Eurasian Milfoil still hanging around Sudbury lakes

A group of people who live on Long Lake in Sudbury are planning to map an invasive species that has taken over.

At least 18 lakes in the city are still dealing with Eurasian water-milfoil, almost a decade after the invasive species was first seen in Sudbury area waters.

The fast-spreading milfoil forms a thick underwater shade that kills aquatic plants and is also an nuisance for swimmers, boaters and lakefront property owners.

It spreads quickly because parts of the plant can detach from the root system and create new plants — earning the moniker "zombie plant."

"Milfoil can be spread a number of ways. Some of those ways involve boating practices, kayaking, canoeing, fishing," Lori Adams, a member of the Long Lake Stewardship Committee said.

"Once milfoil has been established, it's capable of altering the biological environment of the lake and causing a decrease in the richness and diversity of aquatic plants and organisms, and also fish habitats."  

Education key in battle against species

Adams said that milfoil not only reduces property values by making the water less enjoyable for outdoor recreation, but can also threaten the natural balance of lakes.

One of her group's challenges is to make sure people using the lake understand how quickly the plant can spread.

"By increasing awareness of our residents on Long Lake, in terms of where the dense milfoil beds are located and encouraging all to not boat and fish in these areas, it's helpful in not causing the milfoil stems to fragment and then naturally reseed and create new milfoil beds."

Group laying plans to identify the milfoil

The City of Greater Sudbury, the Greater Sudbury Watershed Alliance and the Long Lake Stewardship Committee have held awareness and education campaigns in the past to help stop the spread of milfoil.

The city also ran a pilot project in 2011 to introduce insects called weevils to help stop the spread. That program was eventually scrapped, as the lake's natural vegetation did not survive.   

The committee is now turning to mapping the milfoil on Long Lake itself. 

Adams said the group has broken up into 10 mapping teams of volunteers, to survey and map 60 500 square metre sections of the lake. With assistance from the city, they'll have resources packages with information, including on how to identify milfoil.

"Once a team has gone out in the boat and located a milfoil bed, GPS coordinates will be taken and the bed will be drawn on the hardcopy map that will be available," Adams said.

Volunteers have a specific raking method they will use to collect samples

"One of the volunteers will then put the rake below the surface and pull up and that sample that is collected on the rake head will then be used to determine the fullness or the density of the milfoil in that bed," Adams explained.

"The data that is recorded on the maps — the location of the beds and the coordinates and the densities — will be made digitally available as well, and our lake residents then will be able to have those on their cell phones when they're out on the boat."

The group had initially planned to do the mapping this Sunday but the milfoil hasn't grown fully and rose to the surface yet. It typically rises in July.

The mapping is now scheduled for two weeks, from August 8-22.