Reef health update | 26 February 2026

Over the past week, sea surface temperatures across the Marine Park have remained relatively stable.

However now that we are well into summer, there is heat build-up in the system, particularly in the Far Northern and Northern regions of the Marine Park.

The USA’s National Oceanic and Atmospheric Administration (NOAA), which monitors ocean temperatures globally, has updated the coral bleaching alert levels across parts of the Marine Park, meaning the risk of coral bleaching has increased with the Far Northern region at alert level 2 and the Northern region at alert level 1. The Central region remains at warning status and Reef health monitoring is ongoing across all regions.

The Bureau of Meteorology forecasts scattered rainfall across Marine Park catchments over the coming week, with temperatures expected to remain close to monthly averages.

Temperature

Sea surface temperatures are currently around 0.7°C above average in the Southern region and between 0.8°C and 1.2°C above average in the Central, Northern and Far Northern regions.

Forecasts for March indicate that temperatures in the Far Northern region are likely to remain elevated, reaching up to 1.2°C above average, while other regions are expected to stay between 0 and 0.8°C above the long-term average.

Rainfall

From 16 to 22 February, localised heavy rainfall occurred in the Mackay–Whitsunday catchment, with weekly totals between 150 and 500mm and some daily totals exceeding 200mm.

Heavy rainfall can lead to freshwater runoff into the Marine Park, and subsequent lower salinity in Reef waters. This runoff may also carry sediments, nutrients and pesticides, placing additional stress on nearby marine ecosystems.

Reef health

Over the past week, 70 Reef Health Impact Surveys were completed across 11 reefs in the Northern, Central and Southern regions of the Marine Park, with most surveys conducted in the Northern region.

Low to high levels of coral bleaching (1–60%) were recorded on five reefs in the Northern region, and medium levels (11–30%) were recorded on one reef in the Southern region. Low level damage was reported on 23 reefs and disease on 21 reefs, mostly in the Northern region.

Additional observations from Eye on the Reef monitoring programs also reported coral bleaching on 21 of the 38 reefs surveyed. No surveyed reefs showed fully bleached or recently dead coral.

Crown-of-thorns starfish control

The Crown-of-thorns Starfish Control Program continues to manage ongoing outbreaks across the Marine Park, with updates shared in the first weekly Reef Health Update of each month.

Our response and ongoing work

Crown-of-thorns starfish (COTS) outbreaks continue across the Marine Park and specialised dive teams are working across targeted reefs to survey and cull these predatory starfish.

Management actions remain focused on supporting Reef resilience, including enforcing compliance with zoning rules and encouraging responsible use of the Marine Park.

The Reef Authority continues to work closely with the Reef Joint Field Management Program, the Crown-of-Thorns Starfish Control Program, researchers, tourism operators, contractors and partners to ensure management actions are guided by the latest data across the World Heritage Area.

Reef health update | 5 February 2026

Sea surface temperatures remain stable across the Marine Park and are only slightly above average for this time of year.

Above-average rainfall fell across all Marine Park catchments in January, with the most rain falling in the Cape York region. Water quality monitoring is ongoing to understand how these conditions may affect nearby reefs.

Summer is also a busy time for Reef wildlife. From late January through April, thousands of baby turtles are hatching and making their way to the Marine Park, with many nesting beaches and islands seeing regular activity, especially at dawn and dusk. Seabird breeding is also underway, with many species nesting on islands and feeding across the Reef during February.

Temperature

In the Far Northern region, temperatures are around 0.1°C above the long-term monthly average. The Northern, Central and Southern regions remain 0.4–0.7°C above average.

Overall, temperatures are lower than earlier in summer but still a little warmer than usual for this time of year.

Rainfall

Between 26 January and 1 February 2026, the highest recorded rainfall occurred in the Wet Tropics with some days exceeding 200mm.

With catchments already saturated, further rainfall increases the likelihood of freshwater and sediment runoff entering the Marine Park. Current forecasts indicate a high chance of continued rainfall in the coming week.

