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 0.3–0.7°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.

Our response and ongoing work

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 partner institutions to ensure decisions are guided by the most up-to-date information.

Management efforts remain focused on supporting Reef resilience like repositioning parts of our crown-of-thorns starfish control fleet to respond early to an emerging outbreak in the north and compliance patrols enforcing the zoning rules and encouraging responsible use of the Marine Park.

Marine Monitoring Program teams and partners are currently in the field sampling water quality and tracking flood plumes across the Cape York, Wet Tropics, Burdekin, Fitzroy and Mackay–Whitsunday catchments following recent heavy rainfall linked to ex-tropical cyclone Koji and tropical lows.

Reef health update | 29 January 2026

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.

Our response and ongoing work

We’ve repositioned parts of our crown-of-thorns starfish control fleet to respond early to an emerging outbreak in the north, while continuing control work in the central and southern Reef to support long-term coral protection.

The Marine Monitoring Program and partners are currently in the field sampling water quality and tracking flood plumes across the Cape York, Wet Tropics, Burdekin, Fitzroy and Mackay–Whitsunday catchments to better understand conditions and support timely management responses.

Our focus remains on building Reef resilience through strong compliance, effective management, and responsible use of the Marine Park.

We do this by working with government partners, Traditional Owners, researchers, tourism operators and contractors, and using the best-available knowledge to base our management actions.

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. 

Reef health update | 15 January 2026

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.

Reef management

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 works year-round with the Reef Joint Field Management Program, the COTS Control Program, Traditional Owners, researchers, contractors and partner institutions. Together, we ensure management decisions are guided by the most current, reliable and comprehensive Reef health 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.

Our flagship COTS Control Program continues to build on the significant outbreak suppression achieved in recent years. This science-informed, data-driven reef prioritisation approach allows control efforts to be deployed strategically, protecting coral at high-value reefs in a tangible, cost-effective and scalable way.

To inform our management, the Marine Monitoring Program is in the field sampling water quality and monitoring flood plumes in the Cape York, Wet Tropics, Burdekin and Mackay−Whitsunday catchments. This information is critical to understanding the impacts from the recent rainfall events.

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.

Reef health update | 8 January 2026

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.

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 works year-round with the Reef Joint Field Management Program, the Crown-of-thorns Starfish (COTS) Control Program, Traditional Owners, researchers, contractors and partner institutions. Together, we ensure management decisions are guided by the most current, reliable and comprehensive Reef health 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.

Our flagship COTS Control Program continues to build on the significant outbreak suppression achieved in recent years. This science-informed, data-driven reef prioritisation approach allows control efforts to be deployed strategically, protecting coral at high-value reefs in a tangible, cost-effective and scalable way.

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.

Reef health update | 24 December 2025

As summer continues, the Reef Authority is working with our science, tourism and Traditional Owner partners to closely monitor conditions across the Marine Park.

The Bureau of Meteorology (BoM) forecasts a low pressure trough to develop across northern Australia, currently expected to bring elevated rainfall over Queensland in the coming week.

During early and mid-December, sea surface temperatures remained above average. 

Temperature

From 15 to 21 December, sea surface temperatures across the Marine Park were on average 0.7–1.0°C above historical averages for December, remaining relatively stable from the previous reporting period.

However, some reefs in the Far Northern region have experienced temperatures above the threshold for heat accumulation. 

Degree heating weeks (DHW), which measures the duration and intensity of thermal stress, remained largely unchanged at an average of 0.4 DHW across all regions of the Marine Park during the reporting period.

Rainfall

From 15 to 21 December, the Normanby and Wet Tropics catchment areas received 150–200mm of rainfall, increasing the risk of freshwater impacts on inshore and offshore reefs. Work is underway to quantify the impacts from this second high rainfall event in the Northern region, which may exacerbate impacts from a nearby freshwater intrusion that occurred in early December.

Reef health

Between 15 and 21 December 2025, 31 Reef Health Impact Surveys (RHIS) were conducted on seven reefs across the Marine Park:
•    Two reefs in the Northern region recorded low levels (between 1 to 10%) of coral bleaching.
•    Coral bleaching was also reported on 10 additional occasions in the Northern and Central regions from 28 surveys conducted through other Eye on the Reef monitoring programs.

