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Big Lake Milfoil Mitigation

With the discovery of variable-leaf water-milfoil (also commonly referred to as variable watermilfoil and abbreviated here as VWM) in Big Lake during the fall of 2019, it became clear that organizations in the Downeast Lakes region needed to spring into action.  The quick-spreading nature of this invasive species has created the need for an immediate and thorough response. This urgent need has led DLLT to organize the fight against the spread of this new arrival to the Downeast Lakes region.  DLLT is the fiscal agent for project funding contributions which go toward prevention, surveying, and mitigation efforts.  Key stakeholders this ambitious partnership include:

  • Downeast Lakes Land Trust

    Volunteer IPP’ers (Invasive Plant Patrol), on the lookout for milfoil.

  • Passamaquoddy Tribe
  • Lake Stewards of Maine
  • Woodland Pulp, LLC
  • Grand Lake Stream Guides Association
  • Princeton Rod and Gun Club
  • Big Lake Campmeeting Association
  • Big Lake Road Association
  • Town of Grand Lake Stream

“The problem of invasive milfoil is too big and too important for any one organization to tackle alone,” said former DLLT President David Montague, “which is why it’s so important for all of us to work together on this issue. With support from Maine Department of Environmental Protection and Department of Inland Fisheries & Wildlife, this local initiative is critical for protecting the lakes and the vitally important fishery.”

How You Can Help

DLLT is busy fundraising to help with the costs of this removal effort.  Support the efforts of this coalition by clicking the button below and making a donation! Make sure to write “milfoil” on your donation note.

  There are many ways you can help!

  • Before moving boats between waterbodies, ALWAYS Clean, Drain, and Dry your boat, trailer, motor, and equipment.
  • Attend or participate online in Invasive Plant Patrol training, and help look for invasive variable watermilfoil on the lake
  • Providing access points for survey efforts; including providing space for temp storage of small boats and/or trailers
  • Join a local Invasive Plant Patrol Team
  • Provide SCUBA support for survey/removal efforts
  • Help outreach efforts to the community, including social media outreach
  • Help construct survey team equipment
  • Assist with mapping efforts (GIS projects)
  • If you find a ROOTED plant please reach out to us with the location! Drop a buoy or take a gps point if you can. The more eyes finding plants the faster we’ll be able to remove them.
  • Donate to the removal efforts online or by sending a check to DLLT with “Milfoil” in the memo. 


Contact us at either of the following locations:

DLLT Office                  (207)796-2100
137 Milford Rd
Grand Lake Stream

Tribal Env Dept            (207)796-6156
9 Industrial Park Rd
Princeton                    Joe Musante:

2020 Progress

Three people on boat in Big Lake with suction harvesting tools to removed variable water milfoil.During the fall of 2020, volunteers from the Lake Stewards of Maine and the Maine DEP undertook an extensive survey effort, and DEP contracted with New England Milfoil, a private company specializing in variable watermilfoil (VWM) removal, to remove infestation sites using scuba divers and suction devices that capture plant particles that could otherwise drift away and take root in other parts of the lake. While these measures showed some success in VWM removal, we are still in the very early stages of the fight against this invasive plant.

The formation of this coalition will allow Downeast Lakes Land Trust and partner organizations to spread the workload more efficiently, and collectively improve the fight against VWM infestation. In an effort to contain the spread, DLLT interns and volunteers will be performing courtesy boat inspections each summer at various launches on Big Lake. 

Please do your part, and help stop the spread of VWM by checking your boat for plant materials before transporting, and by cleaning, draining, and drying all surfaces and compartments before launching on a new waterbody.  The vigilance of local residents, boaters, and recreationists in the area is paramount to the future success of these collaborative efforts. We hope that by catching this unfortunate infestation early, we will be able to protect Big Lake and the many beautiful lakes in the Downeast Lakes region for future generations.

2021 Progress

During the summer and fall of 2021, the Big Lake Milfoil Coalition made great strides in the fight against the highly-invasive variable watermilfoil (VWM). An in-depth, level three survey of Big Lake and all tributaries was completed, revealing several VWM infestations and allowing the Coalition to collect important geographic data. The primary infestation continues to be located in Clifford Bay (the area of original discovery), with additional infestations in Musquash Bay, and at the mouth of Big Musquash Stream. Floating patches were observed by boaters and surveyors in many areas of the lake, and several smaller infestations were promptly removed by trained volunteers to prevent spread. Most of this crucial survey work and data collection was completed by passionate volunteer lake monitors who traveled from all across the state of Maine to assist with these removal efforts which are critical to the economic and environmental well-being of the Downeast Lakes region.

This fall, using funding from Maine Department of Environmental Protection, the Coalition contracted New England Milfoil for 8 weeks of diver-assisted suction harvesting, removing more than 23,000 gallons of this aquatic invasive. DLLT and coalition members are so thankful for the many volunteer hours spent on the water, as well as the generous donations that are helping make these efforts possible.

Local camp owner and dedicated volunteer, Bill Inglee, remarked about the severity of the threat and importance of the formation of the Coalition. “Until the discovery and identification last year of invasive non-native variable-leaf milfoil last summer by our local Game Warden, Brad Richard, and Joe Musante, Passamaquoddy Tribe biologist, few of us in the Big Lake area fully understood the serious threat milfoil posed to pristine northern lake areas such as our own. Capable of clogging a watershed, undermining the native fish population, and spreading further in a wonderful northern area like ours, with pristine waters and few people, the discovery was extremely disturbing news to say the least.”

