Abstract:
To investigate the impact of the ten-year fishing ban on fish community structure and diversity, this study conducted fish resource surveys in four sections of the middle Yangtze River—Zhijiang, Jianli, Yueyang, and Huangshi—during the spring and autumn seasons from 2022 to 2024. A total of 91 species belonging to 15 families and 10 orders of fish were investigated. Cyprinidae fish are the most abundant (59 species, 64.84%), with lake-type fish (47.25%) and omnivorous fish (65.93%) being the predominant ecological types. Relative Importance Index (IRI) analysis identified eight dominant species: silver carp, bighead carp, crucian carp, grass carp, silver bream, snakehead, shortjaw goby, and yellow catfish, predominantly medium-to-large economic fish. In 2024, 72 fish species were monitored in the middle reaches of the Yangtze River, representing an increase of 10 species compared to 2022, while the average catch per unit effort (CPUE) rose by 11.35% to 10.40 kg per haul. The Shannon-Wiener diversity index remained relatively stable (3.22—3.06). The abundance/biomass comparison curve indicated low disturbance in the fish communities. Cluster and NMDS analyses separated the fish community into two distinct clusters: Zhijiang formed one cluster, while Jianli, Yueyang, and Huangshi formed another. Following the implementation of the 10-year fishing ban in the Yangtze River, CPUE showed an upward trend. Key fish resources such as the four major carp species and croaker recovered relatively quickly, indicating phased success of the ban. However, the diversity index remained relatively stable, suggesting that species diversity recovery is a long-term process. These findings provide scientific support for evaluating the effectiveness of the fishing ban and dynamically adjusting related policies.