Trophic Structure of Fish Assemblages in the Eastern Region of the Yellow Sea Determined by C- and N-Stable Isotope Ratios

Information on the food web structure of fish assemblages is necessary for ecosystem-based fishery management. In this study, we investigated spatial and temporal variations in the trophic structure of fish assemblages in the eastern region of the Yellow Sea. We analyzed the species composition, abundance, and δ13C and δ15N values of fish assemblages and their potential food sources collected at the two sites during the four seasons of 2023. Spatial and temporal differences in the abundance and diversity of fish assemblages were observed between the sites and among the seasons. The isotopic values of fish assemblages with isotopic niche indices differed significantly between sites and seasons. In addition, the isotopic niche indices showed different seasonal patterns between the sites. However, the isotopic distributions and niche indices of fish assemblages showed no clear spatial or seasonal trends. These results suggested that the effect of site-specific variability in environmental factors and community characteristics is linked to different ambient environmental conditions. Overall, this study is important for understanding the ecological role of fishery resources and enhancing ecological-based fishery management in the eastern region of the Yellow Sea under severe anthropogenic effects and climate change.