Widespread occurrence of coral diseases in the central Maldives
Coral diseases are one of the most important causes of coral reef decline worldwide. Although they are well investigated in some areas of the Caribbean and the Great Barrier Reef, they have been poorly studied in the Indian Ocean, and particularly in the Maldives, where the presence of coral pathologies has been reported only recently. In order to fill this gap, we investigated the prevalence, local host range and distribution of five coral diseases, namely brown band disease, skeleton eroding band, black band disease (BBD), ulcerative white spot and white syndrome (WS), in the central part of the Maldivian Archipelago, focussing, in particular, on the dominant coral genus Acropora. We estimated an overall disease prevalence of approximately 1.51%. Malè North Atoll was the most affected area; however, coral diseases were present at all study sites. WS was the most widespread disease, whereas BBD affected the highest number of scleractinian genera. We found symptoms of disease on 18 genera belonging to eight families. Acropora was the most affected genus in terms of pathogen diversity. These results provide baseline disease levels for the Maldives and can therefore serve as gauge for monitoring future change.