关键词: 长江下游, 近岸鱼类, 群落结构, 多样性

Abstract: To understand the characteristics of nearshore fish community in the lower reaches of the Yangtze River in autumn, a survey in different sections was conducted in September 2016. The results showed that a total of 38 species of fish were collected, belonging to 6 orders, 11 families and 31 genera. Cyprinidae was the predominant family, accounting for 63.2% of the total species richness. The community composition was dominated by smallsized fish, which accounted for 81.6% of total species and 98.0% of total catch. The dominant species were Hemiculter bleekeri, Hyporhamphus intermedius, Pseudolaubuca sinensis, and Coilia nasus, accounting for 68.3% of the total catch and 40.6% of the total weight. Among the four feeding functional groups, species from omnivorous and carnivorous groups accounted for a relatively high proportion (47.4% vs. 39.5%). Freshwater sedentary fish was the most common one in four ecological groups (81.6%). Among the three habitats, the pelagic fish accounted for highest proportion (36.8%). The diversity values based on the catch number were as follows: Margalef richness index 4.03, Shannon index 2.18, Simpson dominance index 0.18, and Pielou evenness index 0.60. In conclusion, the diversity of nearshore fish community in Anhui section of Yangtze River was higher than that in Jiangsu section, which is related to the differences in river channel type and human activity intensity.

Key words: lower reaches of the Yangtze River, nearshore fish, community structure, diversity.