Stewart Island cull puts oyster farm out of business

An oyster farmer has been put out of business after a parasite outbreak led to the large scale culling of oysters in Stewart Island.

The Ministry of Primary Industries (MPI) is currently testing remaining oyster stocks in Big Glory Bay in the deep south to see if any are still infected with the invasive parasite, Bonamia ostreae.

In June, the government ordered a cull of Stewart Island oysters in a bid to stop the parasite's spread.

While most operators in the area also farm mussels, New Zealand Bluff Oyster Company in Big Glory Bay focuses exclusively on oysters.

Its general manager Rodney Clark said the steps taken by MPI to eradicate the parasite have had a catastrophic effect on his business of 14 years.

"If it hadn't been for friends and family we would have been on the streets," Mr Clark said.

Mr Clark said he had received $30,000 in compensation but that amount would only cover outstanding rent and phone bills while the full amount was expected to be in the millions.

MPI detected the parasite in two oyster farms on Stewart Island in May this year and began testing in mid-June.

Bonamia ostreae can cause lethal infections in shellfish, particularly flat oysters, potentially endangering the 4000 tonnes of farmed oysters on Stewart Island.

The Ministry is also testing and culling farmed oysters in the Marlborough Sounds to stop the parasite spreading to wild oysters.

MPI is currently awaiting results from the latest round of testing in Big Glory Bay.

Ministry spokesperson David Yard said they would continue regular testing until they were sure the outbreak is eradicated.

A ministry factsheet says experience from overseas and previous infections shows that farms and wild stocks infected with the disease can lose 80 to 90 percent of stocks within two years.

Overseas oyster beds infected with the disease never fully recovered, the ministry says.