Invasive Elodea Threatens Daniels, Stormy Lakes
Two lakes near Nikiski are home to a very unwelcome variety of water weed. Elodea wasn’t known to be on the Peninsula even a few years ago, but now it’s posing a serious threat.
At this week’s Borough Assembly meeting, Kenai Wildlife Refuge supervisory biologist John Morton gave the lowdown on this plant, that’s typically found in home aquariums.
“It’s a very bad plant. It’s prolific, it grows very, very quickly, it reproduces vegetatively,” Morton told the Assembly.
He said the important thing to note is that it does not need seeds to reproduce. Elodea can clone itself.
The Kenai Peninsula isn’t the only place in Alaska where this stuff has turned up. Anchorage, Cordova and Fairbanks are all seeing it, too. Morton says the best study of what can happen if the spread of elodea isn’t slowed or stopped is Chena Slough in Fairbanks, where it’s been growing for about a decade.
“Eighty to ninety percent of Chena Slough is covered by elodea. This used to be grayling habitat and now it’s pretty much an aquarium,” Morton said.
The concern on the Peninsula is that elodea could choke out areas that support fish. Right now, it’s only known to live in Daniel’s Lake and Stormy Lake up by Nikiski. Fisheries biologists first noticed the weed last fall when they were treating Stormy Lake to rid it of Northern Pike. The props on their boat motors were cutting through the elodea.
Over the winter, biologists augured through the ice and discovered that elodea continues to grow even under the ice. In March, a working group that includes property owners was established to help sort out the problem. Last month, permits were submitted to the Department of Environmental Conservation for chemical treatments. Morton says they’ll continue surveys on other lakes next month and hope to begin those chemical treatments by July.
They’ve got two different treatments in mind. The herbicide Diquat suppresses growth by killing the plant, but leaving the root. It’s also relatively cheap at $200 per surface acre. He says another herbicide, Fluridone, is the preferred chemical for eradication.
“The problem is, it’s very expensive: $750 per surface acre. And it has to be maintained at a small dosage: 45-90 parts per billion, for 45 days. So it’s a very long haul; you have to constantly monitor and pump more chemical into it,” Morton said.
He lobbied the Assembly for some funding to help curb the spread of elodea. He says the Wildlife Refuge has already set aside $40,000 and that there are matching grant funds available for any money the Borough could pitch in. The cost to totally eradicate both Daniels and Stormy lakes could be as much as $300 thousand if work begins this year. He says the window of opportunity to get ahead of elodea is small. More surveys this summer will determine the scope of growth.
“The reason we can’t wait is because this is a very, very scary plant. You saw the price tag on this stuff, you can see how bad it would be if it started multiplying by lakes.”
Right now, it’s assumed that the source of the contamination is science lab kits or aquariums. If nothing is done to halt its spread, it could be transferred from lake to lake by boats or float planes.
“And once it does that, we cannot contain it. It is gone.”
He says the problem is new enough that only this spring did state agencies decide who would be in charge of combating the problem at the state level; with ADF&G focused on Pike eradication, any efforts to eliminate elodea will be handled through the Department of Natural Resources.