Crews began eradicating elodea — an invasive aquatic plant — in two Nikiski-area lakes this week.
Staff from the Kenai National Wildlife Refuge, a representative from the Homer Soil and Water Conservation District and representatives from SePRO Corporation — an herbicide producing company — descended on Beck Lake Tuesday and Daniels Lakes Wednesday to begin treatments.
John Morton, supervisory fish and wildlife biologist with the refuge, said the crews treated all 200 acres of Beck Lake with both pellet and liquid forms of the herbicide fluridone.
“The reason you put the liquid fluridone down is because it’s fast acting,” Morton said. … “And the other thing is … it mixes well in the lake. And then we also put down the pelleted fluridone and that’s a slow release so it will continue to release over an extended period of time.”
SePRO and the U.S. Environmental Protection Agency have tested fluridone, and the product was applied and will be applied during future treatments at a level well below EPA’s maximum contaminate level.
The herbicide is not harmful to people or animals, but may have some effect on native aquatic plants, representatives with SePRO said at an April public meeting in Nikiski. Morton said people should not use lake water treated with fluridone to irrigate crops, gardens or lawns because the herbicide works by interrupting the photosynthesis process.
Crews treated five areas of the 600-acre Daniels Lake where elodea is present, which Morton said added up to about 100 acres of treated area. Because the attack on elodea was focused on select areas, crews used pelleted fluridone as well as another chemical called diquat.
Diquat is a contact herbicide that kills elodea fairly quickly above the root mass, Morton said. It is considered a “moderately toxic material” by the EPA, according to the Kenai Peninsula Cooperative Weed Management Area’s Integrated Pest Management Plan for Eradicating Elodea from the Kenai Peninsula. The chemical interferes with the plant’s cell respiration.
“The whole idea is to knock the biomass down this spring so that these fragments don’t go off and start new colonies elsewhere,” Morton said. “The whole object of course is to try to keep it to these five treatment areas.”
To treat the lakes one boat applied pellets and one applied the liquid chemicals while traveling at about 3-5 mph. Crews followed GPS lines to ensure exact coverage. So the two applicator boats don’t have to move out of their lines, a third boat ran between the staging area and the boats transporting additional unopened product. Treatment at each lake took one day, Morton said.
In the third week of July treatment for Stormy Lake is scheduled to begin. He said the eradication for Stormy Lake is beginning later because the team is waiting for funds approved by lawmakers this past session to be made available.
Before beginning treatments, crews resurveyed the three lakes to see if the elodea had spread. Morton said the infestation for each was about where it crews thought it would be based to two previous surveys.
“It hadn’t spread too much,” Morton said. Elodea is most prevalent in Beck Lake, he said.
In September all three lakes will receive a second treatment of pelleted fluridone so the concentrations will carry through the winter, Morton said. Additional treatments of the lakes will be in the springs of 2015 and 2016.
Last summer, crews sampled 68 lakes on the Kenai Peninsula to verify that the infestation is only in the Nikiski area.
“Now as we’re actually beginning to treat these three lakes, we’re really going to go in with a fine-tooth comb and really start looking at small lakes and ponds in the area and really make sure that it’s not other places that we might have overlooked,” Morton said.
While elodea has not been found elsewhere on the Kenai Peninsula, it has infested lakes in the Anchorage, Fairbanks and Cordova areas. None of these lakes have been treated. If no eradication action is taken, elodea can choke off aquatic habitats.
Morton said the hope is that the Kenai Peninsula’s eradication plan becomes a model for other infected water bodies in the state.
Morton said if people have concerns about elodea eradication near their property to contact him at 907-260-2815.