Reef Health Updates

About Reef Health Updates

As the lead managers of the Great Barrier Reef, the Reef Authority keeps an eye on the Reef year-round — with efforts stepped up over summer, a typically high-risk period from extreme weather. The Reef Authority releases updates on the health of Reef which includes; sea surface temperatures, rainfall and floods, cyclones, crown-of-thorns starfish outbreaks, and coral disease. These updates are based on forecasts, water temperature heat mapping, in-water surveys, citizen science and aerial surveys.

Publisher

Great Barrier Reef Marine Park Authority

Category

science · society & culture

Language

en

Explicit

No

First episode

8 Jan 2026

Latest episode

4 Jun 2026

Latest episodes

18 episodes in the feed.

1. 

   4 Jun 2026

   Reef health update | June 2026

   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.

2. 

   7 May 2026

   Reef health update | 7 May 2026

   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.

3. 

   30 Apr 2026

   Reef health update | 30 April 2026

   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.

4. 

   23 Apr 2026

   Reef health update | 23 April 2026

   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.

5. 

   16 Apr 2026

   Reef health update | 16 April 2026

   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.

6. 

   9 Apr 2026

   Reef health update | 9 April 2026

   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.

7. 

   2 Apr 2026

   Reef health update | 2 April 2026

   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.

8. 

   26 Mar 2026

   Reef health update | 26 March 2026

   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.

9. 

   19 Mar 2026

   Reef health update | 19 March 2026

   Tropical Cyclone Narelle (currently Category 5) has developed in the Coral Sea and is forecast to decrease to a Category 4 before crossing the Far Northern region of the Marine Park and making landfall on Friday. The system is expected to bring strong wind and wave action and heavy rainfall, which are likely to damage some reefs and increase the likelihood of freshwater runoff into the Marine Park. Sea surface temperatures have eased slightly over the past week, particularly in the Northern region (between Innisfail and just above Cooktown), while remaining relatively stable elsewhere. Encouragingly, coral bleaching alert levels have eased in recent days. The USA’s National Oceanic and Atmospheric Administration (NOAA), which monitors ocean temperatures globally, has downgraded the Far Northern and Northern regions to bleaching watch status following a drop in sea surface temperatures. Most other areas of the Marine Park are expected to return to no heat stress conditions. Temperature Temperatures are still slightly above the long-term monthly average for March across the Marine Park. The Far Northern (between Cape York and north of Cooktown) region is around 0.6°C above average, the Northern region (between Innisfail and just above Cooktown) around 1.1°C above average, and the Central (between Mackay and Innisfail) and Southern (between Bundaberg and Mackay) regions are around 1°C above average. Despite recent decreases in sea surface temperatures, some reefs in the Far Northern and Northern regions have accumulated exposure to heat stress that can cause some coral species to bleach. The most likely outlook from NOAA’s four-month forecast suggests heat stress will remain low to moderate across the Marine Park into winter. Rainfall From 9–15 March, heavy rainfall occurred in parts of the Burnett–Mary, Wet Tropics and Fitzroy catchments. Weekly totals ranged from 300–400mm in some areas, with several locations receiving more than 200mm in a single day. Rainfall in the Burnett–Mary catchment is among the highest on record for this time of year. Flooding has been reported in the Burnett River, and flood warnings remain in place across affected catchments. These conditions may lead to freshwater runoff into the Marine Park, which will continue to be monitored. Reef health Over the past week, 139 Reef Health Impact Surveys were completed across 19 reefs in the Far Northern, Northern and Central regions. In the Far Northern region, most surveyed reefs showed no to low coral bleaching, with a small number recording low to medium levels (1–30%), and no fully bleached coral or mortality observed. Coral bleaching in the Northern region varied, from moderate to very high (11–90%). Of the six reefs surveyed, four showed moderate to very high levels of coral bleaching. On these reefs, some corals were fully bleached, and two reefs also recorded small areas of coral mortality. These impacts are likely linked to a combination of exposure to recent heat stress and floodwaters. In the Central region, one reef recorded low levels of bleaching, with no fully bleached coral or mortality. Additional observations from Eye on the Reef monitoring programs reported coral bleaching on 9 of the 22 reefs surveyed. Coral damage was recorded on 12 reefs and coral disease on seven 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.

10. 

