Nova Scotia oyster producers guarding against bacteria spread by climate change

An oyster-dwelling species of bacteria is moving northward because of warming ocean temperatures, and oyster producers and regulators in Nova Scotia are already preparing themselves for the migration.

Vibrio parahaemolyticus, or VP — which can cause serious illness and is occasionally fatal — is spread by the consumption of raw or undercooked seafood.

A recent study found that the spread of Vibrio bacteria was directly related to rising water temperatures. Tom Smith, executive director of the Aquaculture Association of Nova Scotia, said that the association began crafting a strategy to deal with VP last year.

Crafting new strategies

The Aquaculture Association now offers mandatory workshops and has compiled a guide for oyster producers on best practices to reduce the risks of VP.

"The big thing here is training and educating farmers first about handling procedures," Smith told CBC's Information Morning

The association has also launched a new monitoring program, tracking water temperatures and VP levels around the province to control of the spread of the bacteria.

Mitigating the risks

Smith said although there have been no outbreaks of VP in Nova Scotia, the association has already recorded warmer ocean temperatures off Nova Scotia than normal, creating the conditions for the spread of the bacteria.

The measures that have been put in place, including halting the oyster harvest whenever the water temperature rises above 25 C, mitigate the risks.

Charles Purdy runs Bay Enterprises, an oyster farm in Malagash, with his wife and daughter.

'Nothing like now'

Lately, Purdy said they've been making changes to control the bacteria, including daily monitoring of the water temperature and testing for VP if the temperature goes above 12 C.

In past years, he said, "we did periodic testing, but nothing like now."

Purdy said his daughter has taken the workshops on VP offered by the Aquaculture Association, and following those workshops moved their ocean storage pen for harvested oysters to deeper water, to keep the water temperature at a safe level.

Increasing costs

All these measures have come at a price.

"It's probably put our costs up about 12 to 18 per cent."

Purdy says they haven't adjusted their prices to reflect these costs — even though they potentially could, since the demand for their oysters far exceeds what they can supply.

Keeping their customers safe, Purdy said, is worth the expense.