Lake Minnetonka WEATHER

Zebra Mussels

Zebra mussels were discovered in Lake Minnetonka by a local resident on July 27, 2010 and confirmed by MN DNR biologists on July 28, 2010.

The zebra mussel is a small, fingernail-sized mussel first found in Lake St. Clair near Detroit in 1988. This native of the Caspian Sea region in Asia is tolerant of a wide range of environmental conditions. To date, they have spread to parts of all the Great Lakes, the Mississippi River, and are showing up in inland lakes. A common problem they present is the clogging of water-intake systems of power plants, water treatment facilities, and the cooling systems of boat engines. Eventually, they may eliminate native mussel species. They also are safety hazards when in contact with feet and other body areas.

One factor in the rapid spread of zebra mussels is the reproductive rate of a female zebra mussel. Spawning generally occurs in the spring and can continue through the summer until fall. Over the course of a year, a female zebra mussel can produce up to one million eggs. These develop into microscopic, free-swimming larvae called veligers that begin to form shells. At about three weeks, they begin to firmly attach themselves to solid objects such as submerged rocks, dock pilings, boat hulls, and water intake pipes.

More information is learned through research projects, some conducted on Lake Minnetonka. More information is available through the following resources.

Additional Information

  • USGS and MAISRC Zebra Mussel Veliger Project 2019/2021
    In 2019, MAISRC and USGS researchers conducted an experimental application of low-dose copper in Lake Minnetonka, St. Albans Bay treated and Robinsons Bay control. The concentration was substantially lower than previously used for adult zebra mussels in Minnesota lakes. This ‘suppression strategy’ has shown promise in early-stage trials. The objectives of the study were to determine the effectiveness of low-dose copper for reducing zebra mussel recruitment and to monitor the response of native biota. In 2020, additional research will be conducted to determine the 2nd-year impact to the zebra mussel population and non-target aquatics. See the 2019-2021 Project Update HERE.
  • MN DNR Zebra Mussel Webpage
  • MN DNR Aquatic Invasive Species Website Page
  • MN DNR Stop Aquatic Hitchhikers