Coral reefs on Saipan in the Northern Marianas are in danger of dying out because of bleaching caused by a warming ocean.
Environmental experts said just 15 percent of a species called staghorn coral remains in the Saipan lagoon.
Coral bleaching occurs when seawater temperatures get too warm for the corals, causing them to expel the algae that give the corals their color.
Current reports by the National Oceanic and Atmospheric Administration say that 2016 is, so far, the second warmest year on record.