Some of the massive coral bommies rolled onto the tidal flats by Cyclone Debbie at Manta Ray Bay in the Whitsundays. Image: Queensland Parks and Wildlife Service

The thriving inshore reefs at Manta Ray Bay in the Whitsunday Islands were one of the region’s most popular snorkelling sites until wave action from Severe Tropical Cyclone Debbie virtually demolished them in March 2017, uprooting hundreds of tonnes of huge Porites boulder coral bommies and pushing them toward the beach into the intertidal zone.

Whitsundays tourism figure Al Grundy was serving as Chair of Tourism Whitsundays at the time and said the bay had hosted “the most amazing corals” but the cyclone damage had all but destroyed it environmentally and economically.

“We couldn’t really get boats in to the beach anymore and the reefs were gone. Everything else was just rubble. So it looked like a total loss.”

Al Grundy appealed to the Queensland Parks and Wildlife Service (QPWS) for help, resulting in a bold collaborative operation between the tourism industry, reef managers and researchers to try to improve the situation.

After a rigorous project assessment including safety, biosecurity, ecological and environmental considerations and a cost-benefit analysis, the decision was made to attempt to physically return the Porites bommies to the reef.

Over the course of a single day at low tide, trained machine operators contracted to QPWS moved 400 tonnes of the bommies back into the deeper water using cranes and other heavy equipment.

The project cost about $30,000 and was funded by QPWS under the Tropical Cyclone Debbie recovery fund.

Heavy machinery including cranes and excavators were used to move the bommies back into deeper water. Image: Queensland Parks and Wildlife Service

Did it work?

Sixteen months after the operation, a team working to evaluate the effectiveness of various reef restoration efforts as part of NESP Tropical Water Quality Hub Project 4.3 conducted a rapid ecological survey of the repositioned Porites bommies. They found promising signs of recovery, including partially surviving Porites colonies, new coral recruits and thriving fish populations. Importantly, tourism visitation to Manta Ray Bay had also resumed. Their survey findings have recently been published in the journal Ecological Management and Restoration.

Project leader Dr Ian McLeod of James Cook University’s TropWATER facility said all the indications from the survey were encouraging. “What it really looks like is that this is an intervention action that has been quite successful,” he said.

“There has been new coral recruitment and a return of fish populations, plus local tourism operators are now using it as a snorkel and dive site again. Early indications are that, yes, it was worth it.

“For restoration efforts like this to remain successful in the long term, however, it’s essential that strong action is taken to reduce greenhouse gas emissions to tackle climate change.”

A scientific diver carries out surveys on repositioned bommies at Manta Ray Bay. Image: Dr David Williamson

The evaluation also provided ‘lessons and recommendations’ including that bommies should be returned to as close as their original positions as fast as possible and that thorough impact assessments were vital to obtaining the needed authorisation to undertake the works.

Mr Grundy said the restoration works meant that the island’s reefs were ‘like a phoenix, rising from the ashes’. “We’ve seen this economic benefit return to the region, also the private visits are back so there is that social benefit as well,” he said.

“I think this a great example of how there is this changing attitude toward reef restoration projects. Even if it’s on a relatively small scale like this, when it comes to reefs, sitting on our hands just isn’t an option anymore.”


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