The Early Life Stage Fish Community Structure and Its Relationship with Environmental Factors in the Offshore Waters of the Liaoning Province in the Yellow Sea

Monthly variation in the community structure of ichthyoplankton in the offshore waters of the Liaoning Province, China, in the Yellow Sea was evaluated based on spawning ground and ecological survey data collected from April to December 2021. The effects of environmental factors on ichthyoplankton community structure were examined using cluster analysis, non–metric multidimensional scaling, Mantel tests, and canonical correspondence analysis. Furthermore, species distribution models were applied to forecast the potential distribution of spawning grounds for dominant species under various climate change scenarios. Results indicated that spawning in the offshore waters of Liaoning Province peaks between May and August 2021. Major spawning grounds are found around the estuaries of the Dayang and Yalu Rivers. Engraulis japonicus appearred as the dominant species within the ichthyoplankton community. Species composition of fish eggs was not significantly different from July to September, indicating minimal species turnover. A similar pattern was observed in the composition of larval fish from May to July and August to September, with low species turnover. Yet, considerable intermonthly changes occurred in other months. Seawater surface temperature, seawater bottom temperature, seawater bottom salinity, and depth were recognized as pivotal environmental variables that shape the ichthyoplankton community structure and abundance. The predicted spawning grounds indicate a continuous expansion trend under the RCP2.6 scenario, fluctuating contraction under the RCP4.5 and RCP6.0 scenarios, and severe degradation under the RCP8.5 scenario. This research offers essential data to support the conservation and sustainable utilization of fishery resources in the offshore waters of Liaoning Province, China, in the Yellow Sea.