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.