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Milfoil Progress Report


LEA’s milfoil program has experienced another productive summer, but we are still struggling for resources and funding to keep aquatic invaders at bay. Despite some setbacks with malfunctioning equipment and stretched staff, we were able to work well into October and Long Lake, Brandy Pond, and the Songo River are all well controlled. The massive infestation in Sebago Cove still needs more attention, time, and funding and while progress was made in several infested areas of Sebago Lake, more work is needed there as well.

Our accomplishments in Long Lake cannot be overstated. Last summer’s discovery of milfoil in Mast Cove was a shock to everyone invested in Long Lake’s future. Invasive variable leaf milfoil is a threat to tourism, recreation, property values, and the ecosystem. As soon as we identified this invader in Long Lake, LEA began an intensive, rapid response effort to remove the plants and prevent the spread. We spent weeks of work and tens of thousands of dollars tackling the area and removing hundreds of bags of plants from the infested marina. However, LEA staff remained worried milfoil was not controlled in the area. We continued to find new patches spread throughout Mast Cove and fragments were washing up near the Causeway in Naples.

Divers remove a large milfoil plant with the Suction Harvester in Long Lake.

Thankfully, our control team was able to turn the tide this summer. We laid a large number of benthic barriers in and around the infested marina, and continued harvesting the remaining area. This consistent approach appears to be working, as we only found four small plants outside the marina in our last survey. Inside the marina, milfoil continues to lurk, but it is no longer the dominant plant. The invasive milfoil is generally tucked away in hard-to-reach areas, or rocky shallows we are unable to tarp. The risk of the plants spreading further into Long Lake is low, but the crew will continue to patrol this area until the plants are completely suppressed.

On the rest of Long Lake, LEA surveyed the majority of the shoreline for invasive species. Only two areas were found to have plants: Salmon Point Campground in Bridgton, and Birch Point in Naples. Both of these areas had benthic barriers placed over the plants. No plants were found when we revisited either site at the end of the season, but they will continued to be monitored for regrowth. Finding so few plants outside of the original infestation site gives us hope that we have successfully prevented this infestation from spreading.

Because of limited resources and a short summer, we were unable to spend as much time in Brandy Pond, Sebago Lake, Sebago Cove and the Songo River. These areas showed significant regrowth, and that meant the team had to scramble to cover as much ground as possible. Many spots in the Songo River that had been cleared of milfoil for years showed re-growth in 2018, showing the resiliency of this invasive plant. At the end of the season, we were able to focus back on Brandy and the Songo and this helped tremendously with these infestations. Our year-end surveys showed very few plants, and we are happy with the current state of these waterbodies.

In Sebago Cove we were unable to spend as much time in the area as we hoped, and the milfoil experienced strong regrowth. We have managed to maintain control over some areas, but in others the milfoil grew back to near its original extent. This was extremely disheartening to our crew that worked so hard to gain a foothold in the Cove and is a cruel reminder of how insidious variable leaf milfoil can be.

This work requires long term thinking, making tough choices, and prioritization of goals. This summer, we were able to make large strides in Long Lake, but we are going to need to recalibrate our technique and strategy on Sebago Cove. Looking ahead, the remaining control work of Long Lake will require much less time, and more crew time will be available for the Cove next summer. All in all, another good summer, but not without its challenges. Long Lake, Brandy Pond and the Songo River are all in good shape, and while much work still needs to be done on Sebago Cove, we are optimistic about the future.

Interactive map of LEA’s control work in 2018. Zoom in to see areas where control

work was conducted!

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