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The PEI oyster industry harvested 14 million pounds of oysters last year, sold domestically in Ontario and Quebec or exported to the U.S. or other markets.Robert F. Bukaty/The Canadian Press

Prince Edward Island’s oyster growers are on tenterhooks as they await test results to confirm if a parasite that is deadly for oysters has spread to any of the 800 leaseholders who farm along the island’s north and south shores.

Regardless of the outcome, the executive director of the PEI Aquaculture Alliance Board Peter Warris says the island’s world famous oyster industry, valued at $23.7-million last year, is determined to adapt and continue operating, as other markets stricken by the parasite have done in the past.

The Canadian Food Inspection Agency (CFIA) confirmed a case of the parasite called multinucleate sphere X, or MSX, in Bedeque Bay on the island’s south shore after the province reported a significant oyster mortality this spring. MSX is not known to be a threat for humans.

The CFIA has taken ten survey samples from areas linked to Bedeque Bay. So far, of the four samples that have been reported on, three are presumptively positive and require further genetic testing, said the industry group. The leases linked to Bedeque Bay have been placed under quarantine while more testing is under way. The CFIA is also investigating an oyster mortality reported in the Mill River area of western PEI on a public fishing bed.

The oyster industry in PEI is made up of a long-standing public fishery and aquaculture, which has boomed in the last decade. Farmers lease parts of the ocean from the federal government to grow oyster in bags and cages in bays and estuaries around the island. In the spring fishery, oysters are harvested and sold to processors and held at approved clean water leases prior to exporting.

So far, Mr. Warris said no mass mortalities have been reported in the aquaculture industry. “Potentially that could happen,” he said adding the MSX has a 90 to 95 per cent mortality rate. “Obviously that would be devastating for the individual farm operation.”

There’s uncertainty about the situation will affect the industry going forward, he said. “It’s not the end of anything but it’s a significant adaptation to a new set of circumstances,” he said.

The PEI oyster industry harvested 14 million pounds of oysters last year, sold domestically in Ontario and Quebec or exported to the U.S. or other markets. A provincial government study said that in 2019, Prince Edward Island accounted for 32 per cent of the national economic value of oysters.

MSX is usually detected when there is an unexplained die-off of oysters. The disease has occurred in Nova Scotia and British Columbia but not in P.E.I. until now. Losses from the disease occur throughout the summer, reaching 90 to 95 per cent within two to three years of initial infection. Disease activity increases with higher salinity and water temperature.

It’s unknown exactly how MSX is transmitted, though it’s suspected to travel through other organisms, according to the province, which produced a fact sheet on the infection. The origin of the parasite in Bedeque Bay is unknown but an investigation is under way.

There’s no known treatment for MSX and control measures are focused on preventing the spread of disease. In its fact sheet, the province said oyster growers should anticipate movement restrictions in certain areas but the details are still being determined.

The province suggested mitigating further spread by avoiding moving oysters or using vessels in different areas until the extent of the infection is known.

It added that trade impacts are expected to be minimal. The province said it would be looking at other impacted areas to learn the best ways to support the industry.

In a statement Wednesday, Matt MacFarlane, third party critic for Fisheries, said shellfish growers, processors and others in the industry are rightfully concerned about their livelihoods.

“It is unacceptable how little research has been done on this by our government. The lack of attention to this known parasite from successive PC and Liberal governments, including the current King government, puts Island oyster harvesters in an incredibly vulnerable position,” the Green representative wrote in a statement.

The province did not respond to a request for comment. CFIA did not respond to questions by deadline.

With a report from Canadian Press

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