Scientists race to save Florida's elkhorn corals with bold cross-breeding experiment

Florida’s elkhorn corals have nearly vanished after a devastating marine heatwave in 2023. The species, once a key reef-builder in the region, now faces functional extinction in the Florida Keys and Dry Tortugas. Scientists are now racing to restore them using a bold new approach: cross-breeding with heat-resistant corals from Honduras. Before 2023, elkhorn corals thrived across Florida and the Caribbean. But record ocean temperatures triggered a catastrophic bleaching event, wiping out almost all of Florida’s colonies. With too few survivors left to reproduce naturally, researchers turned to external solutions.

Andrew Baker, a marine biologist at the University of Miami, searched beyond Florida for genetic diversity. In 2024, he led an expedition to Tela Bay, Honduras, to collect resilient elkhorn colonies. These were transported to Florida for cross-breeding experiments. The first lab-bred generation, dubbed 'Flondurans,' combined Florida’s elkhorn corals with their Honduran counterparts. This spring, nearly three dozen of these young, lab-grown corals were planted onto reefs in Dry Tortugas National Park. Bailey Marquardt, a doctoral student at the university, oversaw the delicate transfer from land to ocean in April. The project aims to test whether these hybrid corals can better endure rising sea temperatures. If successful, they could offer a lifeline for Florida’s struggling reefs.

The outplanting of 'Flondurans' marks a critical step in coral restoration efforts. These experimental hybrids now grow in the wild, facing real-world conditions for the first time. Their survival could determine whether cross-breeding becomes a viable strategy to save Florida’s elkhorn corals from extinction.