Emotions are running high as the authorities grapple with destruction of millions of flat oysters in Big Glory Bay.

And everyone is praying the disease bonamia ostreae does not enter the adjacent wild fishery in Foveaux Strait.

Culling of caged oysters began this week in the first stage of an operation to remove all farmed oysters from Stewart Island.

This drastic action will also have to include removal of large quantities of mussels, which harbour oysters on the growing ropes.

In the meantime the Bluff oyster fishery centred on Foveaux Strait continues unabated.

The catch this year has been set at 10 million, with quota holders electing to shelve another five million to protect the fishery, rather than harvesting the total allowable commercial catch set by the Ministry for Primary Industries at 15 million.

There are 11 boats in the fishery which runs through the winter to the end of August.

Barnes Oysters, a co-operative that includes major fishing companies Sanford, Independent, United and Skeggs, handles two thirds of the catch and has so far caught about 70 percent of its quota.

Its operations manager, Graeme Wright, is frustrated and angry, like many others in a vital industry that adds $20 million plus to the local economy.

But he realises the need to be positive and pro-active in dealing with a difficult situation.

And the industry has known hard times before.

“The wild fishery has had some huge ups and downs,” Graeme said.

A separate bonamia pathogen – exitiosa – is endemic to the wild fishery and has caused substantial losses, but until now the lethal bonamia ostreae has not been recorded in the deep south.

Neither disease is harmful to humans.

The Bluff fishery was closed for three years in the 1990s due to a bonamia outbreak and suffered a setback in 2014 when an estimated 28 percent of the population, some 250 million oysters, died.

The current conservative catch is estimated to be less than 2 percent of the total biomass.

There is finger pointing over the contamination of the Stewart Island fishery.

A 2015 report into an ostreae outbreak in the Marlborough Sounds recommended removal of all farmed oysters in that region to stop the spread but this was not adopted by MPI.

That report has not been made public but its release has been requested by numerous parties.

Helen Cave, co-owner of Southern Seafoods, employs six people in mussel and oyster farming on Stewart Island and doubts the outbreak can be contained.

“There are oysters everywhere in Big Glory Bay – it’s a huge area.

“Killing every last sandfly would probably be easier.”

Helen, also owner of Stewart Island’s sole watering hole, the South Sea Hotel, is unsure about how compensation should be applied.

“It’s not just the money, it’s people’s livelihoods down here.

“It’s not a wealthy community here.”

She said there had been poor communication and that some of those sent to oversee the removal operation had little idea of what was involved and had not visited the affected sites.

While the focus is on the plight of Stewart Island, the situation is devastating for Marlborough Sounds oyster farmers as well.

Pioneer mussel and oyster farmer Bruce Hearn faces a loss of “a couple of million” oysters.

He is the biggest of about eight farmers in the Sounds and has been marketing flat oysters under the Tio Point brand for 10 years.

“We’re looking at 30 years of dedication going down the tubes,” he said.

“We’re not getting much sleep.”

The farms have a destruction notice in place but the oysters remain in the water in the meantime until disposal is organised.

The oyster outlook is dire, for those farmed at least, but the evidence is the species has been hit hard before and it has always recovered.

Oysters will still be on the menu – but they may be scarcer for a while.