Invasive zebra mussels discovered in St. John River watershed in Quebec

Zebra mussels have already wreaked havoc in the Great Lakes, altering ecosystems and the food chain, and damaging water pipes in municipal water systems, power plants and other industrial sites.

Now the invasive species has spread — or been carried — to the east and is at the edge of New Brunswick.

Zebra mussels have been discovered in the St. John River watershed, according to the New Brunswick Invasive Species Council. 

"We are saddened to share that an established zebra mussel population has been discovered in Lac Témiscouata, just across the border into Quebec," the council announced on its website Thursday.

Although the mussels have not yet been detected in New Brunswick, Lac Témiscouata flows into the province's Madawaska River and then into the St. John River, which flows through the entire length of the province and empties into the Bay of Fundy at Saint John. 

Waterways don't even need a direct connection for zebra mussels to spread.

All they need is human activity, especially recreational boating, said Anthony Ricciardi, a biology professor at McGill University in Montreal, who has been studying zebra mussels for 30 years.

Young zebra mussels often attach to vegetation, which frequently gets caught up in propellers, anchors and other parts of boats. The mussels can also survive out of water for several days, so when the boat is returned to the water in another location, the mussels can settle into a new habitat. 

Ricciardi said humans are "exclusively responsible" for spreading zebra mussels among waterways.

They are also the key to slowing the spread by ensuring they haven't picked up any aquatic hitchhikers, he said. 

"So the best thing you could do is try to reduce the spread and by recognizing the role that people play," said Ricciardi. "And I would emphasize the role of recreational water users, especially boaters, because that is almost certainly how the species got into Lac Témiscouata.

"Throughout Earth's history, species have moved into new regions. But under human influence, species like the zebra mussel are spreading faster than ever before and to remote areas that they could never reach without human assistance."

Although species have always moved into new territory, it's now "happening at a speed that is unprecedented," he said. 

Council urges precautions

Kristin Elton, program director for the New Brunswick Invasive Species Council, urges anyone spending time in the Madawaska or upper St. John rivers to be vigilant and take precautions to prevent bringing zebra mussells into the province. She said they should "clean, drain and dry" all boats, trailers, and other recreational equipment after leaving those areas. 

Elton said it's important to get control of zebra mussels before they become a problem in New Brunswick. 

"Billions of dollars have been spent in the Great Lakes since they were first detected in the 1980s, just trying to manage those impacts. And we don't want to see that happen here. So we're trying very hard to get the word out to people to try and learn what they look like, report them if you see them. "

Anyone who sees zebra mussels can report the sighting to the council or to Fisheries and Oceans Canada, and include:

• the exact location of the sighting (GPS co-ordinates if possible).
• photos of the mussels.
• the date observed.

Zebra mussels are native to the Black Sea region of eastern Europe and western Asia. After being first observed in Ontario in 1988, they can now be found throughout all of the Great Lakes, Lake St. Clair (between Michigan and Ontario) Lake Winnipeg, and in the Eastern Townships of Quebec.

Zebra mussels are filter feeders that attach themselves to any available surfaces, such as boats, docks, rocks, plants, and native mussels. The females can produce up to one million eggs in a breeding season, according to the New Brunswick Invasive Species website. 

The larvae can float in the water for up to a month before attaching to available surfaces, colonizing in densities of up to 700,00 individual mussels per square metre. 

Zebra mussels negatively impact freshwater ecosystems by filtering water to the point where plankton, the foundation of many food chains, can no longer survive. 

A single zebra mussel can filter as much as one litre of water a day, according to Nature Conservancy Canada's website.

"As a result, the decreased levels of plankton in the water upset the balance of food chains in ecosystems."

The over-filtering also lets in more sunlight, warming up the water and increasing toxic algae blooms, pathogenic bacteria, and avian botulism, which impacts fish and wildlife, according to the invasive species council.

Because they colonize so densely on surfaces, the mussels can also interfere with recreational activities and vital infrastructure such as navigational buoys. 

And they are razor-sharp, which is dangerous for beach walkers or swimmers. In areas infested by zebra mussels, large stretches of the shoreline can be covered by a layer of sharp shells. 

Elton said zebra mussels can take an economic toll as well, as they clog intake pipes used by municipal water supplies and industry. 

"They get into infrastructure … municipal water intake pipes, power plants, that kind of thing."

Between 2017 and 2019, municipalities in Ontario spent $4.5 million a year trying to manage the mussels, the New Brunswick council said.