Abundance, distribution and partial mortality of the massive coral Siderastrea siderea on degrading coral reefs at Barbados, West Indies

The abundance, distribution and partial mortality (amount of tissue loss) of colonies of the long-lived massive coral Siderastrea siderea were examined on seven fringing reefs along a eutrophication gradient at Barbados, West Indies. Size-frequency distributions are strongly skewed towards small colonies and spatial distributions of colonies are aggregated or clumped on all reefs. Partial mortality of damaged colonies, as measured by the percent of dead surface area and number of separated live tissue patches, is substantial and varies significantly between reefs. Partial mortality is positively correlated with colony size (diameter). There is no apparent gradient in partial mortality among the seven reefs when the amount of tissue loss is corrected for colony size and thus no correspondence in amount of coral surface damage with the reported eutrophication gradient.