How to respond to the discovery of the invasive waterweed elodea in Soldotna’s Sports Lake will be addressed at an upcoming public meeting.
Kenai Watershed Forum Invasives Specialist Jennifer Peura said she will be outlining treatment options for Sport Lake’s elodea, as well as going over the weed’s history in Alaska, during the April 12 meeting, from 5:30-7:30 p.m. at the Cook Inlet Aquaculture Building on Kalifornsky Beach Road.
Other speakers will be Kenai Peninsula Cooperative Weed Management Area President Matt Steffy, biologist John Morton of the Kenai National Wildlife Refuge and representatives of the chemical manufacturer SePRO, which makes the herbicides that have been used to kill elodea in other Kenai Peninsula lakes.
Elodea is believed to have entered Alaska as an aquarium plant, and has been the focus of a long-running state-wide eradication effort. The weed, which can reproduce asexually from small fragments and continues to grow beneath ice in the winter, can grow thick enough to de-oxygenate the surrounding water, destroying fish habitat.
On Feb. 22, staff from the Alaska Department of Fish and Game found elodea fragments while drilling holes in the ice for an ice-fishing event with local students. Of the 120 fishing holes they drilled (mostly around the boat launch, Peura said), the Fish and Game staffers found bits of elodea in one. Another hole examined afterwards also had elodea fragments, possibly stirred up by the ice-fishing students.
A March 13 search by Kenai National Wildlife Refuge staff had more concerning results: they found elodea in six of 28 sampling holes drilled at sites around the lake’s perimeter.
Elodea’s ability to spread via fragments carried in boat propellors and floatplane rudders makes an infestation of Sport Lake especially concerning, Peura said.
Near the Kenai Spur Highway and stocked with rainbow trout and silver salmon fingerling by Fish and Game — who also maintain a public boat launch there — Sports Lake becomes a popular recreation site in the summer. Floatplanes are docked in front of many of the homes on its shore. In addition to local pilots and fishermen, Peura said the lake is also visited by boaters traveling from Anchorage or other parts of the state, who test their motors there before setting out for other bodies of water.
In one respect, Sports Lake’s elodea was found at a lucky time — just before the lake thaws and begins attracting boaters and pilots. Peura said elodea is also more likely to be discovered in the winter because it doesn’t go dormant like native plants do, “so if there’s a plant there, it’s easier to recognize it as elodea.” Once the ice melts, Peura said, it would be theoretically possible to kill the elodea quickly using the herbicide diquat — a contact killer that can eliminate aquatic plants in about 72 hours — before the peak of the recreational season.
That is unlikely to happen because of the state permits required to deploy herbicides. The Alaska Department of Natural Resources Division of Agriculture applied for these permits for Sports Lake with the Alaska Department of Environmental Conservation on Thursday, Peura said. Before being decided on, the applications must be held for a 30 day public comment period and an agency review period of at least 40 days — likely to be longer, Peura said.
“We probably won’t get the permits until the middle of July, which presents a potential vector for the spread of elodea,” Peura said. “So there’s the idea of, ‘What do we want to do to prevent the spread?’ We have in the past closed things down.”
Nikiski’s Stormy Lake — which in 2012 became the first elodea site to be found on the peninsula — was closed from 2013 until fall 2015, when its elodea population was killed by diquat and another herbicide, fluridone.
In the meantime, Peura said she is reaching out to homeowners around Sports Lake, mailing them flyers on Thursday to announce the April 12 meeting. She’s also seeking information from Sports Lake’s floatplane pilots about other lakes they’ve visited, in order to estimate where else elodea may be growing.
Reach Ben Boettger at firstname.lastname@example.org.