There are many aspects of coral disease that are poorly understood. The relationship, if any, between human activities and the incidence of coral disease is particularly important since it is frequently assumed that the number and prevalence of diseases are increasing, and are indicative of a general decline in the marine environment. Certainly a good understanding of these issues would assist in the conservation of coral reefs by identifying targets for mitigating management programmes. In situ observations of coral disease and associated mortality were therefore compiled from more than 150 sources, and reviewed. Although there have been cases where disease has caused major changes in the composition and structure of reefs, most notably in the Caribbean, these are exceptions when compared to the number of locations at which disease has been observed. With the exception of white-band disease, most frequently observed diseases do not appear to be specific in their host requirements, affecting species in many different genera. The overwhelming majority of disease in the Caribbean (97% of locations) has been recorded from coral reefs where human activities are expected to have medium to high impacts. Regional scale patterns in the incidence of coral disease may therefore be suitable bio-indicators of disturbance to coral reefs. This potential relationship should be investigated further with a view to using patterns of disease to monitor specific sources of stress on reefs. (C) 2000 Elsevier Science Ltd. All rights reserved.
