Update on Eurasian Milfoil from AlBeRo President Alex Tyrrell

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Last September, I wrote to you about the rapid and uncontrolled spread of Eurasian milfoil in Beaven and Round lakes. At the time, I had just finished spending two days surveying the plant in our lakes with Samuelle Durochers, an environmental technician from CRE Laurentides who was hired by the association to survey and map the Eurasian milfoil in our lakes.

Last week we received the maps that CRE Laurentides produced. Unfortunately, these maps confirm what I shared with you at the time; that Eurasian milfoil is present almost everywhere on our lakes that it can grow, with varying degrees of density.

Here are the maps that we received last week based on the data collected in late August 2021.


As you can see, some areas of our lakes have been completely taken over by this invasive plant. In these areas there is virtually no biodiversity. Fish cannot swim through, native plants are outcompeted and cannot grow.

In other parts of the lakes, milfoil plants are starting to appear in smaller numbers, growing amongst native plants. Those areas are represented by stars on the maps above. Without human intervention these patches of low density Eurasian milfoil will eventually turn into high density zones.

Once high density Eurasian milfoil colonies have wiped out much of the biodiversity in our lakes, ecosystem restoration will be very difficult. We will have lost our seed bank, populations of native plants and their genetic diversity. The fish and animal populations will suffer as well.

High density Eurasian milfoil on Round Lake in 2021; almost no other plants are present in these high density zones present in both lakes

For the moment we, as people who care about Beaven and Round lakes, have a window of opportunity to take action. While removing Eurasian milfoil permanently from the entirety of our lakes is not possible, we can certainly control the spread while protecting the remaining biodiversity. This could be done by selectively pulling out Eurasian milfoil in low density zones where it is growing fast and outcompeting native plants.

When looking at this previous map produced by CRE Laurentides based on 2018 we can see that several low density zones from 2018 have become high density zones in 2021.

The same pattern is observed when looking at the 2016 map completed as part of a study.

Our board of directors will be meeting on February 10th to discuss the new maps and the various options we have to control the plant and save the biodiversity of our lakes. We already know that provincial and federal government funding is not available for the moment since many lakes are facing the same threat and there is no program in place to deal with it. We have joined with an alliance of lake associations to pressure Quebec to take action. Caring for lakes in this respect falls on the shoulders people who care about them and local municipalities.

We would like to hear from as many lake residents as possible ahead of our February 10 board meeting. If you have suggestions, advice, resources to offer including boats, funds, time to volunteer, scuba diving equipment, skills or anything else that you think could be useful please reach out as soon as possible and I will take your comments, offers and suggestions to the board of directors. We raised over $6500 in donations since last summer and will be considering the possibility of purchasing harvesting equipment to be used by volunteers and/or contracting the work out to a firm or individuals. We need all the help we can get. If you are able to donate please send an e-transfer or contact our treasurer, Huguette Messier at messierh@hotmail.com. Please reply to this email to reach me directly.

Eurasian milfoil was introduced into Quebec’s lakes and rivers by humans. Since it was not previously present, it has not been part of the balance of the ecosystem. When a problematic and aggressive invasive species, that was introduced by humans conquers an ecosystem biodiversity suffers and only human intervention (like suction harvesting pictures above) can restore a balance. Under these circumstances we need to do everything we can to protect our lakes. I hope you will join with the association in our efforts to address these important issues.

Water quality is important too…

Water with elevated amounts of fecal coliform and phosphorous pouring into Beaven Lake (November 2021)

We are waiting on the results and analysis on the water testing of bays and tributaries that was conducted in the summer of 2021. It is worth noting that some of the high-density milfoil areas are in proximity to previously identified sources of water pollution from septic tanks or animal agriculture. Maintaining proper water quality is an important factor in the fight against Eurasian milfoil as water polluted from faulty septic tanks or animal agriculture fertilizes aquatic plants. This in turn speeds up the aging process of lakes and water ways. I will share the results and analysis of our water tests with you when we receive them from the Organisme de bassin versant RPNS in about six weeks time.

Let’s work together to protect our lakes,

Alex Tyrrell B.Sc. Env

President AlBeRo

Leader – Green Party of Quebec


Alex Tyrrell and Samuelle Durocher conducting milfoil survey in 2021


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