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Students discover new invasive species in Agate Bay

Aug 25, 2017 08:37AM ● Published by Editor

By Jamey Malcomb - The Lake County News Chronicle - August 25, 2017


Earlier this summer, some local kids made a discovery along the shores of Agate Bay in Two Harbors.

The kids found evidence of curly-leaf pondweed, an aquatic invasive species, in the bay. They took a photo and uploaded it to a phone app. Sure enough, they had discovered the first evidence of an infestation of the plant in Agate Bay.

The youths were part of the "Water Watchers" program, a partnership between the Lake County 4-H Club and the University of Minnesota Extension, which teaches students about aquatic invasive species on the North Shore. The six-week course met weekly and took a hands-on approach to learn about being a scientist and answered questions about AIS in a scientific way.

"An invasive species is not from this area and causes harm either economic, to human health or the environment," Lake County Soil and Water Conservation District AIS coordinator Sonja Smerud said. "Curly-leaf pondweed is really dense, so it out-competes native plants, which can create less diversity and makes dense enough stands that are hard to boat or swim through. It also has a really quick die-off that creates a phosphorous issue."

Curly-leaf pondweed is not native to the U.S. The plant's leaves are serrated and resemble the sides of lasagna, Smerud said. It begins growing in the spring, and the leaves begin to poke through the water in June, then dies off in midsummer. The plant has been found in other places around Lake Superior.

"It's been in Lake Superior before and in Knife River, but this is a newly found infestation in Agate Bay, which is a problem because it is a highly used marina," Smerud said. "Early detection is always the best method of containment because there is no way to stop the infestation once it starts."

The only way to get rid of curly-leaf pondweed is to either pull it out by hand or use a special vacuum, but these methods pose a risk, too. The plant can regenerate itself from a single leaf left behind. An infestation is notoriously hard, if not impossible, to eradicate once established. The best containment, Smerud said, is for boaters, anglers and others using Lake Superior to be vigilant and prevent the spread of the plant to other inland lakes.

"If you've had your boat in Lake Superior, clean it out, drain it out and let it dry out for five days or get it washed at Little Dog car wash before you go to another lake," Smerud said. "If people are aware that it is there, they can be more conscientious of their use of Agate Bay. It won't hurt anyone out there swimming or anything like that, we just want people to be aware of it."

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