Is it working?  On the left, a typical rake sample of elodea from Beck Lake during surveys in 2013. (Photo by C. Anderson) On the right, a rake sample 13 weeks after Beck Lake was treated with fluridone in 2014. (Kenai National Wildlife Refuge photo)

Is it working? On the left, a typical rake sample of elodea from Beck Lake during surveys in 2013. (Photo by C. Anderson) On the right, a rake sample 13 weeks after Beck Lake was treated with fluridone in 2014. (Kenai National Wildlife Refuge photo)

Refuge Notebook: Progress on eradicating elodea from the Kenai Peninsula

I am fascinated by how plants and animals are named. Elodea, the first submersed freshwater invasive plant to infest Alaska, was named by the famous French botanist André Michaux. Michaux was first sent to the U.S. in 1785 by Louis XVI. After the misguided French king was beheaded, Thomas Jefferson asked Michaux to lead another American expedition in 1793. Michaux collected several specimens in the Midwest that he later assigned to the new genus Elodea, meaning “marshy” in Greek.   

Elodea does indeed grow in marshy habitat. But where introduced outside its native range, elodea can also turn otherwise clear lakes into marshy habitat due to several unusual traits. It’s incredibly facile at dispersing, reproducing asexually from just a plant fragment. It’s marvelously prolific, continuing to photosynthesize under the ice after native plants have senesced.

And, unlike most native plant species that have evolved to occupy specific depths or one stratum in the water column, the perennial elodea can root into the bottom substrate as deep as 30 feet and send continuous strands to the top of the water column where it spreads across the water’s surface. Its growth can be so hyper-abundant that boat traffic is impeded and lakeshore property values drop, and the biological oxygen demand so great that salmon and other fish are deprived of oxygen. Elodea represents an enormous economic and ecological threat to aquatic and fisheries resources of the peninsula, particularly in the 4,000 or so lakes and ponds of the Kenai Lowlands.

ADVERTISEMENT
0 seconds of 0 secondsVolume 0%
Press shift question mark to access a list of keyboard shortcuts
00:00
00:00
00:00
 

For these reasons, partners in the Kenai Peninsula Cooperative Weed Management Area decided that elodea had to be eradicated from the peninsula after it was first detected in Stormy Lake in September 2012. During summer 2013, surveys of 69 high-risk lakes confirmed that the current elodea distribution on the peninsula is constrained to just three lakes north of Nikiski. Stormy Lake is co-managed by Alaska State Parks and the Kenai National Wildlife Refuge. Beck and Daniels Lakes, with many private landowners, drain into Bishop Creek, which wanders in and out of the Refuge enroute to the Cook Inlet.

This past winter, the U.S. Fish and Wildlife Service, Alaska Department of Natural Resources, Homer Soil & Water Conservation District, Alaska Department of Fish & Game, Alaska State Parks, Cook Inlet Aquaculture Association, UAF Cooperative Extension Service, Kenai Peninsula Borough, Kenai Watershed Forum and a few dedicated Daniels Lake residents developed a plan that detailed how this eradication was to come about.

We chose to work primarily with fluridone — a selective, systemic herbicide that inhibits carotene formation, a plant pigment needed for photosynthesis, thereby preventing the formation of sugars necessary to sustain elodea. Working closely with SePRO, the manufacturer of fluridone products sold under the trade name Sonar, we developed a prescription that calls for four treatments over a 3-year period (2014-16).

We applied the first two treatments to each of the three infested lakes this summer. Beck and Daniels Lakes were first treated in early June. We applied both liquid and slow-releasing pelleted fluridone in Beck Lake. In Daniels, because elodea has not yet spread throughout the lake, we applied both pelleted fluridone and diquat, a nonselective contact herbicide, to five treatment areas that total less than 100 acres of the 640-acre lake.

Stormy Lake was also treated with both fluridone formulations, but not until late July due to delayed funding. We then applied a second round of pellets to all three lakes in mid-September, with the expectation that very low concentrations (< 8 ppb) of fluridone under the ice would continue to have herbicidal effects on elodea all winter.      

To monitor treatment efficacy, we established 50 sites in each of the three lakes (150 sites total). Pre- and post-treatment elodea populations were measured in late May and early September, respectively. 

So how are we doing? For two lakes, the results were spectacular. Thirteen weeks after the first treatment, elodea occurrence in Beck Lake (the most infested of the 3 lakes) decreased from 70 percent to 12 percent of sites, with average abundance declining by 87 percent. In Daniels Lake, elodea occurrence decreased from 22 percent to ZERO — not a fragment was found! But this dramatic outcome is likely due (at least in part) to diquat, which kills exposed plants on contact but not roots beneath the sediment.