Reef health

Recent monitoring shows limited impacts from coral bleaching. Between 26 January and 1 February, 143 Reef Health Impact Surveys were completed across 14 reefs in the Marine Park, with 12 of the 14 reefs showing no or only limited coral bleaching impacts.

On the two reefs where bleaching was recorded:

• One reef in the Northern region recorded low levels of bleaching (1–10%).
• One reef in the Southern region recorded higher bleaching levels (31–60%), which is being closely monitored.

Additional observations from Eye on the Reef monitoring programs reported coral bleaching on 13 of the 20 reefs surveyed. These reports indicate that impacts remain localised, rather than widespread, at this stage of summer.

Crown-of-thorns starfish control

Crown-of-thorns starfish (COTS) outbreaks continue across the Marine Park, with the most severe outbreaks in the Southern region (Swain Reefs) and the Northern region between Cairns and Lizard Island. Specialised dive teams are working across targeted reefs to survey and cull these predatory starfish.

Crown-of-thorns starfish (COTS) management continues to deliver strong coral protection outcomes. Since July, COTS control teams have surveyed or treated 153 reefs across the Marine Park:

• 61 reefs (around 40% of those surveyed) now have COTS at sustainable levels, supporting coral growth and recovery.
• 57 reefs (around 37%) are under active culling to suppress outbreaks and protect coral.
• COTS have been detected on 35 reefs (around 23%), with control planned as resources allow.

Sea surface temperatures remain relatively stable across the Marine Park and slightly above the long-term average for this time of year.

We’ve moved some of our crown-of-thorns starfish control vessels north to respond early to a new outbreak, while keeping control efforts underway in the central and southern Reefs to protect coral cover.

High rainfall across Reef catchment areas during January has contributed to some cooling of sea surface temperatures with increased cloud cover and rain, reducing the risk of heat stress on reefs. However, this has led to flood plumes in the Northern, Central and Southern regions of the Marine Park. Water quality monitoring is underway to understand how these conditions may affect nearby reefs.

Temperature

In the Far Northern region, sea surface temperatures are around 0.2°C above long-term monthly averages. The Northern, Central and Southern regions remain 0.5–0.8°C above average, which is lower than earlier in summer but still warmer than typical for this time of year.

Rainfall

Between 19 and 25 January, a trough and tropical low brought heavy rainfall to Far Northern Queensland. Some weather stations recorded 200–300mm of rain, increasing the likelihood of freshwater runoff from Cape York catchments flowing into the Marine Park.

Reef health

From 19–25 January, 55 Reef Health Impact Surveys were completed across 12 reefs in the Northern and Central regions.

Results from recent monitoring show that nine of the 12 reefs surveyed (75%) recorded no coral bleaching impacts. This aligns with the modest levels of heat stress that have accumulated across the Reef so far this summer.

Coral bleaching was observed on three reefs:

• In the Northern region, one reef recorded low bleaching prevalence (1–10%), with only 5% of the bleached coral were fully bleached and very low levels of recent coral mortality (under 3%).

• In the Central region, two reefs recorded low to medium bleaching prevalence (1–10% to 11–30%).

Additional observations from other Eye on the Reef monitoring programs reported coral bleaching on nine of 27 reefs surveyed in the Northern region, indicating that impacts remain localised at this stage.

Flood plumes from rivers in the Wet Tropics and Mackay–Whitsunday catchments have extended into the Marine Park. These plumes, which contain freshwater and sediments, may be contributing to coral bleaching and recent mortality on some inshore reefs.

Recent satellite imagery has also identified a developing flood plume from the Fitzroy catchment flowing into Keppel Bay. The Marine Monitoring Program and survey partners will continue to assess its extent and potential impacts in the coming weeks.

Crown-of-thorns starfish control

Crown-of-thorns starfish (COTS) outbreaks continue across the Marine Park, with the most severe outbreaks in the Southern region (Swain Reefs) and the Northern region between Cairns and Lizard Island. Specialised dive teams are working across targeted reefs to survey and cull these predatory starfish.

