Disease outbreaks are increasing in number and severity worldwide, with increasing evidence that pathogenesis is associated with both climate-driven and anthropogenic impacts. Management of marine environments can benefit from spatial analyses leading to early-warning systems to predict and forecast the locations of potential global hotspots and reservoirs of disease to form mitigation strategies. In this study, we draw upon the concepts of spatial epidemiology to provide a basis for controlling marine disease outbreaks. To aid in developing an early warning system model in a marine system, we used an extensive global meta-analysis from 50 years of disease reports affecting tropical reef-building corals encompassing 1,860 independent studies.
Results/Conclusions
Coral disease levels were 3-fold higher at sites with anthropogenic impacts than control sites, while total coral cover was not different between sites with anthropogenic impacts and control sites. This indicates that disease levels serve as earlier indicators for multiple chronic disturbances on coral reefs than measurements of coral mortality. Furthermore, data extracted from surveys of over 168,000 reef-building corals across 12,100 m2 of reef illustrates that the number of corals appearing visually healthy can provide similar early information for chronic disturbances on reefs as disease levels, eliminating the need for disease expertise. With a global analysis of reported disease outbreaks, we found that disease is widespread geographically, extending beyond the previously believed hotspots in the Caribbean despite low amounts of monitoring effort outside this location. The type of disease elevated on a reef site can aid in elucidating the type of chronic impact. Synthesis of the coral disease literature revealed that studies that applied the concepts of spatial epidemiology were able to provide progress in clarifying the contributors to coral disease that are necessary for ameliorating disease progression. Using this data, we can develop early-warning systems to aid in management of disease outbreaks.