Zebra Mussel Lake Ecology Impacts Monitoring

In the spring of 2018, PRWD staff worked with the University of Minnesota Aquatic Invasive Research Center (MAISRC) to develop methods and protocols to effectively monitor and observe changes in lake ecology due to zebra mussel infestations.  It was recommended that we conduct zooplankton monitoring such as the MN DNR is currently following on select lakes, which does include Detroit Lake.

Since zebra mussels are extremely efficient feeders, they filter out the good phytoplankton and zooplankton out of the water column which small fish fry feed upon and leave behind harmful blue-green algae.  At Multiple locations on Sallie, Melissa and Detroit, PRWD coordinates zooplankton testing with the DNR and add phytoplankton composition and biomass sampling (per MAISRC recommendation).  PRWD ships the samples to MN DNR who performs the analysis and will draft reports with findings.

Below is an image of a phytoplankton sample taken in late June 2018.


Zebra Mussels Infestations In Our Watershed

The Pelican River Watershed and Becker County have been working tirelessly to try and stop zebra mussel infestations in our area lakes through education and boat inspections for the last several years.  Our first infestation was discovered in Lake Melissa in 2014, followed by Sallie and Detroit in 2016 and Floyd Lake in 2018.  However, our vigilance continues and decontamination units are available for use in Becker County.  They are located at various lakes on week-ends, but a scheduled decontamination is available by calling the AIS Coordinator located in the Becker Soil and Water Conservation District  office at (218) 846-7360.  Accesses continue to be monitored during the summer months and  Inspectors will direct you to decontamination units if AIS risk is present.

PRWD has zebra mussel samplers, as shown below, in several area lakes that are checked weekly to monitor potential ZM spread.  Administrator, Tera Guetter, serves on the MN DNR state advisory committee and the University of MN research committee to assist with the development of comprehensive AIS programs.

At the present time, no successful eradication or control measures have been found.  Research will continue to pursue a solution that will not negatively effect native populations.  The PRWD continues to review research data from around the country to determine if any methods could be administered in this area.

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Zebra Mussel Attached to Native Clam (Lake Melissa)

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Zebra Mussels Attached Sampler (Lake Melissa)


 Zebra Mussel Research in Minnesota

The University of Minnesota Aquatic Invasive Species Research Center has dedicated staff and funding to study the impacts, spread and the most effective and efficient ways to control zebra mussels.  To read about current projects involving zebra mussels and their findings since 2012, click on the link below.

  University of Minnesota Aquatic Invasive Species Research Center (MAISRC)

Zebra Mussel Facts

Species and Origin: Zebra mussels and a related species, the Quagga mussel, are small, fingernail-sized animals that attach to solid surfaces in water. Adults are 1/4 to 1 1/2 inches long and have D-shaped shells with alternating yellow and brownish colored stripes. Female zebra mussels can produce 100,000- 500,000 eggs per year.

Impacts: Zebra mussels can cause problems for lakeshore residents and recreationists. Homeowners that take lake water to water lawns can have their intakes clogged. Mussels may attach to motors and possibly clog cooling water areas. Shells can cause cuts and scrapes if they grow large enough on rocks, swim rafts and ladders.

Means of spread: Mussels attach to boats, nets, docks, swim platforms, boat lifts, and can be moved on any of these objects. They also can attach to aquatic plants, making it critical to remove all aquatic vegetation before leaving a lake. Microscopic larvae may be carried in water contained in bait buckets, bilges or any other water moved from an infested lake or river.

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Zebra Mussel are native to the area of Eastern Europe and Western Russia.  They were introduced to our country via the shipping industry through the Great Lakes.  Once established, they quickly spread.

  • 1986 - Zebra Mussels found between Huron and Erie
  • 1988 - Monitoring of spread begins
  • 1990 - Congress passes the Non-indigenous Aquatic Nuisance Prevention and Control (NANPC) act
  • 1992 - Established populations found in Mississippi River near Winona, MN
  • 1993 - Lake Superior listed as infested.
  • 1995 - Lower St. Croix River designated infested.
  • 2001 - Lake Pepin infested
  • 2003 - Populations found to have spread from Great Lakes to inland lakes.
  • 2005 - Populations established in Mille Lacs
  • 2007 - ZM populations found in lakes around St. Paul, Alexandria, and Prior Lake
  • 2009 - Pelican Lake in Ottertail County infested.
  • 2010 - Infestations found in:  Gull Lake in the Brainerd area, Lake Minnetonka and Red River near Wahpeton, ND
  • 2013 - Infestations found in:  Crow Wing Lake Chain, Sand and Little Sand (Itasca), Lake Winnipeg (Canada)
  • 2014 - Lake Melissa in Becker County infested
  • 2016 - Lake Sallie and Detroit Lake infested
  • 2018 - Floyd Lake infested
  • 2020 - Long Lake infested

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Recent Water Levels
Detroit 1334.7 ft
Last Updated: 8/17/2020
Floyd(s) 1354.8 ft
Last Updated: 5/4/2020

Melissa 1329.093 ft
Last Updated: 8/17/2020
Sallie 1330.07 ft
Last Updated: 8/17/2020

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