As of 31 December 2025:

• 128 reefs have been surveyed or treated

• 44 reefs (around 34%) now have COTS at sustainable levels

• 63 reefs (around 49%) are undergoing active culling

• 21 reefs (around 17%) have COTS present, with control planned as resources allow

Crown-of-thorns starfish control program data is updated monthly, with year-to-date updates included in the first Reef Health Update each month.

Reef health update | 22 January 2026

Heavy rainfall over the past few weeks has led to flood plumes flowing into the Marine Park in the Northern, Central and Southern regions. These plumes are being closely monitored, with water quality checks underway through the Marine Monitoring Program.

Temperature

Sea surface temperatures have eased in some areas this week. The Far Northern region cooled by about 0.4°C, the Northern region stayed steady and the Central and Southern regions warmed slightly by 0.2–0.3°C. Temperatures across all regions are now close to the long-term average for this time of year

With cooler temperatures in the Far Northern region, heat stress has eased and reefs here have returned to a bleaching watch status.

Rainfall

Between 12 and 18 January, very heavy rainfall continued in the Mackay–Whitsunday and Fitzroy catchments following the tropical low linked to ex-tropical cyclone Koji. Some rainfall stations recorded more than 300 mm, with parts of the Mackay–Whitsunday region receiving over 500 mm.

Reef health

From 12 – 18 January, 124 Reef Health Impact Surveys were completed across 19 reefs in the Northern, Central and Southern regions. Low to medium levels of coral bleaching were recorded on nine reefs. At one reef in the Northern region, a small number of coral colonies were fully bleached, with very low levels of recent coral mortality observed.

Additional Eye on the Reef reports also noted coral bleaching on 11 reefs across all three regions. Some low to medium bleaching has been seen at offshore reefs in the Southern region, likely linked to short periods of heat stress earlier in January.

Flood plumes from the Wet Tropics and Mackay–Whitsunday catchments have moved into parts of the Marine Park. These plumes, which carry fresh water and sediment, may have contributed to bleaching and coral stress on some inshore reefs. Flood plumes from the Fitzroy catchment may develop in coming weeks and are being monitored.

Crown-of-thorns starfish control

Crown-of-thorns starfish (COTS) continue to affect reefs across the Marine Park. The most severe outbreaks remain in the Southern region (Swain Reefs) and in the Northern region between Cairns and Lizard Island. Since December, surveillance and control activities have been carried out on 128 reefs. Around one-third of these reefs now have COTS at levels that allow coral to recover, while active control is underway on about half of the reefs to reduce impacts.

Our response and ongoing work

Climate change remains the greatest threat to the Great Barrier Reef and addressing it requires urgent global action alongside strong local and regional management to build Reef resilience.

As Reef managers, the Reef Authority continues to work closely with the Reef Joint Field Management Program, the COTS Control Program, researchers, tourism operators and other partners to ensure decisions are based on the latest available data.

Every day, field officers are monitoring conditions, undertaking conservation actions on reefs and islands, and ensuring people are following the rules designed to protect the Reef.

Our work focuses on strengthening the Reef’s long-term resilience through:

managing crown-of-thorns starfish

enforcing compliance with the Reef’s zoning plan

supporting responsible tourism and recreation

collecting, analysing and sharing up-to-date Reef health information.

To inform our management, the Marine Monitoring Program and partners are currently in the field monitoring water quality and flood plumes across Cape York, the Wet Tropics, Burdekin, Fitzroy and Mackay–Whitsunday catchments.

We are also adapting management approaches to respond to a changing climate and other pressures, including supporting reef rehabilitation efforts and targeted regional actions to maintain ecosystem function.

