Numerical simulation study on the connectivity of Acropora millepora around Hainan Island

Under the dual influence of natural factors and human activities, coral reef ecosystems are degrading. Understanding the dispersal is crucial for ecological protection and restoration. This study focuses on the coral reefs of Hainan Island, using a three-dimensional hydrodynamic-Lagrangian particle coupling model to simulate coral larvae dispersal and analyze ecological connectivity. Results show that the spatial dispersal pattern of coral larvae around Hainan Island is primarily influenced by ocean currents and the continental shelf. In spring, larvae disperse northeastward along currents, while in autumn, they move from the northwest of Hainan Island to northern Vietnam. Connectivity varies seasonally, with higher connectivity in spring than in autumn. The exchange of larvae between coral reef areas mainly relies on high self-recruitment and the auxiliary recruitment from neighboring coral reefs. This study provides a scientific basis for protecting Hainan's coral reefs and offers a methodological framework for similar ecosystem research.