Pickerel Lake, Colchester


2004 Aquatic Plant Survey Map of Pickerel Lake

(1.5 MB, .pdf format*)

Transect Data (233 KB, .pdf format*) | 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 82.2-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 hybrid of Myriophyllum heterophyllum and M. laxum, and 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 Myriophyllum hybrid covered the substrate, producing stems that reached within 60 cm of the surface. Few other species occurred with the Myriophyllum hybrid, although occasional plants of the rootless Utricularia gibba were found among the milfoil shoots.

   Shoots of the Myriophyllum 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 Myriophyllum 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 Cabomba caroliniana and, in small patches, other species, primarily along the eastern shore. Utricularia radiata was scattered among the milfoil on one section of the shore. Potamogeton epihydrus was recorded in two patches near the southern end of the lake. Nuphar variegata and 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. Brasenia schreberi was very abundant in the southwest cove, occurring there with Nymphaea odorata, Nuphar variegata and Utricularia purpurea. Brasenia, Nymphaea and Nuphar also were abundant in the cove at the lake’s northwest corner. Also occurring in that area were Potamogeton pulcher, Potamogeton pusillus, Potamogeton bicupulatus, Utricularia radiata, Utricularia gibba and Utricularia purpurea.

Find Common Plant Names

(65 KB, .pdf format*)

Species recorded in our 2004 survey of Pickerel Lake. Click on plant to view herbarium mount. (invasive species in bold)

Brasenia schreberi

Cabomba caroliniana

Eleocharis acicularis

Myriophyllum heterophyllum X laxum

Nuphar variegata

Nymphaea odorata

Potamogeton bicupulatus

Potamogeton epihydrus

Potamogeton pulcher

Potamogeton pusillus

Utricularia gibba

Utricularia purpurea

Utricularia radiata

Sagittaria sp.

Unidentified sedge

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