Crown-of-thorns starfish control

Crown-of-thorns starfish (COTS) outbreaks continue to impact reefs across the Marine Park, with the most severe outbreaks occurring in the Southern region, including the Swain Reefs, and in the Northern region between Cairns and Lizard Island. The Crown-of-thorns Starfish Control Program and Reef Joint Field Management Program COTS Response teams have conducted surveillance and culling on 121 reefs:
•    COTS are currently at sustainable levels for coral growth and recovery at 40 of these reefs.
•    Cull operations are currently active at 61 of these reefs to suppress outbreaks and protect coral from starfish predation. 
•    COTS have been detected on an additional 20 reefs, where culling will commence when resources are available.

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 works year-round with the Reef Joint Field Management Program, the Crown-of-thorns Starfish (COTS) Control Program, Traditional Owners, researchers, contractors and partner institutions. Together, we ensure management decisions are guided by the most current, reliable and comprehensive Reef health 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.

Our flagship COTS Control Program continues to build on the significant outbreak suppression achieved in recent years. This science-informed, data-driven reef prioritisation approach allows control efforts to be deployed strategically, protecting coral at high-value reefs in a tangible, cost-effective and scalable way.

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.

With calmer winds and clearer conditions typical of the season, summer is one of the most popular times to visit the Reef. Visitors can help protect it by reporting sightings or incidents through the Eye on the Reef app, available on Google Play and the Apple Store.

The Reef Authority wishes you a safe and enjoyable festive season. Reef health updates will resume in the second week of January.
 

Reef health update | 18 December 2025

With summer now upon us, reporting has shifted to weekly updates, allowing conditions to be tracked more closely as they change.

While the summer months period typically bring calm conditions and clear water across the Great Barrier Reef, it also often coincides with warming sea surface temperatures across the Marine Park.

The first half of December has continued the warm trend seen throughout spring. Sea surface temperatures remain above average, and while a weak La Niña is underway, rainfall forecasts for the remainder of 2025 suggest conditions are likely to stay close to average.

Temperature

The average monthly sea surface temperatures for November 2025 were the highest on record for the Great Barrier Reef. 
In the first half of December, sea surface temperatures across the Marine Park remained about 1°C above the long-term average, which is slightly lower than the November averages.

Looking ahead, Bureau of Meteorology forecasts show:

• Sea surface temperatures are expected to be 0.4–0.8°C above average throughout January 2026 across most of the Marine Park
• Some offshore areas may reach up to 1.2°C above average
• These forecasts still indicate a warm summer, although predicted temperatures have eased slightly when compared with long-term averages to earlier outlooks.

Degree heating weeks (which measures the duration and intensity of thermal stress) have now begun accumulating on most reefs in the Far Northern region and on some inshore reefs in the Central and Southern regions. While current thermal exposure remains well below thresholds linked to widespread coral impacts, this early onset of degree heating week accumulation has been driven by higher-than-average sea surface temperatures during spring.

Rainfall

A low-pressure trough spanning across the top half of Australia is bringing increased cloud cover and a higher chance of thunderstorms and rainfall across Queensland, especially in the Burdekin and Burnett–Mary catchments and is currently forecasted to persist at least until 21 December.

Reef health

Between 1–14 December 2025, 77 Reef Health Impact Surveys were completed across 11 reefs in the Marine Park.

• In the first week of December, three reefs in the Northern regions recorded low levels (1–10%) of coral bleaching.
• In the second week of December, five reefs in the Northern and Central regions recorded low to high levels of coral bleaching. This isolated coral bleaching is attributed to a flush of fresh water following a high rainfall event in early December in the Northern region of the Marine Park.  

Crown-of-thorns starfish (COTS) continue to affect several reefs, with the most severe outbreaks occurring in the Southern region (Swain Reefs) and the Northern region between Cairns and Lizard Island.

We are working closely with partners to understand conditions across the Reef, drawing on scientific data, modelling, in-water surveys, and observations provided by Marine Park users through the Eye on the Reef app.

Each year, as summer progresses, impacts from warm water are expected. Local conditions and weather patterns will largely determine how reefs respond, highlighting the importance of ongoing monitoring and management.

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 works year-round with the Reef Joint Field Management Program, the Crown-of-thorns Starfish (COTS) Control Program, Traditional Owners, researchers, contractors and partner institutions. Together, we ensure management decisions are guided by the most current, reliable and comprehensive Reef health 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.

Our flagship COTS Control Program continues to build on the significant outbreak suppression achieved in recent years. This science-informed, data-driven reef prioritisation approach allows control efforts to be deployed strategically, protecting coral at high-value reefs in a tangible, cost-effective and scalable way.

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.

With calmer winds and clearer conditions typical of the season, summer is one of the most popular times to visit the Reef. Visitors can help protect it by reporting sightings or incidents through the Eye on the Reef app, available on Google Play and the Apple Store.