    12 Mar 2026

    Reef Health Update | 12 March

    Reef health update - 12 March 2026 Sea surface temperatures eased slightly across the Marine Park over the past week. A tropical low crossed the Marine Park on 5–6 March. The system, together with a monsoon trough, brought heavy rainfall to the Cape York, Wet Tropics and Mackay–Whitsunday catchments. While this has helped keep temperatures down across the Reef, it also increases the likelihood of freshwater runoff entering the Marine Park. Another tropical low (34U) is forecast to develop in the Coral Sea off the East Coast of North Queensland. Forecasts continue to be monitored for any potential impacts to the Reef. Temperature Over the past week sea surface temperatures dropped from around 30°C to 29.1°C in the Far Northern region following recent weather systems. Sea surface temperatures in other regions also declined slightly, by around 0.1–0.4°C. Despite this, sea surface temperatures remain above the long-term average. The Far Northern, Central and Southern regions are currently around 0.7–0.9°C above average, while the Northern region remains around 1.3°C above average. As a result, heat stress continues to build across parts of the Marine Park. Some reefs in the Far Northern and Northern regions are experiencing conditions that may lead to bleaching in heat-sensitive corals. Rainfall From 2–8 March, heavy rainfall fell across the Cape York, Wet Tropics and Mackay–Whitsunday catchments. Weekly totals reached 300–400mm in some areas, with several locations receiving more than 200mm in a single day. Overall, rainfall for March so far is above to well above average in these regions. Heavy rainfall can increase the risk of freshwater runoff entering the Marine Park. Reef health Over the past week, 73 Reef Health Impact Surveys were completed across nine reefs in the Northern and Central regions. Monitoring shows that coral bleaching impacts remain varied across the reefs surveyed. Surveys on reefs in the Northern region recorded coral bleaching ranging from low levels (1–10%) to very high levels (61–90%). One reef in the Central region recorded medium bleaching levels (11–30%). Two reefs in the Northern region recorded small areas of fully bleached coral (less than 5%) and low levels of recent coral mortality (less than 3%). Coral damage was recorded on five reefs and coral disease was observed on four reefs. Additional observations from the Eye on the Reef monitoring programs also reported coral bleaching on eight of the 13 reefs surveyed. In the coming weeks, Reef Authority and Queensland Parks and Wildlife Service teams will carry out additional surveys in areas that have experienced high heat exposure to better understand impacts on reef health. 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 were also in the field sampling flood waters from the Annan and Endeavour rivers, with further sampling planned for the Normanby River in the coming week. The Reef Authority’s management decisions are informed by data collected by our teams on the water, including the Reef Joint Field Management Program and Crown-of-thorns Starfish Control Program as well as the collaborative efforts of researchers, tourism operators, contractors and partners. Management actions remain focused on supporting Reef resilience, including enforcing compliance with zoning rules and encouraging responsible use of the Marine Park. #reefhealth #lovethereef #greatbarrierreef

11. 

    5 Mar 2026

    Reef Health Update | 5 March 2026

    A tropical low is developing in the Coral Sea off the east coast of North Queensland. The Bureau of Meteorology advises there is currently a low to moderate chance of it developing into a tropical cyclone. Increased wave action from this system may affect some shallow reef habitats. Monsoonal activity and the tropical low are expected to bring heavy rainfall to most Marine Park catchments. This increases the risk of flooding and freshwater runoff into the Marine Park. SeaWeek 2026 is being celebrated from 28 February to 8 March, with this year’s theme “Caring for Planet Water”. The week highlights the importance of ocean literacy and the role healthy oceans play in regulating climate, supporting biodiversity and sustaining communities. It’s a timely reminder of the connection between weather, water quality and Reef health, and the shared responsibility to care for our marine environment. Temperature Heat stress continues to build across parts of the Marine Park. Some reefs in the far northern and northern regions are experiencing conditions that may lead to bleaching in heat-sensitive corals. Over the past week, sea surface temperatures in the far northern region increased from 29.5°C to 30°C and are now about 1.5°C above the long-term monthly average. Sea surface temperatures in the north regions are also about 1.5°C above the long-term monthly average while those in the Central and Southern regions remained relatively stable at 0.8°C to 1°C above average. Rainfall Rainfall was average across most Marine Park catchments over the past week. However, monsoonal activity and the tropical low are expected to bring heavier rainfall in the coming week. Reef health Over the past week, 91 Reef Health Impact Surveys were completed across six reefs in the northern and central regions. Low levels of coral bleaching (1–10%) were recorded on four northern reefs and one central reef. One northern reef also recorded low levels of physical damage (e.g. from anchors). No disease was recorded in surveys. Eye on the Reef monitoring programs also reported coral bleaching on 12 of the 28 reefs surveyed. No surveyed reefs showed fully bleached or recently dead coral colonies. Crown-of-thorns starfish control As of 28 February 2026, the Crown-of-Thorns Starfish Control Program and Reef Joint Field Management Program response teams have surveyed and, where needed, culled starfish on 157 reefs this financial year. Of these reefs: Crown-of-thorns starfish are at sustainable levels on 61 reefs (39%). Active culling is underway on 57 reefs (36%) to suppress outbreaks. Starfish have been detected on 39 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. Our response and ongoing work 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 from across the World Heritage Area.

12. 

    26 Feb 2026

    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.

13. 

    12 Feb 2026

    Reef Health Update | 12 February 2026

    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 (http://www.gbrmpa.gov.au/learn/reef-health/reef-health-updates)

14. 

    5 Feb 2026

    Reef Health Update | 5 February 2026

    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.

15. 

    30 Jan 2026

    Reef Health Update | 22 January 2026

    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.

16. 

    30 Jan 2026

    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.

17. 

    15 Jan 2026

    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.

18. 

    8 Jan 2026

    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 (https://www2.gbrmpa.gov.au/our-work/programs-and-projects/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.

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