Oyster virus may cause devastating results for Tasmania
2017-11-28 16:55:47   copyfrom:    hits:

Oysters affected by Pacific oyster mortality syndrome or POMS (Photo: NSW Government)AUSTRALIATuesday, November 28,

Oysters affected by Pacific oyster mortality syndrome or POMS. (Photo: NSW Government)


Click on the flag for more information about AustraliaAUSTRALIA 
Tuesday, November 28, 2017, 02:30 (GMT + 9)


Oyster supplies in Tasmania are being threatened by a viral disease, which is concerning to producers ahead of the Christmas period.

The concern in the sector stems from the fact that the virus causing Pacific Oyster Mortality Syndrome (POMS), which is harmless to humans, weakens oysters and makes them lose their ability to close their shells, allowing them to be eaten or die by dehydration, ABC News reported.

Josh Poke, an oyster farmer in Cambridge near Hobart, said the disease had caused his stock to fall to about 60 to 70 per cent of what it was.

Some producers have reported having seen their oysters die, and Poke still expects to be able to get his untouched oysters out of the water in time to be sold over the Christmas season.

Given this context, representatives of the sector call for protection for Tasmania's iconic seafood, stating the industry is going through a drought.

A more dramatic crash in the national supply is expected next year when South Australian oyster stocks are also set to plummet.

The South Australian oyster industry used to rely on Tasmania, but the import of Tasmanian baby oysters stopped when POMS first broke out 18 months ago.

Executive officer of the South Australian Oyster Growers Association (SAOGA) Trudy McGowan said the shortage could last through until 2019.

Apart from the loss of 100 jobs, there would be a drop in revenue from AUD 35 million to AUD 15 million (USD 26.6-11.4 million).

"It really is as if our industry is going through a drought just like what farmers experience," she said.

"We're in a situation where we can see what's coming, but it takes time to build hatcheries, it takes time to produce that. So unfortunately we've got about probably another year and a half at least of very difficult times for our industry," regretted the SAOGA representative.

In Tasmania, the body responsible for oyster growers is still adding up the losses and work is underway to breed oysters resistant to the POMS virus.

While efforts made by IMAS continue to be able to produce POMS-resistent oysters, producers and scientists expect to tackle the virus by putting batches of oysters in refrigerated containers at times when POMS is most active will help to reduce oyster mortality.

Dr Sarah Ugalde, who along with IMAS colleagues Dr Christine Crawford and Lewis Christensen, is working with oyster farmers to tackle the virus, said at the end of summer the oysters that spent time in the refrigerator will be compared with those that remained outside.

“This potential solution was identified quite by accident when some oysters that had been temporarily stored in a refrigerator during a POMS outbreak showed a surprisingly high survival rate,” Dr Ugalde said.

“We are now putting that observation to the test through this scientific trial The POMS virus is temperature dependent and only becomes active when water temperatures are consistently above 18 degrees Celsius,” the scientist explained.

"We know that oysters can survive for over one week in very cool conditions, such as a home refrigerator. Putting farmed oysters in refrigerated containers when the POMS risk is high is a simple, small step that could help to make a big difference," she added.

“The tubes and baskets that the oysters grow in on a farm can be lifted and put into the containers without individual oysters being handled or disturbed, which will help to minimise stress.”

Dr Ugalde said Tasmanian farmers had faced the loss of up 95 per cent of their oysters after POMS was first detected in Pitt Water in January 2016 and spread rapidly to other major oyster growing regions on the East Coast of Australia.

Tests are to continue until March or April, and if the results are good, this system could be used together with other management measures to reduce POMS impact. 

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