Investigating the Determinants and Drivers of Scleractinian Coral Disease in Coral Reef Ecosystems

Abstract

Coral reefs rely upon stony coral species of the order Scleractinia to continue growing and building new reef. These corals are under threat from a variety of sources, and disease is perhaps the most poorly understood of these threats. While there is some research that suggests possible causal mechanisms related to environmental disturbances, particular pathogens, and direct human activities, there is not a lot of clarity on the true nature of coral disease, and whether it is pathogenic in nature, or an innate response to environmental stressors. Thus, it is a question that requires further investigation. This study examined three reef sites near George Town, Exuma, Bahamas. By taking surveys of coral populations, including data on size, diversity, abundance and their health status, as well as environmental and sedimentation data, various hypotheses relating to drivers of coral disease were tested. Species diversity, abundance, and size of corals were found to not be significant determinants of a reef’s infection rate, suggesting that pathogenic transmission may not be an important mechanism behind the spread of coral disease. Nevertheless, statistically significant and circumstantial evidence was found that suggests the main determinant of infection rates at a reef site may be driven by the species makeup of that particular reef.