Eurasian watermilfoil has been discovered growing in Shamineau Lake in Morrison County, the Minnesota Department of Natural Resources (DNR) said Monday.
The nonnative, invasive aquatic plant was discovered in several locations in the northwest area of the lake and east of the public boat access. The DNR conducted further surveys in July to determine the full extent of the distribution of Eurasian watermilfoil in Shamineau, but none was found elsewhere in the lake.
Shamineau Lake supports a highly diverse submerged aquatic plant community, with stands of white water buttercup, clasping-leaf pondweed, northern watermilfoil, sago pondweed, flat-stem pondweed, fern pondweed and large-leaf pondweed.
“Northern watermilfoil is one of the most dominant aquatic plants in Shamineau Lake and should not be confused with Eurasian watermilfoil,” said Christine Jurek, DNR regional invasive species specialist. “Northern milfoil has five to nine pairs of leaflets compared to Eurasian watermilfoil, which has 12 to 21 leaflets.”
The Eurasian watermilfoil was discovered by Conservation Officer Jeff Halverson. The DNR sent crews to Shamineau Lake to search for Eurasian watermilfoil and found rooted plants growing in the lake between three – 12 feet of water.
Eurasian watermilfoil can form dense mats of vegetation and crowd out native aquatic plants, clog boat propellers and make water recreation difficult. The DNR and the local lake association have decided to hire divers to remove the Eurasian watermilfoil by hand and reduce the likelihood that boaters might accidentally carry the plant from the lake on trailered watercraft.
“Hand pulling will most likely not eradiate the plant from the lake, although it may be a better choice than herbicide treatments that would kill the northern watermilfoil that is dominant in Lake Shamineau,” Jurek said.
“The DNR has more than 20 years’ experience with attempts to eradicate milfoil from Minnesota lakes,” said Chip Welling, DNR aquatic invasive species management coordinator. “We also have learned a lot from monitoring efforts in other states. Milfoil can be managed, but complete eradication is not a realistic goal.”
Boaters who use Shamineau Lake are urged to be extra thorough when looking for and removing aquatic plants from their boats, trailers, nets, anchors and other equipment. It is unlawful in Minnesota to transport aquatic plants or prohibited invasive species on roads or to launch watercraft with them attached. Eurasian watermilfoil has now been discovered in 261 lakes, rivers or streams in Minnesota.
The lake will be designated as an infested water later this month. That means restrictions on bait harvest and transport of water from the lake will be in effect.