CHARACTERISTICS OF FISH ASSEMBLAGES OF POYANG LAKE AT THE INITIAL STAGE OF THE FISHING BAN

To systematically investigate fish assemblages of Poyang Lake at the initial stage of the fishing ban, quantitative field investigation on fish communities from a total of 21 sampling sites was carried out in four consecutive seasons represented by April as spring, July as summer, October as autumn in 2020 and January as winter in 2021. A total of 57 fish species was collected throughout the study, which belonged to 8 orders, 12 families, and 43 genera. There were 4 dominant species, namely Hemiculter bleekeri, Coilia brachygnathus, Saurogobio dabryi, and Pseudobrama simoni. Migratory and riverine fish accounted for 45.61% of total species. The number of species with an average body weight of less than 20 g per individual represented 88.47% of the total catch. Non-metric multidimensional scaling based on fish abundance divided the samples into two spatial groups, the channel and the main lake of Poyang Lake. Fish abundance of sampling sites in the channel was significantly lower than that in the main lake, while fish diversity was higher in the channel. Fish abundance and biomass varied significantly in four seasons. Diversity during summer and autumn seasons which witnessed high water levels was found higher than those during spring and winter seasons which had low water levels. A new euryhaline fish species, Mugil cephalus, which has never been recorded in this area, was collected both at the channel (S20) and the main lake (S9) sites during the October sampling. This possibly reflected the fishing ban effects on reducing the fishing pressure and promoting the fish resource recovery and migration, and other potential human related factors. Longer term monitoring and tracking is needed. This study provided basic information for assessing the ecological effects of the fishing ban and references for developing fish resources conservation strategies in Poyang Lake.