Conservationists need help stopping the spread of a dangerous plant in Big Lake

Its long, spindly stalks with thick leaves floating near the water’s surface may look harmless, but conservationists warn this invasive plant carries deadly consequences to lakes in the MatSu and beyond -- and they need the public’s help stopping it.

Elodea is an aquatic plant native to parts of the Lower-48 and used as decorative vegetation in home aquariums. But its explosive growth in lakes can crowd out native species, can kill fish and can even grow so thick it chokes boat motors. Worse, it easily gets attached to watercraft and can spread through just a small clipping accidentally transported from one lake to another, said Jillian Jablonski, a habitat programs director for the Tyonek Tribal Conservation District.

“It can grow so abundantly that it really makes any type of recreation impossible, depending on the lake,” she said. “It really kind of takes over and changes the whole aquatic ecosystem.”

The plant was first found in Alaska at a large lake in Cordova in 1982. How it got there isn’t known, but biologists think someone likely dumped a home aquarium containing it into the lake, inadvertently introducing the plant and forever changing the vegetation there. Since then it’s been found at several lakes around the state, including Big Lake in 2019.

“It’s by no means taking over the lake, it’s just a concern given how popular Big Lake is,” she said.

Elodea loves cold water, doesn’t die under the ice and can only be stopped by herbicide treatments. Jablonski spearheads a task force aimed at stopping the spread, and her team wants MatSu residents to help. They plan to hold a so-called elodea rodeo education event at Big Lake North July 21 from noon to 6 p.m., she said.

“Our vision for this is to really just raise awareness and be out at the Big lake North recreation site talking to people, showing them what elodea looks like, what other native plants look like … as well as talk about what we can do to prevent the spread,” she said.

Perhaps most critically, however, Jablonski said her team wants to gather information on where boaters who frequent Big Lake are taking their watercraft. Since the plant is so easy to inadvertently move from lake to lake, understanding other places Big Lake users spend their time will help her team know where to go elodea hunting next.

“No one is going to ask anyone to stop their recreation use,” she said.

Finding elodea in the water is an investigation process that includes team members scraping the bottom of the lake with sampling rakes to examine the vegetation, she said. Users who think they’ve seen elodea growth can call Alaska’s invasive species hotline at 1-877-INVASIV.

The top way anyone can prevent the spread is to follow the guidelines known as “clean, drain, dry,” she said. Those ask waterway users to clean vegetation off their gear after each use, drain all water from equipment and let it completely dry out before heading to a different river or lake.