Reef health update | June 2026

While heat stress has eased across the Great Barrier Reef Marine Park from summer, sea surface temperatures remain slightly above average in some regions for this time of year.

Climate conditions remain neutral; however, there are increasing signs that an El Niño may develop later this year, bringing drier conditions to northern Queensland in the months ahead.

As winter settles across the Reef, seasonal wildlife sightings are increasing. The annual humpback whale migration is now underway, with thousands of whales expected to travel through the Marine Park on their journey from Antarctic feeding grounds to breeding and calving areas in tropical waters. Dwarf minke whales are also beginning to arrive in northern Reef waters, while manta ray sightings have increased during these cooler months.

The return of these iconic species is one of the Reef's great natural spectacles and a reminder of the importance of protecting marine habitats. Visitors are encouraged to enjoy wildlife encounters responsibly by giving animals space to behave naturally and safely.

Temperature

Sea surface temperatures in the Far Northern and Northern regions remain approximately 0.5–0.8°C above long-term monthly averages. Temperatures in the Central and Southern regions are closer to average, sitting around 0.2°C above normal.

The Bureau of Meteorology forecasts sea surface temperatures to remain above average through winter and into August.

Climate forecasts suggest an El Niño may develop later this year, which can increase the likelihood of warmer and drier conditions across northern Queensland. However, other climate factors, such as conditions in the Indian Ocean and tropical weather systems that influence rainfall and cloud cover, also affect local weather, so conditions may vary across the Reef catchment.  

Rainfall

The Indian Ocean Dipole, which can influence regional rainfall patterns is currently neutral and forecasts remain uncertain.

Should both El Niño and a positive Indian Ocean Dipole develop during winter and spring, northern Queensland could experience drier-than-average conditions over the coming months.

Reef health

Over the past month, 521 Reef Health Impact Surveys were conducted across 43 reefs;

• In the Far Northern region, one reef was surveyed, recording no coral bleaching and low levels of coral damage.
• In the Northern region, 24 reefs were surveyed. Coral bleaching was recorded on 18 reefs, ranging from low (1–10%) to moderate (11–30%) prevalence. Coral damage was recorded on 20 reefs.
• In the Central region, 8 reefs were surveyed. Three reefs recorded low levels of coral bleaching and 7 reefs recorded low coral damage.
• In the Southern region, 10 reefs were surveyed. Eight reefs recorded low to moderate coral bleaching prevalence and four reefs recorded low coral damage.

Coral disease was recorded on 20 reefs across the Marine Park during the reporting period.

Additional Eye on the Reef monitoring programs reported coral bleaching on 29 of 41 reefs surveyed during May.

The coral bleaching observed across the Marine Park is likely associated with prolonged heat exposure experienced during summer, while much of the coral damage recorded in the Far Northern and Northern regions is consistent with impacts from Severe Tropical Cyclone Narelle.

Reef health update | 07 May 2026

Sea surface temperatures continued to ease across the Marine Park this week.

Queensland’s wet season has also come to an end, ranking as the 9th wettest on record since 1900, with most Marine Park catchments receiving above-average rainfall.

Climate conditions remain neutral, however, sea surface temperatures in the Pacific Ocean (between the Tropic of Cancer and the Tropic of Capricorn) are warming. Current Bureau of Meteorology outlooks indicate a possible El Niño developing by late winter, which could bring drier conditions to Northern Queensland in the months ahead.

Temperature

Sea surface temperatures declined slightly, dropping by 0.3–0.6°C across the Marine Park.

Over the coming month, temperatures are expected to sit close to average, although some offshore reefs in the Far Northern and Northern regions may remain slightly above average (up to 0.8°C).

Rainfall

With the start of the dry season, rainfall was below average across most catchments, with totals generally below 25mm. The Wet Tropics was the exception, receiving up to 150mm.

Looking ahead, forecasts suggest a low chance of above-average rainfall across the Marine Park during May.

Reef health

Over the past week, 49 Reef Health Impact Surveys were conducted across six reefs.

In the Northern region, five reefs were surveyed, with low to moderate coral bleaching recorded and low to moderate coral damage observed across all sites.

In the Central region, one reef was surveyed with no bleaching and low coral damage.

Coral disease was recorded on three reefs during this period.

Additional Eye on the Reef monitoring reported coral bleaching on 11 of 14 reefs surveyed across the Marine Park.

Crown-of-thorns starfish control

As of 30 April 2026, the Crown-of-Thorns Starfish Control Program and Reef Joint Field Management Program response teams have surveyed and, where needed, culled starfish on 204 reefs this financial year.

