Located in the Lyman F. Anderson Agriculture and Conservation Center One Fen Oak Court Room 234 Madison, WI 53718-8812 Map to Fen Oak 608-224-3730 lakes@co.dane.wi.us
The zebra mussel is a tiny (1/8-inch to 2-inch) bottom-dwelling clam native to Europe. The mussel takes its name from its striped shell. Zebra mussels were introduced into the Great Lakes system in 1985 or 1986 and first turned up in Lake St. Clair. They were first found in Wisconsin waters of Lake Michigan in 1989. Zebra mussels have been found on Lake Monona and are likely in Mendota and Waubesa.
The exotics clog water-intake systems of power plants and water treatment facilities, along with the cooling systems of boat engines. According to the Dane County Fisheries Biologist, Kurt Welke, their presence can also damage the aquatic ecosystem. They can severely reduce and may eliminate native mussel species. Because they filter plankton (microscopic plants and animals) from the surrounding water, water clarity may improve, but the long-term effects aren't well understood at this time. Newly hatched larval fish need zooplankton and phytoplankton to survive and zebra mussels, which are incredibly efficient filterers, are competing with native fish for the same food source. Ironically, even though zebra mussels filter out many planktonic species, the nuisance blue-green algae - often the summer bane of the Madison lakes - is not one of them. In simple terms, zebra mussels take out the good stuff, but not the bad stuff.
Four species of carp native to Asia (grass, black, bighead and silver) have been introduced to North America. Among these Asian carp, the bighead and silver have gained recent notoriety. Both species have established large populations and impacted native fishes in the Mississippi and Illinois Rivers, and are moving north toward Lake Michigan. It is possible that the silver carp is already in Wisconsin.
Eurasian Water Milfoil is a submersed aquatic plant native to Europe, Asia and northern Africa. It is one of eight milfoil species found in Wisconsin and the only one non-native to the state. It first showed up in Wisconsin's counties in the 1960's and in the past three decades, has expanded its range to about 310 lakes including seven lakes in Dane County (Crystal Lake, Fish Lake, Kegonsa Lake, Mendota Lake, Monona Lake, Waubesa Lake, Wingra Lake).
Because of its potential for explosive growth and its incredible ability to regenerate, Eurasian watermilfoil can successfully outcompete most native aquatic plants, especially in disturbed areas. In a number of Wisconsin lakes, Eurasian watermilfoil has formed huge monoculture stands with vast mats of surface foliage that shade-out native aquatic plants and diminish the aesthetic beauty. Recreational activities like swimming, boating and sport fishing are also diminished on Wisconsin lakes infested with Eurasian watermilfoil.
For pictures and info refer to the field guide to aquatic plants and animals.
Boaters using Wisconsin waterways can help prevent transporting exotic plants and animals from one lake or river to another by taking the following precautions with their boats and equipment:
Yahara Waterways Water Trail Guide now available!
