Scientists for the first time in Wisconsin plan to use a bacteria to kill zebra mussels — in this instance, in a Florence County lake.
Researchers with the U.S. Geological Survey want to apply the biological pesticide next month to sections of Keyes Lake in the hope of killing off zebra mussels that have attached themselves to native mussel beds.
If experiments prove successful, the treatment could one day be a tool to control the spread of destructive zebra and quagga mussels, both invasive species.
Zebra mussels were discovered in the Great Lakes in the mid-1980s, and turned up in inland Wisconsin lakes in 1994. They can now be found in 163 lakes and rivers in the state, according to the state Department of Natural Resources. Quagga mussels are in the Great Lakes, but have not yet invaded inland lakes of Wisconsin.
The pair of tiny, sharp-shelled species devour plankton, disrupting ecosystems. They proliferate in areas by the tens of thousands and push out native species, clog water intake systems and play a role in spurring algae blooms.
On inland waters, worries run the gamut — from the potential for declining land values to the loss of native mussel populations. On the Great Lakes, the invasive mussels threaten a multibillion-dollar recreational sport fishing industry while fouling beaches by spurring weed growth that rots on shore.
Zebra mussels are believed to have hitchhiked from Eurasian ports in the ballast of ships, and now are often transported between lakes by boats and bait buckets.
The state Department of Agriculture, Trade and Consumer Protection said this week it is reviewing a request by the geological survey for an experimental use permit to spread the bacteria, known by its trade name, Zequanox, in targeted areas of the lake.
There have been past experiments in 2012 — in DuPage County, Ill., and near Alexandria, Minn. — but the research on the 195-acre Keyes Lake will be a first in Wisconsin involving testing in public waters.
The lake was chosen because zebra mussels were found there in 2010 and because it also has a healthy population of native mussels, said James A. Luoma, a research scientist for the geological survey in La Crosse.
The agriculture department has conducted an environmental assessment of the product and found no potential environmental harm if it is used as advised by the manufacturer. The public can comment on the plans until June 19.
Luoma said a team from the agency plans to spread 25 to 30 pounds of the product in enclosed areas of the lake in about 5 feet of water where both native and zebra mussels have been found.
In some experiments, "we've had a 90% kill rate," Luoma said. "It's pretty toxic."
But apparently it is not toxic to anything else.