The Reefs of Amami-Oshima

The reefs around Amami-Oshima are mostly fringing reefs, built up over time as coral polyps attached to submerged rocks and secreted limestone layers. The reef system exists largely because of the Kuroshio current, which carries warm water and coral larvae northward from the Philippines. Recent research suggests the current's contact with the island shoreline also stirs up nutrients that feed reef life. The reefs support crabs, sea urchins, sponges, and a wide range of fish species, and attract migratory wading birds to the shallow reef flats. They also serve a practical role, absorbing wave energy and providing coastal protection for the island.