FISH BACKGROUND INVESTIGATION AND COMMUNITY STRUCTURE ANALYSIS OF FIVE BACKBONE ARTIFICIAL RIVERS IN SHANGHAI

In this study, a total of 13379 fish specimens were collected from 20sections using gill nets in June (summer) and November (autumn), 2021 to reveal the fish species resources formed in five backbone artificial rivers of Shanghai Huangpu River in the past half-century. Sixty fish species were identified, belonging to 45 genera, 17 families, and 8 orders, comprising 41 species of Cypriniformes belonging to 28 genera and 2 families, 8 species of Perciformes belonging to 8 genera and 7 families, 2 species of Migratory fish, 8 species of estuarine fish, and freshwater species. There were 9 dominant species with IRI≥1000 in total, and Coilia nasus was the dominant species in all 5 rivers. ABC curve demonstrated that except for the Jinhui River, small and medium-sized fishes dominated other rivers, and fish communities were severely disturbed. β_C index and β_R index reflected that the Chuanyang River and the Dazhi River in Pudong had the highest difference in fish composition; the difference in fish composition between the Jinhui River and the Longquan River in Punan was the least. The 20 sections were divided into three groups; group Ⅰ (D1 and Z2 sections), group Ⅱ (the Jinhui River, the Longquan River, and the Dazhi River except for the Z2 section), and group Ⅲ (the Chuanyang River and the Dianpu River except for the D1 section). Pseudobrama simony, Coilia nasus, Carassius auratus, and Hemiculter leucisculus were the main diverging species causing the differences in fish community structure among groups. As suggested in the study, more fish species were preserved in these five artificial backbone tributaries than in the headstream, mainstream, and natural tributaries of the Huangpu River, and population density would be a crucial reason for the significant spatial differences in fish community structure in these rivers.