Community structure characteristics of ichthyoplankton during the water-sediment regulation scheme in the Yellow River in 2020 and 2021.

The Water-Sediment Regulation Scheme (WSRS) will deliver large amounts of water and sand to the Yellow River basin within a short period of time. This will significantly change the physicochemical environment of the Yellow River estuary and the surrounding marine ecosystem. Its effects on the spatial and temporal distribution patterns of ichthyoplankton are still unknown. In this study, six surface horizontal trawl surveys of ichthyoplankton were conducted during the WSRS in 2020 and 2021 using plankton nets. The results were as follows: (1) the estuarine sedentary fish Cynoglossus joyeri was the main species controlling the succession pattern of summer ichthyoplankton communities in the Yellow River estuary. (2) The WSRS influenced the ichthyoplankton community structure by changing the runoff, salinity, and suspension environment in the estuary. (3) The northern and southeastern parts of the estuary near Laizhou Bay were the main aggregation areas of the ichthyoplankton community.