Joanne Burghardt, SLCA President
Alastair Gorman, SLCA Lake Steward

Eurasian Water-Milfoil (EWM) is an invasive water plant present in Steenburg Lake. We are not alone; the invasion is widespread throughout Ontario. And while it is nearly impossible to eradicate, we can minimize or halt the spread.

The SLCA Board voted at the January meeting to take the following actions aimed at halting the spread of EWM, including:

1. Continue the Clean, Drain & Dry campaign.
2. Launch an EWM education program to assist our members in identifying EWM and understanding how to remove it by hand.
3. Invite a representative from the Invasive Species Centre to present a workshop for lake members.
4. Remain vigilant to the appearance of a 'floating mat' which would require further attention.

Watch for more information on identifying and controlling EWM in our Spring newsletter. There are also reading materials in the Invasive Species section of steenburglake.ca.

BACKGROUND:

In 2018, an invasive species survey, conducted by the Federation of Ontario Cottage Associations (FOCA), identified EWM in several spots on Steenburg Lake.

EWM readily propagates by way of stem fragmentation and has likely fostered the subsequent spread throughout the lake.

In August 2024, several property owners reported EWM in the area of their docks. We don’t know how long it has been there, but to date we have not seen it breaking the surface and forming the dense floating mats it is known for, nor any reported evidence of flowering.

See our Invasive Species page for helpful materials

The Invasive Species Centre put us in touch with Jeff Berthelette, Invasive Species Awareness Program Outreach Liaison, Ontario Federation of Anglers and Hunters (OFAH).  

Jeff’s observations:

• EWM is an aggressive invasive species. Once you have it in your lake it will be there indefinitely. Almost impossible to eradicate. It will come back. 
• EWM is widespread in the area lakes.
• EWM has bloom and fallback years. It will grow exponentially and then die off when it has absorbed all the nutrients it needs to survive. It will come and go.
• Jeff echoed what we already knew: management strategies are not easy, and they are very expensive. Lake-wide herbicide treatment can only be done by a licensed professional, under strict conditions, and it is prohibitively expensive.
• The weed can be removed manually under strict conditions but there is a high risk of spreading it if bits and pieces float away and root themselves. 
•  EWM generally grows in up to 3 metres of water but can root itself in as much as 30 feet.

Jeff’s recommendations:

1. Large crops of EWM can be roped off to keep boat traffic away, avoid chopping it up and spreading it.
2. Floating mats of EWM can be roped off to keep boat traffic away.
3. Clean, Drain & Dry boats to avoid spreading to other lakes.
4. Launch a program on the lake to educate owners on what EWM looks like and how to safely remove it by hand from their shoreline. You do not need a work permit under the Public Lands Act, if you can follow all of these rules:

• you are the waterfront property owner or conducting work on behalf of the property owner
• minimize the removal of native aquatic vegetation (e.g., wild rice)
• dispose of the plants/material you remove on dry land to prevent it from re-entering the water
• use, operate or store any wheeled or tracked machinery/equipment on dry land, or on a barge or vessel
• only use mechanical devices (e.g., rake, cutter bar) or your hands to remove plants, and do not dredge the bed of the waterbody
• do not carry out work during fish spawning season or during the time of other critical fish life stages, as set out in the In-water Work Timing Window Guidelines (May 1 – July 15 and October 1-May 1).