Abstract: To clarify the structure and spatiotemporal variation of fish community in river confluence area, a yearround survey was conducted in the estuary of Wanhe River in Anqing. The results showed a total of 65 species (13651 fish) were recorded, belonging to 8 orders, 16 families, and 54 genera. The dominant species were Hemiculter bleekeri,Coilia nasus and Pseudobrama simoni. The values of community diversity indices were: Margalef index 6.92, Shannon index 2.56, Simpson index 0.88, and Pielou index 1.64. The results of clustering analysis showed fish communities from the eight sampling sites could be classified into north bank and south bank groups, with significant difference between the two groups (R=0.583, P=0.029). The results of variance analysis showed that there were no spatial and temporal differences in the characteristic values of fish community diversity. Spatially, the total number of caught individuals and the number and weight of small fish at sites 2 and 3 in the upstream of Wanhe confluence area were significantly higher than those at other sites. Temporally, fish catches and small fish catches in spring and summer were significantly higher than those in autumn and winter. In general, fish community diversity was high in the waters of the Wanhe confluence area, with lower diversity in the north bank than in the south bank. There was a clear characteristic of fish miniaturization.

Key words: Anqing section of the Yangtze River, river confluence area, fish community, ecological group, diversity.