Bleaching has damaged the world's northernmost coral reef in Japan, a researcher said Tuesday, the latest example of a global phenomenon scientists have attributed to high ocean temperatures. Healthy coral reefs protect shores from storms and offer habitats for fish and other marine life, including ecologically and economically important species. About 30 percent of the coral reef off the coast of Tsushima island in Japan, which lies in the temperate zone some 1,000 kilometres (620 miles) southwest of Tokyo, suffered bleaching when Hiroya Yamano's research team observed the area last December.