justnorth posted on November 14, 2007 17:26 :: 1965 Views
Weather permitting, the Department of Natural Resources (DNR) will be treating Geneva Lake in Freeborn County north of Albert Lea with a fish toxicant (rotenone) on Thursday, November 15.
In the event that conditions on November 15 are not right for application, it will be applied on the first suitable day thereafter. If the lake freezes for winter prior to treatment, the DNR plans to treat the lake under the ice. Signs and other advisories will be used to inform the public.
Rotenone is a substance derived from the roots of various tropical plants that is commonly used to eliminate problem fish from shallow lakes and wetlands. Geneva Lake has become infested with carp and the DNR has been working to eradicate them.
Carp, according to Jeanine Vorland, DNR Area Wildlife Manager at Owatonna, root up beneficial aquatic vegetation, which causes water quality to deteriorate, and fish and wildlife habitats to disappear. “Geneva Lake is an important and historic wildlife lake,” Vorland said, “and we are taking every reasonable action available to us to get rid of the carp. Drawing down the water levels in the lake and then applying rotenone gives us the best chance of doing that.”
The DNR has previously attempted to eradicate the carp by lowering water levels in the lake to create nearly complete winterkill conditions but a string of mild winters prevented that from happening, Vorland said. This spring local citizens encouraged the DNR to consider to treating the lake with rotenone during this year’s drawdown as the lake was already being lowered to encourage new growth of emergent plants such as bulrushes, arrowhead and cattails.
Fisheries and habitat assessments indicated rough fish continue to have deleterious impacts despite the low water levels and partial winterkill, prompting the DNR to plan for a rotenone treatment this fall. Even though water levels were very low this summer, fall conditions increase the likelihood of success.
“We’re hopeful the combination of improved fish screens and rotenone will take care of the carp problem,” Vorland said.
Although rotenone poses no human health risks when used according to label instructions, Vorland said the DNR is taking additional safety measures. The public will be asked to stay away from the lake during the time helicopters are applying the rotenone and anyone working with or near the fish toxicant will be wearing special protective gear.
“Rotenone has been used for some 70 years without any significant incidents but it can cause health problems if the spray comes into contact with the eyes or skin or if it is inhaled or ingested,” Vorland noted. To eliminate the possibility of spray drift, he added, the toxicant will be applied in large liquid droplets during relatively calm conditions.
Rotenone breaks down rapidly and poses no health risk to humans or dogs following application and access to the lake will be permitted the day after treatment. Hunters, Vorland said, should have no concerns about harvesting and consuming waterfowl from the lake following the treatment.
Vorland noted that reclamation of Geneva Lake “has been a long process and there has been a level of frustration for all of us. But the support we have received from many people with an interest in this lake
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