In a troubling development for marine ecosystems, a study published on October 23, 2025, reveals that two crucial reef-building coral species in Florida have been declared functionally extinct. This alarming conclusion follows a devastating marine heat wave that struck the Florida Keys and the Dry Tortugas, severely impacting the corals” ability to thrive.
During early June 2023, divers observed vibrant and healthy coral reefs in the lower Florida Keys. However, within weeks, rising water temperatures due to a marine heat wave began to take their toll, causing widespread coral bleaching. The corals, which typically exhibit a rich orange-brown hue, began to lose their color and turn bone white, a sign of distress and impending death.
The average sea-surface temperature in these regions exceeded 87 degrees Fahrenheit for several weeks, leading to unprecedented levels of heat stress on the corals. Research indicated that the accumulated heat stress was significantly greater than levels recorded since the 1980s, when these species—staghorn and elkhorn corals—were predominant in the area. The conditions were so severe that some corals succumbed to acute heat shock within a matter of days.
As the summer progressed, the situation worsened. By the end of the season, a staggering 97.8% to 100% of the surveyed acroporid corals, including staghorn and elkhorn, had perished. Only a few of the 200 transplanted corals in the Lower Keys survived, while in the Dry Tortugas, surviving corals were quickly overrun by seaweed, indicating a potential shift from coral-dominated systems to macroalgae-dominated environments.
The decline of these coral species was not sudden; even prior to the heat wave, their populations had been shrinking due to various stressors, including hurricanes, loss of herbivorous fish, diseases, and ongoing bleaching events. The current heat wave marked a critical turning point, leading experts to declare these species functionally extinct on Florida”s reefs. While some individuals remain, their numbers are insufficient to fulfill their ecological roles, which has significant implications for the overall health of the reef ecosystem.
Despite the dire situation, experts suggest that restoration efforts could still provide a glimmer of hope. Unlike the California condor, which cannot recover without human intervention, there are still healthy coral populations scattered throughout the Caribbean that could be used to aid in restoration. Techniques such as assisted gene flow, where surviving corals are bred with other populations to enhance genetic diversity, may be pivotal in bolstering their numbers.
Additionally, advancements in coral propagation methods, such as microfragmentation and cryopreservation, have opened new avenues for mass production and genetic preservation of coral species. However, significant challenges remain, particularly in coordinating international efforts to exchange endangered species and scaling up restoration projects to effectively revive entire ecosystems.
With ocean temperatures continuing to rise due to climate change, the question remains: can restoration efforts succeed in time? Experts emphasize the urgent need for global action to reduce carbon emissions to ensure that any restoration initiatives have a fighting chance against the ongoing threat of climate change to coral reefs.
