The individual corals around the island were usually quite healthy, but there were only limited areas of living coral. There were small sections of healthy corals, then large sections of dead colonies or colonies suffering from heavy sedimentation, mainly due to runoff from a nearby river. From reports made by the Insitute of Oceanography, which has been studying Nha Trang Bay for the last 90 years, we know that the corals have been declining in the past years.