The Minnesota Department of Natural Resources (DNR) says a new treatment failed to kill zebra mussels in two lakes.
The DNR used copper sulfate, a chemical commonly used to treat lakes for swimmers’ itch, to treat Lake Irene in Douglas County and Rose Lake in Otter Tail County.
DNR invasive species specialist Nathan Olson said the agency did not find any zebra mussel larvae or large zebra mussels during scuba searches this summer. But Olson said during fall searches the DNR did find adult zebra mussels in both lakes.
This is more bad news for Texas biologists and fisheries managers hoping to find ways to stop what appears to be the inevitable spread of the invasive mollusks in the state’s waters.