In This Issue

Caribbean's resilient corals succumb to heatFire corals (Millepora) are reef-building organisms with branching structures that provide habitat for a variety of marine life.For more than 30 years, fire corals have flourished on degraded Caribbean reefs in which traditional reef-building corals have declined.As marine heatwaves become more frequent and intense, it remains unclear whether fire corals can withstand increasingly severe thermal stress.Emilia Dell'Antonio et al. surveyed fire coral populations at 10 sites around the Caribbean island of St. John; some of the sites had been monitored for up to 36 years.The authors documented the extent of coral mortality following unprecedented heatwaves in 2023 and 2024.Temperatures peaked in October 2024, which was the hottest October ever recorded since monitoring began.By March 2025, around 84% of colonies had died.The dead colonies subsequently became dominated by algae, threatening species that depend on fire coral habitat for survival.The decimation of fire corals demonstrates that the short-term "winners" are unlikely to be future reef builders.According to the authors, fire coral recovery in the Caribbean may take decades, given the sparse number of surviving colonies.-D.B.