Reef Health Updates

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.

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.

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.

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.

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.