| Estuaries are the unique ecosystem with variable environment and higher diet foundation, are the spawning grounds, feeding grounds and nursery grounds of many fishery species, which greatly contribute to the fisheries yields. So, estuary ecosystem health is critical to the sustainable recruitment of fishery species. In the present study, based on the projections of fish abundance increment distribution under three climate change scenarios (RCP2.6, RCP6.0 and RCP8.5) in the Yangtze River estuary and Yellow River estuary by the dynamic bioclimate envelope mode, the fishery ecosystem health in Yangtze River estuary and Yellow River estuary was evaluated by hierarchical grey comprehensive evaluation model. The health evaluation system in Yangtze River estuary and Yellow River estuary included environment, fishery community structure and ecosystem function and service. During 2015–2050, the highest health index was found in RCP2.6 scenario both in Yangtze River estuary and Yellow River estuary, and then was RCP6.0 scenario, the lowest health index was found in RCP8.5 scenario. The health level gradually decreased with the increase of greenhouse gas emission levels. The health index showed the “high-low-high” trend with time under RCP2.6 scenario both in Yangtze River estuary and Yellow River estuary; however, it was “low-high-low” trend under RCP6.0 scenario. Under RCP8.5 scenario, the amplitude of health index fluctuation was lower than those under the other scenarios, and there were some differences between two estuaries, the health indices showed a “low-high-low” changing trend in Yangtze River estuary, meanwhile, the health indices firstly increased, then decreased, finally showed a slight increase in Yellow River estuary. If the health index in 2050 was regarded as the final results, the health levels under RCP2.6 scenario were higher than those under the other scenarios in two estuaries. The health index under RCP2.6 scenario was 0.61 in Yangtze River estuary, and it was 1.9 times and 1.8 times for RCP6.0 and RCP8.5 scenarios, respectively. The health index under RCP2.6 scenario was 2.8 times and 2.2 times for RCP6.0 and RCP8.5 scenarios in Yellow River estuary, respectively. |
