Oyster deaths increase raises fears for jobs

File photo / Simon Baker

A mystery increase in oyster deaths has raised fears for hundreds of jobs in the upper North Island.

New Zealand Oyster Industry Association executive Tom Hollings says an investigation has been launched into unusually high levels of juvenile oyster deaths around Kawhia and the Bay of Plenty.

It could put the jobs of hundreds of oyster farmers and up to $15m revenue at risk, he says.

"We are talking about half our industry. That's a big loss.

"Our people are very worried."

Aquaculture New Zealand CEO Mike Burrell says the increase in the death rate of young oysters has been seen on farms in the Bay of Plenty and north of Kawhia since mid November.

Typical mortality rates for cultivated Pacific Oysters are between five and 10 per cent.

This year, the rates on some farms have varied between 30 to 80 per cent - something that is "very concerning" for the industry, he says.

Aquatic disease specialists from the oyster industry association and MAF Biosecurity New Zealand have taken about 250 samples for analysis.

They are expected to report back early next week.

MAF Response Manager Richard Norman says the investigation is still in its early days.

He would not speculate on what is causing the die-back or potential solutions.

"What is clear is that both MAF and the industry understand the urgency around the issue and the need to identify the problem and find ways to address it," he says.

The New Zealand Food Safety Authority says there is nothing to suggest any food safety concern in New Zealand oysters.

There has been no detection of any problem with other oysters, including New Zealand's renowned Bluff oysters, it says.

It is expected main impact of the die-back will be to reduce the amount of juvenile oysters available for stocking oyster farms for 2011 harvests.