Daniel Sabourin takes the helm. Improvised captain of this little expedition, he pilots his pontoon to travel the 20 kilometers that separate him from the other end of Lake Aylmer, a huge body of water straddling the Eastern Townships and Chaudière-Appalaches. He wants to observe some specimens of an unwanted visitor: the Eurasian watermilfoil.
A church looms on the horizon, then docks and a boat launch appear in the foreground. This is the Disraeli marina. “Just in front, there are plenty of watermilfoils,” he says, pointing to a few warning buoys. The tops of plants, still young on the eve of summer, tickle the surface of the water there.
Mr. Sabourin is a member of the Lake Aylmer Residents’ Association, which has about 700 members and whose fight in recent years has been to slow the progress of this aquatic plant capable of establishing large colonies that destroy the native flora and make swimming impossible and navigation difficult.
Eurasian watermilfoil was spotted for the first time in this lake in 2006, but each sounding reveals an increasingly important presence. Lake Aylmer is far from the only place struggling with this problem: a government count – most certainly partial – lists 205 lakes and rivers affected in Quebec.
Leaning over the front of the pontoon, François Côté — a citizen visiting from Lac du Huit, where he is also leading a fight against the Eurasian watermilfoil — pulls up a few plants to examine them more closely. This invasive alien species, possibly introduced into the North American wild through aquariums, looks a bit like elongated dill stalks.
All you need to do is transport a small fragment of Eurasian watermilfoil from one lake to another for a new population to take root. Dispersal is mainly done by boaters who do not wash their boat before each new lake adventure. In the north, seaplanes also help.
An ambitious project
The example of Lake Aylmer is interesting for several reasons. In particular because five municipalities surround it, which complicates any intervention. But also because the local association of local residents is involved in the issue of invasive alien species with unusual determination.
“The message we are sending to the municipalities is: we must not wait,” explains Andy Lauriston, the coordinator of the “sentinels” of Lake Aylmer. Beige hat, white beard, worn safety jacket: this shoreline resident has been patrolling the lake in a kayak for years to monitor the progress of Eurasian watermilfoil. Every summer, he spends 15 to 20 mornings criss-crossing his stretch of shore for this purpose.
Mr. Lauriston agrees: it will be impossible to eradicate the invader. However, its growth can be moderated by uprooting dives, for example. In addition, the local residents’ association has been pushing for years for the installation of boat washing stations at each of the five public boat ramps.
The goal is not to prevent the introduction of Eurasian watermilfoil—it’s too late for that—but rather that of other invasive species, such as the zebra mussel, which wreaks havoc in other Estrie lakes. “Right now, if there are bugs who want to come here, the door is wide open,” laments Mr. Lauriston.
Across Quebec, boat washing initiatives based on goodwill often meet with poor support. A few years ago, a pilot project carried out in a garage near Lake Aylmer, where discount car washes were offered, met with dismal failure. “There were zero in the summer,” sighs Mr. Sabourin, who is also a municipal councilor in Weedon. Strong political action therefore seems essential.
Since 2019, the association has offered an ambitious project to local decision-makers. It would include the installation of four boat wash stations on the main roads leading to Lake Aylmer. Visiting boaters should wash their watercraft there (priced at $50, for example) to get a coupon. This would open a barrier giving access to one of the ramps. The municipalities bordering Lac Mégantic adopted such a system this spring.
To take charge of this file, the Table de concertation intermunicipale du lac Aylmer was founded in 2020. This group, chaired by Denyse Blanchet, the mayor of Stratford, also includes the mayors of Beaulac-Garthby, Weedon, the parish of Disraeli and the town of Disraeli. Discussions are held there about the washing station project, but satisfying everyone’s constraints proves to be complex.
“I’m sure we’ll get there, but maybe not at the speed that the association would like,” agrees Mme Blanket. The challenges are many: finding funding, adopting bylaws in each municipality, ensuring a sufficient supply of water for washing stations, etc. On the other hand, some parties do not want to discourage nautical visitors from outside, as their local economy depends on it. So for the moment, no deadline has been set.
A Quebec federation
Constance Ramacieri has lived for 45 years on the shore of Lake Lovering, in Magog, in the Eastern Townships. Involved within her local association in the fight against Eurasian watermilfoil, she “understands the need to protect the lake”. “I want my kids and grandkids to still enjoy it for years to come,” she says.
Mme Ramacieri is president of the Quebec Federation for the Defense of Lakes and Watercourses. This organization, founded last March, brings together lakeside associations with the aim of disseminating good practices. He makes watermilfoil his hobbyhorse, but that’s only the first step. “It’s schooling: if we wash the boats for watermilfoil, we also wash them for other species”, explains the lady under her straw hat.
The federation also aims to represent local associations to governments. “It’s clear, there is a total disinterestedness on the part of the Quebec government”, indicates its president, who has already called on the Coalition avenir Québec in view of the fall elections. In particular, it calls for a national prevention campaign, knowing that controlling the plant is costly and difficult.
Lovering Lake, where Mme Ramacieri lives, has been the subject of “tarping”, that is to say that large tarpaulins have been placed at the bottom of the water in order to smother the largest colonies of Eurasian watermilfoils. This was done at a cost of $200,000 over four years. François Côté’s Lac du Huit is visited every summer by five specialized divers, at a cost of $70,000, who spend three weeks pulling out the exotic plant. A floating vacuum cleaner filters the water to remove fragments of watermilfoil.
For its part, Lake Aylmer benefited in 2020-2021 from a “tidal range”, that is to say a lowering of the level of the lake, at the beginning of winter, so that the first cold spells kill the roots of plants exposed to air. This technique is possible thanks to a dam installed at the head of the lake, which was once used to regulate the flow of the Saint-François River to facilitate log driving.
According to Richard Carignan, a retired biology professor from the University of Montreal who specializes in the study of lakes, these methods of controlling Eurasian watermilfoil are mainly used to “buy time”. The key, according to him, is obviously to avoid the spread of the unwanted aquatic plant.
For infested lakes, there is nevertheless very long-term hope: the Eurasian watermilfoil runs out of steam when the phosphorus and nitrogen, which are found in excess in the sediments of polluted lakes, run out. “We’ve been polluting our lakes for generations,” says Mr. Carignan. To empty the watermilfoil pantry, “you will have to treat your lake well for generations”.
With Paul Fontaine