Coral cover is rebounding across parts of the Great Barrier Reef, although scientists warn that repeated marine heatwaves continue to threaten its recovery.
Australia’s Great Barrier Reef
Parts of Australia's Great Barrier Reef are showing encouraging signs of recovery after severe coral losses from recent mass bleaching.
The Australian Institute of Marine Science (AIMS) surveyed 121 reefs between August 2025 and June 2026 as part of its long-running monitoring programme. Its latest assessment found that hard coral cover had increased across much of the northern Great Barrier Reef and showed signs of improvement in the central region. Conditions in the southern region remained broadly stable.
The improvement follows substantial coral losses associated with the severe 2024 mass bleaching event.
A welcome respite
One important difference was that the 2025–26 summer was less extreme than the preceding two years.
Cloud cover and cooler waters associated with late-summer monsoon conditions reduced heat stress on many reefs. Bleaching still occurred, particularly in the north, but was generally less severe.
This relative respite gave surviving corals an opportunity to grow and damaged reef communities to begin rebuilding.
The results demonstrate that the Great Barrier Reef retains a considerable capacity for recovery when conditions allow. However, AIMS cautions against interpreting the improvement as evidence that the reef's longer-term problems have been resolved.
Recovery needs time
Some of the corals responsible for rapid recovery are also among those most vulnerable to extreme heat.
Fast-growing Acropora corals, for example, can quickly increase coral cover during favourable periods. But they are particularly susceptible to bleaching, meaning gains accumulated over several years can be lost during a single severe marine heatwave.
Cyclones and outbreaks of crown-of-thorns starfish add further pressure. AIMS reports that another wave of crown-of-thorns starfish is developing in the northern Great Barrier Reef, while the full effects of a powerful cyclone that crossed the region in March are not yet reflected in the latest assessment.
The broader picture is therefore one of resilience combined with increasing volatility.
The Great Barrier Reef can recover from substantial damage, but it needs sufficient time between major disturbances. As ocean temperatures continue to rise, those recovery periods risk becoming shorter.
The latest results are consequently encouraging—but also underline the importance of reducing the longer-term pressures driving increasingly frequent and severe marine heatwaves.
