Androscoggin Milfoil Project

Androscoggin Milfoil Update

June 17, 2021

At the end of May, our new milfoil survey team began the season’s work of looking for invasive variable milfoil on Androscoggin Lake, focusing on the Inner Cove, where we had removed the milfoil last fall. Unfortunately, we found that the plants had grown back and were covering an even larger area than last fall. Most plants were in 3-4 feet of water, with several already growing to within a foot of the surface. 

On June 7th, staff from the DEP joined us and carefully removed all the plants we had found, which filled one-third of a large garbage bag. We are continuing to survey the cove, five days a week, monitoring regrowth and looking for plants in other areas. We have now found milfoil scattered throughout a larger area and in deeper waters. So far, the infestation appears to be small enough that we remain optimistic for a good outcome. Our strategy is to be as thorough and aggressive with our efforts now to prevent its spread and save hundreds of thousands, even millions of dollars in future years. Yellow DEP buoys that say “Avoid Milfoil Area” mark the outside edge of the area where plants have been found. Please do not enter this area. Boat props and fishing lures can fragment the plants, causing them to spread into other parts of the lake. Photo: Our milfoil survey team staff members Silas Mohlar and Gus Cooke surveying the Inner Cove.


Invasive Milfoil in Androscoggin Lake

May 24, 2021

With the summer season almost here, we are ramping up to fight the new invasive milfoil infestation on Androscoggin Lake. If you missed it, here’s a quick recap of what happened last fall.

In September, a volunteer member of the invasive plant patrol team for Androscoggin’s lake association (ALIC) found a suspicious plant in the Inner Cove at the northern end of the lake, near the public boat launch. DNA testing confirmed the plant was invasive variable water-milfoil. Water-milfoils are rooted, submersed aquatic plants that grow in lakes and streams. Five species are native to Maine; two invasive species threaten Maine’s waters.

Because attacking an infestation early provides the best hope, 30 Mile and ALIC immediately went to work with the Maine DEP and Lake Stewards of Maine to implement a rapid response. After two long days of surveying and two days of removing plants, by mid-October we had done everything we could for the season, removing all the plants we had found.


Why is Milfoil a Threat?

May 24, 2021

Invasive species outcompete the natives. In an organism’s native habitat, its growth is balanced by other organisms that have evolved to compete with or eat it. Invasive plants like variable milfoil are free from their natural competitors and can outcompete native plants for space and sunlight, growing and spreading rapidly, unchecked. Native plants provide both a food source and habitat. When those are altered, invasive plants can drastically alter delicate relationships in the food web. The dense growth and rapid spread of milfoil also dramatically impede swimming and fishing, greatly hurting property values and tourism.

Variable water-milfoil is an extremely hardy perennial. Because it can reproduce by fragmentation, when a disturbance like a motorboat or fishing lure passes through a colony of plants, the chopped-up pieces are each capable of forming a new plant. Milfoil can spread throughout a lake or move from lake to lake on a propeller, trailer, fishing gear or anchor. Photo: Lakes Environmental Association


Finding Milfoil: Volunteers Needed

May 24, 2021

Beginning this week, staff from 30 Mile will be back out on Androscoggin Lake, looking for new invasive plant growth and plants we missed last fall. Maine DEP divers will survey the deeper areas of the cove. As we find invasive milfoil, we will carefully remove it. This intensive effort will continue throughout the summer and into the fall. 

We also must confirm, through a full lake survey, that the milfoil isn’t growing anywhere else in the lake. Androscoggin is a big lake and there are many places where variable milfoil could be. This effort will be ongoing throughout the summer and will depend upon the support of MANY volunteers. 

If you are already a trained volunteer, we are counting on you now more than ever. If you are not yet trained but eager to help, we will be offering several trainings throughout the season - no experience necessary. What’s involved in volunteering? You will spend time on the water, on your own schedule, looking for plants that don’t belong. Many different species of native (good) plants grow in the lake, and several are look-alikes for variable water-milfoil, so basic knowledge of plant identification is important. Most surveying is conducted from the surface, with the naked eye when conditions allow, or with a scope, as shown here. ANY time you can spend looking for invasives while you are out enjoying the lake is helpful. The more eyes the better! 

For updates on training opportunities and our progress, watch our future newsletters, Facebook page, and website.  

To volunteer on Androscoggin or become a plant surveyor for another lake in the watershed, please contact Lidie at


Invasive Milfoil Found in Androscoggin Lake

October 16, 2020

In early September, a volunteer “plant patroller” on Androscoggin Lake, Katherine Mahoney, collected a suspicious aquatic plant from the Inner Cove at the northern end of the lake, 400 yards north of the state boat launch. Because the plant was a milfoil and we could not rule out the invasive types, it was sent in for DNA testing. At the end of September, the results came back: It was variable water-milfoil, Myriophyllum heterophyllum, an invasive species.

This is the first time an invasive aquatic plant has been found anywhere in the 30 Mile River watershed and poses a serious threat to not only Androscoggin Lake, but to other lakes and ponds in the watershed and beyond. Invasive milfoil can devastate a lake. Once it takes hold, it can strangle portions of that lake, pushing out native plants and other organisms, changing natural habitat, and making it difficult or impossible in many places for swimming, boating, fishing, and other recreational activities. This typically results in a drop in property values around that lake, which has a ripple effect on the economies and businesses of surrounding towns.

Because invasive milfoil grows and spreads rapidly, identifying infested areas early and implementing aggressive, immediate control efforts are critical and provide our best hope. Upon learning the DNA results, 30 Mile immediately went to work with the Androscoggin Lake Improvement Corporation (ALIC), the Maine Department of Environmental Protection (DEP) and the Lake Stewards of Maine (LSM) to organize a rapid response.

Through this important collaborative effort, on October 3rd we were able to successfully deploy an early response team of 17 trained plant patrollers (see photo above) – 15 volunteers and 2 staff from 30 Mile and LSM – to survey both the Inner Cove and the Androscoggin Yacht Club basin. Volunteers came not only from Androscoggin Lake’s plant patrol team, but from teams on Flying Pond, Lovejoy Pond, Parker Pond and beyond. Towards the end of the day, surveyors found a patch of variable milfoil about 12 feet in diameter, in water 3 feet deep, 100 feet south of where the original plant was found.

On October 5th, Lidie Robbins of 30 Mile returned to the cove with DEP staff. A DEP diver (photo right) carefully removed by hand all of the invasive milfoil that could be found in that area. On October 15th, a team from LSM, 30 Mile and the DEP surveyed the cove again and found four additional clusters of plants, which will be removed within a few days.

Beginning in the spring of 2021, ALIC and 30 Mile will conduct repeated surveys of both the cove and all other littoral zones of the entire lake, and will organize plant removal work as necessary. We will need additional help and plant patrol volunteers to make this effort a success. 30 Mile will also be working with volunteers across the watershed to ramp up surveys of other lakes and ponds. If you are interested in becoming a volunteer plant patroller, please contact Stay tuned for more information and ways you can get involved.