Ex-Tropical Cyclone Koji formed on 10 January 2026 and made landfall between Ayr and Bowen on 11 January as a category 1 system. The system moved through the Central region of the Marine Park between Ayr and Mackay, bringing heavy rainfall. Early reports indicate flood plumes have formed in the Marine Park from nearby catchments, and flood warnings remain in place. Freshwater runoff into the Marine Park is expected to continue, and river plumes are being surveyed by the Marine Monitoring Program.

Temperature

From 5 to 11 January 2026, sea surface temperatures dropped slightly by 0.2−0.3°C across the Marine Park but remain approximately 0.4−0.9°C above average in all regions.

In the Northern, Central and Southern regions of the Marine Park, temperatures are not high enough to build up heat stress.

In the Far Northern region, heat stress is still building with most reefs under a Bleaching Warning or Watch level, meaning coral bleaching is possible. A few reefs near the Torres Strait boundary are under Bleaching Alert Level 1, meaning there’s a risk of some reef-wide bleaching if warm conditions continue.

Rainfall

During the reporting period, rainfall exceeded 200mm in many parts of the Cape York, Wet Tropics and Burdekin catchments, with some rainfall stations recording over 300mm in the Mackay−-Whitsundays region.

Reef health

During the survey period, 33 Reef Health Impact Surveys were carried out on three reefs in the Far Northern and Northern regions, and no coral bleaching was observed. However, bleaching was reported eight times through 23 surveys from other Eye on the Reef monitoring programs, across the Northern, Central and Southern regions.

Due to the high rainfall in the catchments adjacent to the Marine Park, early satellite imagery and reports from the ongoing water quality monitoring conducted by the Marine Monitoring Program indicate flood plumes have developed in the Marine Park across the affected catchments.

Crown-of-thorns starfish control

As of 31 December 2025, crown-of-thorns starfish (COTS) outbreaks are impacting reefs throughout the Marine Park, with the most severe outbreaks occurring in the Southern region (Swain Reefs) and in the Northern region between Cairns and Lizard Island. The COTS Control Program and Reef Joint Field Management Program (RJFMP) COTS response teams have actioned 128 reefs for surveillance and culling where required.

- COTS are at sustainable levels for coral growth and recovery at 44 actioned reefs

- Cull operations are currently active at 63 reefs to suppress outbreaks and protect coral from starfish predation.

- COTS have been detected on 21 reefs and culling will be initiated when resources are available.

Following recent rainfall across parts of northern Queensland, the Reef Authority is working closely with our partners to monitor conditions across the Marine Park.

The Bureau of Meteorology forecasts a monsoon trough will develop in the coming days, along with a tropical low off the coast of far northern Queensland. This is expected to bring high levels of rainfall to catchments of the Wet Tropics and Cape York with a moderate chance of it developing into a tropical cyclone by 8 January 2026.

Temperature

From 29 December 2025 to 4 January 2026, sea surface temperatures across the Marine Park remained above average, with the highest temperatures recorded in the Far Northern and Northern regions at 29.1−29.8°C. Waters were slightly cooler in the Central and Southern regions at 28.6−28.3°C.

Most reefs in the Far Northern region are under Bleaching Warning conditions and are continuing to accumulate heat stress. Some reefs close to the Torres Strait boundary in the Far Northern region have reached Bleaching Alert Level 1, meaning some bleaching is expected if warm conditions continue.

Rainfall

The onset of the Australian summer monsoon brought heavy rainfall across Great Barrier Reef catchments, with the Normanby and Burdekin catchments receiving over 200mm, and some parts of the Wet Tropics receiving over 1000mm.

Reef health

Over the survey period, a total of 11 Reef Health Impact Surveys (RHIS) were conducted on four reefs across the Marine Park. High (31–60%) coral bleaching prevalence was recorded at one reef in the Northern region, and the presence of coral bleaching was reported on seven other occasions from 18 surveys conducted by other Eye on the Reef monitoring programs. Due to the high rainfall in the catchments adjacent to the Marine Park, there will be runoff flowing into the Marine Park, along with the potential for flood plumes. Inshore coral reefs and seagrass meadows may be exposed to reduced salinity and sedimentation. The Marine Monitoring Program has been in the field sampling water quality from the Tully River flood plume arising from minor flooding between Cairns and Townsville.

