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Elodea: Alaska’s first invasive plant

Elodea can choke vital bodies of water and starve native plants and fish for nutrients. Learn how you can help keep it from spreading.

by | November 17, 2022

Elodea on a dock.
A clump of Elodea pulled from an infestation on Alexander Lake. If all Alaskans aren’t diligent in their decontamination (Clean.Drain.Dry) procedures Elodea could become a much larger problem throughout the state. Dan Coleman, DNR.

Elodea is a fast growing invasive plant species that has invaded Alaska’s waters. It has the notorious title of our first aquatic invasive plant. To be clear, this is not something to celebrate. 

We capitalize Elodea and write it in italics because it is short for the scientific name for Elodea canadensis and Elodea nuttallii or a hybrid of the two. You may hear it called American waterweed, Canadian waterweed, or pondweed. It has some unique characteristics that make it challenging to find and completely remove from a body of water.

Elodea was first discovered in Eyak Lake in Cordova in 1982. Scientists didn’t understand yet how the plant could spread to other lakes, so they left it alone. Aquatic plant surveyors then found a large patch of Elodea in the Chena Slough in Fairbanks in 2010. At this point, public officials sounded the alarn through a statewide awareness campaign to spread the word about invasive species.

What is an invasive species?

First off, what exactly are invasive species? They are any plant or animal that is not native to the area and cause some form of economic or environmental harm. Elodea is highly invasive and listed high on invasiveness rankings within the state. 

Why is Elodea bad in Alaska?

Elodea tends to grow quickly and outcompete native vegetation. This can result in a monoculture, which means all the vegetation in an infested area eventually becomes Elodea and almost nothing else. A lack of plant diversity is bad for native fish, bird, and aquatic insect species. Dense Elodea monocultures can get so thick that it can even harm another invasive species: northern pike. Yikes!.

It doesn’t take much for Elodea to become established. Just a small fragment of the plant is needed for it to take root and create a new infestation. This is bad news for resource managers who are trying to control the spread of Elodea.

Elodea can survive periods of freezing temperatures. Even folks out ice fishing may encounter and potentially spread the highly invasive species. Fragments can get trapped in ice during breakup and transport Elodea several miles downstream to start a new invasion.

Elodea as seen through the surface of a lake.
A close up shot of Elodea shows just how thick the invasive waterweed can grow in a lake. Walt Nesbett

How does Elodea affect Alaskans?

Large Elodea infestations can also limit the type of recreation that is possible on a lake. That’s because once it gets established it tends to grow in thick tangled mats — and it has been known to lower property values! If you love to be on the water, or you’re a lakefront homeowner, that last tidbit should really get your ears tingling.

Unchecked Elodea populations will wreak havoc on the salmon resource that is so valuable for Alaskans, and the source of many livelihoods. The dense stands of Elodea can slow the flow of water and cause sediment to settle in areas that used to be good spawning grounds for salmon.

A study that came out of the University of Alaska Fairbanks estimated that if Elodea continues to spread across Alaska’s pristine landscape it will cost the commercial sockeye fishing industry $159 million per year in lost revenue!

The list of damaging effects from Elodea infestations is nothing to joke about and this list only scratches the surface of the detrimental effects of just one invasive species.

Close-up photo of an Elodea plant.
Close-up of an Elodea plant. Dan Coleman, ADNR

How will you know if you see Elodea?

Elodea can look similar to some native plants to the untrained eye.

  •  Elodea leaves typically grow in whorls of three around the stem
  •  The leaves are often densely packed around the stem
  • The stem is long and slender and typically lighter in color than the leaves

But it’s important to note that individual plants may vary in how they look depending on their growing conditions. If you’re unsure, take ample photos and note your location and report it to the Alaska Department of Fish and Game, but never transport any live specimen!

What should you do about Elodea?

There are a lot of things you can do to prevent the spread of invasive species.

First, learn what Elodea looks like that way you will be able to identify it if you come across it. If you have a smartphone you can download the Alaska Weeds ID App to aid in plant identification.

Next, properly clean your gear before moving to a new location. Familiarize yourself with the Clean. Drain. Dry and Play. Clean. Go. campaigns.

  • Thoroughly inspect and clean all your gear after each use 
  • Drain all water from your equipment 
  • Dry your gear as best you can before moving to a new location. It’s best to allow your gear time to completely dry before using it again.

Finally, know how to report an invasive species.

  • Note the location. Use GPS coordinates when available, but if not use as many landmarks as possible to be able to find the same spot again.
  • Take pictures, lots of them! It’s important to get photos that capture the characteristics well. Be sure to put something of a known size, like a quarter or your license in the photo to show scale.
  • Call 1-877-INVASIV (1-877-468-2748).

Let your friends and family know why it’s important to you to keep Alaska wild and free from invasive species like Elodea.

Get your free ID guide

If you’re interested in helping identify invasive species in Alaska stop by or contact CIAA, at eheale@ciaanet.org, for a copy of the pocket ID guide of “Selected Invasive Plants of Alaska”

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