The impacts of fishing and nutrient influx from Yangtze River on the ecosystem in East China Sea

As the main nutrient inputs of East China Sea (ECS), nutrient concentrations of the Yangtze River increase significantly due to high-speed economy development, which play a very important impact on the East China Sea ecosystem. In this study, by integrating MEC and EwE model, we analyzed the impact of Yangtze nutrient fluxes change and fishery on the ecosystem of ECS from 1960 to 2000. Our research shows that under high fishing pressure, the main fish production decrease significantly, average trophic level recession and small fish take the main position of ecosystem. But the increasing nutrition influxes from Yangtze River have a certain influence for the ecosystem to slow the decline tendency of fish because it can stimulate the plankton growth. This research provides a method to study the entire ecosystem from the prospective of both environmental and fishery factors, extending from physical conditions to higher ecosystem, to achieve a top–down and bottom–up management.