While these measures showed some success in VWM removal, we are still in the very early stages of the fight against this invasive plant. Ongoing efforts will continue in 2022, and for several more years, to monitor and remediate the situation. The vigilance of local residents, boaters, and recreationists in the area is paramount to the future success of these collaborative efforts. “While much work still remains to be done, this year went remarkably well and we are very optimistic about the future,” said Inglee. “And for the local camp community, there is a new appreciation for the positive role played by DLLT in protecting the environment all around us in such a dynamic and effective way.”

2022 Progress

New England Milfoil spent 12 weeks mapping and removing variable watermilfoil (VWM) from Big Lake this summer. Variable watermilfoil is an invasive non-native species capable of clogging a watershed and undermining the native fish population. Since its discovery in Big Lake in 2019, our community sprang into action: DLLT organized the Big Lake Milfoil Coalition, volunteers have conducted extensive surveys, and Maine Dept. of Environmental Protection has been contracting with New England Milfoil (NEM) for diver-assisted suction harvesting every season since.

This 2022 season, NEM mapped 38 acres of extremely dense VWM in Clifford Bay, including 26 acres near the mouth of Clifford Stream. The strategic approach for this season was to maintain a relatively VWM-free channel connecting Clifford Stream to Clifford Bay while completely removing other areas of lower density infestation. Crews of volunteers worked from August through October, mapping the spread of VWM so that contracted divers could remove known patches.


Diving teams started the removal effort by pulling all the known small patches in Long Lake before moving to Big Musquash Stream and Grand Falls Flowage. Little River and a cove near Peter Dana Point were entirely cleaned up. The remaining weeks focused more closely on Clifford Bay, where VWM is quite dense. NEM removed plant growth in the mouth of Clifford Stream and the southern end of the bay to reduce fragmentation of milfoil by boaters accessing the stream. Typically, plants were found in 4 to 9 feet of water. Divers experienced certain areas where the VWM seemed to grow directly from the rocks! The rocks had to be moved out of the way to get at the roots which is no small task. Even if the entire summer’s work had focused only on Clifford Bay, it would not have been possible to remove all the known milfoil growth due to the extremely dense nature of the infestation in that area.

Crews worked through most weather conditions, rain or shine, and strategically shifted areas based on weather and visibility. Their dedication to the project reaped a grand total of 13,183 gallons of VWM removed from Big Lake waters this season! The work is still far from being complete. Please do your part, and help the Coalition stop the spread of milfoil by checking your boat for plant materials before transporting, and by cleaning, draining, and drying all surfaces and compartments before launching on a new waterbody. The vigilance of local residents, boaters, and recreationists in the area is paramount to the future success of these collaborative efforts.


2023 Progress

Downeast Lakes Land Trust contracted with New England Milfoil (NEM) for 11 weeks of location and extraction services using a DASH boat. The first of NEM’s 11 weeks began July 31st and their work concluded the week of October 23rd.

What is a DASH boat? “Diver Assisted Suction Harvesting (DASH) is the extraction of plants using a diver, suction tube, a unique set of pumps mounted on a boat and a bagging or filtration system,” Higgins Lake Foundation.

The Combat Wounded Veteran’s Challenge group provided divers who removed a total of 247 gallons of milfoil. NEM reported removing 27,682 gallons of VWM! Maine’s Department of Environmental Protection (DEP) applied an herbicide treatment at the end of August to the areas around Clifford Bay and Deep Cove where the milfoil infestation was most dense. Post application surveys showed a positive response to the treatment and more surveys will be conducted in 2024. New signs from DEP were posted at public boat launches to inform users of the infested waters and reminding people to properly inspect, clean, and dry their boats. Courtesy boat inspections (CBI) were conducted at public boat launches during high use weekends over the summer months.

Need for Support

Downeast Lakes Land Trust helps to coordinate efforts and continues to provide staff support where needed. DLLT paid for a share of the costs to host the Veteran’s group which amounted to $8,110. NEM submits a weekly invoice for services, the costs of which are detailed in the chart on the following page. DLLT received a grant award from the Maine DEP in the amount of $53,040 and has taken in $15,000 in donations for this cause. To summarize, and without accounting for any overhead for staff time, the 2023 direct costs for milfoil mitigation amount to $97,850. Donations and grants add up to $68,040. This leaves a shortfall in funding for 2023 of $29,810.

2024 Coalition Plans

  1. Continue contracting New England Milfoil DASH crew for VWM removal and post removal surveys in high density areas of infestation throughout the four-lake system. These high-density areas are in Clifford Bay and Clifford Stream, and the mouth of Big Musquash Stream predominately, but have also included some denser sites in Long Lake and Grand Falls Flowage in previous seasons where needed.
  2. Tribal invasive species removal divers will continue to focus their efforts on incipient populations of VWM outside the dense populations where it is less efficient for a DASH crew to set up and move frequently. These are areas the tribal team has worked on in 2022 and 2023, keeping familiarity and being able to note effectiveness. Seeing how an area reacts to different methods of removal allows for quick adjustments. Particularly resilient patches vs hand pulling or DASH can be then attacked with benthic barriers.
  3. Tribal divers also will continue to respond to reports of new infestations in the system, being able to quickly provide pre-removal surveys to mark and do the removal hopefully in the same day.
  4. Tribal invasive species removal diver team is in the process of purchasing and outfitting their own DASH boat to be used on this system. The summer of 2024 will likely be a year of learning and training to be fully operational for DASH work in 2025. 
  5. US EPA started the process of making detailed bathymetric maps of the four affected lakes in 2023. Long and Lewey Lakes have both been surveyed with the data being worked on for digital maps to be available hopefully by field season 2024. This work is scheduled to continue for the foreseeable future for Big Lake and Grand Falls Flowage, focusing on infested or high-risk areas first. These maps will not only give very accurate depth data, but also give insight into bottom composition and plant community locations.