Scientists have made a "game-changing" breakthrough they hope will future-proof Queensland's oyster farming industry against the devastating impacts of climate change.
Researchers in the state's south-east have successfully bred Blacklip rock oysters, a fast-growing, disease-resistant, heat-tolerant species they hope will help the clean green aquaculture industry not only survive but expand exponentially.
Blacklip rock oysters have been reared in a Northern Territory hatchery, but never this far south, where most of Queensland's farms are currently located.
At the Bribie Island Research Centre, Queensland Fisheries' scientists Max Wingfield and Aiden Mellor are working to give growers options in what and where they farm.
All but one of Queensland's oyster farmers produce Sydney rock oysters.
The oysters prefer cooler water and their northern limit is the Town of 1770, restricting oyster farms to just 15 per cent of Queensland's vast coastline.
Sydney rock oysters have been plagued by the parasitic 'QX' disease, which wiped out many oyster crops in New South Wales this year.
"We're trying to find another species that oyster farmers can grow together, so when they have one problem with one oyster, the other one can still get to market," Mr Mellor said.
It was a tricky task to get the mollusc's planktonic free-swimming larvae to "settle" and form shells in the Bribie Island Research Centre's oyster nursery. The spat (baby oysters) had to survive winter outside in the salt-water ponds.
Huge potential
Blacklip rock oysters can be farmed much more widely geographically, but there has been a major barrier.
The process of catching their young in the wild and successfully raising them is time-consuming, unreliable, and frustrating.
Bowen Fresh Oysters owner, John Collison, runs Australia's only Blacklip rock oyster farm.
It takes up to eight months of growth to tell whether the spats he has gathered from ocean currents are Blacklip rock oysters or other more plentiful, less productive species. The success rate is just five to 10 per cent.
"The hatchery is much more efficient," Mr Wingfield said.
"We can provide 100 per cent Blacklip oyster spat, with all the advances that modern aquaculture is making with selective breeding and improvement."
Queensland's oyster aquaculture industry was valued at just $500,000 in 2019–2020, but Fisheries Minister Mark Furner described the breeding breakthrough as "a game-changer."
"Blacklips and other tropical rock oysters have an estimated production value of $72.6 million, potentially more than double the value of the barramundi industry," Mr Furner said.
Mr Collison agreed the research could transform oyster farming.
The 72-year-old, who has been growing oysters for more than 40 years, said it would cut his work by three-quarters.
"It's unbelievably good," he said.
"I owe them the world with what they've done.
"They [Blacklip] are a fantastic oyster. They're really hardy, they handle a lot of temperature range, they cop a flogging, and they just go go go — and they taste really good."
Another 35 prime adult oysters have been sent from Bowen to the research centre so the breeding experiment can be replicated.
Feeding them a special diet of microalgae, the scientists will attempt to get the broodstock to spawn in January 2023, with the aim of delivering hundreds of thousands of juvenile oysters north to the farm.
Baby steps
Much more work will be needed before the industry can be expanded.
Blacklip rock oysters have been found as far south as the Town of 1770 in Queensland, but the full extent of their range is unknown because most of Australia's ancient shellfish reefs have been destroyed.
"Because they're not recognised as native to Moreton Bay, we have to go through the appropriate process," Mr Wingfield said.
"The regulators need to be confident that the Blacklip wouldn't pose any sort of an environmental problem if they were farmed in south-east Queensland."
Oyster farming is considered one of the cleanest forms of aquaculture. They do not require feeding, and farms provide habitat for other species.
"They do a fantastic job in filtering and cleaning the water and improving the water quality of the environment," Mr Wingfield said.
