Coral Restoration's Wake Up Call

Rebuilding degraded coral reefs started as a noble endeavor, but now some coral scientists are confronting a dark reality.

FLORIDA KEYS — Until last summer, Pickles Reef was seen as a bright spot in the field of coral restoration. The Coral Restoration Foundation, one of the largest reef restoration organizations in the world, had spent the better part of two decades working to breathe new life into this degraded site, outplanting tens of thousands of small colonies of coral, mostly fast-growing elkhorn and staghorn.

Pickles looked relatively healthy, with coral outplants reaching maturity and even beginning to spawn. There was hope.

Then came July and August of 2023, when a relentless, record-shattering marine heat wave triggered widespread coral bleaching and put reefs throughout the Keys in a death grip. Bleaching is a phenomenon in which heat-stressed corals expel the symbiotic algae that they rely on for most of their food and turn ghost-white, often leading to widespread coral mortality. The heat in the Florida Keys was so extreme that in many cases, corals didn’t have time to bleach. Instead, they simply roasted to death.

It was around 10:30 a.m. on a sunny Sunday morning this July when scientists and interns from CRF arrived at Pickles, approximately 5 miles off the coast of Tavernier, Florida. As they suited up in their dive gear, Phanor Montoya-Maya, the foundation’s restoration program manager, announced that the team’s primary task was to search for survivors. One by one, the divers stepped off the back of the dive boat and descended to the shallow reef below.

Montoya-Maya and others quickly became fixated on a small group of staghorn corals that they’d planted two years earlier. Somehow, these colonies, situated on an outer edge of the reef, had survived the previous summer’s heat. Montoya-Maya gave a thumbs-up, signaling his excitement, and then took time to remove several predatory yellow-footed snails, which feast on coral tissue, before he and the others spread out to look for other colonies.