Thwarting Aquatic Invaders

Invasive Mussels


Invasive species have few natural predators or control agents, allowing them to reproduce and grow rapidly and threaten ecological stability, and the diversity and abundance of native species. They can also threaten our traditional uses of lakes and rivers for agriculture, domestic water supplies and recreation. Exotic species can be transported to new sites attached to boats, trailers, and equipment. Many of these invasive species have the ability to withstand extended periods of time out of water or in small amounts of water, making their transport to new locations possible.

Flathead Lake and the other waters of the Flathead watershed are at risk due to the potential for accidental introduction of invasive aquatic species. Zebra mussels, Eurasian watermilfoil, whirling disease, and New Zealand mud snails are a few of the destructive and aggressive invader species that threaten our waters.

Species specific information

We’re assembled more detailed information on several of aquatic invasive species: Zebra mussels & other invaders.

Montana’s action plan

In October 2002, Montana finalized a statewide management plan to deal with aquatic nuisance species, and in February 2004, Montana Fish, Wildlife and Parks hired a statewide coordinator to implement the plan. The main emphasis of the plan is to prevent the spread of these invaders into new locations. Once introduced into a new location, there is usually very little that can be done to mitigate the impacts.

Flathead Basin action plan

The Flathead Basin Aquatic Invasive Species Work Group formed in 2009 to expand efforts to prevent introductions of aquatic invaders in the watershed. Participants include resource management agencies from federal, state, tribal and local governments and conservation groups. The Flathead Basin Aquatic Invasive Species Action Plan was finalized in 2010 to guide our collaborative efforts and build prevention and education programs, as well as help secure funding for boat inspection and wash stations and other prevention strategies.
What YOU can do:

Before leaving any lake, river, or reservoir:

  • Remove all plants, sediment or animals from your boat and trailer.
  • Drain all water from your boat, including from the motor, live well and bilge. Do not transfer any water from one waterbody into another.
  • Never release live bait into a waterbody or transport aquatic animals from one waterbody to another. Always discard unwanted bait with household trash in the landfill. Likewise, dispose of fish carcasses with trash.

Before launching your boat in a different body of water:

  • Wash your boat, trailer and all fishing gear and equipment. High pressure hot water is best.
  • Air dry your boat and equipment for as long as possible between fishing trips.

If you find a suspicious mussel or aquatic weed:

  • Note the date and location where the sample was found.
  • Store the mussel or a piece of the plant in rubbing (isopropyl) alcohol.
  • Contact your local Montana Fish, Wildlife and Parks office (Kalispell office – 752-5501) or call the Aquatic Nuisance Species Coordinator at 406-444-2448 as soon as possible. The earlier we detect a new infestation the better.

Volunteer and spread the word about preventing introductions of aquatic invaders:

  • Contact the Flathead Lakers to volunteer for aquatic invasive species prevention and education projects.
  • Share information about the threat of aquatic invaders and how to prevent their spread with your friends and neighbors.

Check out these local videos to learn more:

Boat Launch Triva – a humorous video filmed in Polson

They’re Coming – a more serious look at the problem by the Flathead Lake Bio. Station

Keep Aquatic Invaders OUT of the Flathead