A Reef survey voyage is heading from Cairns to Thursday Island to check the impact of Severe Tropical Cyclone Narelle on the far northern Great Barrier Reef.

Scientists warn some reefs may have been hit by destructive 13-metre-high cyclonic waves as well as coral bleaching from a marine heatwave over summer.

The two-week mission by the Reef Authority and Queensland Parks and Wildlife Service (QPWS) will target about 60 priority reefs north of Lizard Island, where numerical wave models suggest the worst damage is most likely at mid to outer shelf reefs.

Other priority sites with high cultural values, island infrastructure, and seabird and turtle nesting habitats will also be assessed.

Reef Authority Chief Scientist Dr Roger Beeden said the voyage would deliver the first true picture of cyclone damage in the water.

• “We will not know the real extent of the damage until our scientists are on the reef and under the water,” Dr Beeden said.

“Models show very large waves were possible on far northern reefs, with significant wave heights up to 13 metres north of Princess Charlotte Bay. It is possible individual waves during Narelle may have been up to twice as high,’’ he said.

“On coral reefs, cyclone damage is always patchy. One part of a reef can be badly hit while another section can escape major damage because the reef itself absorbs wave energy and creates shelter behind it.

“These voyages are critical. They turn modelling into hard evidence and help direct our response where it is needed most.”

Dr Beeden said Narelle was an exceptionally rare cyclone.

“Narelle lasted 18.5 days. Globally, cyclones last less than four days on average,” he said.

“Most systems weaken quickly over land or cooler water. Narelle did not. It tracked close to coral reefs across northern Australia from March 15 to 27.”

QPWS ranger and trip coordinator Aurora Spicer said the joint survey using drones and in-water surveys would help assess extremely remote reefs hit by the storm.

• “These surveys are vital in the far northern Marine Park, where damage can be severe but also highly localised,” Ms Spicer said.

“Our teams are working side by side with Reef Authority scientists to assess impacts on the water and build a clearer picture of reef condition.”

“That information will help guide management action and support the Reef’s recovery and resilience.”

The survey comes as broader Reef monitoring shows mixed conditions.

Sea surface temperatures have cooled across most of the Marine Park but remain slightly above the April average. Bleaching risk has eased, with NOAA Coral Reef Watch downgrading the Northern, Central and Southern regions to “no stress”.

In the Northern region near Cairns, a regional coral bleaching event has been linked to earlier heatwaves and flood plume impacts. All four northern reefs recently surveyed also showed severe storm damage from ex-Tropical Cyclone Narelle.

For interviews, stills and vision, click here: Field Management Reef Health response trip | Media package | Brandfolder

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Contact: Great Barrier Reef Marine Park Authority
Media Hotline: (07) 4750 0846 | media@gbrmpa.gov.au