As a result of studies of coral reefs in the Sudanese Red Sea, I wish to suggest that the recolonization of rock areas in the rich reef crest cone1,2 may be facilitated by the grazing of the algal lawn by echinoids. Although the settlement of coral planulae (the free-swimming larvae) has not been investigated3, growth studies suggest that the larva is damaged by filamentous algae4 and therefore requires a bare rock surface for successful settlement, metamorphosis and early growth.