ABOUT 30,000 oysters bred to be genetically resistant to a devastating disease have been released into Tasmanian waters for the first time.
The baby oysters, called spat, are carrying the hopes of the nation’s oyster industry.
Over the next couple of weeks, scientists and industry will be watching closely to see whether the 3mm specimens can tough out the threat of the Pacific Oyster Mortality Syndrome present in the waters swirling around them.
Australian Seafood Industries, which has co-ordinated the selective breeding program, hopes the survivors might be able to get to hatcheries as soon as possible.
“Selectively bred POMS-resistant oysters are essential for the long-term survival of the industry,” ASI general manager Matt Cunningham said.
Last week’s release of genetically resistant spat are the result of five years of selective breeding.
Hobart-based CSIRO scientist Peter Kube said crews would begin testing survival rates over the next two weeks at the release sites, Little Swanport and Pipeclay Lagoon.
“These come from our best available family lines,” Dr Kube, an aquaculture geneticist, said.
“These will be very important tests.”
It is the first time researchers have been able to carry out tests in Tasmania, because this is the first summer the disease has been present locally. Previously the tests have been in NSW.
POMS has devastated oyster industries wherever it has spread, starting in France in 2008 then New Zealand in 2010 and NSW later the same year.
Reacting swiftly to the Australian outbreak in 2010, ASI commissioned Dr Kube and other researchers with the task of breeding a POMS-resistant oyster.
Since 2011, Dr Kube has progressively bred together families of oysters that have shown a level of resistance to POMS, resulting in some family lines that last year had survival rates as high as 80 to 90 per cent.
With each new, stronger family line, the offspring have been exposed to disease in waters in NSW. The industry-funded research has been jointly undertaken by the CSIRO, IMAS and the NSW Department of Primary Industries.
“All up, several hundred thousand oysters have been exposed to disease and then counted as either alive or dead,” Dr Kube said.
Mr Cunningham said the current trials were using much younger oysters than usual, which could affect survival rates.
“We don’t know what to expect because young spat are very susceptible to disease,” he said.
“But even if we have low level survivors, they will be valuable breeding stock going into the future.”
The infectious disease continues to spread throughout Tasmanian oyster farms following the outbreak this summer, although some exposed farms have remained disease-free and are still producing healthy oysters for the consumer market.
A Pacific oyster farm at Great Bay, on Bruny Island, is among those that have so far managed to escape the disease.
But owner Ben Dreimann said he was worried because a nearby farm had tested positive.
“There are no signs of disease here yet, but I’m really nervous,” he said.
Mr Dreimann said he was looking forward to when POMS-resistant oyster seed was available.
“It would give me a lot more confidence that I could continue farming,” he said.
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