Lake Dunmore / Fern Lake Association

Milfoil Updates

Reported: Febraury, 2011

            The past year yielded the most milfoil our lakes have seen to date, with plant totals multiple times higher than any season in our history. The milfoil crew, led by Joe Carr, was six men strong, five on SCUBA and one snorkeling. We also employed a suction harvester contractor to assist with the more densely populated areas of both lakes. We purchased a pontoon boat to make for easier, safer and more practical SCUBA dives. Through the use of the pontoon boat the crew was able to move more swiftly and safely from point to point with five SCUBA setups, six men and return with ease from a long picking session transporting a heavy load of milfoil.

            2010 was the first year in history that there was a large enough milfoil population on both lakes that it was well into August before we got ahead of the growth. We feel the substantial milfoil growth started with the high water in 2008 that flooded many yards around Lake Dunmore. We believe the flooding added extra nutrients to the lake. Fern Lake was not as impacted by those rains, but also saw an increase in growth. Further, in 2010 the unseasonable warm spring lead to an explosion of growth in both lakes. We were behind the eight ball by the time we were fully staffed in early June. Over the winter months we made some changes that allowed us to be in a better position to deal with our situation. We didn’t anticipate the growth we saw early in 2010 but we quickly realized that we had to switch from a 50/50 surveying harvesting operation to primarily a harvesting operation.

            We applied for and received a mechanical suction harvesting permit and a bottom barrier permit. Specific sites on both lakes were identified and approved for suction harvesting. The bottom barrier technology was not used, and at this time with a 6 member crew and the ability to do suction harvesting, we believe we will be able to control the spread.

          For the first time Lake Dunmore showed a substantial population of mature plants along the east shore, a location south of Brushes Cove referred to as “the spine”. This location resulted in very high plant totals. This was also the first time that large mature milfoil plants established a hold on the midsection of the lake. This is of significant concern as there is very high boat traffic in this main body of the lake. Other growth on Lake Dunmore was in the same historic areas. There were high plant numbers in North Bridge Bay and North Bay, and increased numbers in North Cove.

            In 2010 Fern Lake experienced an early season explosion in population. The growth on Fern is directly attributed to the very warm spring. There was a great increase in plant populations along the west shore, along a span of about fifteen hundred feet. This is another location that the crew spent a lot of time on and it wasn’t until the suction harvester was available that the crew was really able to get a good hold on it.  Historic patches are still a concern on Fern Lake and the shoreline is an area that has seen quite a bit of growth. Shoreline watch hours are a must on both lakes as well as member volunteer hours. We have seen excellent results by one man in North Cove on Lake Dunmore as well as a couple in South Cove and need to see it more widespread on both lakes.

            In 2011 we plan to construct our own suction harvester equipment to be incorporated with the pontoon boat.  This will give much greater availability of the equipment and lower our operating costs over the coming years.

            We changed our method of reporting quantities of plants pulled to cubic yards and we also segregated each lake into 4 larger sections for reporting purposes. The full report to the state does include details observations on site specific areas in each lake and is available for your review at the Milfoil Cabin at Camp Songadeewin.  Historic unit counts were converted to cubic yards for comparative purposes. We will continue to track using the cubic yard methodology.

                Below are the comparative harvesting counts for each lake.

Plants Harvested

Lake Dunmore (in cubic yards)

Fern Lake (in cubic yards)