Abstract: Based on the surveys of fish resources from June 2018 to May 2019, we analyzed fish community structure and species diversity in the Duhe River, and investigated the effects of environmental disturbance on fish community structure. Results showed that 38 species from 8 families and 4 orders were recorded, with cyprinids having most species (26), accounting for 68.4% of the total species captured during the investigation. Aristichthys nobilis, Opsariichthys bidens,and Hemiculter leucusculus were the dominant species in the river. Omnivorous, bottom, and settlement fish were mainly ecological types, accounting for 50.0%, 50.0%, and 89.5%, respectively. Hypophthalmichthys molitrix and A. nobilis accounted for 49.8% and 16.6% by relative weight and O. bidens,H. leucusculus, Zacco platypus accounted for 30.0%, 17.4%, and 12.7% by relative individual number, respectively. The fish community diversity indices were at the moderate or rich level. The Shannon index (H), Margalef index (R) and Pielou index (J) of the S3 region in the middle stream were higher than that of S1 and S2 regions in the upstream and S4 region in the downstream. The H and R of summer and autumn were higher than those of spring and winter, while the J of spring and winter was higher than that of summer and autumn. The community similarity (S′) indices among seasons were between 0.50 and 0.75, indicating moderately similar or higher. The community similarity (S′) indices of different two regions were moderately similar (S′>0.50), except that between S1 and S3 regions and between S3 and S4 regions, which were moderately dissimilar. The abundance-biomass curve (ABC) showed that biomass curve was above on abundance curve and W statistic was positive (0.0267>0), which indicated that fish community of Duhe River was relatively stable and was less affected by disturbance. However, compared with the historical data, fish species and ecological types have been changed. Accordingly, we proposed suggestions for the protection of fish resources in the Duhe River.

Key words: Duhe River, fish, community structure, biodiversity.