Elodea is Alaska’s first aquatic invasive plant and it can be a doozy to deal with, especially in areas where it has an established population. Elodea is very good at outcompeting native vegetation and has been seen in Alaska growing even under the ice when native plants have senesced, or died back for the winter months.
For the past year, we’ve been assisting partners working to mitigate an elodea infestation in Crescent Lake. Let’s look at what’s happened so far.
Elodea discovered
Elodea was discovered in Crescent Lake in September of 2023 by U.S. Forest Service (USFS) staff. Since then USFS has been working on securing permits and seeking grant funding for treatment starting in 2025. USFS also created an Elodea working group with local organizations and partners to garner help and support for the work ahead.
Mapping the infestation
Through the working group it was determined that more extensive surveys need to be completed in order to map the entire elodea infestation as well as its potential spread since it was first found in 2023. This mapping will aid in the herbicide treatment that is slated to start in 2025 (pending funding). The week of September 9 was selected for partners to help with the additional surveys of Crescent Lake and Creek.
On the ground work
A CIAA crew of three was able to help with part of the Crescent Creek survey. This required a 6.2 mile hike up to Crescent Lake where the survey started at the bridge and continued about a mile downstream until the creek became too steep and had too high of a gradient to survey.
Once at the lake we spread out in the creek and moved slowly along looking for green vegetation. When we would find some we would stop and identify it. It did not take long to find elodea in the creek but luckily only a few rooted populations were found in the beginning stretches of the creek.
Unfortunately we did find a significant amount of elodea fragments—stuck on down trees, overhanging branches, and even on exposed rock bars—throughout our creek survey. This means that there is a high potential for elodea to continue its downstream spread if it is not treated in the coming years.
Crescent Lake infestation
The extent of elodea in Crescent Lake is relatively small in relation to the lake size and is mostly constrained to shallower portions of the lake with just a few bands being present. There are just under 10 infested acres within the lake, which is good news. The largest hurdle for treating the infestation is within the creek but the rooted patches are small enough that careful manual removal by hand will likely be the best way forward.
Why should you care?
Elodea degrades fish habitat, can make boat travel difficult, fouls float plane rudders, and alters freshwater habitats by decreasing flow and increasing sedimentation. Elodea also has the potential to aid other aquatic invasive species like northern pike, giving them more cover to hide from potential prey species like salmon.
Elodea can also spread by fragments breaking off and traveling downstream! This is one of the reasons why Crescent Creek needed to be surveyed, so the downstream movement of the population could be monitored.
How to help
You might be asking yourself at this point how you can aid in keeping Alaska wild and free from invasive species like elodea. The first step is to know what it looks like! Making a correct identification in the field can save time and money for organizations who are responsible for investigating reported sightings. If you are unsure if the plant you see is elodea, take good photos and report it anyways. It is better to be safe than sorry with a plant as invasive as elodea.
Anytime you are out recreating on a waterbody keep your eyes peeled and remember to clean, drain, and dry your equipment before moving to a new waterbody to avoid transporting any species to a new location. And never dump any unknown plants into a new waterbody, especially if you do not know what that plant is. Elodea is thought to have started as an unknowing dump of an aquarium plant and now it has cost millions of dollars across the state to remove populations and survey for new infestations.
There is hope
The permitting process, which is required to do any type of treatment, is moving forward. Everyone working on the project is hopeful that funding will come through to start treatment in 2025. With any luck CIAA can aid in the eradication process during treatment in order to return the Kenai Peninsula to an elodea-free state. Any source population of elodea out there is a risk for all water bodies throughout Alaska.
