Aquatic Invasive Species

A boat propeller engulfed with quagga mussels

Aquatic invasive species are non-native marine or freshwater organisms that cause or are likely to cause environmental or economic harm or harm to human health.1 They do this by:

  • Outcompeting native species,
  • Threatening the safety of park employees and visitors,
  • Changing or degrading the experience of park visitors,
  • Requiring intensified maintenance and monitoring, and
  • Altering natural ecological processes2

Examples of aquatic invasive species currently threatening national parks include: zebra mussels in Glen Canyon National Recreation Area, Glacier, Yellowstone and Grand Teton National Parks, lionfish and pike killfish in Everglades National Park, and Asian shore crab in Cape Hatteras National Seashore.

Also referred to as aquatic nuisance species, they can be brought into parks on visitor boats and boating equipment. In fact, "any activities that come into contact with any body of water have the potential to spread non-native plants, pathogens, and other invasive species among water bodies.3 Given this, NPS concessioners who manage boating and water guide operations are an integral part of the NPS’ line of defense against aquatic invasive species. The NPS is actively tackling invasive species through national and local programs. However, parks must also rely on NPS concessioners and visitors to prevent their introduction into parks in the first place. Concessioners are in a unique position to help educate the public about aquatic invasive species and the steps necessary to prevent their introduction or spread. These basic steps are:

  1. CLEAN: Before leaving any water, clean all equipment (boats, trailers, waders, anchors, decoys, etc.) by removing all mud, scum, plants, fish, or other tiny animals. If possible, use high-pressure, hot water. Drain the boat hull and live well away from all park surface waters.
  2. INSPECT: Inspect all equipment, including clothing, for the presence of any hitchhikers.
  3. DRY: Before transporting anywhere, dry all equipment. If possible, allow 5 days of drying time before entering new waters.4

Boating and water guide concession operators should check with their park contacts about any aquatic invasive species monitoring efforts at their park. The park may have educational materials concessioners can help to distribute and messaging to share on guided excursions.

Concessioners in parks with water recreation opportunities should be familiar with, and, as appropriate, support efforts to prevent the spread of aquatic invasive species.

For more information, visit the National Park Service Invasive Species and National Park Service Marine and Great Lakes Invasive Species websites


1 Executive Order 13112, 1999

2 Marine and Great Lakes Invasive Species, NPS Nature and Science Website

3 Grand Teton National Park Website, Plan Your Visit

4 Greater Yellowstone Ecosystem Pocket Guide, Aquatic Nuisance Species