In Stormy Lake, where elodea grew unhindered most of the summer before being treated on July 23, the population had not yet been significantly affected by herbicidal action when surveyed in mid-September. Although many strands were showing pink tips (a sign of necrosis), elodea fragments were everywhere in Stormy, even washed up on yellow pond-lily pads. The good news is that with fluridone uptake occurring under the ice, we expect elodea to continue dying over the winter.

Sometime in February, we’ll auger through the ice to take water samples for assaying fluridone concentrations. After the ice goes out in May, we’ll resample our 150 sites for elodea. No promises, but I anticipate that elodea will be all but gone in Beck and Daniels Lakes, and very sparse in Stormy Lake, by next spring. Scheduling of the third herbicide treatment in 2015 depends on what we find about fluridone concentrations and elodea populations after ice-out, but it will likely be in late June.  

Despite great progress, it ain’t over ‘til the fat lady sings or, in this case, until elodea is gone, gone, gone. Even after elodea is no longer detected on our 150 sites, we will survey extensively elsewhere to ensure it no longer occurs on the Kenai Peninsula. 

 

Dr. John Morton is the supervisory biologist at Kenai National Wildlife Refuge. Find more information about the Refuge at http://kenai.fws.gov or http://www.facebook.com/kenainationalwildliferefuge.

Biologists from Kenai National Wildlife Refuge, Homer Soil & Water Conservation District (SWCD), Alaska Department of Natural Resources and SePRO stage 20-lb pails of pelleted fluridone for the second treatment of Stormy Lake in September 2014.  The Fairbanks SWCD also participated to learn more about how to eradicate elodea from Chena Slough and Lake. (Photo courtesy Kenai National Wildlife Refuge

Biologists from Kenai National Wildlife Refuge, Homer Soil & Water Conservation District (SWCD), Alaska Department of Natural Resources and SePRO stage 20-lb pails of pelleted fluridone for the second treatment of Stormy Lake in September 2014. The Fairbanks SWCD also participated to learn more about how to eradicate elodea from Chena Slough and Lake. (Photo courtesy Kenai National Wildlife Refuge

More in Life

These poached pears get their red tinge from a cranberry juice bath. (Photo by Tressa Dale/Peninsula Clarion)
A dessert to stimulate the senses

These crimson-stained cranberry poached pears offer a soft and grainy texture.

File
Minister’s Message: Palm Sunday — ‘Hosanna in the highest!’

The fact that Jesus came back to Jerusalem for Passover was an intentional decision of Jesus.

Cecil Miller took leave from Akron (Ohio) Police Department to join the U.S. Navy Seabees during World War II. When he returned to the force after his military service, he was featured in an October 1945 article in the Akron Beacon Journal.
The Man Called ‘Greasy’ — Part 2

Two distinct versions of Cecil “Greasy” Miller received the most publicity during his brief tenure on the southern Kenai Peninsula.

The cast of Seward High School Theatre Collective’s “Charlie and the Chocolate Factory” rehearse on Thursday, April 3, 2025. (Jake Dye/Peninsula Clarion)
‘A jaunt into a fantastical world’

Seward theater collective returns for second weekend of “Charlie and the Chocolate Factory.”

“Octoparty,” by Kenai Alternative High School student Adelynn DeHoyos, and “Green Speckled Ocean,” by Soldotna High School Student Savannah Yeager are seen as part of the 34th Annual Visual Feast Kenai Peninsula Borough School District Juried Student Art Show during an opening reception at the Kenai Art Center in Kenai, Alaska, on Friday, April 4, 2025. (Jake Dye/Peninsula Clarion)
‘Consume a bunch of art’

The 34th Annual Visual Feast showcases art by Kenai Peninsula Borough School District students.

Debbie Adams joins Kenai Mayor Brian Gabriel in cutting a ribbon during the grand opening of Debbie’s Bistro in its new location in the Kenai Municipal Airport in Kenai, Alaska, on Saturday, April 5, 2025. (Jake Dye/Peninsula Clarion)
Debbie’s Bistro opens in Kenai Municipal Airport

The menu features waffles, waffle pizzas and waffle sandwiches.

Photo courtesy of the Pratt Museum
During her brief time on the southern Kenai Peninsula, Dorothy Miller, wife of Cecil “Greasy” Miller, was a part of the Anchor Point Homemakers Club. Here, Dorothy (far left, standing) joins fellow area homemakers for a 1950 group shot. Sitting on the sled, in the red blouse, is Dorothy’s daughter, Evelyn, known as “Evie.”
The Man Called ‘Greasy’ — Part 1

There are several theories concerning the origin of Cecil Miller’s nickname “Greasy.”

Sweet potatoes, tomatoes, cauliflower, kale, onions and buckwheat are served in this rich, healthy salad. (Photo by Tressa Dale/Peninsula Clarion)
Salad, reinvented

This salad is exciting, complex, and has a much kinder kale to carb ratio.

File
Minister’s Message: Unexpected joy

This seems to be the way of life, undeniable joy holding hands with unavoidable sorrow.

Most Read