Drone imagery captured by scientists in Australia has revealed the alarming extent of coral mortality rates of 92% after last year’s bleaching event at Lizard Point on Queensland’s Barrier Reef, marking one of the highest coral mortality rates ever documented globally.

The footage has been published as a part of the study ‘Coral bleaching and mass mortality at Lizard Island revealed by drone imagery’ which has appeared in the scientific journal, Coral Reefs just this past week.

It was captured by a team from Griffith University in Queensland out on a mission to assess the impact of the Fourth Global Coral Bleaching Event, declared by the National Oceanic and Atmospheric Administration (NOAA) in April 2024 and the cause of extensive bleaching and mortality across the entire reef system.

The study’s lead author, Dr Vincent Raoult from Griffith University’s School of Environment worked with collaborators from Macquarie University, James Cook University, and CSIRO and GeoNadir to analyse 20 sections 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 marks one of the highest coral mortality rates ever documented globally,” said Dr Raoult. “Despite lower heat stress at Lizard Island compared with other parts of the Great Barrier Reef, 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.”

Professor Jane Williamson from the School of Natural Sciences at Macquarie University, senior author on the study, said the findings underscored the urgent need for action on climate change.

The research team used high-resolution drone imagery to map coral bleaching in March 2024, returning in June to assess survival and mortality rates across the same reef areas.

“Using drone-derived imagery, we followed the amount of bleached and living coral during and after the bleaching event,” said Professor Williamson. “Use of this technology lets us upscale the effects of the bleaching event over larger areas but still in high precision.”

The team recorded the highest coral bleaching mortality on the Great Barrier Reef, with over 92% of corals experiencing mortality. 

“Our results are concerning for coral resilience, considering the increasing frequency and intensity of extreme heat events predicted for the near future, with potentially irreversible consequences for reef ecosystems such as those studied in our Great Barrier Reef,” Williamson added.

More alarming still is that coral mortality actually exceeded 99% in some areas measured. 

Coral reefs at Lizard Island have experienced repeated disturbances over the past decade, including severe bleaching in 2016 and 2017, cyclones, and Crown-of-Thorns outbreaks. These events have only compounded the ecosystem’s vulnerability, despite some signs of recovery in recent years.

The team behind the assessment 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.

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