In 1996 and 1997, concrete box structures were installed in a shallow reef edge at Miyako Island, Okinawa (24°55'45"N 125°15'55"E) for rearing the commercially important top shell snail Trochus niloticus. Corals quickly attached on the quartz sandcoated fiberglass reinforced plastic latticed substrata on the bottom of the box. Within few years after severe damage of corals following extensive bleaching in 1998, however, the lattice was covered by Acropora-dominated coral colonies. In November 2005, coral coverage in four boxes was 50 to 90%. There were 25 species and the average size of the coral colonies was around 50 cm.
The accidental and rapid recruitment of corals on these aquaculture structures seems to have created an ideal environment for coral recruitment and growth. This finding provides a unique opportunity to gain insight into critical mechanisms of coral recruitment that may be used to improve coral reef restoration. The present paper deals with the aquaculture structures, environment, species diversity of corals, and possible factors that may have contributed to coral recruitment and growth.