Two Coral Species Have Vanished From Florida Reefs, Leaving Coasts Exposed

Two cornerstones of Florida’s reef—staghorn and elkhorn corals—have slipped into functional extinction across the state. After the searing 2023 marine heat wave, their remaining colonies are too sparse to build reef structure or sustain the ecosystem roles they once commanded, The Conversation reports.

Photo: Wikimedia Commons / U.S. National Oceanic and Atmospheric Administration, License: Public Domain

Staghorn and elkhorn are now functionally extinct off Florida.

How Fast It Fell Apart

The collapse was swift. Sea-surface temperatures stayed above 87°F for weeks, pushing accumulated heat stress to levels 2.2 to 4 times higher than any year since satellite records began.

Field teams tracking more than 52,000 elkhorn and staghorn colonies across 391 reef sites found mortality of 97.8% to 100% in the Keys and Dry Tortugas; cooler waters farther north tempered losses but did not prevent them. Those figures reflect an ecosystem-wide break point, reports the University of Southern California.

Why It Matters

For at least 10,000 years, these branching builders shaped Florida’s shallow reefs, creating three-dimensional habitat for fish and invertebrates and helping break storm energy before it hits shore. Their disappearance strips the reef of “tall trees,” leaving a landscape increasingly dominated by mound-building species that do not replace the lost architecture or coastal protection at similar scales, The New York Times reports.

Photo: Wikimedia Commons / National Marine Sanctuaries, License: Public Domain

A 2023 marine heat wave triggered mass bleaching and death.

Heat, Bleaching, and an Extinction Vortex

Bleaching hit nearly everywhere as overheated corals expelled their symbiotic algae. In the middle and lower Keys, some colonies died within days from acute heat shock. With survivors scattered and few and far between, reproduction falters and inbreeding risks mount—classic conditions for an “extinction vortex,” according to The Conversation.

What Comes Next

Scientists stress that recovery will not happen unaided. Teams are safeguarding genetic stock in nurseries and aquaria and testing assisted gene flow, microfragmentation, and cryopreservation to rebuild numbers and diversity—The University of Miami reports. Researchers and restoration groups are also weighing regionally resilient lineages and long-term strategies to help corals tolerate warmer seas. But every intervention hinges on cutting ocean heating; without curbing emissions, scientists warn, restoration gains will be temporary.