Fighting zebra mussels in the Eastern Townships

Blue Massawippi, a non-profit based in the Eastern Townships, gets its name from the lake it's been protecting since it was created in 1968. 

These days, the group of volunteer conservationists watching over the Massawippi, one of three major lakes between Sherbrooke, Que., and the Vermont border, is in the fight of its life.

"For the first time this year, in October, we found some zebra mussels on our collectors [in Lake Massawippi]," said Philippe-David Blanchette, one of the organization's directors.

"We weren't in panic but we were really disturbed by what we found," he said.

Preventing the spread of an invasive species is a massive undertaking, one Blanchette says Blue Massawippi has already started but can't do alone. 

In an effort to get rid of as many zebra mussels as possible over the next year, before the population can grow and spread, Blue Massawippi is aiming to raise $500,000 to pay for diving expeditions and other related costs.

"The Ministry [of Wilfdlife] helped us organize a huge diving enterprise so we can find where are the mussels, what kind of mussels, young mussels, adult mussels, what was the status of the invasion?" said Blanchette.

"We're building a huge financing campaign and also working with the municipality, to try to intervene and stop the invasion."

What's so bad about zebra mussels?

Zebra mussels are a freshwater species native to the Caspian Sea region of southeastern Europe. They can be identified by their triangular shape, flat underside and zigzagged patterns of black or brown with white and yellow.

The species is considered invasive in Canada because they breed very quickly — females can release up to one million eggs each breeding season.

They out-compete native species for food, affect fish spawning areas and create clearer water that allows sunlight to penetrate deeper, promotes the growth of undesirable vegetation and can lead to toxic algal blooms which zebra mussels don't eat.

"It's really a huge threat for biodiversity," said Blanchette. "Frankly, it just takes all the place, takes all the food and won't leave anything else for the other species in the lake."

Zebra mussels can also clog water intakes and give headaches to municipalities because they're difficult to remove if they spread unchecked.

So far, so good

Blanchette says the early prognosis of the Lake Massawippi invasion is good. The zebra mussels that have been collected so far are young and concentrated in the northern section of the lake.

"What we've found so far is...a juvenile population. We found like 10 or 12 adults...really fresh mussels that had been introduced probably this summer."

"The divers are trying to take as [many mussels] out of the lake as possible, because as long as the water is under 12 degrees the mussels can't reproduce."

Ariane Orjikh, the general manager of Magog Conservation Inc. (MCI) and one of the divers involved in the operation, has been battling zebra mussels in neighbouring Lake Memphremagog since 2018.

MCI and diving school Plongée Magog were both recruited by Blue Massawippi to tackle the new problem.

"There is a lot of preparation ... we are diving twice a day, each time it's one hour — two hours a day," she said.

"The water is four degrees, it's the coldest conditions we can have right now."

Orjikh said when warmer weather returns, it's crucial that people in the region be careful when they're swimming, boating or practising water sports — and they should report zebra mussels when they spot them.

"It's very important that everybody washes their clothes and their equipment when they change lakes," she said. "Now we have just Lake Memphremagog and Lake Massawippi that have zebra mussels in the Eastern Townships."

She says the mussels spread through tiny, invisible larva in the water.

"But when it enters into a lake it's too late, you can try to control it but it's very, very difficult, almost impossible."

Costly operation

Sending divers into the lake is the only way to safely remove the mussels without harming other plants and animals but the boats, equipment, maintenance and resources required cost a lot of money. 

Blanchette says private donors and local organizations like the Massawippi Foundation helped get things rolling right away, raising around $100,000. Some municipalities bordering the lake have also chipped in and he's hoping Blue Massawippi will be able to get some provincial and federal subsidies as well.

Next year, access to the lake is expected to be limited to one entry point in Ayer's Cliff and there will be a washing station set up where boats will have to be rinsed on the way in and out of the water.

"It's really a long-term effort," said Blanchette. "We have to act really strongly now and in the spring and then we'll have to monitor and continue the diving probably for at least five years."