气候变化对长江口鱼类资源密度分布的重塑作用

本研究以2012-2013年长江口鱼类资源密度分布为基础,通过动态生物气候分室模型(DBEM)预估了不同气候变化情景下(IPCC,RCP2.6、RCP6.0和RCP8.5)长江口鱼类资源密度增量分布的变化.在RCP2.6、RCP6.0和RCP8.5这3种气候变化情景下,鱼类资源密度增量、底层鱼类资源密度增量随着时间推移均呈递增趋势,且递增程度和增量重心分布范围随着温室气体排放的增加而扩大(RCP8.5＞RCP6.0＞RCP2.6).鱼类资源密度增量重心主要分布在长江口崇明岛沿岸水域,长江口外侧水域资源密度增量相对较低,并且资源密度增量重心有向南迁移的趋势.

Reshaping the Distribution of Fish Abundance by Climate Change:A Case Study in the Yangtze River Estuary

Climate change affects the distribution of fish species and thus alters the pattern of fish abundance. However, effects of climate change on China coastal fisheries have not been studied yet. Estuaries play an important role in the function of marine ecosystem, hence they are key habitats for many fishery species and form ideal fishing grounds. Here we investigated the impacts of climate change on fish abundance by estimating the distribution of dominant and important species in the Yangtze River estuary. The analysis was performed using the dynamic bioclimate envelope mode, and the distribution data of fishery species were based on the survey during 2012-2013 in the Yangtze River estuary. Three climate change scenarios (RCP2.6, RCP6.0 and RCP8.5) were evaluated combined with the projection data from the Geophysical Fluid Dynamics Laboratory. The water temperature in the Yangtze River estuary was estimated. Without human activities, the increment of fish abundance, particularly the demersal fish abundance, increased over time in all three climate change scenarios. The increment and the distribution followed the order RCP8.5>RCP6.0>RCP2.6. The distribution of fish abundance increment in RCP8.5 was wider than those in the other two scenarios. It is expected that the fish abundance increment will be mainly in the north of the Yangtze River estuary in 2020 and 2030, and in 2050 the increment may migrate to the southern part, and there will be less increment in the offshore water body of the Yangtze River estuary. The center of fish abundance increment will be mainly located in the coastal area of the Chongming Island. These results suggest that the climate change greatly contributes to the fish abundance distribution in the Yangtze River estuary, and that the effects of climate change on fish abundance distribution vary in different scenarios. Therefore, climate change should be considered in the future adaptive fishery management in the coastal waters.