Parts of the Great Barrier Reef have suffered the largest annual decline in coral cover since records began nearly 40 years ago, according to a new report.
Northern and southern branches of the sprawling Australian reef both suffered their most widespread coral bleaching, the Australian Institute of Marine Science (AIMS) found.
Reefs have been battered in recent months by tropical cyclones and outbreaks of crown-of-thorns starfish that feast on coral, but heat stress driven by climate change is the predominant reason, AIMS said.
AIMS warns the habitat may reach a tipping point where coral cannot recover fast enough between catastrophic events and faces a "volatile" future.
AIMS surveyed the health of 124 coral reefs between August 2024 and May 2025. It has been performing surveys since 1986.
