Data from: A long-term perspective to the effects of the 2023 marine heat wave on stony corals in the Caribbean

Marine heat waves (MHW) are a leading cause of death for stony corals, and
it is reasonable to expect that a record-breaking MHW would negatively
impact coral communities. 2023–2024 provided a test of this assertion in
St. John, US Virgin Islands, where an intense MHW brought temperatures of
30.6°C and degree-heating weeks of 23.23°C-weeks. On reefs where coral
cover has been low for decades, the 2023/24 MHW did not have discernible
effects on coral cover. Nonetheless, there was a trend between 2023 and
2024 for mean coral cover to decline by small absolute (≤ 3%), but large
relative (13–27%) amounts, with these changes affecting multiple genera
and perturbing coral assemblages, especially at 14-m depth. These trends
are eclipsed by the massive changes that have affected these coral
communities over the last four decades; the 2023/24 MHW was the latest in
a series of disturbances transitioning these reefs to low coral cover.
This MHW did not statistically depress coral cover, but it changed coral
assemblages, intensifying the ecological perils of rarity, extirpation,
and perhaps local extinction.