Professor Jane Williamson, Head of the Marine Ecology Group at Macquarie University’s School of Natural Sciences, says the images show an alarming decline in the reef’s health in an area reported to escape severe bleaching at the end of 2023.

Professor Williamson and her collaborators, Drs George Roff (CSIRO), Vincent Raoult (Macquarie University), Stephanie Duce (James Cook University), along with Associate Professor Karen Joyce (James Cook University) and Joan Li from GeoNadir, have calculated that nearly all of the corals that were bleaching in the March image are now dead.

Williamson says: “Substantial bleaching associated with heat stress has occurred across Australia’s Great Barrier Reef over the 2023/4 summer.

“Our data show that over 97 per cent of corals bleached at a Lizard Island reef have now died.

“We no longer have the luxury of ignoring bleaching events if we wish to maintain this World Heritage Area. We all need to act now.”

The March imagery was taken by George Roff, and the June imagery as part of the Sea Cucumber Monitoring Project (SCMP), funded by the Great Barrier Reef Foundation as part of the Reef 2050 Integrated Monitoring and Report Program (RIMReP).