Mass mortality of macrobenthic communities in the lagoon of Hikueru atoll (French Polynesia)

Epibenthic macrofauna communities (corals, molluscs, echinoderms, and macro algae) were investigated at Hikueru Atoll, Tuamotu Archipelago. The very lo w diversity and abundance that we observed (1 coral genus, and 2 mollusc, 1 echinoderm, and 17 macroalgal species) is likely to be the result of a mas s mortality event that occurred 18 months earlier. Hydrological surveys sug gest that this high mortality was the result of a major dystrophic crisis. Other atoll lagoons in the Tuamotu Archipelago have also been affected by h igh mortalities in the past, but Hikueru appears to have been the most freq uently and intensely affected. The present study confirms that mass mortali ties associated with phytoplankton blooms may be one of the major disturban ces affecting coral reef ecosystems.