Voyageurs National Park’s Water Invaders

While they may not be readily apparent from the surface, aquatic invasive species (AIS) are a very real threat to the ecosystems of places like Voyageurs National Park. Across Minnesota and much of the United States, species such as the spiny water flea, zebra mussels, and Asian carp are already affecting habitats and food chains in waterways where they have been introduced.

In Northern Minnesota, including parts of Voyageurs, the spiny water flea has already decreased the biomass of zooplankton in some lakes by up to 40-60%. This decrease in a key food source in the lake-based food chain may cause declines in natural fish populations that feed on these organisms, and is likely having negative effects on popular species like walleye. Other invasive species can damage critical fish habitat. Rusty crayfish, another species that has infiltrated parts of Voyageurs, survive by eating the vegetation that usually provides habitat for many freshwater fish.

Besides their effect on the fish populations so prized by anglers at Voyageurs, some invasive species can directly impact boaters by clogging boat motors, damaging equipment, or disrupting the lakes in general. In the long run, these issues can become a damaging economic burden for individuals, small businesses, public land managers, and communities.

In order to combat these problems and avoid long-term negative consequences, many different groups and agencies are working together to understand them. Groups such as the International Joint Commission (IJC), the National Park Service, the University of Minnesota, and the Minnesota Department of Natural Resources are conducting research on the effects, spread, and prevention of aquatic invasive species in Voyageurs and its surrounding watershed.

As Voyageurs National Park copes with the emerging effects of species such as spiny water flea and rusty crayfish, the park also works to make sure that other species don’t manage to invade in the first place. So far, Voyageurs has been able to avoid invasion of zebra mussels, but many fishing lakes within driving distance have been infested, including Lake Superior, many waters in Crow Wing County, Itasca County, and as close as Red Lake.

With multiple jurisdictions involved in the Rainy-Lake of the Woods Watershed in both the U.S. and Canada, solutions and further measures to prevent invasion will take time, effort, and cooperation between many different groups. Regional scientists and resource managers are exploring ways to complete a comprehensive AIS risk assessment for the entire watershed to give us a better picture of the current state of our ecosystems and any emerging issues.

Other areas have begun pilot programs to start to address these issues. Recently, resort owners on Lake Vermilion and Pelican Lake went through voluntary MN DNR training and became part of a program run by the North St. Louis County SWCD to help with early detection of AIS. This resort ambassador program is intended to help create community accountability in our waterways and is being explored for areas like Kabetogama in the future.

Koochiching County helped bring in a decontamination unit near Rainy Lake which has been available for public use for several years. For boaters who frequently launch from the Rainy Lake Visitor Center or nearby marinas, we encourage you to use the decontamination station (location rotates around entry points on Highway 11). St. Louis County is working with the Park Service and others to establish new decontamination stations near the park. Both counties run boat inspection programs at major entry points and are exploring other prevention methods. Voyageurs is also working on a rapid response strategy so that staff may be able to prevent a zebra mussel infestation if a new introduction is detected early and in a confined area such as a marina.

Great Fishing!Molyeux4.jpg

You Can Help

As a visitor to Voyageurs National Park, you can play an important role in ensuring that you do not contribute to the spread of these species. These invasions can happen both intentionally and unintentionally. Deliberately transferring species into a new environment, such as dumping a home aquarium into a lake, is an easily avoidable intentional introduction. Unintentional introduction, such as having AIS attached to the boat or fishing gear that you bring into the park, is harder to avoid. But by being vigilant and following a few key suggestions, you can help make sure that you don’t accidentally introduce invasive species.

To ensure that you don’t bring invasive species into or out of the waters of Voyageurs, remember to Clean, Drain, Dry, and Dispose!  

  • Clean your boat as best you can with hot water both before and after boating in the park, using decontamination stations where they are available.

  • Drain live wells, bilge, and anything else that holds water before you leave the access area after boating.  

  • Dry your boat and fishing equipment before using them in a new lake. Boats should either be dried for five days or washed with hot water before launching in a new lake (and before they arrive at Voyageurs).

  • Dispose of unwanted bait and fish parts in the trash. Encourage others to do the same!  If everyone does their part, we can help keep our waters clean and free of damaging aquatic invasive species.

More great information on AIS prevention can be found on the Minnesota Department of Natural Resources’ website.

VNPA is partnering with NPS to support prevention efforts specifically with volunteers, visitor education and funding. Thank you for helping keep Voyageurs wild and protecting it from aquatic invasive species.

Protecting Voyageurs National Park’s Interior Lakes

Fortunately, the park’s beautiful interior lakes are not currently infested with invasive animal species, making it all the more important for visitors to be vigilant and do their part to help protect them.

The National Park Service has adopted the following measures to protect the interior lakes in Voyageurs National Park from the spiny water flea, other exotic species, and fish diseases:

  • artificial bait only on all interior lakes

  • no privately-owned watercraft allowed in interior lakes (the park will continue to provide canoes and rowboats for rent and through a commercial partner on Mukooda Lake)

  • no float plane landings on interior lakes

If you plan to explore the park’s interior lakes, please follow these best management practices:

  • Bring a separate set of gear that is likely to contact lake water (including fishing gear) to use on the interior lakes, or before using any gear on an interior lake, make sure that all gear has been thoroughly dried for 5+ days or washed with hot water (>140 degrees F)

  • When leaving any lake, remove aquatic plants and animals, including gelatinous or cotton batting-like material from equipment, including fishing line

Photos by Susan Potter, Bob Molyneux