On the coral reefs of Curaçao and Bonaire (Netherlands Antilles) the sea urchin Diadema antillarum is a major coral predator. In areas with high coral cover, up to 8.2% of the Diadema population (with a density of 8.5 animals/m2) was feeding on living coral surfaces at night. Acropora species are the most heavily attacked corals.