Crown-of-thorns starfish control

As of 31 December 2025, crown-of-thorn starfish (COTS) outbreaks are impacting reefs throughout the Marine Park, with the most severe outbreaks occurring in the Southern region (Swain Reefs), and in the Northern region between Cairns and Lizard Island.

The COTS Control Program and Reef Joint Field Management Program COTS response teams have actioned 128 reefs for surveillance and culling where required.

• COTS are at sustainable levels for coral growth and recovery at 44 actioned reefs.
• Cull operations are currently active at 63 reefs to suppress outbreaks and protect coral from starfish predation.
• COTS have been detected on 21 reefs and culling will be initiated when resources are available.

Reef health update – 12 February 2026

Summary

Sea surface temperatures have increased slightly across the Far North, North and Central regions over the past week, with little change in the southern region. Temperatures are tracking slightly above the long-term average with the Northern region (Cooktown – Innisfail) experiencing above-average conditions.

The Bureau of Meteorology has forecast a tropical low (23U) to form in the Coral Sea. There is a low chance (5–10%) it will develop into a tropical cyclone by the weekend. The system is expected to remain offshore and may bring localised rainfall to Marine Park catchments in the coming week.

The breeding season continues across the Reef, with turtle hatchlings emerging from nests and making their way to the sea from late January through April, especially at dawn and dusk. Seabirds are also nesting and feeding across island and reef habitats, and many fish species are spawning and laying eggs during the warm summer months, taking advantage of the productive wet season conditions.

Temperature

Sea surface temperatures are currently around 0.4–0.5°C above the long-term average in the Far Northern, Central and Southern regions. The Northern region is averaging around 1°C above the long-term monthly average.

While there has been some accumulation of heat stress, particularly in northern Reef waters, this remains below the level where we would expect to see significant coral bleaching impacts.

Rainfall

From 2–8 February, rainfall was lower than expected in the Marine Park catchments, with average rainfall occurring in the Wet Tropics and Mackay–Whitsundays. Heavy rainfall is currently forecast in areas which may be affected by the Tropical Low 23U.

Reef health

America’s National Oceanic and Atmospheric Administration’s (NOAA) coral bleaching alert level for the Northern region has moved from bleaching watch to bleaching warning, meaning coral bleaching is possible, following the recent temperature increases. Monitoring is ongoing across the Marine Park.

During the past week, 86 Reef Health Impact Surveys were completed across 10 reefs in the Northern, Central and Southern regions.

Low to medium levels of coral bleaching (1–30%) were recorded on four reefs in the Northern region and one reef in the central region. Most surveyed reefs showed no to low levels of bleaching.

Additional observations from Eye on the Reef monitoring programs reported coral bleaching on 11 of the 26 reefs surveyed. Impacts remain localised and are being closely monitored.

Crown-of-thorns starfish control

The Crown-of-Thorns Starfish Control Program continues to manage ongoing outbreaks across the Marine Park, with updates shared in the first weekly Reef Health Update of each month.

Our response and ongoing work

Marine Monitoring Program teams and partners are sampling water quality and tracking flood plumes in the Burdekin. On Magnetic Island, training is underway to support local citizen scientists to help monitor water quality.

Crown-of-thorns starfish (COTS) outbreaks continue across the Marine Park and specialised dive teams are working across targeted reefs to survey and cull these predatory starfish.

Management efforts remain focused on supporting Reef resilience, including enforcing zoning rules, encouraging responsible use of the Marine Park and responding early to emerging risks.

The Reef Authority continues to work closely with the Reef Joint Field Management Program, the Crown-of-Thorns Starfish Control Program, researchers, tourism operators, contractors and partners to ensure decisions are guided by up-to-date information.

For more information, visit - www.gbrmpa.gov.au/learn/reef-health/reef-health-updates