Scientists deploy hybrid 'Flonduran' corals to revive Florida's dying reefs

Nearly three dozen young elkhorn corals have been moved to the ocean off Florida’s coast this spring. The effort aims to revive a species nearly wiped out by extreme heat in 2023. Scientists are testing whether cross-breeding can help these corals survive warming waters. Before 2023, elkhorn corals were once a dominant reef-building species across Florida and the Caribbean. But an intense marine heatwave that year triggered mass bleaching, killing nearly all of Florida’s colonies. In the Florida Keys and Dry Tortugas, so few healthy corals remain that natural reproduction is no longer possible.

In response, Andrew Baker, a marine biologist at the University of Miami, searched for genetic solutions beyond Florida. He discovered a resilient reef in Tela Bay, Honduras, where elkhorn corals thrived despite warm, polluted conditions. Meanwhile, researchers Keri O'Neil and Baker at The Florida Aquarium successfully cross-bred Florida and Honduran corals in the lab, creating a new hybrid called 'Flonduran'. This April, doctoral student Bailey Marquardt led the team that moved 35 young lab-grown elkhorn corals—including the first 'Flondurans'—to reefs in Dry Tortugas National Park. The outplanting marks a critical test of whether these cross-bred corals can better withstand rising ocean temperatures.

The project represents a key step in restoring Florida’s elkhorn corals after their near-total collapse. If successful, the 'Flonduran' hybrids could offer a lifeline for reefs facing increasingly harsh conditions. Scientists will now monitor their growth and resilience in the coming years.