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US Fish & Wildlife Service FieldNotes

ECOLOGICAL SERVICES: Recent sunny weather may mean a bumper crop for Alaska's Elodea infestations!

Region 7, May 29, 2013
Elodea infestation in Anchorage's Sand Lake. Sand Lake is a short distance from Lake Hood.
Elodea infestation in Anchorage's Sand Lake. Sand Lake is a short distance from Lake Hood. - Photo Credit: n/a
Snagged by watercraft, trailers, and float planes, Elodea fragments are easily transported to new waters.
Snagged by watercraft, trailers, and float planes, Elodea fragments are easily transported to new waters. - Photo Credit: n/a

Elodea. believed to be Alaska’s first fully submerged aquatic invasive plant, you may have seen Elodea choking out areas of Sand Lake, Little Campbell Lake, or Delong Lake in Anchorage and Chena Slough in Fairbanks. It’s also being found in a growing number of lakes and slow moving rivers/sloughs in Cordova and on the Kenai Peninsula.

 Should Alaska visitors and residents be concerned? Yes! Elodea survives under ice. When introduced to a new waterway, Elodea grows rapidly, overtaking native plants, filling the water column, and changing the habitat conditions to which native fish are adapted. Thick mats form at or just below the water surface and can foul boat propellers and float plane rudders, causing a hazard. In addition to impeding fishing, navigation, boat launching, and paddling, it can also reduce waterfront property values.

Team founder of the Anchorage Rowing Association and long-time rower Marietta “Ed” Hall explained, “As a rower on Sand Lake since 1998, the recent exponential growth in Elodea has been shocking. When I pass over certain sections of the lake Elodea snags my small six inch keel and nearly capsizes me. It’s obvious how damaging this weed will become to all users if it’s not controlled.”

The growing negative impact of Elodea can most recently be seen in the closure of Stormy Lake (located within the Captain Cook State Recreation Area near Nikiski) to watercraft and aircraft for the 2013 summer season in an effort to prevent its spread.

How does it spread? Fragments of Elodea snagged by watercraft, trailers, floats planes or other outdoor equipment are easily spread to new waters. New infestations can also result from intentional (albeit well-meaning) releases from school/home aquariums (In Alaska, live specimens of Elodea are used to teach students about cell structure—it’s also a popular aquarium plant).

Although Elodea has only been confirmed in 15 waterbodies in Alaska to date, its foothold in float plane lakes like Sand Lake (only three miles away from Alaska’s busiest float plane base, Lake Hood) make it only one step away from invading any number of additional waters across the state.


  • Support eradication efforts. Elodea is expensive and difficult to control
  • Teachers, students & aquarium hobbyists: don’t let it loose!
  • Boaters: avoid disturbing heavily vegetated areas by not motoring through them. CLEAN: Carefully inspect and remove any visible aquatic plants/fragments from your boat and trailer before leaving the waterbody. DRAIN: Allow water to drain from live wells, bilge tanks, and dispose of water from all tanks that hold lake/stream water, including coolers, before launching at your next site. DRY: Allow the craft and equipment to dry completely before the next use.
  • Float planes: Before entering the aircraft remove visible plants and pump water from floats. Before takeoff don’t taxi through heavy plant growth; raise and lower rudders. After takeoff raise and lower rudders to free plant fragments while over the waters you are leaving or over land.
  • Report sightings: Note location (GPS or mark on map) and water depth/clarity. Take a specimen (photo at a minimum). Take as much of the entire plant as you can, including the tiny flower on a long thin stalk if present. Put the sample in a zip lock bag, book, or wax paper and store in a cool place. Call the Alaska Department of Fish and Game invasive species hotline: 1-877-INVASIV. It’s critically important to figure out where Elodea is—and where it isn’t—so we can help prevent it from spreading further. We need you on the lookout this summer!
  • Educate yourself and others about invasive species: Learn about your local aquatic habitats and the organisms they support. Learn about invasive species that threaten your local areas and share information with others.

Contact Info: Katrina Mueller, 907-786-3637, katrina_mueller@fws.gov