I’ve planted coral. I want to say upfront that I’m aware of the complexity around that statement — the debates about whether reef restoration is a meaningful response to a climate-driven problem, the questions about genetic diversity and transplant survival, the risk that “someone is fixing it” becomes an excuse to not address the causes. I’ve read those arguments carefully and I think they’re important.
I also think the people I spent three days with off the coast of Townsville, painstakingly attaching coral fragments to steel frames on a degraded section of reef, are doing something that matters.
The Scale Problem — and Why Restoration Exists Anyway
The honest context for coral reef restoration is this: the Great Barrier Reef contains approximately 348,000 square kilometres of reef area. The coral area in need of restoration — degraded, bleached, or dead sections — is in the tens of thousands of square kilometres. The capacity of any current restoration program to cover that area is a fraction of a fraction of a percent.
Reef restoration, done at current scales, cannot save the Great Barrier Reef. Anyone telling you otherwise is either misinformed or selling something.
What restoration can do — and this is not nothing — is maintain genetic diversity in degraded reef sections during the period when ocean temperatures are being brought under control; demonstrate proof-of-concept techniques that could be deployed at scale if the technology and funding are available; provide ecologically significant interventions at specific high-value sites; and — critically — keep scientific and public engagement with reef recovery active, because the reef needs advocates as much as it needs fragments.
The Main Approaches
Coral gardening is the most widely practised restoration technique. Fragments of coral are broken or cut from healthy colonies, suspended on underwater structures (trees, frames, or ropes) in well-circulated water where they grow rapidly, then transplanted to degraded reef substrate once they’ve reached sufficient size. The technique is borrowed from mariculture practice developed in the Caribbean and has been adapted extensively for Indo-Pacific reef conditions.
The advantage of coral gardening is that it’s relatively low-technology and can be performed by trained volunteers as well as professional divers. The disadvantage is that it produces genetically limited stock — most fragments are clones of a small number of donor colonies — and transplant survival rates on severely degraded substrate can be low.
Assisted gene flow is a more recently developed approach that involves identifying naturally heat-tolerant coral genotypes — colonies that survived bleaching events that killed their neighbours — and using their gametes or fragments to produce offspring with enhanced thermal tolerance. These offspring are then transplanted to reef areas, with the goal of producing populations that can survive future warming events better than the wild-type corals they replace.
Research groups at the Australian Institute of Marine Science and James Cook University have been developing heat-tolerant coral strains through selective breeding and, more controversially, by introducing symbiotic algae strains (Durusdinium trenchii, a more thermally tolerant zooxanthellae species) to coral larvae. The trials are in early stages, but initial results suggest that assisted evolution can produce corals with meaningfully improved bleaching resistance.
Coral spawning capture and larval seeding involves collecting the mass coral spawn — the annual simultaneous gamete release that occurs on the GBR in late spring — concentrating larvae in protected onshore tanks, allowing them to develop to the settlement stage, and then delivering them to degraded reef areas where they settle on prepared substrate and establish new colonies. The technique, pioneered largely by researchers at the Southern Cross University and AIMS, has successfully produced new coral colonies at trial sites and is being scaled up.
The Volunteers and the Work
The dive I described at the opening of this article was through Reef Restoration Foundation, an organisation based in Townsville that runs coral nurseries on degraded reef sections off the North Queensland coast and recruits volunteer divers to assist with maintenance, fragment harvesting, and transplanting.
The work is not glamorous. On the first day, I cleaned the coral nursery frames — removing algae and invertebrates that compete with the growing coral fragments — a task that requires a soft brush, patience, and the buoyancy control to avoid disturbing the frames without touching the coral. On the second day, I harvested fragments from donor colonies and attached them to nursery frames. On the third day, I transplanted month-old fragments from the nursery to a reef section that had been cleared of competitors.
At the end of three days, I had contributed a few hundred coral fragments to an area of reef that, if conditions remain stable, will show visible recovery within two to three years.
The scope is small. The feeling of having done something specific and physical and concrete for a reef I care about is not small. Both things are true.
What Needs to Happen for Restoration to Matter
The conditions under which restoration efforts could have a meaningful effect on reef outcomes are not mysterious. They are:
Rapid and substantial reduction in greenhouse gas emissions, bringing ocean warming under control and extending the intervals between mass bleaching events to allow genuine reef recovery.
Improved water quality in GBR catchments, reducing the nutrient runoff that drives crown-of-thorns outbreaks and degrades reef resilience.
Investment in scaling restoration technology — particularly larval seeding and assisted gene flow — from proof-of-concept trials to genuine operational capacity.
Political will to enforce, fund, and sustain all of the above across timescales measured in decades rather than electoral cycles.
None of this is technically impossible. The science is largely done. The techniques are established or in advanced development. The constraints are political and economic, which is to say they are human constraints — the kind that humans have, historically, occasionally been persuaded to overcome.
Where to Get Involved
For divers who want to contribute to reef restoration directly, several organisations in Queensland accept trained volunteer divers:
Reef Restoration Foundation runs regular volunteer programs off Townsville and occasionally Cairns. The Australian Coral Reef Society publishes information on research programs seeking citizen science participants. Many liveaboard operators in the Coral Sea have partnerships with restoration and monitoring programs that guests can contribute to.
The minimum requirement for most programs is Open Water certification and a willingness to do repetitive, careful work over multiple dives. Advanced certification and previous experience with buoyancy-sensitive tasks helps but isn’t always required.
Go. Plant something. The reef will do the rest, if we give it the chance.
