Parasites put pressure on oyster fishers ahead of fall season in P.E.I.

A deadly parasite is biting into one of Canada’s most prized catches: oysters. (CTV News)

A deadly parasite is biting into one of Canada’s most prized catches, with oyster fishers in several provinces now dealing with Dermo.

The highly damaging oyster disease, most recently detected in Prince Edward Island, is slashing yields and shrinking profits in an industry that’s already struggling with another parasite, Multinucleate sphere unknown (MSX).

While the Canadian Food Inspection Agency (CFIA) says neither pose risks to human health or food safety, P.E.I. Shellfish Association President Bob MacLeod says buyers won’t touch oysters from bodies of water where they suspect cases of Dermo.

“It’s going to be a lot of hardship,” he said, adding the province’s next big oyster season starts in September. “That could destroy our whole fall.”

This year, Dermo has also been detected in Quebec and Newfoundland and Labrador, following earlier detections in Nova Scotia and New Brunswick.

MSX, which has a mortality rate of up to 95 per cent for oysters, is already present in the region. Because of both parasites, MacLeod said some fishing spots are now off limits, forcing fishers to find new areas, paying higher travel costs.

Plus, some rivers are being overfished, meaning fewer catches and potentially fewer oysters on the market.

“That can really impact everybody,” MacLeod said.

He added that it would help if the CFIA was faster at determining whether suspected cases are confirmed.

In a statement to CTV News, the agency said it only officially recognizes results from samples tested at facilities in the National Aquatic Animal Health Laboratory system. Positive results from any other lab are treated as suspect positive cases that must be reported to the CFIA for further investigation.

When the CFIA receives notice of a suspect detection, it collects and tests samples from the area. The agency says extensive subsequent sampling can be required before it is able to confirm the positive result, which can be time-consuming.

Dermo can exist in some oysters, but not others in a given area, and not all infected mollusks show signs of disease, according to the agency.

The Canadian Aquaculture Industry Alliance told CTV News it’s calling on the federal government to make two changes in relation to shellfish production. The first is to double funding for the Canadian Shellfish Sanitation Program. The second is to launch a pilot insurance program for farmers.

With both parasites creeping through oyster beds, fishers say the next few weeks could make or break this fall’s harvest.