Ocean currents affect spatial patterns of fish communities in the Yellow Sea–Bohai Sea ecotone

Abstract Background Understanding the drivers of spatial patterns in fish communities is important for protecting fishery ecosystems. However, the influence of ocean currents on the spatial patterns of fish communities remains poorly understood. This study investigated the impacts of ocean currents on the spatial patterns of fish communities and analyzed their driving mechanisms in the Yellow Sea–Bohai Sea ecotone during a one-year investigation. The distribution of ocean currents and spatial patterns of the fish communities were visualized using the data collected from Copernicus Marine Data Store and one-year fish resource surveys. To estimate the impacts of ocean currents on the spatial patterns of fish communities, we developed a vector method, which quantified the spatial aggregation direction of fish communities on the basis of the Bray‒Curtis similarity coefficient and spatial azimuth angles, defined as the community similarity trend. Subsequently, cosine correlation was used to study the relationship between the fish community and ocean currents. The ecological processes of the ocean current driving mechanism were analyzed via multivariate statistical analysis. Results The fish community similarity trends were strongly correlated with ocean currents. The fish community in the summer was divided into three station-groups located in the eastern, northwestern, and southwestern parts of the survey waters. The fish community in the winter was composed of two station-groups located in the eastern and western parts. The environmental factors exhibited spatial variations that were mainly affected by ocean currents, including the Yellow Sea Warm Current, coastal currents, and the Yellow Sea Cold Water Mass. The spatial patterns of the fish communities were associated primarily with temperature and depth in the summer and with temperature and salinity in the winter. Conclusions The spatial patterns of the fish communities in the Yellow Sea–Bohai Sea ecotone corresponded to the influence of ocean currents. Driven by ocean currents, environmental factors such as water temperature and salinity varied spatially, leading to the migration of typifying fish species to suitable habitats and then the formation of unique spatial patterns of the fish communities.