Research institute denies spreading oyster disease

NELSON: A Nelsonbased independent science research institute has denied claims it might have been linked to the transfer of an oysterkilling pathogen to Stewart Island.

The Ministry for Primary Industries last year ordered the removal of farms growing flat oysters in Marlborough and Stewart Island, in a bid to halt the spread of the parasite Bonamia ostreae.

It was first discovered in oysters originally taken from the Marlborough Sounds in 2015 and last year at Stewart Island, prompting fears it could threaten the Bluff wild oyster industry.

Cawthron Institute was involved in the initial discovery and has been involved in research to support flat oyster aquaculture.

A recent media report suggested material may have been transferred from Cawthron to Big Glory Bay in Stewart Island, but chief executive Charles Eason said the material used for the analysis of the parasite was from oyster farms in the Marlborough Sounds and Cawthron had never sent flat oysters to Stewart Island.

‘‘It is not possible to say how the parasite got into New Zealand, Big Glory Bay or Marlborough. There are a number of ways it could have happened, for example unintentional dispersal via ship ballast water or biofouling on a vessel,’’ he said.

There had always been full and open communication with the public about the pathogen, including the publication of initial findings in 2016 in a scientific journal, he said.

Prof Eason said Cawthron was an independent, nonprofit, communityowned research organisation with dedicated, highly ethical scientists working on environmental restoration, as well as supporting primary industries where it could.

‘‘When the globally ubiquitous Pacific oyster virus finally arrived in New Zealand several years ago, and devastated the Pacific oyster industry, our scientists responded and have bred oysters that are resilient to the virus, just as kiwifruit have been bred for resistance to PSA.’’

Prof Eason said the Bonamia ostreae outbreak was devastating for all affected, and Cawthron had been referring queries to the Ministry for Primary Industries.

A Cawthron spokesperson said it was unlikely the institute would take action but it was monitoring responses carefully.