Micro-crevice structure enhances coral spat survivorship

This study examined effects of microstructure (hereafter termed “micro-crevices”) on the surface of settlement substrata, which provides refuge for minute coral spats from grazing and, hence, could enhance coral spat survivorship. Survival of coral spats settling on plain tile-surfaces or in artificially-made micro-crevices on the tile-surfaces were monitored in situ using three scleractinian coral species; Echinophyllia aspera, Favites pentagona, and Platygyra contorta. All coral spats settling on the plain tile-surfaces died without traces of skeleton within the first four months of the experiments while some spats that settled in the micro-crevices still survived by the end of the one-year experimental period with survival rates of up to 12%. The results demonstrated the role of micro-crevice structure enhancing coral spat survivorship in the three coral species. Hence, given grazing activity, micro-crevice structure may be a significant factor influencing development of scleractinian coral communities.