DNR attempts to stop zebra mussels with pesticideby Dan Gunderson, Minnesota Public Radio
Frazee, Minn. — The Minnesota Department of Natural Resources applied pesticide to a northern Minnesota lake this week, hoping to stop a zebra mussel infestation.
It's the first time the DNR has tried to reclaim a lake from the invasive species. The DNR often doesn't find zebra mussels in a lake until the population is established.
Residents on Rose Lake, about 10 miles east of Detroit Lakes, applaud the effort, but say the state needs a much more aggressive approach to protecting Minnesota lakes from zebra mussels.
DNR Invasive Species Specialist Nathan Olson is confident the tiny mollusk just arrived on Rose Lake.
"It is under investigation," Olson said. "We do know an individual moved a boat lift with zebra mussels attached to it and placed it here in Rose Lake."
The boat lift is gone now and a yellow plastic barrier surrounds the area where it the boat lift was on the lake.
About a dozen people watch from shore as a boat moves slowly back and forth applying the pesticide copper sulfate to the water. Two hoses come off the side of the boat and dangle in the water. The pesticide is dispersed beneath the water surface.
This area will be treated at least three times this fall and possibly again next year. It will be at least two years before he knows if the $15,000 effort is successful, Olson said.
AN AVOIDABLE SCENARIO
Terry Kalil, vice president of the Becker County Coalition of Lake Associations, believes the infestation could have easily been avoided.
Kalil, who lives on a nearby lake, said if this boat lift owner had followed state law there would be no zebra mussels in Rose Lake. Kalil said it reflects ignorance and apathy on the part of state residents.
It's against the law to move any equipment carrying invasive species, and carries a fine of $250. The fine can be up to $500 for introducing invasive species to a lake.
"There are a great many people who for them a $250 fine — 'Who cares? I don't care. I'm not going to decontaminate my boat.' "
DNR officials also support tougher penalties for people who move zebra mussels or other invasive species.
Some lake associations are contacting county officials about the possibility of closing ramps to allow boats to leave or enter or leave the lake only when an inspector is on site to ensure boats are clean.
Otter Tail County Coalition of Lake Associations President Jeff Stabnow said everything possible should be done to stop zebra mussels. He said state leaders need to look at the potential economic impact. He worries people will want to move away from lakes infested with zebra mussels, and that will drive down lakeshore property values.
"In a number of these counties up in this part of the country, over half of the income for government, county government and all that, is impacted by the property values on the lakeshore," Stabnow said. "So the potential is huge."
IMPACT NOT YET KNOWN
It's still not clear how zebra mussels will affect lakes in the long term.
Olson said fish populations could shrink because of competition for food. Zebra mussels filter water making it very clear, and the extra sunlight in the water could cause an explosion of plant growth in lakes.
"Our lake ecosystems are stressed already with development and just land use practices in the watershed," Olson said. "When you start to add on top of that a zebra mussel, there may be a breaking point."
The DNR is monitoring the fish population in several infested lakes. The DNR says there are now 50 lakes in the state considered to be infested with zebra mussels.
- Morning Edition, 10/07/2011, 7:25 a.m.