Relief for recovering Reef as monsoon cools waters
Australian Institute of Marine Science
* A late summer monsoon in 2026 brought the Great Barrier Reef a reprieve from unfolding coral bleaching.
* Coral cover across all three regions of the Reef increased slightly or remained at similar levels to that recorded last year, indicating limited impacts from 2025's mass bleaching event and a regional bleaching event in the Northern and Central regions recorded earlier in 2026.
* Bleaching likely prevented continued increases in coral cover that would normally be expected in the absence of disturbance.
* Coral cover levels increased modestly or remained stable on many reefs and substantial declines were uncommon.
* The Reef faced other impacts from flooding and tropical cyclones. Increases of crown-of-thorns starfish in the Northern Great Barrier Reef in recent years indicate the initiation of the fifth recorded wave of outbreaks for the Reef since the 1960s.
Video and images: https://aimsimages.fotoware.com.au/fotoweb/albums/ammOXLfBQ30KpvqJ/
A late summer monsoon in 2026 brought the Great Barrier Reef a reprieve from unfolding coral bleaching, aiding its initial recovery from recent climate-induced disturbances, according to the Australian Institute of Marine Science’s (AIMS) annual survey report on the ecosystem.
Coral cover across all three regions of the Reef increased slightly or remained at similar levels to that recorded last year, indicating limited impacts from 2025’s mass bleaching event, and the regional bleaching event in the Northern and Central regions recorded earlier in 2026.
The Reef faced other impacts from flooding and two tropical cyclones including Narelle, but most of the surveys for this report were completed before its passage as a category 5 system over the Northern region in March. Increases of crown-of-thorns starfish in the Northern Great Barrier Reef over the last few years indicate initiation of the fifth recorded wave of outbreaks for the Reef since the 1960s.
The coral cover levels recorded over the 2025/26 field season were:
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Northern region (Cape York to Cooktown) increased by 16.7% relative to 2025 levels (from 30% to 35.1%)
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Central region (Cooktown to Proserpine) increased by 10.2% relative to 2025 levels (within the margin of error from 28.6% to 31.6%)
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Southern region (Proserpine to Gladstone) decreased by 2% relative to 2025 levels (from 26.9% to 26.4%, which is within the margin of error).
Coral cover levels in all three regions of the Reef continue to be above or just below the long-term average.
AIMS Long-Term Monitoring Program (LTMP) leader Dr Mike Emslie said coral cover levels increased modestly or remained stable on many reefs and substantial declines were uncommon.
“The Reef experienced a summer of above average sea temperatures once again, but the late summer monsoon activity, which increased cloud cover and reduced sea temperatures, likely limited the severity and extent of bleaching in the 2025/26 summer,” he said.
“We did not see a repeat of the 2024 and 2025 mass bleaching events, or a repeat of the significant impacts from the 2024 event. Bleaching events vary markedly and do not always result in coral mortality. It depends on the intensity and duration of the heat stress.”
2026 is the 40th year of data for the LTMP, which provides a critical trusted, long-term view of the Reef.
A total of 121 coral reefs were surveyed for this year’s report. Most of the reefs surveyed (106) had moderate to high coral cover (between 10% and 50%):
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only three reefs had hard coral cover less than 10%;
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64 reefs had coral cover between 10% and 30%;
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42 reefs had cover between 30% and 50%;
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12 reefs had coral cover between 50% and 75%; and
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there were no reefs with cover greater than 75%.
Of the reefs surveyed, 16% showed a decline in coral cover, 56% showed no change and 28% had an increase.
“While many reefs did not lose coral cover, bleaching likely prevented the continued increases in coral cover that would normally be expected in the absence of disturbance,” Dr Emslie added.
The report includes a detailed examination of impacts from the 2024 mass bleaching event on different types of corals, finding shifts in coral communities not revealed by declines in total hard coral cover. In last year’s report, AIMS detailed substantial declines in coral cover from the high levels of recent years mostly due to the 2024 bleaching event.
“From our detailed surveys of permanently marked sites at 71 reefs, we found that reefs dominated by fast-growing, habitat-building, bleaching-sensitive Acropora corals were the most severely impacted by the event. The reefs with high levels of Acropora now exist in a highly vulnerable state. It’s possible that what looks like complete recovery on these reefs can be reversed in just a year,” said Dr Emslie.
“The acute heat stress in the Southern Great Barrier Reef during the 2024 event also increased the prevalence of bleaching and mortality in reef habitats 10 to 15m deep across most types of coral. Normally coral bleaching mostly impacts shallow water corals because this is where sea temperatures are highest.
“Future warming trends are likely to put corals at deeper depths at greater risk of impacts from intensified coral bleaching severity and mortality as found in the Southern Great Barrier Reef in 2024.”
Dr Emslie said while this year’s results provided evidence of initial recovery and that coral cover levels are higher than that of many coral reef ecosystems globally, the Great Barrier Reef remained a system under pressure.
“We have seen six mass bleaching events between 2016 and 2025. Before the ‘90s, bleaching events were exceptionally rare on the Great Barrier Reef. This increased frequency and escalating impact is compounded by the damage from cyclones, floods and outbreaks of crown-of-thorns starfish,” he said.
“While the Reef is showing resilience, it is being pushed and its capacity to recover is limited.”
AIMS CEO Professor Selina Stead said the long-term value of the 40-year-old LTMP dataset was growing in importance.
“It underpins management considerations like zoning and crown-of-thorns starfish control and provides a barometer of reef health at a time when coral reefs globally face increasing existential threats from warming oceans and other stressors,” she said.
“While evidence of recovery is encouraging, the risks for coral reefs are increasing. We can help them survive the threats posed by climate change through reducing global emissions, good reef management, and developing evidence-based science interventions that support reef adaptation and recovery.”
About the Long-Term Monitoring Program
The LTMP quantifies long term trends in the status of coral communities across the Great Barrier Reef, and completed its 40th year of continual data collection this year.
Researchers use hard coral cover as one indicator of the condition of each reef. Percentage hard coral cover is estimated by experienced scientists during manta tow surveys and is a metric which allows AIMS scientists to provide an overview of the Great Barrier Reef’s status and keep policy makers, managers and other scientists informed in a timely manner.
AIMS invested in targeted, in-water bleaching surveys during and after the 2024 mass bleaching. These surveys provided scientists with new insights into coral bleaching. These findings will be shared in the peer review process.
The LTMP also carries out fixed site surveys on 71 reefs across the Great Barrier Reef. The detailed information from these surveys includes what types of corals and species of fish are present, their abundance, and causes of mortality from crown-of-thorns starfish numbers, coral disease and bleaching observations.
About us:
More about the Australian Institute of Marine Science:
The Australian Institute of Marine Science (AIMS) is Australia’s tropical marine research agency. In existence for half a century, it plays a pivotal role in providing large-scale, long-term and world-class research that helps governments, industry and the wider community to make informed decisions about the management of Australia’s marine estate. AIMS science leads to healthier marine ecosystems; economic, social and environmental benefits for all Australians; and protection of coral reefs from climate change. More here: https://www.aims.gov.au/
Contact details:
Jo Manning
AIMS Media Officer
[email protected] / 0456 196845
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An AIMS scientist conducts a manta tow survey over corals on the Great Barrier Reef. Image: LTMP
