed that fish species had strong selectivity.Analysis of biomass composition, diversity index and dominant species showed that the fish population had an evident trend of miniaturization, the ability to resist risks was reduced, and the biological habitat tended to be fragmented.