Farmed oysters in Stewart Island need to be pulled out of the sea if the Bluff oyster industry is to be saved, a local community board says.
The Ministry for Primary Industries (MPI) has been considering pulling up thousands of the shellfish in Big Glory Bay in Stewart Island to stop the spread of Bonamia ostreae.
The lethal parasite has been found in two oyster farms in the area and there are fears it might spread to the nearby wild oyster population in the Foveaux Strait.
This would be a disaster for the $20 million Bluff oyster industry, which employs hundreds of people across Southland.
The strain first appeared in Marlborough Sounds two years ago, but this is the first time it has been found in another area in New Zealand.
A related strain of bonamia devastated the Bluff oyster industry in the early 1990s, and again in the early 2000s.
A meeting of 100 people from the Bluff oyster industry on Tuesday called for MPI to order an urgent, complete cull of the shellfish.
Bluff Oyster Management Company represents all 17 Bluff oyster quota owners. Its operations manager, Graeme Wright, said ripping up the shellfish was the only option.
Graeme Wright Photo: RNZ / Ian Telfer
"The ministry convened a ... technical advisor group panel which is an international panel of science experts headed by their own MPI science people.
"And it clearly states that based on international literature and best science the only way of minimising the spread of Bonamia ostreae is to remove all of the infected farmed oysters from the water forever."
He said the number of farmed oysters was "miniscule" compared to what was in the wild beds in the Foveaux Strait.
Bonamia ostreae is a naturally occurring parasite that specifically affects flat oysters, Mr Wright said.
And where it has infected areas in Europe it has caused "devastation".
"Overseas evidence and experience is it will be final, it will be the end," Mr Wright said.
He said he expected the government to announce a decision tomorrow.
Bluff Community Board chair Ray Fife Photo: RNZ / Ian Telfer
Bluff community board chair Ray Fife said the decision was vital to the town's survival.
He said the infection has the potential to wipe out the entire oyster beds.
"You are looking at 95 to 100 percent mortality rate. It's really bad, really bad."
Mr Fife said it was a "race against time" and the ministry needed to make the decision urgently.
"It's a bullet those oyster farmers - they will be biting that bullet - and pull all your oysters out for the good of the whole industry.
"Not only the wild oysters off Foveaux Strait but their industries in Big Glory [Bay] as well."
Bluff, in Southland Photo: RNZ / Ian Telfer
'This isn't new' - MPI minister
Minister for Primary Industries Nathan Guy said officials responded quickly to try and stop the spread of the lethal parasite.
He said he was concerned because the parasite could have a big impact on commercial oyster farms in Southland.
But Mr Guy said the wild oyster fishery was well-established.
"In fact this parasite that we are talking about, they've had a different strain of it that has affected the wild fishery.
"So this isn't new, it's just something that we are having to deal with."
MPI acted quickly after the parasite was discovered and the farms were in lockdown, Mr Guy said.