Abstract
Coral reefs have been deteriorated all over the world due to the high temperature in summer recent years. Reefs in Sekisei Shouko Area, which locates between Ishigaki and Iriomote Islands in Okinawa, were seriously damaged in 2016 to become bleached up to 90% of total corals and be finally destroyed to 70%. Promotion of the natural recovery from massive extinction needs specific consideration for the life-cycle of corals and improving technologies for the bottle-neck processes of corals' reproduction. Larval settlement on the sea-bed base and subsequent initial growth of young corals are the most important processes to be enhanced. Since 2007, the promotion technology has been developed for the growth of young corals by applying feeble electric current on them. Field observation and experiments were conducted to find suitable electric current density and favorite design of the growth net for the young corals. GMC, Galvanic Method for Corals, was developed by authors and found effectively improving the growth rate and suggested heat tolerance. The settling plate was also developed with microasperity, or small topography, on its surface to promote larvae settlement. The total system for the recovery from massive bleaching is also discussed practically in this paper.
