A “silent extinction” is threatening Brazil’s fire coral population, according to a new study published in the journal Coral Reefs today.

Fire corals are critical reef-building organisms in Brazil that provide essential shelter and ecological complexity, often on hard-to-access reef edges.

The research reveals that recent extreme heatwaves have devastated the endemic species, leaving some on the brink of total collapse, but this damage had gone undetected.

The study draws from the Coral Vivo Institute’s monitoring of fire corals, which began after the first wave of bleaching severely affected Brazil in 2019. 

Monitoring was conducted before, during, and after the most recent bleaching event, which occurred during a heat wave in early 2024. The heatwave was a consequence of the El Niño-Southern Oscillation phenomenon.

Fire corals have historically been neglected in monitoring efforts of this kind. In part, their position on reef edges which makes them difficult to access. 

Another factor influencing the limited attention given to them is the rarity of three of the fire coral species found in Brazil compared to “normal” corals.

But researchers from the Coral Vivo Institute and the University of São Paulo, warn that these organisms are just as vital, providing shelter and structure for marine life.

Millepora braziliensis, a species endemic to Brazil, experienced 100% bleaching and lost all living cover in the monitored colonies in the municipality of Tamandaré in the state of Pernambuco.

The species is currently listed as critically endangered by Chico Mendes Institute for Biodiversity Conservation (ICMBio, linked to the Brazilian Ministry of the Environment) and the International Union for Conservation of Nature (IUCN).

Another endemic fire coral species in the Bahia region, Millepora nitida, also experienced bleaching. It was slightly more resilient but still experienced 40% bleaching.

Bleaching is the greatest threat to the world’s coral reefs. The 2023-2024 event was the fourth global occurrence of this phenomenon and affected true corals along the Brazilian coast, as reported in a study by the same group published in September 2025.

“The results reinforce the need for urgent conservation to protect corals,” said Miguel Mies, a coordinator of the study and scientific director of the Coral Vivo Institute.

These corals are facing rising threats due to extreme heat waves caused by phenomena like the El Niño Southern Oscillation, and global warming.

Mies added that while laboratory restoration projects exist, they are often too costly and the lab-grown corals frequently perish in subsequent heatwaves.

“Unlike the 2019 bleaching event, for which we were unprepared, what’s happening now is being well documented to inform public policy. We need to strengthen conservation efforts and raise awareness about the importance of curbing climate change,” Mies added.

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