Of these reefs:

• Crown-of-thorns starfish are at sustainable levels on 91 reefs (45%)
• Active culling is underway on 67 reefs (33%) to suppress outbreaks
• 47 reefs (25%) have COTS present and will be targeted based on priority and operational conditions

The program uses a science-based prioritisation process to focus effort on reefs with high ecological and economic value, with the aim of maximising coral protection.

Reef health update | 30 April 2026

Sea surface temperatures continue to ease across the Marine Park, and with the changing of seasons we are seeing the last of the turtle hatchlings and seabird nesting, as humpback and Minke whales begin arriving in the Reef’s breeding grounds.

Queensland’s wet season is also coming to an end, with rainfall over the summer months among the highest levels recorded since 1900.

Temperature

Sea surface temperatures declined slightly, dropping by 0.3–0.5°C across the Marine Park, temperatures remain 0.4–0.5°C above the long-term April average.

Rainfall

Weekly rainfall totals were below average across most Marine Park catchments, with less than 50mm recorded.

Reef health

Over the past week, 43 Reef Health Impact Surveys were conducted across six reefs.

In the Northern region, four reefs were surveyed. Two recorded low coral bleaching, and three showed low to moderate coral damage. Higher bleaching levels in the Northern region are likely linked to prolonged heat exposure over summer combined with earlier flood plume impacts. Coral damage in the Far Northern and Northern regions is likely the result of storm impacts from Ex-Tropical Cyclone Narelle.

In the Central region, one reef was surveyed with no coral bleaching or damage recorded.

In the Southern region, one reef was surveyed with no coral bleaching or damage recorded.

No coral disease was observed over the past week.

Additional Eye on the Reef observations from across the Marine Park reported coral bleaching on 16 of 20 reefs surveyed.

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.

Reef health update | 23 April 2026

Ex-Tropical Cyclone Maila crossed Cape York Peninsula as a tropical low on 15 April, bringing moderate rainfall of up to 50mm to coastal Cape York and Wet Tropics catchments.

Sea surface temperatures continue to ease, and with the changing of seasons we are now seeing the first humpback whales arriving in the Marine Park, as they migrate from Antarctic waters to their traditional breeding grounds.

A recent Reef Authority and Queensland Parks and Wildlife Service voyage in the Far Northern region completed 75 surveys across five reefs, providing early insights into cyclone impacts. Reefs closest to Ex-Tropical Cyclone Narelle’s path showed moderate to severe structural damage, while more sheltered reefs to the south of the cyclone’s path recorded low to minimal impacts. Damage was generally higher on reef areas exposed to incoming waves. The team also observed island vegetation damage, localised erosion, and coral colonies washed up on beaches or cays, along with low levels of coral bleaching on two reefs.

Some planned sites could not be accessed due to weather conditions associated with Ex-Tropical Cyclone Maila; however, Crown-of-thorns starfish control teams are scheduled to return to these areas and are expected to access these sites and undertake surveys to improve our understanding of Reef health impacts.

Temperature

Sea surface temperatures declined slightly this week by around 0.1°C across the Marine Park. Temperatures remain 0.5–0.7°C above the long-term April average.

Rainfall

Weekly rainfall totals were average across most of the Marine Park catchments over the past week. Weekly totals reached up to 150mm in Cape York and the Wet Tropics, and up to 100mm in the Mackay–Whitsunday region.

Reef health

Over the past week, 225 Reef Health Impact Surveys were conducted across 22 reefs.

In the Far Northern region, five reefs were surveyed. Two recorded low bleaching, and all showed low to severe coral damage.

In the Northern region, five reefs were surveyed, with bleaching ranging from low to very high (up to 90%). Three reefs also recorded low to severe coral damage. Higher bleaching levels in the Northern region are likely linked to prolonged heat exposure over summer combined with earlier flood plume impacts. Coral damage in the Far Northern and Northern regions is likely the result of storm impacts from Ex-Tropical Cyclone Narelle.

In the Central region, 11 reefs were surveyed. Eight showed low to moderate bleaching, and four recorded low coral damage.

In the Southern region, one reef was surveyed, showing moderate bleaching and low coral damage.

Coral disease was recorded on six reefs across the Marine Park.

Additional Eye on the Reef observations from across the Marine Park reported coral bleaching on 12 of 17 reefs surveyed.

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.

Sea surface temperatures continued to cool, dropping by a further 0.4–0.6°C this week across the Marine Park.

Ex-Tropical Cyclone Maila has weakened and was downgraded to a tropical low on 11 April. The system crossed the Cape York Peninsula on 15 April, bringing moderate to heavy rainfall in some areas.

