Quantitative evaluation of the effects of ecological factors on the distribution of important fishes in Leizhou Bay

【Objective】To quantify the effects of biological and abiotic ecological factors on the distribution of important fishes in Leizhou Bay, and clarify the response of fishes to changes in various variables, so as to provide examples for future prediction of changes in the abundance of fishery resources in this area and fishery management and research based on community perspective. 【Method】Based on the data of bottom trawl fish survey conducted in Leizhou Bay every spring and autumn from 2018 to 2020, the relative importance index(IRI) was used to screen out the important ecological fish species and construct the joint species distribution model(JSDMs). Then, redundancy analysis(RDA) was combined to verify the effect of ecological factors on the population distribution of important fish species. 【Result】A total of 217 fishes had been identified in spring and autumn during 2018-2020 in Leizhou Bay and 17 of them(IRI≥100) were viewed as ecologically important fishes; constructed joint species distribution model well presented the actual distribution of fishes(posterior fit effect R²=0.46); environmental factors had the greatest effect on the distribution of important fishes in Leizhou Bay(up to 61.3%), among which the effect of dissolved oxygen(DO) was the greatest(DO=4.39-10.36, 21.6%), and the tolerance of different fishes to different ecological factors or habitat preference was also one of the reasons for the inter-annual distribution fluctuation. Overall, the effect of interspecific interaction on fish distribution was relatively small(38.7%), but played a decisive role for some fishes such as Johnius fasciatus(84.5%), J. belangerii(73.0%) and Lagocephalus spadiceus(60.9%). 【Conclusion】Environmental factors mainly affect the distribution of fishes in Leizhou Bay, and there are obvious interannual differences among different fishes due to environmental tolerance or habitat preference. The effect of interspecific interaction on the distribution of fishes is relatively small, but it plays a key role in some fish, such as J. fasciatus, J. belangerii and L. spadiceus.