How healthy is the Great Barrier Reef?

The overall health of a reef is influenced by the condition of the ecosystems that support it, as well as the pressures being placed on those ecosystems. The cumulative impacts of these pressures can weaken ecosystem health, which varies in both condition and stability. The current outlook of the Reef as reported by the 2024 Outlook Report is one of continued deterioration.

The Reef is a complex and extensive system that faces multiple pressures. Climate change is the greatest threat to the Reef, while water quality also continues to impact the Reef and cumulative pressures are reducing the Reef’s ability to recover from stress. Improving water quality is critical to reducing these pressures and supporting the Reef’s resilience.

Coral health

Recent observations of hard coral extent show a significant decline, driven by the 2024 mass bleaching event. In 2025 the Long-Term Monitoring Program annual summary reported:

  • 48% of surveyed reefs experienced a decline in coral cover compared to 2024
  • 42% showed no net change
  • 10% recorded an increase in cover.

The effects of mass bleaching events can take years to unfold, and are often exacerbated by disturbance events such as cyclones, crown of thorn outbreaks and further thermal stress.

Beyond coral: other key ecosystems

A healthy reef is more than just healthy coral. Other species and ecosystems play a vital role in maintaining the Reef’s overall health:

  • Invertebrates: These species support nutrient cycling, primary production, and other ecosystem functions. However, they are impacted by climate change, ocean warming, acidification, habitat loss and declining coral cover resulting in reduced food and shelter. While some species show resilience, there is limited knowledge on the overall condition of invertebrates.
  • Seagrass: Seagrass meadows are below optimal levels but remain stable or improving in some areas. Increased sediment and nutrients can reduce light availability, which in turn decreases the extent of inshore seagrass meadows. Additionally, poor reproductive effort can impact their ability to recover following a disturbance. This is impacting regions differently, with seedbank stocks currently low in the Fitzroy and Burnett Mary regions but remaining consistent and abundant in other regions.
  • Mangroves: Mangrove forests provide critical ecosystem services such as carbon sequestration, coastal stabilisation, habitat for a diverse range of species. They also hold cultural significance for First Nations peoples. Mangroves are currently recorded as good condition and stable between 2005 and 2021 within Reef report cards and very good in the 2024 Great Barrier Reef Outlook report. However, they face risks from coastal development, climate change, rising sea levels and excess nutrients, sediment and pesticide loads, especially during periods of high rainfall.

Crown-of-thorns starfish

Excess nutrients, as observed after significant flood events, may also influence outbreaks of coral-eating crown-of-thorns starfish, which can devastate the Reef.

Wetlands

Wetlands are critical in supporting the healthy functioning of the Reef. They can improve water quality by filtering out land-based pollutants, but they are, in turn, negatively affected by those pollutants.

Overall, the condition of many coastal freshwater wetlands continues to be affected by excess rates of nutrients and sediments, as well as things such as changing water quality and invasive species.

Further information

For a comprehensive review of the Reef’s current state and condition, refer to:

Additionally, the Australian Institute of Marine Science produces an annual report assessing coral condition as part of their long-term monitoring program.