Biosecurity New Zealand announced in March Bonamia ostreae had been found in a routine test of wild oysters from Foveaux Strait.
Numerous public meetings and updates followed, as those in the industry worried about what the future could hold.
No further oysters tested positive.
The agency yesterday announced - on the last day of the oyster season - it would be strengthening its testing processes for the oyster parasite after a review found human error contributed to incorrectly interpreted results being reported.
The test actually returned an inconclusive result.
In addition, the agency would look to remove legal controls that prevent fishing in a small area of Foveaux Strait, following consultation.
Biosecurity New Zealand readiness and response director John Walsh said even with the inconclusive result, because of the importance of the wild Bluff oyster fishery, it would have taken the action it did at the time while looking to further test the inconclusive find it had.
‘‘We have now done that additional testing through Australia’s national laboratory, the Australian Centre for Disease Preparedness, which returned a negative result,’’ Mr Walsh said.
‘‘We are now confident there is no evidence of Bonamia ostreae in Foveaux Strait.’’
He said while the news would come as a relief to affected communities, the original reporting of a positive result was likely to have caused great anxiety.
‘‘We apologise for that. We have reviewed the situation and put corrective actions in place to ensure this cannot happen again.’’
The agency explained in an update that testing process was complex: initial ‘‘screening’’ tests were run by Niwa - these returned positive results for the three oysters in question.
Biosecurity New Zealand’s animal health laboratory (AHL) then repeated the Niwa method - this also returned a positive result.
AHL then did further confirmatory testing using its PCR methodology, which returned negative results for the three oysters.
‘‘Based on our case definition, this means an overall ‘inconclusive’ result should have been reported.’’
The internal audit showed there was poor communication between laboratory and operational staff at Biosecurity New Zealand that contributed to the misreporting, and measures had been implemented to prevent it happening again.
The audit also highlighted improvements that could be made in the surveillance and testing programme for B. ostreae, which is contracted to Niwa.
Biosecurity New Zealand and Niwa were now working on an end-to-end process review.
The parasite was first found in New Zealand in 2015 in oysters from the Marlborough Sounds, and then in 2017 in oysters in Stewart Island’s Big Glory Bay.
Consequently, a programme was funded to protect wild populations, which included removing several flat oyster farms in Big Glory Bay, and running surveillance to look for early signs of the parasite in the wild.
Barnes Wild Bluff Oysters manager Graeme Wright said he was looking forwards to hearing details over the next few days.
He believed the industry would confer with Biosecurity New Zealand via video call.
As the result was inconclusive, while the news was good, vigilance was still needed given the parasite’s history, he said.
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"Nearly half a year after an oyster-killing parasite was found near Bluff, the government agency in charge of the response has had to apologise, announcing the positive result was incorrect" any compensation to those affected?....... crickets.
How much did this cost?