Ministry for Primary Ministry officials are meeting with Southland locals over the discovery of a parasite deadly to oysters in Foveaux Strait.
Oyster cages being pulled from Big Glory Bay in 2017 as farmed shellfish were culled to stop the spread of bonamia ostreae. Photo: RNZ / Maja Burry
Routine surveillance recently detected three wild oysters infected with bonamia ostreae in the south-western area of the Strait. No infection was found at five other sample sites in the Strait.
High numbers of the parasite can kill the shellfish.
Bonamia ostreae was first found in New Zealand in 2015 in oysters from the Marlborough Sounds.
In 2017 it was discovered in the shellfish in Big Glory Bay in Stewart Island, leading to a major cull of farmed oysters.
Millions of dollars was paid in compensation to oyster farmers whose shellfish were destroyed as part of MPI's biosecurity response.
Duthie said the removal of oyster farms from Steward Island in 2017 was done in a bid to reduce any risk of spread, but it was always considered possible that a find in wild oysters could occur.
"Foveaux Strait is a dynamic waterway with strong currents and the parasite can remain dormant," Duthie said.
The immediate focus was to carry out more testing in Foveaux Strait to understand if and where else the parasite was, she said.
Dr Duthie said oyster quota holders, who were in the middle of this year's oyster season, would be able to continue to fish and MPI would work with them on the best course of action.
There was likely to be a small temporary and voluntary 'no take' zone around the area where the oysters were found until longer term options were explored.
As part of the biosecurity response MPI would be in Southland today, talking to the local community, she said.
"We want to involve local people, including the iwi of the area, in our response."
Bonamia ostreae is not a food safety issue and fresh good quality Bluff oysters remain safe to eat.
Duthie told Morning Report the infection was found in an area used by fishers but it had not been fished yet this season.
"It could well spread through the wild fishery, which is why we put those restrictions on five years ago and why we've been doing all this surveillance."
