Diversity and Prevalence of Coral Diseases in the Nearshore Regions of the Northern South China Sea.

Coral reef ecosystems have rapidly degraded under the combined pressures of climate change and human activities, with diseases further eroding ecosystem function and habitat resilience. Over the past few decades, different coral diseases have been prevalent in all coral reef regions of the world. However, there are few reports on the prevalence of coral diseases in the South China Sea (SCS). Therefore, this study conducted a systematic survey of coral disease diversity and prevalence in the nearshore regions of the northern SCS, covering seven survey sites along the coastlines of Guangdong Province and Hainan Island. Six common coral diseases were identified: Pink-Line Syndrome, Trematodiasis Inflammation, White Syndrome, Skeletal Eroding Band, Ulcerative White Spot, and Growth Anomalies. The results revealed the prevalence and regional distribution patterns of coral diseases in the nearshore regions of the SCS and further assessed the susceptibility of coral species and host specificity of the common diseases. Additionally, environmental parameters and stress-related phenomena affecting corals were recorded, and generalized linear mixed models (GLMMs) were applied to identify variables significantly correlated with coral disease prevalence. The findings further emphasize the critical role of regional environmental heterogeneity in shaping the prevalence patterns of coral diseases, providing important scientific insights to support coral disease management and coral reef ecosystem conservation in the SCS.