Florida scientists and volunteers are ramping up coral restoration efforts as ocean temperatures soar, raising fears of another catastrophic bleaching event. Recent data showed sea surface temperatures in parts of Florida Bay reaching 97 degrees Fahrenheit, sparking concerns of a mass die-off similar to the record-breaking 2023 summer, which was the worst coral bleaching event in South Florida history, according to NOAA scientists.
Early Warning Signs Emerge
Although federal officials have not yet reported widespread bleaching in the Florida Keys this season, early signs of heat stress are appearing near Miami. Colin Foord of Coral Morphologic, who operates the Coral City Camera at Government Cut, reported that roughly 25 percent of corals near PortMiami are already bleached. "Miami has been feeling that heat stress for actually three years straight," said Dalton Hesley, a coral restoration ecologist at the University of Miami's Rosenstiel School. "We're ground zero for the coral crisis."
Decades of Decline
Florida's reef systems have suffered severe decline over the past several decades. Since the 1970s, warming oceans, disease outbreaks, hurricanes, and pollution have destroyed more than 90 percent of the state's coral cover. "There's been a suite of stressors that have really decimated our reefs to the point that they're on the brink," Hesley explained.
Innovative Restoration Efforts
To combat the loss, researchers are employing selective breeding to develop heat-tolerant coral strains. In a pioneering project, scientists from the University of Miami and the Florida Aquarium crossbred native Florida elkhorn coral with resilient strains from Honduras. The resulting juvenile corals have been planted on a Miami reef. "It's the first time ever that it's been permitted and we've gone ahead and outplanted," said Andrew Baker, a marine biologist at the University of Miami Rosenstiel School. "We're going to see how well these do over the next few months, particularly over the course of a warm summer, to see if they are more thermally tolerant."
Building a Super Coral Reef
Scientists hope these crossbred varieties, combined with Miami's native urban corals, will help establish highly resilient reef systems. "They are tough, so they are special. We're trying to better understand why, so we can integrate that into gardening and restoration. So we're building that super coral reef," Hesley said. Work is also taking place at Paradise Reef, where the Rescue a Reef program grows threatened staghorn corals on underwater metal structures before transplanting them onto damaged wild reefs. During a recent maintenance trip, volunteers cleaned algae from the nursery and planted more than 150 coral fragments back onto the reef. Over the last decade, the program has restored approximately 2,000 corals at this local site.
Urgent Need for Broader Action
The scale of the threat remains severe. During the 2023 heatwave, federal researchers documented near-total bleaching across multiple reef systems. Biologists emphasize that localized restoration and selective breeding cannot fully reverse decades of decline without broader action to address climate change and pollution.
