26 Mar 2021

Rāhui to protect Bluff oysters after bonamia ostreae parasite found

6:34 pm on 26 March 2021

A Rahui will be placed on an area in Foveaux Strait following the discovery of a deadly parasite that could put the entire bluff oyster trade at risk.

Oysters pulled up from Big Glory Bay.

(File photo) Photo: RNZ / Lydia Anderson

Three wild oysters were found to be infected during routine surveillance with bonamia ostreae, four years after a huge cull to get rid of it from other oyster growing regions.

Bomamia ostreae was first found in New Zealand in the Marlborough Sounds six years ago and then again in 2017 from Oysters in Big Glory Bay on Stewart Island.

The threat back then led to the removal of oyster farms in Stewart Island and Marlborough.

A crisis meeting was held today in Invercargill with local stackholders feeling anxious about the discovery.

Ministry for Primary Industries Biosecurity manager Cath Duthie acknowledged there was some anxiety amongst the locals, however, she says the meeting was constructive.

Dr Duthie said intensive sampling is needed to figure out exactly what the problem is and the Rahui will aid that.

"This will be in the form of a legal notice, whereby we prohibit any fishing or any recreation in a very small area that is about four to five nautical miles of the coast of the saddle off Stewart Island," she said.

"It shouldn't effect people very much at all."

Cath Duthie said testing would begin in the area within the next day.

"We do need to know exactly how large this infection is and that will give us some really good guidance on how we manage this going forward."

Dr Duthie said for the moment fishing can continue outside of the Rahui zone.

The Bluff Oyster Management Company's general manager, Graeme Wright, said the news of the discovery was devastating.

"Obviously it was detesting when it first hit at Big Glory Bay and we always hoped it wouldn't make its way into the Strait's but I guess that was always hopeful," he said

However, Wright said the meeting was positive and there is a clear way forward.

"The way forward is to just work out what we are up against, it is a very small area that is currently being detected and it is a very small amount of oysters."

"It is very localised so there will be an extensive testing and monitoring program to know exactly where we are and we will make a plan from there."

Meanwhile, Bluff Community Board Chair Raymond Fife said the community are in shock and locals are fearing for worrying times ahead.

Fife said the local bluff economy relys heavily on the oyster trade.

"Through the oyster season is it quite a number of people employed, and it is not only the people fishing, it is the oyster openers, its the engineers firms that do day to day maintenance on the boats as well," he said.

Fife said locals were up in arms during the last outbreak.

"Particularly the concern that it was at Stewart Island it could quite easily spread to Foveaux Strait.

"This strain of the parasite is deadly and it has the potential to wipe out the whole oyster industry."

While the parasite is incredibly dangerous to oyster, it doesn't affect food safety.

More meetings with stakeholders will be held in the next few weeks, to sort out the issue.

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