Pieces of broken coral are being rescued and rehabilitated in "nurseries" so they can be transplanted back onto the Great Barrier Reef, but marine scientists say it's no substitute for action on climate change.
A recent report from the UN has recommended that the reef be added to the World Heritage "in danger" list, and urged "ambitious, rapid and sustained" action on climate change to protect the site.
The report was complied 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 some good news for the reef with the coral nurseries across the far north recently enjoying successful coral spawning events.
Several organisations are collecting broken or near-dead coral and rehabilitating it in coral nurseries in the hope of saving the Great Barrier Reef one broken piece at a time.
'Fragments of opportunity'
Dr Emma Camp is the deputy team leader of the future reef team at the University of Technology Sydney and the co-founder of The Coral Nurture Program.
The program has planted more than 76,000 pieces of coral on the Great Barrier Reef since 2018 at eight different sites between Cairns and The Whitsundays.
Dr Camp said they primarily used "fragments of opportunity", which are corals that have naturally broken off and would not normally survive.
The pieces are then attached to the coral nurseries, which are floating aluminium frames, in the hope of the broken coral regrowing and repairing.
"The pieces that we have planted back onto the reef are fragments of opportunity that were collected and re-attached to the reef that otherwise would have ended up in the sand and would not have survived," Dr Camp said.
"We've documented that several species grow faster in the nursery than they do when naturally on the reef.
"We think that is because they have an optimal environment in the nursery.
"Once the corals are big enough, we take small clippings off the coral and out-plant them back onto the reef.
"We have actually seen our corals spawn in the nursery, which is great because we get more material back into the system."
'No replacement for climate action'
Despite the ongoing success, Dr Camp said climate change was still the biggest threat to the reef.
"It doesn't matter what the restoration process is. We fundamentally must address climate change and we have to address the reliance on fossil fuels. If not, we are going to continue to see coral bleaching.
"What we are doing is trying to buy time and increase resilience, but it is not a replacement for climate action."
New nurseries
Ryan Donnelly is the CEO of the Reef Restoration Foundation (RRF), which has coral nurseries set up off Fitzroy Island and Hastings Reef 55 kilometres north-east of Cairns.
A new nursery is also about to be installed off Moore Reef 50 kilometres due east of Cairns.
"Our nurseries are made up of what we call coral tree frames, which is just PVC pipe that has cross members that we can hang coral off," Mr Donnelly said.
"By hanging them, they are free from attack by parasites, predators and competitors, and they also get prolonged access to sunlight for photosynthesis.
"The corals actually grow faster and into a healthy state; we accelerate the natural process of recovery."
'Making a 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.
"It was the first time we had witnessed it and it could possibly be the first time it happened," Mr Donnelly said.
"It gives us a lot of confidence moving forward and we have learnt a lot in the five years that we have been doing this. It has given us added impetus to keep going because we are making a difference.
"It's not just about that site. When you get corals to spawn, those fertilised larvae settle in distant reefs so all levels of coral restoration makes a difference."
Despite regrowing broken coral and seeing it spawning for the first time, Mr Donnelly said more needed to be done to address climate change.
"Nothing is going to turn this ship around unless we are able to stop the march of global warming," he said.
"We have a hell of a challenge ahead of us in terms of global warming but, in the meantime, there is a role for just about everyone in the world to make some sort of a difference."
Working together
Great Barrier Reef Foundation managing director Anna Marsden said more regular and severe heatwaves were being experienced on the reef.
"There have been six mass bleaching events since 1998, which don't allow the reef enough time to naturally recover," she said.
"Coral restoration efforts combine the knowledge of our marine science experts with the experience and resources of the tourism operators who are out on the reef every day.
"Together their actions are helping to accelerate the natural recovery of local reefs."
