Ningaloo Reef Suffers Unprecedented Coral Mortality Amid Record Underwater Heatwave

Record-breaking underwater heatwave: A recent scientific report reveals that the longest-lasting, largest, and most intense underwater heatwave ever recorded has devastated nearly 70% of Western Australia’s World Heritage-listed Ningaloo Reef.

• Widespread bleaching: Initial assessments from August 2024 to May 2025 indicated 30–90% coral bleaching across the 1,500-km reef system.

• New findings show severe mortality: A fresh survey by Curtin University researchers shows coral mortality has exceeded 60% across eight northern lagoon sites, from the Osprey Sanctuary Zone to the Tantabiddi Sanctuary Zone.

• Impact beyond Ningaloo: Intense bleaching extended to other previously resilient areas, including the offshore Rowley Shoals and remote northern Kimberley reefs.

• Ecosystem degradation: Many coral branches are now infested with sponges, algae and other opportunistic organisms, reducing overall reef diversity and weakening structural integrity.

• Global ecological concern: Coral reefs support nearly one-third of marine species, and large-scale mortality threatens countless dependent organisms.

• Pre-existing stress: Ningaloo was already under pressure—low oxygen levels in March 2022 caused a sharp decline in live coral cover, leaving the ecosystem vulnerable before the 2024–25 heatwave struck.

Source: DTE