Drone surveys show coral was practically wiped out near Queensland's Lizard Island last year and scientists say repeated bleaching from a warming ocean gives it little long-term chance of survival.
Karen Joyce, Associate Professor of Remote Sensing at James Cook University, was part of the team that surveyed the reef. She said they used advanced drones to collect high-resolution imagery of the reefs in March and June 2024.
"We then analysed 20 sections, each measuring 10m x 10m, across the northern and southern reefs of Lizard Island. The average bleaching mortality rate reached was 92%, with bleaching affecting an average of 96% of living corals of the surveyed areas.
"This is one of the highest rates of bleaching mortality ever recorded, despite corals at Lizard Island being exposed to lower levels of cumulative heat stress than others in many parts of the Great Barrier Reef during this bleaching event," said Dr Joyce.
Lead author Dr Vincent Raoult from Griffith University's School of Environment and Science said the mortality rate is unprecedented.
"These results highlight the fragility of coral ecosystems facing increasing stress from climate change and the possible devastation resulting from the 2024 global bleaching event," said Dr Raoult.
Dr Joyce said the long-term outlook is concerning.
"There are predictions of increasing frequency and intensity of extreme events impacting coral reefs in the near future along with several studies showing a growing inability of corals to successfully recover," said Dr Joyce.
The team responsible for this work – JCU, Griffith University, and collaborators from Macquarie University, the CSIRO and GeoNadir - are now running additional surveys at Lizard Island to track the recovery, if any, of corals into 2026 as part of an Australian Museum Lizard Island Critical Grant.
Link to paper here.