Reef health update | November 2025

The Great Barrier Reef is entering one of its most active seasons, with turtle nesting, seabird breeding and juvenile fish becoming more visible across the Reef. It is also preparing for its second coral spawning event, following the first spawning in early November. This natural release of eggs and sperm plays an important role in regenerating the Reef and supporting the renewal of its ecosystems.

As this period of renewal unfolds, the Reef is entering summer under continued warm conditions, with sea surface temperatures remaining above average and a weak La Niña underway. While La Niña years can bring increased rainfall, long-range forecasts indicate rainfall is likely to remain around average for the rest of 2025.

Temperature

Throughout November, sea surface temperatures across the Marine Park were 1.3–1.5°C above average.
Looking ahead, Bureau of Meteorology forecasts indicate a high probability of above-average sea surface temperatures continuing through December.

• The Far Northern and Northern regions are expected to remain 1–1.5°C above average.
• The Central and Southern regions are forecast to stay 0.8–1.5°C above average.

Longer-range projections suggest sea surface temperatures will be closer to the long-term averages than those temperatures in recent months. In January, sea surface temperatures across the Marine Park are expected to be 0.6–1.0°C above average.

Reef health

Between 1–30 November 2025, 751 Reef Health Impact Surveys (RHIS) were completed across 59 reefs in the Marine Park with only 1 per cent recording low levels (1–10%) of coral bleaching.

Crown-of-thorns starfish (COTS) continue to impact reefs throughout the Marine Park, with the most severe outbreaks occurring in the Northern region between Cairns and Lizard Island and the Southern region (Swain Reefs).

Since July 2025, the COTS Control Program and Reef Joint Field Management Program have undertaken surveillance and culling across 121 reefs.

• COTS numbers are at sustainable levels on 40 reefs (~33%), supporting coral growth and recovery.
• Culling operations are underway at an additional 61 reefs (~50%) to suppress outbreaks.
• COTS have been detected on 20 reefs (~17%), with culling to begin when resources become available.

Our response and ongoing work

The Reef Authority continues to work closely with the Reef Joint Field Management Program, the COTS Control Program, Traditional Owners, researchers, contractors, and management institutions to ensure contemporary, high-quality data informs decisions across the World Heritage Area.

This collaborative, science-driven approach supports rapid, coordinated management and helps guide where action is needed most.

Our work focuses on building Reef resilience through:

• Managing crown-of-thorns starfish
• Enforcing compliance with the Reef’s zoning plan
• Supporting responsible tourism and recreation
• Collecting and sharing up-to-date Reef health information

COTS control operations continue to build on the regional-scale outbreak suppression achieved in recent years. The data-driven reef prioritisation process used by the COTS Control Program ensures effort is deployed strategically to protect high-value reefs and support the Reef’s long-term resilience.

With calmer winds and clear tropical waters typical of the season, summer is shaping up as one of the best times of year for families, divers and nature lovers to explore the Reef. You can help protect the Reef by reporting sightings or incidents through the Eye on the Reef app, available on Google Play and the Apple Store.

Reef Health update | October 2025

The Great Barrier Reef is gearing up for the annual coral spawning, dubbed “the world’s biggest synchronised sex act”, when billions of corals release eggs and sperm into the ocean in a spectacular mass reproduction event that regenerates the Reef.

Likened to an underwater snow blizzard, researchers predict this year’s coral spawning is expected in early November and early December.

Temperature

Queensland recorded its hottest October on record for average air temperatures, and sea surface temperatures across the Marine Park remained about 1°C warmer than usual.

Forecasts show the water is likely to stay 1 to 1.5°C above average through November.

Looking ahead, temperatures in December are expected to stay 1 to 1.5°C above average in the Far Northern and Northern regions, and about 0.8 to 1°C above average in the Central and Southern regions. Across all areas, the water is likely to stay 0.8 to 1°C above average in January.

Reef health

In October 2025, 359 Reef Health Impact Surveys were carried out across 41 reefs in the Marine Park. Minor coral bleaching was seen only in the Northern region, with no bleaching reported elsewhere.

Crown-of-thorns starfish (COTS) are still affecting many reefs, with the worst outbreaks in the Southern region (Swain Reefs) and the Northern region between Port Douglas and Lizard Island.

Since July, the COTS Control Program and Reef Joint Field Management Program teams have surveyed and removed COTS from 93 reefs.

