Guam coral reef Initiative works to save reefs from global collapse

The Guam Coral Reef Initiative is managing coral nurseries to protect and diversify local reef ecosystems in Guam.

The International Union for Conservation of Nature reported that 96 percent of the 127 coral reef ecosystems it assessed are critically endangered. Heat stress from frequent marine heatwaves poses a major threat to these systems, as warming oceans leave reefs with less time to recover between heat events.

While regions like the Caribbean have suffered from extreme ocean temperatures, sea surface temperatures around Guam have generally stayed below the coral bleaching threshold in 2025 and 2026. Despite these conditions, local reefs face risks from the super El Niño, which has caused surface temperatures to reach 105 degrees Fahrenheit during low tides. Ashton Williams of the Guam Coral Reef Initiative says these conditions can cook reef flat animals that cannot move away from the heat.

The initiative also monitors threats from coral disease, invasive species, and increasing storm damage from typhoons. Biologists are now working to increase the genetic diversity of the 400 coral species found in the waters around Guam. The initiative manages two nurseries, including a deep water site at Dogleg Reef in Apra Harbor. Since March, biologists have outplanted 479 pieces of coral at this site to help colonies reproduce more successfully.

The program aims to select and breed corals that are thermally tolerant to survive rising ocean temperatures.