Pickerel Lake, Colchester

2004 Aquatic Plant Survey Map of Pickerel Lake

Transect Data | Water Data

Pickerel Lake was created with construction of a dam at what is now the lake’s southern end. Houses line the eastern shore of the 82-acre lake, and the western side remains forested and undeveloped. Pickerel Lake was dominated by two invasive species during a July 2004 survey, although a number of native species occurred in small patches, primarily in small coves in the lake’s northwest and southwest corners, and a total of 15 aquatic species were recorded.

The two invasive species – a  variable-leaf watermilfoil hybrid (Myriophyllum heterophyllum x M. laxum), and fanwort (Cabomba caroliniana) – covered the bottom of the lake with dense growth through much of the lake, which has a maximum depth of 10 feet and a mean depth of 6 feet. Even in the deepest water, the variable-leaf watermilfoil hybrid covered the substrate, producing stems that reached within 60 cm of the surface. Few other species occurred with the hybrid, although occasional plants of the rootless humped bladderwort (Utricularia gibba) were found among the milfoil shoots.

Shoots of the variable-leaf watermilfoil hybrid formed large mats on the surface in some areas in the lake’s northern end. One resident said mats of severed stems sometimes interfere with use of the state boat ramp. Milfoil floating by the ramp also represents a threat to other state lakes because of the difficulty involved in removing the vegetative material from boats and trailers that have been in Pickerel Lake. The species reproduces primarily with vegetative fragments, and any piece of stem with leaves on it can serve as a propagule, establishing a new population. Residents have expressed concern about the abundance of aquatic plants and have asked state officials for advice in managing the situation.

While the variable-leaf watermilfoil hybrid occurred in nearly monospecific stands in the deepest water, the species shared shallower water on the eastern and western sides of the lake with fanwort and, in small patches, other species, primarily along the eastern shore. Floating bladderwort (Utricularia radiata) was scattered among the milfoil on one section of the shore. Ribbon-Leaf pondweed (Potamogeton epihydrus) was recorded in two patches near the southern end of the lake. Yellow water lily (Nuphar variegata) and watershield (Brasenia schreberi) also occurred at the lake’s southern end.

The greatest diversity of aquatic plants occurred in coves at the lake’s southwest and northwest corners. Watershield was very abundant in the southwest cove, occurring there with white water lily (Nymphaea odorata), yellow water lily, and purple bladderwort (Utricularia purpurea). Watershield, white water lily, and yellow water lily also were abundant in the cove at the lake’s northwest corner. Also occurring in that area were spotted pondweed (Potamogeton pulcher), small pondweed (Potamogeton pusillus), snailseed pondweed (Potamogeton bicupulatus), floating bladderwort, humped bladderwort, and purple bladderwort.