The MSC Foundation has completed a new phase of its marine restoration project in the Bahamas, transplanting 32 fragments of elkhorn coral—an endangered species—grown in nurseries on reefs near Browns Cay. With this action, its Super Coral Reefs program has now replanted over 285 corals.
Given the forecast of a summer with record ocean temperatures, the Foundation has also decided to temporarily halt new transplants. The aim is to protect the remaining fragments in underwater nurseries, where they are sheltered until sea conditions become more favorable.
Elkhorn coral (Acropora palmata) is a keystone species in the Caribbean, but it is critically endangered; reports indicate a 97% population decline across the Caribbean since the 1980s and its complete disappearance in many locations following the 2023-24 marine heatwave. For the Bahamas, elkhorn coral is vital, acting as a natural barrier that protects the coasts and provides shelter for fish and invertebrates essential to local fishing and tourism.
“Exceptionally warm ocean conditions are expected this year, which could put corals under significant stress,” said Emeline Bouchet, director of the Marine Program at Ocean Cay’s Marine Conservation Center. “NOAA’s Coral Reef Watch forecasts Level 2 bleaching conditions for the northern Bahamas through September. Therefore, we have preserved more fragments in our underwater nurseries, where the team can closely monitor and manage them. Restoration is not simply about planting more corals, but also about placing them in the best position for them to thrive.”
As part of the program, coral fragments are cultivated in underwater nurseries before being transplanted to natural reefs. This careful process promotes ecosystem regeneration and allows for the collection of data that will serve as a basis for future restoration efforts.
Browns Cay was selected after reef studies and biodiversity assessments confirmed it met the ideal conditions for relocating the species. Weather forecasts indicated a higher risk of marine thermal stress in the northern Caribbean in late summer. This temperature increase disrupts the relationship between corals and the microscopic algae that live within them, which give them their characteristic color and provide much of their food. When corals suffer thermal stress, they expel the algae and lose their color, a phenomenon known as coral bleaching. Deprived of their primary food source, corals become severely weakened, making them more vulnerable to disease and potentially causing their death.
The corals collected, cultivated, and transplanted at Ocean Cay come from selected colonies that demonstrated natural tolerance to heat stress and a 100% survival rate during the 2023-24 heatwave. With temperatures expected to reach even higher levels during the next marine heatwave, marine scientists will conduct monthly monitoring of the coral reefs around Ocean Cay to assess the health and resilience of both the transplanted and native corals. Using photogrammetry, researchers create 3D models that record the growth and health status of the colonies over time. The next steps will involve resuming replanting efforts once the marine heatwave has passed and replenishing the nursery with fresh coral fragments to ensure a continuous cycle of growth and restoration.
