Aquatic Invasive Species

Spiny water fleas appear as a gelatinous mass on a fishing line.
Spiny water fleas can be found in many Minnesota lakes including the 4 main lakes of Voyageurs National Park.

Voyageurs National Park aims to protect interior lakes from exotic species and fish disease

Exotic species such as the spiny water flea rusty crayfish, zebra mussel, and fish diseases are threats to the aquatic ecosystems of regional lakes including those in Voyageurs National Park. Spiny water fleas have recently invaded multiple lakes in the region, including the large lakes within Voyageurs National Park. Rusty crayfish have invaded at least one lake in Voyageurs National Park and many lakes in the region. Zebra Mussel were first detected in the fall of 2021 in Black Bay of Rainy Lake. Viral hemorrhagic septicemia (VHS), a fish disease, has not yet been introduced into any lakes in Minnesota, but has caused fish kills in most of the Great Lakes and in some inland lakes in Michigan and Wisconsin.

The Minnesota Department of Natural Resources (DNR) has designated the following water bodies as infested: Rainy Lake, Rainy River, Namakan Lake, Kabetogama Lake, Sand Point Lake, Crane Lake, and Little Vermilion Lake. The infested waters designation triggers specific Invasive Species Laws which can be found in the most current Minnesota DNR Fishing Regulations.

The National Park Service and DNR are working in concert to prevent the spread of the aquatic invasive species and fish diseases by:

  • Implementing Best Management Practices for visitors, partners, and staff
  • Conducting public education at boat launch areas about exotic species, invasive species laws, and Voyageurs National Park interim measures to prevent the spread of exotic species
  • Providing information about invasive species and fish diseases at park visitor centers, in park and DNR publications, and on the Voyageurs park website and the Minnesota DNR website

The National Park Service has adopted the following three interim measures to protect the interior lakes in Voyageurs National Park from exotic species and fish diseases:

  • Artificial bait only (on all interior lakes only)
  • No privately-owned watercraft allowed in interior lakes (the park will continue to provide canoes and row boats for rent through the Boats on Interior Lakes program and Commercial Use Authorizations on Mukooda Lake)
  • No float plane landings on interior lakes

If you plan to recreate on the interior lakes in Voyageurs National Park, 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 at least 5 days or washed with hot water (>140 degrees F) for at least one minute

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

The park will conduct a program about exotic species and VHS for any interested party or organization.

To schedule a program call Tawnya Schoewe at 218-283-6670 or e-mail us.

With your help and careful actions, we can try to prevent the spread of zebra mussels, the spiny water flea, rusty crayfish, other invasive species, and fish diseases. Stop aquatic hitchhikers crossing from Rainy Lake to Namakan.


Zebra Mussel


Spiny Water Flea


Rusty Crayfish


Viral Hemorrhagic Septicemia

Last updated: May 2, 2024

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Voyageurs National Park Headquarters
360 Hwy 11 East

International Falls, MN 56649



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