Drones Document Alarming 92% Coral Mortality at Lizard Island

Recent research conducted by a team from Griffith University has revealed alarming coral mortality rates of 92% following a significant bleaching event at Lizard Island, part of Queensland’s Great Barrier Reef. This finding marks one of the highest recorded coral mortality rates globally, significantly impacting the fragile coral ecosystem amid escalating climate change concerns.

The study, published in the journal Coral Reefs, highlights the devastating effects of the Fourth Global Coral Bleaching Event, which was officially declared by the National Oceanic and Atmospheric Administration (NOAA) in April 2024. This event triggered extensive coral bleaching and mortality across the Great Barrier Reef, with Lizard Island being one of the most severely affected areas.

Dr. Vincent Raoult, the lead author and researcher from Griffith University’s School of Environment and Science, along with collaborators from Macquarie University, James Cook University, the CSIRO, and GeoNadir, conducted a thorough analysis of 20 sections of reef measuring 10m x 10m. Their findings indicate that 96% of living corals in the surveyed areas were affected by bleaching, with mortality rates reaching unprecedented levels.

According to 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.” Professor Jane Williamson, a senior author from Macquarie University, emphasized the urgent need for action on climate change, noting, “Our results are concerning for coral resilience, considering the increasing frequency and intensity of extreme heat events predicted for the near future.”

The research team utilized high-resolution drone imagery to monitor coral bleaching in March 2024, returning in June to assess survival and mortality rates across the same reef areas. The technology enabled them to upscale the effects of the bleaching event over larger areas while maintaining high precision. The drones used for the survey, including DJI Mini 3 Pro and Autel Evo II, allowed for detailed mapping of the coral health status before and after the bleaching event.

The results from Lizard Island are particularly distressing as they coincide with other disturbances that have affected the region over the past decade, including severe bleaching events in 2016 and 2017, cyclones, and Crown-of-Thorns starfish outbreaks. These cumulative stressors have exacerbated the vulnerability of the ecosystem, despite some signs of recovery in recent years.

The researchers are currently conducting additional surveys at Lizard Island to track any potential recovery of corals through 2026, supported by a grant from the Australian Museum Lizard Island Critical Grant. The study not only contributes to the body of knowledge regarding coral health but also aligns with the UN Sustainable Development Goals, particularly those focused on climate action and life below water.

The findings underscore the urgent need for comprehensive environmental policies and climate action to mitigate the impacts of climate change on vital ecosystems like the Great Barrier Reef. As the frequency of extreme heat events increases, the long-term viability of coral reefs remains uncertain, posing serious implications for biodiversity and marine life globally.