Several reefs around Queensland’s Whitsunday Islands have been destroyed or very badly damaged by Cyclone Debbie, a survey has revealed.

Authorities are not sure how much of the vast Great Barrier Reef network has been killed or affected by the category four storm and if or how long it will take to recover.

Queensland Parks and Wildlife Service and the Great Barrier Reef Marine Park Authority (GBRMPA) began its study last week and they are expected to continue through the coming week.

Early surveys have found popular snorkelling spot Blue Pearl Bay, near Hayman Island, and Manta Ray Bay, off Hook Island, sustained extensive damage in the cyclone.

Reefs off Hook Island’s Luncheon Bay, Maureens Cove and Butterfly Bay are also partly destroyed.

The cyclone’s eye crossed the islands nearly two weeks ago, generating wind gusts up to 260 kilometres per hour.

Coral was snapped and a blanket of algae has grown over the dead and rotting coral, which lies pulverised on the sea floor.

Some that survived has turned white, having bleached due to stress.

Only large coral, called bommies, have been left standing in some of the areas surveyed so far.

Senior GBRMPA ranger Darren Larcombe said the entire substrate at Manta Ray Bay has been wiped out.

Some areas which were protected from the winds, such as Stonehaven near Hook Island, was found to have healthy coral.

“We are finding small areas of reasonable coral, there’s damage and its widespread, but there are pockets of nice coral that’s reasonably healthy,” he said.

The cyclone’s cost to tourism has not been calculated, but tourism operators said the region was open for business.

Tourism operators from Cairns have been called in to help find sites that may have survived.

Association of Marine Park Tourism Operators’ Brendon Robinson said wet weather, strong winds and poor visibility had hampered efforts to assess the damage.

“The feedback that’s coming back is the more sheltered areas have come out a bit better, but they all seem to suffered some form of damage,” he said.

A piece of coral sits above the water after being ripped up and overturned during the cyclone. Photo: GBRMPA

Tourism operators open for business

Nineteen-year-old Anna Renwick has volunteered to help scientists with the survey until her dive company starts fully operating again.

They are snorkelling but not yet diving.

“We don’t have a place to go diving at the moment,” she said.

“It’s going to take a couple of weeks.”

Park rangers have been working non-stop to clean up the debris from popular camping sites on the Whitsunday and Airlie Beach.

Hill Inlet and Tongue Point are already open and Whitehaven Beach will be ready by Easter.

Tourism Whitsundays spokesman Craig Turner said the region is ready to start receiving visitors again.

“The Whitsundays is known as an aquatic playground, sailing, cruising around the islands, we’re still able to achieve a great result for the tourists,” he said.

-ABC