Encouragingly, the National Oceanic and Atmospheric Administration (NOAA) has now reduced the Coral Reef Watch Bleaching Alert Status to no stress conditions across the entire Great Barrier Reef Marine Park, following further drops in sea surface temperatures - reflecting heat stress easing across the Marine Park.

Since Ex-Tropical Cyclone Narelle, reports from the Eye on the Reef network have identified coral damage on some outer reefs in the Northern region. In response, the Reef Authority and Queensland Parks and Wildlife Service will carry out targeted Reef Health Impact Surveys in the Far Northern region in the coming weeks, weather permitting.

Temperature

Despite the recent cooling, sea surface temperatures remain 0.4–0.5°C above the long-term April average. The Far Northern and Northern regions are still experiencing the effects of accumulated marine heatwave exposure from earlier in summer, which may cause bleaching in some coral species.

Rainfall

Weekly rainfall totals were below average across most of the Marine Park catchments over the past week.

Reef health

Over the past week, 42 Reef Health Impact Surveys were conducted across seven reefs in the Marine Park.

In the Northern region, six reefs were surveyed, with coral bleaching ranging from low (1–10%) to very high (61–90%). These bleaching patterns in the Northern region are likely linked to heat stress and flood plume impacts that accumulated over the summer. Coral damage was also recorded on four of the six Northern reefs surveyed, ranging from low to severe, likely caused by storm impacts from Ex-Tropical Cyclone Narelle. Two reefs in the Northern region also recorded moderate levels of coral disease.

Limited surveys in the Far Northern region mean the full extent of coral bleaching is still emerging, but elevated levels are expected given its prolonged exposure to above-average sea surface temperatures.

In the Southern region, one reef was surveyed and no bleaching was recorded.

Additional Eye on the Reef observations from across the Marine Park reported bleaching on 16 of 32 reefs surveyed across the Marine Park.

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.

Reef health update | 9 April 2026

Sea surface temperatures continued to cool this week, dropping by 0.2–0.4°C across most of the Marine Park.

Tropical Cyclone Maila (37U) has now formed in the Solomon Sea and has rapidly intensified into a Category 5 system. Current Bureau of Meteorology forecasts show the system tracking into the Coral Sea, with a likely coastal crossing near Cape York Peninsula this weekend or early next week. Maila is expected to bring localised heavy rainfall, increasing the risk of flood plumes in the Marine Park and possible damage to coral and seagrass habitats from strong waves.

Encouragingly, coral bleaching alert levels have eased. The USA’s National Oceanic and Atmospheric Administration (NOAA), which monitors ocean temperatures globally, has downgraded the Northern, Central, and Southern regions to no stress conditions, following further drops in sea surface temperatures - reflecting heat stress easing across the Marine Park.

Temperature

Despite recent decreases in sea surface temperatures, they remain around 0.6–0.7°C above the long-term April average. The Far Northern and Northern regions are still experiencing the effects of accumulated marine heatwave exposure from earlier in summer, which may cause bleaching in some coral species.

Rainfall

Weekly rainfall across most catchments was average or below average, with totals generally under 100mm except for the Wet Tropics region receiving up to 150mm.

Rainfall in March was higher than usual across most Marine Park catchments, with the Cape York, Fitzroy and Burnett–Mary catchments having some of the highest March rainfalls recorded.

Reef health

Over the past week, 19 Reef Health Impact Surveys were completed across five reefs in the Marine Park.

In the Northern region, four reefs were surveyed with high (31–60%) to very high (61–90%) coral bleaching recorded on three reefs. These bleaching patterns in the Northern region are likely linked to heat stress accumulated over the summer combined with earlier flood plume impacts. All four reefs surveyed in the Northern region also showed severe coral damage, likely caused by storm impacts associated with Ex-Tropical Cyclone Narelle.

Limited surveys in the Far Northern region mean the full extent of coral bleaching is still emerging, but higher levels are expected given its prolonged exposure to above-average sea surface temperatures.

In the Central region, one reef was surveyed and no bleaching was recorded.

Additional Eye on the Reef observations from across the Marine Park reported bleaching on 11 of 19 reefs. No coral disease was recorded during the period.

Crown-of-thorns starfish control

As of 31 March 2026, the Crown-of-Thorns Starfish Control Program and Reef Joint Field Management Program response teams have surveyed and, where needed, culled starfish on 187 reefs this financial year.

Of these reefs:

Crown-of-thorns starfish are at sustainable levels on 80 reefs (43%).

