FAIRBANKS — Now that the first aquatic invasive plant has been found in Alaska, right here in Fairbanks no less, state and federal officials have to figure out what to do with it.
The plant, which carries the scientific name Elodea canadensis, was documented in the Chena Slough and the Chena River this summer by U.S. Forest Service ecologist Trish Wurtz and biological technician Nick Lisuzzo.
How it got there is uncertain, but Wurtz said it’s “almost guaranteed” that someone dumped it into the slough from an aquarium sometime in the past 10 years. Elodea is commonly used as a plant in aquariums. Wurtz said she and Lisuzzo found “a bunch of red clay balls” in the silt underneath the Nordale Road bridge in the slough. They had been dumped out of a hydroponic growing system or an aquarium.
“It’s a common way aquatic invasives get spread around,” Wurtz, the forest service’s invasive plant program coordinator, said. “You can order the wildest stuff all over the world for aquariums, and if people dump them it’s a real problem.”
Just how big a problem it will be in Alaska remains to be seen, which is one of the reasons Wurtz has organized a meeting Friday at the Department of Natural Resources office in Fairbanks for land managers, biologists and agency representatives. Concerned members of the public can attend.
“We don’t know what level of a threat it is,” Wurtz said. “It’s the first invasive aquatic plant found in Alaska, so it’s not clear how we’re supposed to deal with this.”
Wurtz and Lisuzzo found dense patches of Elodea extending through a mile of Chena Slough between Nordale and Peede roads. The plant sometimes almost fills the slough. They also found the plant in the Chena River, both floating freely and growing attached to the river bottom in several places.
“We went to Chena Slough, and it was all over the place,” Wurtz said.
Amy Larsen, an aquatic ecologist for the National Park Service in Fairbanks who confirmed the finding by Wurtz and Lisuzzo, said “it’s a pretty huge concern.”
The Elodea infestation in Chena Slough “was the highest density of an aquatic plant I’ve ever seen in Alaska,” Larsen said.
Elodea is “highly productive” and can fill up slow-moving waterways and lakes, making fishing or boating virtually impossible, she said. It could also alter stream flow, which could impact spawning salmon in the Chena River or Arctic grayling in Chena Slough.
“This has spread all the way across Russia,” Larsen said. “There hasn’t been anything that stopped it. The way people use motorboats and water vehicles in Alaska, it can easily spread in every direction.”
Also known as common waterweed or Canadian waterweed, Elodea is native to southern Canada and the eastern U.S. It has invaded most of northern Europe, and has spread all the way across Russia to Lake Baikal. It has invaded slow-moving stream systems in New Zealand and is a major problem in irrigation canals in Australia, Wurtz said.
The sale of Elodea has been outlawed by about 10 states, including Maine, New Hampshire and Washington, because of its invasive behavior when released in the wild, Wurtz said.
There are a few aquatic plants in Alaska that look similar to Elodea, most notably clasping-leaf pondweed (Potamageton richardsonii). However, the closest native population of Elodea is more than 1,000 miles from Alaska, Larsen said.
Elodea spreads in two ways: by breaking up and re-rooting after it is washed downstream or by being car by people.
“Immediately at risk are all our downstream waters,” Larsen said. “It probably won’t grow in turbid areas of the Tanana (River), but it could get into all of Tanana Flats or Minto Flats.”
All it would take is a small fragment of the plant caught on somebody’s boat propeller or boat trailer that is transported to one of those places, or other lakes and rivers, and the infestation could easily spread, she said.
Elodea can also freeze solid in ice and remain completely viable.
“That ice can float a really long way,” Larsen said.
Chena Slough is a major spawning area for Arctic grayling from the Chena River in the spring, but grayling biologist Andy Gryska with the Alaska Department of Fish and Game in Fairbanks isn’t sure what effect an Elodea infestation might have on grayling.
“It’s too early to tell,” Gryska said.
Plan of attack
Elodea was found once before in Alaska, in Eyak Lake near Cordova about 30 years ago, but it has not been reported there or anywhere else in the state since then.
The plant was actually discovered in Fairbanks last summer by Allen Batten. He found it at the Nordale Road bridge after canoeing in the slough. Batten, who at the time was the botanist at the University of Alaska Museum of the North in Fairbanks, recognized it as something unusual for Interior Alaska and identified it.
“I noticed a lot of the beds and thought, ‘Gosh, that looks like Elodea,’” Batten said.
He collected a sample and put it in the University of Alaska Fairbanks herbarium. The thought that it might be an invasive plant never occurred to Batten, however.
“I’m sort of mad at myself for not realizing it might be significant,” he said. “I just thought it was a curiosity. I didn’t think about its invasive qualities.”
That didn’t happen until Wurtz and Lisuzzo took a canoe out on the Chena River in July to hone their skills at identifying common freshwater plants in Alaska with a new book they had just received, the “Introduction to Common Native and Potential Invasive Freshwater Plants in Alaska.”
“Neither I nor (Lisuzzo) had ever identified aquatic plants, but since we had this new book we thought it would be good to go collect some plants from the Chena and use the book to identify them,” Wurtz said. “We didn’t expect to find any invasive plants.
Based on a 2005 video produced by the Fairbanks office of the federal Natural Resources Conservation Service about Chena Slough, Elodea has been in the slough for at least six years, Larsen said.
“You can clearly see the plants in the video,” she said.
Eradicating the plant would take an “extensive” effort, Larsen said.
Contact staff writer Tim Mowry at 459-7587.