Of these controlled reefs, COTS numbers are currently at sustainable levels, on 29 reefs (about 31%), allowing coral to grow and recover. Culling is underway at 46 reefs (around 50% of controlled reefs) to control outbreaks and protect coral. COTS have been found on 18 reefs (about 19% of controlled reefs), and culling will begin there when resources become available.

Our response and ongoing work

In late October and early November the Reef Authority conducted crucial Eye on the Reef training with tourism operators, Traditional Owners and teachers. The participants learned how to conduct Rapid Monitoring Surveys, Tourism Weekly Site Monitoring, and Reef Health and Impact Surveys (RHIS) to collect critical data that helps the Reef Authority assess coral health, track recovery, and guide management decisions.

Every data point collected through Eye on the Reef helps us to understand how the Reef is responding to changing conditions, including bleaching and recovery, so we can act where it’s needed most.

The Reef Authority works closely with Traditional Owners, researchers, contractors, and the Queensland Parks and Wildlife Service through the Reef Joint Field Management Program. Together we deliver rapid and coordinated action across the World Heritage Area.

This work focuses on building Reef resilience through:

• Managing crown-of-thorns starfish
• Enforcing compliance with the Reef’s zoning plan
• Supporting responsible tourism and recreation
• Collecting and sharing up-to-date Reef health data to guide decisions

You can help protect the Reef by reporting sightings or incidents through the Eye on the Reef app, available on Google Play and the Apple Store.

Reef Health update | September 2025

Since July 2024, sea surface temperatures around Australia have been the warmest or second warmest on record. Global ocean temperatures have also stayed well above average.

In September, the Marine Park stayed about 1°C warmer than usual, and these higher temperatures are expected to continue into the Austral summer.

Reef surveys showed minimal coral bleaching, but crown-of-thorns starfish outbreaks remain a threat in some areas. 

Temperature 

In September, sea surface temperatures across the Marine Park were about 0.9–1°C above the long-term average. Forecasts show these warmer-than-usual conditions are likely to continue through October to at least December, especially in the Central and Northern regions.

Rainfall 

Rain was recorded along Queensland’s tropical north coast in September, but no flooding or river plumes were reported in the Marine Park.

A negative Indian Ocean Dipole is underway and is likely to persist through spring. This increases the chance of above-average spring rainfall in eastern Australia.

Reef health

During September 2025, 538 Reef Health Impact Surveys were completed across 46 reefs in the Marine Park. Minimal coral bleaching was reported in the outer southern region and no coral bleaching in other areas.

Crown-of-thorns starfish (COTS) continue to affect many reefs. The worst outbreaks are in the Southern region (Swain Reefs) and in the Northern region between Port Douglas and Lizard Island.

The Reef Authority’s COTS Control Program is targeting both the ongoing fourth wave of outbreaks since 2010 and a fifth wave that began in 2022.

Since 1 July this year, the COTS Control Program and the Reef Joint Field Management Program teams have undertaken surveillance and culling on 72 reefs.

Our response and ongoing work

The Reef Authority works closely with Traditional Owners, researchers, contractors, and the Queensland Parks and Wildlife Service through the Reef Joint Field Management Program. Together we deliver rapid and coordinated action across the World Heritage Area.

This work focuses on building Reef resilience through:

• Managing crown-of-thorns starfish
• Enforcing compliance with the Reef’s zoning plan
• Supporting responsible tourism and recreation
• Collecting and sharing up-to-date Reef health data to guide decisions

You can help protect the Reef by reporting sightings or incidents through the Eye on the Reef app, available on Google Play and the Apple Store.

Reef Health update | August 2025

The El Niño–Southern Oscillation remains in a neutral phrase which typically produces more stable weather patterns, although local conditions can vary significantly. The Bureau of Meteorology has updated its forecast for neutral ENSO conditions to persist until at least January 2026.

In 2025, sea temperatures in the Great Barrier Reef have been warmer than usual. This winter was the third hottest ever recorded, and August was the second hottest.

Temperature 

Between 1–31 August, sea surface temperatures across the Great Barrier Reef eased slightly in the north, and in the four management areas:

• Far Northern: dropped from 1.7°C to 1.1°C above average
• Northern: decreased from 1.4°C to 1.1°C above average
• Central: remained stable at around 1.0°C above average
• Southern: recorded the lowest temperatures overall, between 0.6–0.7°C

Warmer-than-average conditions are expected to persist through October 2025.

Rainfall 

There was low rainfall in the Marine Park catchment over August presenting minimal risk of flood plumes or catchment runoff.

Reef health

A total of 288 Reef Health Impact Surveys were completed between 1 – 31 August 2025, across 28 reefs in the Northern, Central and Southern Marine Park regions. Minimal bleaching was reported for all regions.

