Lake Stewards of Maine (LSM), together with Maine Department of Environmental Protection (DEP), York County Invasive Aquatic Species Program (YCIASP), and Little Ossipee Lake Association (LOLA), held a Level 3 Aquatic Invasive Species Survey on Little Ossipee Lake in Waterboro on May 22, 2024.
After swollen bladderwort (Utricularia inflata), an aquatic invasive plant, was discovered on Little Ossipee in late summer 2023, the Maine DEP and YCIASP assisted LOLA in finding the extent of the infestation during a rapid response survey. Following last year’s initial survey, LSM gathered together a crew of over 20 people to perform a full Level 3 Survey on Little Ossipee last week. The team consisted of staff from LSM, DEP, and YCIASP, along with volunteers from Little Ossipee Lake, Lake Arrowhead, Mousam Lake and beyond with LSM’s IPP Travel Team.
Breaking into small teams, the group set to work scanning every cove for swollen bladderwort. The search was fruitful, and together the teams discovered the aquatic invasive plant, already in flower, in its likely origin point in Eon Cove, and scattered across the lake in shallow and protected areas. To document their findings, the volunteers and assisting staff used Survey123 and paper survey forms, which will be proofed, scanned, and submitted to the DEP by LSM.
Swollen bladderwort is one of the four “new” plants added to Maine’s invasive list in 2023. Originating in the lower eastern US, swollen bladderwort acts aggressively outside of its native range, and has been discovered and declared invasive in many Northeast States, as well as Washington State, and even overseas. Swollen bladderwort has been discovered on five lakes in Maine, including Little Ossipee, Mousam, Lake Arrowhead, Tilton Pond, and Horseshoe Pond (Chesterville).
Following inspection of all littoral areas of the lake (with the exception of Eon Cove), swollen bladderwort was discovered in sectors B, C, and E. In Sector B, individual plants were discovered drifting in large numbers out of Eon Cove. In Sector C, larger patches of the plant were discovered on either side of the Bob Fay Memorial Park peninsula, with plants entangled around submerged logs. Plants found in Sector E were found drifting in deeper water, carried by wind. Eon Cove appears to be the nucleus of the infestation. The infestation was mapped using Survey123. Found plants were removed, with their sites marked with labeled buoys. It is noted that at the time of the survey, swollen bladderwort was blooming and easily visible. While in flower, the plant had developed floating rafts, allowing for easy wind dispersal.
Recommendations:
Maine DEP has developed a management plan with LOLA. The management plan includes hand pulling and Diver Assisted Suction Harvesting (DASH), with a DASH boat scheduled to visit in early June 2024. LSM and YCAISP will continue to support the Little Ossipee community with a Live Plant ID training on June 25, and encourages LOLA to continue monitoring for aquatic invasive plants with its IPP Team. Little Ossipee also has several Water Quality monitors, who are encouraged to continue their work. Considering its close proximity to Lake Arrowhead, a heavily infested waterbody with 3 AIS confirmed, LSM recommends continued and thorough IPP monitoring, as well as Courtesy Boat Inspections at the public launch.
