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Invasive species threaten Iowa lakes

By Staff | Jun 20, 2008

So what do Eurasian watermilfoil and zebra mussels have to do with lakes in Iowa.

Potentially, a lot.

Phil Petersen, president of the Okoboji Protective Association, told Estherville Rotarians about the threat of both Eurasian milfoil and zebra mussels Thursday. Eurasian watermilfoil resembles a fern-like moss while zebra mussels are a small D-shaped clam so sharp they can cut swimmers’ feet. Watermilfoil can grow so dense that it clogs props, keeping boats from passing through.

Petersen said since both species are not native they have no natural enemies in our area. Both Eurasian watermilfoil and zebra mussels are transported by boats going from one body of water to another. There have particularly been problems in Wisconsin and Minnesota on boats transferred from Lake Michigan.

In Iowa, Clear Lake is badly infested with zebra mussels, Peterson said. That’s somewhat disturbing, considering there are 12 major boat ramps in the Lakes area where boats could transfer the invasive species. Other Iowa water bodies with zebra mussels are Lake Delhi and the Mississippi River. Eurasian watermilfoil has been found in Twin City lakes and in Palo Alto County.

Eurasian watermilfoil clogs waterways. If you cut it, it grows back very quickly, starting new plants. Usually it is found in relatively shallow waters 10-15 feet deep or less.

Zebra mussels clog water intakes and multiply rapidly.

The Iowa Department of Natural Resources is working with volunteers to help inspect boats using boat ramps in the Lakes area. The DNR maintains a hot water boat wash at the fish hatchery in Spirit Lake to clean off boats with either zebra mussels or Eurasian watermilfoil.

Beginning July 1, the fine will increase from $100 to $500 for transporting aquatic invasive species on public roads and to operate watercraft in a marked aquatic invasive species infestation area.

To volunteer, contact Paula Henry at 332-5444 or go on-line to phenry@iowalakes.edu, Bonnie Simonson at 332-7266 or simonson@pcpizza.com, or Dick Ramsay at 336-5336 or rramsay@mchi.com

For more information about invasive species in Iowa waters, see www.watersafetycouncil.org.