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This article was written by Shane Ross and originally published by CBC News on July 13, 2024 at 1:34 PM ADT. We are sharing the full text here for reference. All rights remain with the original publisher.

MSX harmful to oysters, but poses no threat to humans, according to Canadian Food Inspection Agency

P.E.I. is the second-largest oyster producing province in Canada and the largest oyster producer in Atlantic Canada. (Brittany Spencer/CBC)

A parasite that could threaten P.E.I.’s oyster industry has been detected in Bedeque Bay, about 20 kilometres west of the Confederation Bridge.

The province, the Canadian Food Inspection Agency and Fisheries and Oceans Canada are working to limit the spread of the disease multinuclear sphere X, or MSX.

MSX hinders growth and increases oyster mortality.

However, it poses no risk to human health, nor does it pose a risk to food safety, according to Danielle Williams, disease technical specialist with CFIA.

“You can eat an oyster that has MSX and there’s no problem for humans,” Williams said. “They are very safe to consume.”

She said the CFIA, DFO and the province continue to conduct tracing activities and testing of oysters to gain insight into the presence of MSX in the area, and whether it has spread beyond Bedeque Bay.

“It’s a big concern because of how many oysters can die from this. It can cause up to 95 per cent mortality in an oyster population,” Williams said.

It isn’t just about the impact on our oyster industry, it is about the livelihood of Islanders, their families and our communities— P.E.I. Fisheries Minister Cory Deagle

P.E.I. Fisheries Minister Cory Deagle said the presence of MSX in oysters is “devastating news for our province.”

“It isn’t just about the impact on our oyster industry, it is about the livelihood of Islanders, their families and our communities,” he said in a news release.

“The Island’s oyster industry is part of our culture and tradition. We are proud to be home to the finest oysters in the world.”

P.E.I. is the second-largest oyster producing province in Canada and the largest oyster producer in Atlantic Canada, according to the provincial Department of Fisheries website.

First time on P.E.I.

Oyster harvesters reported their concerns to the provincial authorities in June when they noticed an unusual number of oysters dying. CFIA analyzed samples and determined MSX was present.

Oysters with MSX start dying off at two years, which unfortunately is the market size, Williams said. They may not close their shells as quickly, appear thin and watery when opened and contain brown spots in the inside of the shell.

Williams is urging people not to move oysters and shells from Bedeque Bay and put them into another area.

It’s the first time MSX has been found in oysters on P.E.I., and it will take time before the extent of the impact is known, Deagle said.

“While MSX has been heavily researched over the years, scientists, researchers, and fishers around the globe still do not understand how the disease spreads,” he said.

In the 1950s, MSX wiped out oyster stocks in Chesapeake Bay between Maryland and Delaware. It had never been spotted north of Maine until it was detected in Cape Breton’s Bras d’Or Lake in 2002. It has affected that oyster industry for nearly 20 years.