Only 1 pct of Japan's biggest coral reef healthy: surveyJapan's biggest coral reef has not recovered from bleaching due to rising sea temperatures, with only one percent of the reef in a healthy condition, according to a government study. The overall volume of coral in Sekisei Lagoon in southwestern Japan near Okinawa had already plunged by 80 percent since the late 1980s due to rising water temperatures and damage caused by coral-eating starfish. "If coral reefs don't recover, it means a loss of rich fauna for a variety of creatures and would have grave impact on the ecosystem in the region," ministry official Chihiro Kondo told AFP on Friday.