Great Barrier Reef ‘coral nurseries’ show early signs of success

Pieces of broken coral are being salvaged and rehabilitated in “nurseries” so they can be transplanted to the Great Barrier Reef, but marine scientists say this is no substitute for action on climate change.

A recent UN report recommended that the reef be added to the “in danger” World Heritage List and called for “ambitious, rapid and sustained” action on climate change to protect the site.

The report was respected after UN officials visited the reef in March this year.

Despite fears of another coral bleaching event due to record warm temperatures in November, there is good news for the reef with coral nurseries in the far north which have recently benefited from spawning events of successful corals.

Several organizations collect broken or near-dead corals and rehabilitate them in coral nurseries in hopes of saving the Great Barrier Reef one broken piece at a time.

“Fragments of Opportunity”

Dr Emma Camp is Deputy Team Leader of the Future Reef Team at the University of Technology Sydney and co-founder of the Coral Nurture programme.

The program has planted over 76,000 pieces of coral on the Great Barrier Reef since 2018 at eight different sites between Cairns and the Whitsundays.

A floating platform underwater with corals growing on it
One of the floating nurseries off Cairns.(Provided: The Coral Nurture Program)

Dr Camp said they mainly use ‘opportunity shards’, which are corals that have naturally detached and would not normally survive.

The pieces are then attached to coral nurseries, which are floating aluminum frames, in the hope that the broken coral will regrow and repair itself.

“The pieces we replanted on the reef are fragments of opportunity that were collected and reattached to the reef that otherwise would have ended up in the sand and not survived,” Dr Camp said.

“We have documented that several species grow faster in the nursery than they do when naturally on the reef.

“We think it’s because they have an optimal environment in the nursery.

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Coral cleaned at one of Reef Restorations’ coral nurseries.(Provided: Reef Restoration Foundation)

“Once the corals are large enough, we remove small cuts from the coral and replant them on the reef.

“We’ve actually seen our corals spawn in the nursery, which is great because we’re putting more material back into the system.”

‘No replacement for climate action’

Despite continued success, Dr Camp said climate change was still the biggest threat to the reef.

“It doesn’t matter what the restoration process is. We basically have to fight climate change and we have to fight addiction to fossil fuels. Otherwise, we’re going to continue to see coral bleaching.

“What we’re doing is trying to buy time and build resilience, but that’s not a substitute for climate action.”

Broken pieces of coral floating in the water
Broken pieces of coral can get a second chance if found quickly enough and grown in the right conditions.(Provided: Reef Restoration Foundation)

New crèches

Ryan Donnelly is the CEO of the Reef Restoration Foundation (RRF), which has coral nurseries set up off Fitzroy Island and Hastings Reef, 55 kilometers northeast of Cairns.

A new nursery is also about to be installed off Moore Reef, 50 kilometers east of Cairns.

“Our nurseries are made up of what we call coral tree frames, which are just PVC pipes with crosspieces on which we can hang coral,” Donnelly said.

“By hanging them, they are safe from attack by pests, predators and competitors, and they also benefit from prolonged access to sunlight for photosynthesis.

“Corals are actually growing faster and becoming healthy; we are accelerating the natural recovery process.”

‘Make the difference’

Last month, corals grown at the Coral Nursery off Fitzroy Island, near Cairns, spawned for the first time after being planted four years ago.

A scuba diver cleaning small coral fragments with a brush underwater
Cleaning up a coral tree laden with broken coral fragments off Fitzroy Island.(Provided: Reef Restoration Foundation)

“It was the first time we witnessed this and it may be the first time it has happened,” Mr Donnelly said.

“It gives us a lot of confidence to move forward and we’ve learned a lot in the five years we’ve done this. It’s given us extra momentum to keep going because we’re making a difference.

“It’s not just this site. When you spawn corals, these fertilized larvae settle in distant reefs, so all levels of coral restoration make a difference.”

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