About 70 percent of the coral in the Sekiseishoko area, the largest coral reef in Japan, is dead, an Environment Ministry survey has found.
A ministry official said Tuesday the result showed accelerated coral bleaching was taking place — due chiefly to rising ocean temperatures.
The survey was conducted at 35 points in Sekiseishoko, located between Ishigaki and Iriomote islands in Okinawa Prefecture, last November and December.
Coral bleaching occurs due to an inflow of red soil to the ocean and seawater contamination, as well as higher water temperatures, officials at the ministry’s Ishigaki Ranger Office in Okinawa said.
The bleaching at Sekiseishoko worsened between June and September last year because ocean temperatures were 1 to 2 degrees Celsius higher than normal, topping 30 C.
Coral dies if it remains bleached for a long periods.
According to the survey, 91.4 percent of the coral in the surveyed locations is at least partly bleached.