Nova Scotia biologist adapting COVID-19 technology to detect oyster disease

A biologist at Cape Breton University is hoping a piece of technology used to keep people safe in the pandemic can help protect Nova Scotia's oysters against the effects of warming waters. 

Perkinsus marinus, or "dermo" disease, is a single-cell organism that has contributed to significant oyster declines in the southeastern United States. It has been detected in the northeastern U.S. 

Though dermo is not yet found in Canada, researchers say that could change as ocean temperatures around the province reach record highs. This summer, biologist Rod Beresford is adapting a testing technology — the same one that helped detect COVID-19 in wastewater — to monitor for the threat. 

"As we see how quickly water temperatures are changing in some of these places, it's quickly starting to become a bit more of a concern," said Beresford.

The monitoring is part of a push from researchers to help the region's oysters — and oyster growers — prepare for the effects of climate change. 

"Given dermo's proximity in Maine, that's not a long distance for something to travel, as things move around," he said. "There's all kinds of ways invasive species can be introduced to an area. And as the waters warm, an area that, at one point, may have been too cold, might not be too cold anymore." 

Beresford's research typically focuses on MSX, an invasive oyster parasite that has wiped out much of the oyster production in the Bras d'Or Lake.

MSX arrived in Cape Breton in 2002, and quickly devastated wild and cultivated oyster populations in the region.

Beresford's came to work with local oyster growers, including Joe Googoo from Waycobah First Nation, and aquaculture expert Robin Stuart. The collaboration helped Beresford realize that the key to recovery could be that in shallow water — where the temperature and salinity are changing constantly — oysters survived despite the presence of the parasite.

"If you're an oyster … they're used to living in these changing environments. But if you're a parasite, especially a single cell parasite, that's a bit of a challenge."

That led to the development of a system of floating cages, which has shown promising results for restoring oyster production to the area. 

"We're fairly confident now that you can grow oysters in the Bras d'Or in the presence of this parasite, which is harmless to humans."

Wanting to focus more on the threats posed by climate change, Beresford has now turned to other diseases, and to the threat posed by dermo, which he says is "every bit as bit as destructive as MSX, if not more." 

Dermo attacks the tissues of oysters. Once  ingested, it can proliferate in the blood cells, eventually killing the animal.