Cyclone-hammered reefs can take many years to recover

Storm-ravaged coral reefs might never have the years required to recover if tropical cyclones become more intense and frequent due to climate change, marine researchers say.

A study of coral reefs off Queensland's Whitsunday Islands hammered by severe category four Cyclone Debbie in 2017 showed it could take many years for corals and their fish populations to recover.

"Even six years after Cyclone Debbie, we still found that coral cover remained up to 69 per cent less than it was before," lead researcher Maya Srinivasan said.

"Both damselfish and butterflyfish species' richness and density were significantly lower than they were pre-cyclone".

Debbie sat on the reefs for hours, snapping off robust, large boulder corals and leaving them upside down.

"When it's that destructive, it takes a long time for reef communities to come back," Dr Srinivasan said.

Climate change models predict tropical cyclones will become more intense and frequent, which is bad news for the Great Barrier Reef and its lucrative tourist industry.

Coral reefs hard hit by severe cyclones might need 10 to 15 years to make a full recovery, Dr Srinivasan, of the Australian Institute of Marine Science (AIMS), told AAP.

"But if you get cyclones happening more frequently than that, then they may never have time between events to recover."

Meanwhile, reefs could be hit by coral bleaching events and harmful freshwater run-offs from the land.

But Dr Srinivasan said there were still great reef spots to visit at the Whitsundays, which rely on visits by hundreds of thousands of tourists every year.

The reef research was jointly conducted by AIMS, James Cook University and the Great Barrier Reef Marine Park Authority.