A small municipality in the Outaouais, with help from the province of Quebec, is launching a study to examine the impact of an invasive aquatic plant that could damage the region’s lake ecosystems.
The Eurasian water myrtle grows in thick strands just below the surface of the water.
The fast-growing perennial plant poses a threat to aquatic ecosystems due to its aggressive, relentless growth, which can displace native plants and potentially harm fish communities.
Roch Carpentier, the mayor of Sainte-Thérèse-de-la-Gatineau, which borders the vast Lac des Trente et Un Milles south of Maniwaki, said the lake’s natural wealth benefits all the municipalities that surround it.
“We’re going to do everything we can to help the lake,” he said.
Roche Carpentier, mayor of Sainte-Thérèse-de-la-Gatineau, says he hopes the Eurasian water buffalo can be contained to keep the lake clean. (Christian Millet/Radio-Canada)
He said one of the main advantages of the lake is the cleanliness of its water, and that too much overgrown vegetation can make boating difficult and drive away tourists.
The municipality is already planning to lay a tarp on the water pan for the summer to limit it.
“We will never be able to make it disappear,” Carpentier said in French, but he hopes it will be possible to reduce the spread of the plant.
Eurasian water clover is so invasive in part because of how easily it spreads.
Even a small piece broken off from a plant can create a whole new tangle of vegetation wherever it settles. This can happen when boats pass through the plant mass and their spinning propellers disperse pieces into a body of water.
Carpentier hopes lake users will obey the signs that may be installed to direct boaters away from the waterfall.
A study to compare the health of fish populations
The municipality has given the green light to investigate the health of fish populations in areas affected by the Eurasian water trefoil.
“It’s an exotic, invasive species,” Julie Deschenes, a biologist with Quebec’s Ministry of Forests, Fauna and Parks, said in French. “We would rather not have it.
“What we’re trying to see is if that’s still habitat for the fish.”
Julie Deschenes, a biologist with the Quebec Ministry of Forests, Fauna and Parks, says the new study will determine whether the Eurasian water woodpecker is harmful to the lake’s fish population. (Christian Millet/Radio-Canada)
The study will compare the fish population in areas overgrown with the invasive plant and the number of sites inhabited by native aquatic plants.
To study the lake’s fish population, the team will use a combination of traditional nets and an electrofishing technique that briefly renders the fish unconscious, allowing researchers to collect the fish, identify, count and measure it, and then release it back in the water.
The Lac des Trente et Un Milles study will use different fishing techniques to study the health of the fish population. (Christian Millet/Radio-Canada)
A foreign plant is now widespread in several regions
The Eurasian watercress was not native to Canada—it was introduced to North America in the 19th century — but it has felt at home here for decades.
The plant was first spotted in Canada in Lake Erie in 1961.
In the decades since, it has spread throughout the Great Lakes, the St. Lawrence and many smaller lakes in Ontario and Quebec. It is one of the most common invasive aquatic plants in Ontario.
In 2015, it was identified in New Brunswickwhere it also spreads rapidly.
A researcher measures fish taken from Lac des Trente et Un Milles. The study aims to determine whether the Eurasian water tripper is harming the health of the lake’s fish population. (Christian Millet/Radio-Canada)
Hope for future tourism
Marlène Thonnar, president of a corporation that hopes to turn Lac des Trente et Un Milles into a provincial park, said she hopes the results of the study will help educate lake visitors on how to help keep the ecosystem healthy.
“If we have a lot of scientific information… let’s do it [visitors] understand what they have to do and what they can’t do to preserve the beautiful lake we have, that’s a positive thing,” she said.
Marlene Tonar hopes the results of the study will help educate lake visitors on how to help keep the ecosystem healthy, adding that time is of the essence. (Christian Millet/Radio-Canada)
She added that time is of the essence as Eurasian water clover spreads rapidly in the lake.
“We really have to be quick in this exercise [to raise public awareness]Tonar said.
The Lac des Trente et Un Milles survey will continue from July to the end of November.
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