Biosecurity NZ strengthens testing process of Bonamia parasites in oysters

Biosecurity New Zealand is strengthening its testing processes for the oyster parasite Bonamia ostreae after a review found that human error contributed to incorrectly interpreted results being reported for Foveaux Strait in March this year.

In addition, it will look to remove legal controls that are preventing fishing in a small area of Foveaux Strait, following consultation with mana moana and stakeholders.

At the time, Biosecurity New Zealand informed the Southland and Stewart Island communities that three wild oysters from Foveaux Strait had tested positive for the parasite that causes poor condition and death in flat oysters.

Biosecurity New Zealand’s director of readiness and response, John Walsh, says a review of the March test results found they were reported incorrectly at the time. The testing returned inconclusive results for the 3 oysters.

“However, even with the inconclusive result, because of the importance of the wild ‘Bluff’ oyster fishery, we would have taken the action we did at the time while looking to further test the inconclusive find we had,” said Mr Walsh.

“We have now done that additional testing through Australia’s national laboratory, the Australian Centre for Disease Preparedness, which returned a negative result. We are now confident there is no evidence of Bonamia ostreae in Foveaux Strait.

“While this news will come as a relief to the affected communities, the original reporting of a positive result is likely to have caused great anxiety to mana tangata that hold mana moana over this area and those involved in the wild oyster industry, oyster farmers and the local community, and we apologise for that.

Mr Walsh added that the agency has reviewed the situation and put corrective actions in place to ensure this cannot happen again.

“An internal audit showed there was poor communication between laboratory and operational staff at Biosecurity New Zealand that contributed to the misreporting.”

The audit also highlighted process improvements that could be made in the surveillance and testing programme for Bonamia ostreae, which is contracted to National Institute of Water and Atmospheric Research (NIWA).

Biosecurity New Zealand and NIWA are now working on an end-to-end process review.