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Oysters infected with MSX are harmless to human consumption, but the parasite kills oysters and its recent confirmed presence in New Brunswick and Prince Edward Island, now poses a serious threat to the livelihoods of Maritime oyster producers.

That development has put a spotlight on Dr. Beresford’s work, offering hope to a nervous Maritime industry with an annual aquaculture value of $24 million in New Brunswick, $15 million in Prince Edward Island and $5 million in Nova Scotia, based on 2022 Statistics Canada data.

MSX usually kills oysters at least two years old. Losses due to infection can be as high as 90-95 per cent. July and August, when water temperatures are warmest and salinity high, are optimal months for the parasite’s spread.

As a line of defence, Dr. Beresford says there are “all kinds of advantages for genomics.” Although initially costly, he noted, “the investment is really upfront, but once you have the technology sorted, not only…does it become less expensive as time goes on, but you can then adapt that technology to move, say, from the laboratory to much more of a field-based test.”

The United States has been using genomics for decades, he said, “to build better oysters, stronger oysters, faster growing oysters that are able to cohabitate with this parasite. They may get infected; they may not, but the huge advantage is they no longer die from the parasite at the levels they used to.” Developing an MSX-resistant oyster here, he expects, will be the next big move against MSX in Atlantic Canada.

In the long run, he said, that strategy will be needed to counter many oyster pathogens, previously unknown in Canada’s Atlantic waters, that are now creeping up the eastern seaboard due to changing climate patterns. Another newly confirmed arrival is Perkinsus marinus or dermo disease, which is also lethal to oysters, spreads easily, but poses no risk to human health.

In the meantime, Dr. Beresford, aided by knowledgeable local Mi’kmaq community members and local oyster growers, has been concentrating his MSX research on the Bras d’Or Lake. The Potlotek and Eskasoni First Nations made substantial investments in boats and facilities to support oyster-growing operations in the lake. The goals of providing jobs and a better future for their communities were shattered by a 2002 MSX infection, which forced the business to close.

However, working with indigenous and non-indigenous research colleagues on a multi-year pilot project that involved 12 leaseholders, three of whom were from First Nations, Dr. Beresford recently discovered that by suspending caged oysters in the water column, the mortality of MSX was reduced. The discovery has given new hope that the industry could eventually be re-established.