Crown-of-thorns Starfish (COTS) are affecting many reefs across the Marine Park, with the worst outbreaks in the Southern region (Swain Reefs) and between Port Douglas and Lizard Island.

Since July 2025, response teams from the COTS Control Program and the Reef Joint Field Management Program have worked across 50 reefs to check for starfish and remove them where needed. At those 50 reefs the teams found;

• 15 reefs (30%) have COTS numbers at levels that allow coral to grow and recover.
• 32 reefs (64%) have cull operations active to reduce outbreaks and protect coral.
• 3 reefs (6%) have COTS present, and culling will begin there once resources are available.

Our response and ongoing work

The Reef Authority continues to work closely with the Traditional Owners, researchers, and contractors as well as the Queensland Parks and Wildlife Service through the Reef Joint Field Management Program to deliver rapid, informed and coordinated action across the World Heritage Area.

This work includes building Reef resilience through our compliance and crown-of-thorns starfish control efforts and other active management actions. Collecting and sharing contemporary Reef health data is critical in informing management actions.

We work closely with the tourism industry and local communities to support responsible use of the Marine Park.

Our management actions are geared towards building and supporting Reef resilience, including enforcing compliance with the Reef’s zoning plan and ensuring people are enjoying the Reef in a responsible way. 

You too can help by reporting any incidents through the Eye on the Reef app, which is available for download on Google Play or Apple Store.

Reef Health update | July 2025

El Niño−Southern Oscillation remains neutral

The El Niño−Southern Oscillation remains in a neutral phase which typically produces more stable weather patterns, although local conditions can vary significantly. The Bureau of Meteorology forecasts neutral ENSO conditions to persist until at least December 2025.

Sea surface temperatures across the Great Barrier Reef remain above average, with June 2025 the fourth hottest on record for Marine Park waters.

Between 27 June and 17 July, sea surface temperatures were consistently elevated across all Reef regions:

- Far Northern: +0.8−0.9 °C

- Northern: +0.3−0.8° C, with a moderate warming trend

- Central and Southern: +0.7−1.0° C

Rainfall 

Rainfall in most Reef catchments was below average between 1 June and 20 July. However, rainfall is expected to exceed historical mediums in August which could increase the risk of freshwater flows and sediment runoff into the Marine Park. These conditions can affect coral and seagrass health – especially in inshore areas.

Reef health and monitoring

A total of 338 Reef health impact surveys were completed between 1 June and 20 July across 44 reefs in the Northern, Central and Southern Marine Park regions.

No coral bleaching was observed during this period.

No surveys were conducted in the Far Northern region during this time.

Crown-of-thorns starfish control

A coordinated and proactive response continues to protect coral from the impact of crown-of-thorns starfish (COTS). The Reef Authority’s COTS Control Program, delivered in partnership with the Reef Joint Field Management Program, is a demonstrated effective tool in protecting coral and supporting the health and resilience of the Reef.

Between July 2024 and June 2025:

- 237 reefs were targeted for surveillance and management

- 107 reefs (45% of those targeted) had sustainable COTS numbers, allowing corals to grow and recover

Active culling is underway at 44 reefs with teams working efficiently to reduce starfish densities. The starfish were detected at 86 additional reefs that have been prioritised for action as field resources allow.

This targeted, science-led effort is critical for preserving coral cover and supporting Reef resilience, particularly in areas where coral communities are already under pressure from heat stress. The Swains Reefs in the Southern Regions and reefs between Port Douglas and Lizard Island that still have significant COTS outbreaks, are current priority areas for control efforts. Work to combat coral-eating crown-of-thorns starfish across the Great Barrier Reef is working even under increasing environmental pressures, according to an assessment by University of Queensland researchers. 

Work to combat coral-eating crown-of-thorns starfish across the Great Barrier Reef is working even under increasing environmental pressures, according to an assessment by University of Queensland researchers.

See the research here.

Our response and ongoing work

The Reef Authority continues to work closely with the Traditional Owners, researchers, and contractors as well as the Queensland Parks and Wildlife Service through the Reef Joint Field Management Program to deliver rapid, informed and coordinated action across the World Heritage Area.

This work includes building Reef resilience through our compliance and crown-of-thorns starfish control efforts and other active management actions. Collecting and sharing contemporary Reef health data is critical in informing management actions.

We work closely with the tourism industry and local communities to support responsible use of the Marine Park.

You too can help by reporting any incidents through the Eye on the Reef app, which is available for download on Google Play or Apple Store.