On 8th March 2024, the Reef Authority (GBRMPA), announced that the Great Barrier Reef Marine Park was experiencing a widespread, or mass, coral bleaching event is unfolding across the Great Barrier Reef. This is the fifth mass coral bleaching event the Great Barrier Reef has suffered in the last decade and the seventh on record.
This widespread coral bleaching event was caused by elevated sea surface temperatures that have built up over the Australian summer months and are a consequence of climate change. This heat build-up is consistent with the unprecedented global sea surface temperatures observed in the last 12 months.
The entire length of the Reef – over 2000 km – and over 1000 reefs has been surveyed. Of these, bleaching was recorded on 74 per cent of reefs in the Marine Park, nothing that:
- Half of these recorded high or very high levels of coral bleaching.
- Less than 10 per cent had extreme levels of coral bleaching.
- A quarter of individual reefs surveyed recorded no to low levels of bleaching.
This week, 63 in-water surveys were conducted across our observer network. Of these, 52 Reef Health Impacts Surveys were carried out and most reported coral bleaching of moderate to severe impact. Variable levels of mortality have been found.
The data from the in-water surveys, combined with the aerial surveys, will give a greater overview of the severity of bleaching among different coral types, habitats, and depths. In-water surveys are critical to quantify coral mortality due to bleaching and heat stress over the coming months.
The Great Barrier Reef Marine Park Authority in collaboration with science partners, the Australian Institute of Marine Science and CSIRO, will soon release the Reef Snapshot for Summer 2023-24, which will provide a summary of conditions over the Great Barrier Reef during the past summer, including impacts from elevated sea surface temperatures, cyclones and flooding. For further information you can read our weekly Reef Health update and information on how we assess and monitor coral bleaching on our website: Coral bleaching | gbrmpa.
For more information on coral bleaching head to the ICRI Coral Bleaching Hub.
