Potential distribution of Crassostrea sikamea (Amemiya, 1928) along coastal China under global climate change

Global climate change has led to ocean warming, acidification, hypoxia, and alterations in the biogeochemical circulation, thereby influencing the distribution, abundance, and population patterns of marine organisms. Particularly, oysters, which tend to attach to rocks in intertidal zones, may be more vulnerable to climate change. The Kumamoto oyster, Crassostrea sikamea (Amemiya, 1928), is renowned for its nutritional content, breeding benefits, and ecosystem restoration abilities. Previous research has demonstrated that the geographical range of C. sikamea in China has gradually shifted. In this study, the Maximum Entropy (MaxEnt) model was employed to predict the suitability for C. sikamea under different climate scenarios. We utilized first-hand data collected by our research team over the past 14 years, which consisted of 3030 C. sikamea samples from seven provinces in China. The contribution rate of the environmental variables and the jackknife test revealed that salinity (13-21PSS) and temperature (24.6-25.5 degrees C) are the primary factors influencing the distribution of C. sikamea. The future distribution shows a south -to -north migration pattern triggered by increased sea temperature, resulting in increased suitability at higher latitudes. The migratory effect is more dramatic under the high -emission scenario (Representative Concentration Pathways 8.5 (RCP8.5)) compared to medium-(RCP4.5/RCP6.0) and low -emission scenarios (RCP2.6) and becomes increasingly evident over time. Model predictions indicated that C. sikamea could maintain its suitability under all climate scenarios until the 2050s. However, by the 2100s, the suitability is expected to shift northward beyond the 33-34 degrees N boundary under RCP2.6, RCP6.0, and RCP8.5, extending to the northern coast of Jiangsu. The suitability of C. sikamea within its habitat may experience a significant decline by the 2050s, followed by a gradual recovery over the next 50 years. The potential northward migration of C. sikamea presents new prospects for oyster aquaculture and artificial reefs establishment in China. However, this migration will inevitably lead to significant impacts on the invaded ecosystems and overall biodiversity.