The Fight for Lake Leelanau – Battling Eurasian Watermilfoil

Brian Price

No one was certain it would work in Northern Michigan two years ago. Everyone knew it would require special knowledge and skill to make it work. Thanks to the cooperative efforts of the Lake Leelanau Lake Association and the Grand Traverse Band of Ottawa and Chippewa Indians, the evidence is now clear that sheets of bio-degradable burlap can be successfully deployed to kill large infestations of Eurasian Watermilfoil. Of course, this war with the noxious weed is more complex than that.

The Lake Leelanau Lake Association and the Grand Traverse Band (GTB) of Ottawa and Chippewa Indians are completing the second year of a long-term fight against the Eurasian Watermilfoil. This invasive aquatic plant appeared in the pristine water of Lake Leelanau about three years ago as it grew and spread. The alarm bells went off and Lake Association Biologist, Brian Price began tracking and mapping the quickly emerging “forests” of the boat-choking invasive weed. In partnership, the Lake Association and the GTB began researching options for fighting this destructive plant and raising the money needed to carry on the fight. Inland Lake Specialist and biologist, Dan Mays is the team leader on this project for the GTB.

Dan Mays

Last year, Nature Change documented the partnership’s first efforts to stamp out Eurasian Watermilfoil in Lake Leelanau. The resulting documentary helps viewers understand both the nature of the threat posed by this invasive weed and innovative approaches being used to kill it without using chemicals.

This year’s documentary shows that the burlap barriers appear to be working as hoped and more huge sheets of burlap have been deployed to kill the most extensive infestations. Other control methods such as diver assisted suction harvesting (DASH) are once again being used to remove smaller patches of the weed. These systems are based on pontoon boats and require at least a two-person crews.

For tracking and removing small infestations, even single plants, the project partners have engaged professional and volunteer divers. According to diving instructor, Annalise Povolo infestations of Eurasian Milfoil can look like dense bamboo forests underwater, presenting real problems for boaters and swimmers. She encourages other divers to consider helping out with this underwater weeding project in the years to come.

Annalise Povolo

This year, the partnership has begun working on returning desirable native plants to the areas once overrun by Eurasian Watermilfoil using in-lake transplantation. As shown in this documentary, novel techniques are being used to plant directly into the degrading burlap barriers spread last year.

The project partners agree that once a lake has been infested by Eurasian Watermilfoil, there is probably no way to totally eradicate it. Even small parts of the plant can drift and create new infestations. So, there will need to be continuing effort to watch for new occurrences and remove these offenders from the lake as soon as possible. However, as the extensive beds of Eurasian Watermilfoil are destroyed and the smaller weed patches pulled out, the whole problem becomes more manageable year after year.

 

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