The Coral Triangle spans Indonesia, the Philippines, Malaysia, Papua New Guinea, the Solomon Islands, and Timor-Leste. It contains 76 percent of the world’s known coral species, six of the seven species of sea turtle, 18 species of marine mammal, and over 1,600 species of reef fish. It is, by every measure that has been measured, the most biodiverse marine ecosystem on the planet.
It supports the food security of approximately 120 million people. The protein, livelihoods, and cultural identity of the coastal communities of six nations are inseparable from the reefs.
The 2023–2025 global coral bleaching event — now confirmed by NOAA as the fourth such event and the largest in recorded history — has hit the Coral Triangle at the centre. As of late 2025, 84 percent of the world’s reef area had experienced bleaching-level heat stress. Recovery, where possible, is measured in decades. Some bleaching events kill coral that took centuries to build. The current event has surpassed the previous record (2014–2017) by 16 percentage points and is still ongoing.
What this means in practice is that the architectural species — the corals that build the reefs themselves — are being lost faster than they can be replaced. As they die, the three-dimensional structure of the reef collapses. Fish populations dependent on that structure decline. The fishing economies dependent on those fish decline. The cultural systems built around those economies erode.
This is a story about coral. It is also a story about the people whose lives are about to change.
Future editions of The Ocean will follow what’s happening on the ground in the Coral Triangle communities. We expect to be writing about this for years.
— Sources: NOAA Coral Reef Watch, International Coral Reef Initiative, GCRMN, Marine Conservation Institute, Blue Parks programme