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.