THE COMMUNITY CHARACTERISTICS OF LARVAL AND JUVENILE FISH IN ANQING SECTION OF THE YANGTZE RIVER DURING THE FIRST YEAR OF FISHING BAN

Anqing section is located in the lower reaches of the Yangtze River, which is one of the important fish habitats. In order to understand the community characteristics of larval and juvenile fish and the interannual variation from 2016 to 2021, the daily survey was conducted from the 18 April to the 14 August, 2021. A total of 338922 juvenile fishes were collected and identified, belonging to 31 genera, 9 families and 6 orders. The dominant fish species and quantity of Cyprinidae accounting for 79.48% and 96.59%, respectively. In terms of ecological types, freshwater resident fishes were the absolute dominant in terms of number (95.13%) and species (79.49%). Drifting ovo-producing fishes were the absolute dominant in terms of spawning types, accounting for 92.27% and 48.71%, respectively. Hemiculter bleekeri was the first dominant species, accounted for 44.53%, followed by Hemiculter leucisculus and Xenocypris argentea. The highest abundance of larval and juvenile fish from May to July, with an average of 1093 ind./100 m³, and the peak abundance was observed on the 6 July, reaching 4097 ind./100 m³. Compared with the survey results from previous years, the number of species ranged from 37 to 48 from 2016 to 2020, and 39 in 2021. The average abundance of young and juvenile fish ranged from 355 to 1185 ind./100 m³ from 2016 to 2020, and 916 ind./100 m³ in 2021. The peak abundance ranged from 823 to 4920 ind./100 m³ from 2016 to 2020 and 8081 ind./100 m³ in 2021. Redundancy analysis (RDA) indicated a positive correlation between the abundance of larval and juvenile fish and water flow, water level, turbidity and water temperature. This study investigated the resource status of larval and juvenile fish in Anqing section of Yangtze River in the early period of the fishing ban, enriched the basic data of early fish resources in the Yangtze River trunk stream, and provided support for the evaluation on the effect of the fishing ban.