Assessment of coral reefs off San Salvador Island, Bahamas (stony corals, algae and fish populations)

During assessments at 11 shallow reef sites on San Salvador Island, Bahamas in June 1998 we found low prevalence of disease, bleaching, and recent partial-colony mortality among stony corals (10 cm minimum diameter). Old partial-colony mortality was >50% in Acropora palmata; however, recent tissue losses were low and it had recruits at several sites. Total (recent + old) partial-colony mortality of the Montastraea annularis species complex exceeded 30% on leeward patch reefs and back reefs. Groupers (serranids), snappers (lutjanids), and grunts (haemulids) were rare. Parrotfishes (scarids) were uncommon at most sites and surgeonfishes (acanthurids) were the dominant herbivores. Macroalgae, particularly browns that are seldom grazed by surgeonfishes, were the dominant algal functional group. The green macroalga Microdictyon marinum was extremely abundant and overgrowing Porites porites on leeward patch reefs. To facilitate their conservation, San Salvador Island's reef resources should be designated as a marine reserve.