Fish species diversity in Muling River basin of Heilongjiang Province

Fish species from 28 sampling sites in Muling River basin in May, July and September in 2015 were investigated. 46 fish species belonging to 5 orders, 11 families. 31 species of Cypriniformes contributing 68.89%, followed by Salmoniformes (5species, 11.11%). Siluriformes and Cyprinodontiformes were both included 4 species, while Petromyzoniformes was only 1 species. The annual mean values comprehensive pollution index, Shannon-Wiener, Pielou and Margalef index were 1.10, 1.97, 0.36 and 1.16, respectively. The water quality was moderate or heavy pollution. CCA results showed that water environmental factors influencing fish species varied among three seasons. In spring, main factors were pH, CODMn, DO, Fe3+, TN and ORP. In summer, vital parameters were Fe3+, ORP, TN, pH and TD. In autumn, important variables were WT, NO2--N, COND and NO3--N. © 2019, Editorial Board of China Environmental Science. All right reserved.