Although elodea wasn’t discovered on the Kenai Peninsula until 2012, the peninsula is at the forefront of eradicating it.
The invasive aquatic plant was discovered in Beck Lake, Daniels Lake and Stormy Lake, all in Nikiski. The U.S. Fish and Wildlife Service slammed the brakes on activity in the lakes to prevent further spread, which has so far been successful, according to Kenai National Wildlife Refuge Supervisory Biologist Dr. John Morton — the department has not found the plant anywhere else on the peninsula.
Today, the lakes are essentially clear. The department is still conducting some spot treatments and Stormy Lake will remain closed to the retention of Dolly Varden and Arctic char throughout the winter, but they hope to have the boat launch open again by spring, Morton said in a presentation to the Kenai Peninsula Borough Assembly Tuesday.
“To the best of our knowledge, it only occurred in the three lakes north of Nikiski,” Morton said. “Our main concern is that it doesn’t occur in any of the three lakes. We’re continuing to work with other areas in the state in hopes that they will catch up.”
That is not the case elsewhere in Alaska. Anchorage is still treating elodea in its lakes and the plant was recently discovered in Lake Hood, which is the site of one of the world’s busiest floatplane bases. Cordova still has elodea in several of its lakes and the infestations near Fairbanks are currently being treated.
Elodea doesn’t need much plant material to spread — even a sprig can quickly invade a lake, Morton said. The Fish and Wildlife Service wanted to treat the lake quickly to prevent the planes from inadvertently spreading elodea to other bodies of water in Alaska, he said, but the permitting process through the Alaska Department of Environmental Conservation can take up to 100 days.
Part of that is the department being cautious about spreading chemicals into the environment, but it can delay treatment, he said.
“If you apply in the spring, you’re lucky if you can start treatment by the fall,” Morton said.
However, the borough’s financial aid to the Fish and Wildlife Service has been able to help with the Lake Hood treatment. The Department of Environmental Conservation made a one-time permit exception for the treatment of Lake Hood, and the Fish and Wildlife Service was able to use some of the funds to purchase the chemicals to treat the lake, Morton said.
Without the funds from the borough, the department would have had to apply for National Environmental Policy Act funds, which can take months to be approved.
Unlike indigenous plants, elodea photosynthesizes throughout the winter, even beneath the ice, which allows it to spread quickly, he said. The Fish and Wildlife Service used a tactic of loading the lakes with fluridone, an herbicide that interferes with photosynthesis and kills the plants gradually.
This allows them to die and disintegrate, while the alternative would be to shock the lake and kill everything in it, including the fish. The biologists then maintain the fluridone at levels lethal to elodea in the water column for weeks at a time, monitoring the chemical level constantly, Morton said.
Fluridone is a fairly expensive chemical — the effort to fight elodea in the three lakes on the peninsula ran up a total bill of approximately $660,000, Morton said. However, it is the most effective long-term solution and poses no risk to humans, making it safer for settled areas, he said.
This tactic is being used in the Tanana River Watershed area in the interior, where elodea was discovered in September. Heather Stewart, a natural resource specialist for the Alaska Department of Natural Resources, said the department is not sure how elodea spreads in individual cases, but there are a number of risks.
“I can’t point the finger, as much as I’d like to, because it would make our lives easier,” Stewart said. “We see a lot of fragmenting (of the plant). We think that if we can get these sites at an early part of their establishment, it has less time for that natural dispersion.”
To date, the state has spent nothing on fighting elodea — all of the funds have been provided through the U.S. Fish and Wildlife Service, the U.S. Forest Service, the Kenai Peninsula Borough and other smaller sources, Stewart said. Because Lake Hood is a commercially operating floatplane base, they were able to use the airport plant funds to treat the base.
However, the cost of fighting it in Cordova’s Eyak Lak and other infested bodies of water could range up to $1 million, making it hard to find the funds, Stewart said. On top of that, the Department of Natural Resources does some surveying, but it is difficult to determine where else elodea could be growing in the state, she said.
“I’m pretty sure that we’re also on our way for eradication (in Anchorage) as long as we keep up with the surveys” Stewart said. “That’s kind of the caveat to what we’re dealing with. We have a snapshot of where we think it is, but there’s huge areas that haven’t been surveyed.”
Reach Elizabeth Earl at firstname.lastname@example.org.