Numerical Simulation of Salinity Around Yellow River Estuary During Fish Spawning Period and Its Effect on Spawning Ground Distribution

As China’s second longest river, the Yellow River (YR) carries a large volume of fresh water into the Bohai Sea with abundant nutrients and, thus, plays a crucial role in regulating the temperature and salinity near the YR Delta. In this study, using the runoff data and the Finite Volume Community Ocean Model, we simulated the salinity distribution near the YR Estuary for 2013–2022. We investigated the effect of the YR runoff on salinity dispersion and established the relationship between salinity distribution and the river’s runoff volume. Additionally, we analyzed the relationship between fish eggs and salinity distribution using fish egg data. Findings indicated that the freshwater discharged from the YR converged into Laizhou Bay under the influence of tide. The several years of simulation results (2013–2022) showed that the salinity field near the YR Estuary changed with the variations of river runoff entering the sea. Simultaneously, we found a positive correlation between the area of low-salinity zones (below 27) and the monthly average river runoff, and this relation could be expressed as Y_s=0.7457X_r+78.904. The characteristics of fish egg distribution revealed that fish eggs were primarily distributed in the areas characterized by salinity in the range of 25–29.