Rose Lake in Otter Tail County treated for zebra mussel infestation

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Rose Lake in Otter Tail County treated for zebra mussel infestation
(Released October 7, 2011)

Favorable weather conditions allowed the Minnesota Department of Natural Resources (DNR) to treat a 10-acre section of Rose Lake on Thursday, Oct. 6, for an isolated infestation of zebra mussels in the Otter Tail County lake.

The treatment, using copper sulfate, is the first of three pesticide treatments occurring this fall to kill a small population of juvenile zebra mussels discovered in the lake in late September. DNR biologists believe the invasive mussels were introduced when a boat lift was placed in the 1,200-acre lake this summer.

The DNR hired a licensed aquatic pesticide contractor to apply the treatment, which is commonly used to treat snails that cause swimmers itch. The DNR is paying $14,000 for the three treatments, which take about two hours to complete.

“We know copper sulfate will kill zebra mussels, but we won’t know for sure until next summer if the treatment was successful,” said Nathan Olson, DNR invasive species specialist. “We will be monitoring the site closely.”

It is the first time the DNR has tried to control a small, isolated population of zebra mussels. This technique has not been effective in eradicating large and established mussel populations.

Rose Lake shoreline property owners have been very cooperative. “They provided us access to the lake near the infested site,” Olson said. “We couldn’t have done this without them.”

Rose Lake will be officially designated as an infested water on Monday, Oct. 10. The designation means increased restrictions on bait harvest and transport of water from the lake as well as increased watercraft inspections and enforcement efforts.

The introduction of the invasive mussels in Rose Lake remains under investigation by DNR enforcement officers.