Active culling is underway on 60 reefs (32%) to suppress outbreaks.

Starfish have been detected on 47 reefs (25%), and these reefs will be targeted for culling based on priority and actioned when operationally feasible.

The program uses a science-based prioritisation process to focus effort on reefs with high ecological and economic value, with the aim of maximising coral protection.

Sea surface temperatures continue to ease across the Marine Park this week, dropping by around 0.1–0.2°C.

Heavy rainfall from ex-Tropical Cyclone Narelle caused a major flood in the Far Northern region, with the Pascoe River reaching 19.3 metres - the highest level recorded in more than 50 years and likely a one-in-200-year event. The flood plume may affect nearby ecosystems like seagrass meadows and inshore reefs by lowering salinity and increasing exposure to sediments, nutrients, and pesticides.

The Bureau of Meteorology forecasts a tropical low (37U) may form near the Solomon Islands by Thursday, with a moderate to high chance of developing into a cyclone over the weekend. At this stage, it is expected to stay away from the Queensland coast over the next week.

Temperature

Despite recent decreases in sea surface temperatures, they remain around 0.7°C above the long-term monthly average. The Far Northern and Northern regions are still experiencing the effects of accumulated marine heatwave exposure from earlier in summer, which may cause bleaching in some corals species.

Rainfall

Weekly rainfall totals were mostly average or below average across the Marine Park catchment areas during the past week, with up to 100mm of rain recorded over the reporting period.

Reef health

Over the past week, 43 Reef Health Impact Surveys were conducted across seven reefs in the Marine Park. In the Northern region, five reefs were surveyed with coral bleaching ranging from low (1–10%) to very high (61–90%). In the Central region, two reefs were surveyed and no coral bleaching was observed.

Limited surveys in the Far Northern region mean the full extent of coral bleaching is still emerging, but higher levels are expected given its prolonged exposure to above-average sea surface temperatures.

Additional Eye on the Reef observations from across the Marine Park reported bleaching on 9 out of 24 reefs.

High levels of bleaching in the Northern region may be linked to prolonged heat exposure and impacts from flood plumes. Surveys also recorded moderate to extreme coral damage on three Northern reefs, likely from storm impacts related to Ex-Tropical Cyclone Narelle. One Central reef showed low damage from storms activity, and one reef had moderate coral disease.

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.

We are thinking of communities in the Far Northern region affected by Tropical Cyclone Narelle.

Tropical Cyclone Narelle passed through the Far Northern region of the Marine Park as a Category 5 system and crossed the Queensland coast as a Category 4 on 20 March. The cyclone generated intense winds and strong wave action along its track in the Far Northern Region, with modelling also indicating wide-spread high wave action in the Northern region, particularly across offshore reefs. The extent of damage will be assessed in the coming weeks.

The El Niño–Southern Oscillation (ENSO) climate pattern, La Niña, continues to weaken, and conditions are expected to return to a neutral phase in early autumn. However, forecasts suggest that by winter, the system may shift into an El Niño phase, which often brings warmer and drier conditions to much of Australia.

Temperature

Sea surface temperatures continue to fall across the Marine Park, with the largest drop (0.8°C) recorded in the Northern region, however they remain around 0.6°C above the long-term monthly averages.

Despite recent decreases in sea surface temperatures, some reefs in the Far Northern and Northern regions have accumulated heat stress exposure that can cause some coral species to bleach.

Rainfall

From 16–22 March, localised heavy rainfall was recorded in the Cape York and Wet Tropics catchments as Tropical Cyclone Narelle moved through the region. Weekly rainfall totals ranged from 200–450mm, with some locations receiving more than 100–200mm in a single day.

Flood warnings are active across parts of the Cape York catchment, and significant flooding has been reported in the Pascoe River, which is currently at record levels.

Reef health

Over the past week, 67 Reef Health Impact Surveys were completed across nine reefs in the Northern (between Innisfail and just above Cooktown), Central (between Mackay and Innisfail) and Southern regions (between Bundaberg and Mackay).

Coral bleaching in the Northern region varied from moderate (11–30%) to very high (61–90%). Of the five reefs surveyed, one reef also showed signs of coral mortality. These impacts are likely linked to a combination of exposure to ongoing heat stress and recent floodwaters.

In the Central region one reef was surveyed, with no bleaching recorded.

In the Southern region 3 reefs recorded medium (11–30%) coral bleaching prevalence.

Additional Eye on the Reef observations from across the Marine Park reported bleaching on 9 of 20 surveyed reefs. Coral damage was recorded on 6 reefs, and coral disease was observed on 3 reefs.

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.