The Minnesota Depart≠ment of Natural Resources recently announced that the entire Minnesota River has been added to the state's Infested Waters List.
The Minnesota Department of Natural Resources recently announced that the entire Minnesota River has been added to the state’s Infested Waters List.
In September of 2016, the DNR confirmed reports of zebra mussels in Lac qui Parle Lake. Recent DNR surveys of the Minnesota River have discovered adult zebra mussels attached to rocks behind the Granite Falls dam. Zebra mussel larvae, called veligers, were found at four of seven survey sites on the Minnesota River from Montevideo to New Ulm.
In addition, the Minnesota River from Granite Falls to its confluence with the Mississippi River is now listed on the state’s Infested Waters List for big head carp and grass carp. Individual captures of these species in 2016 and 2017 warranted the inclusion on the list.
Gary Montz, research scientist for the DNR, knows zebra mussels very well. “I’ve been studying these little critters since they showed up in the Duluth/Superior Harbor in 1989, he said.
According to Montz, zebra mussels are native to Europe, Asia, and the Black Sea. They were brought to the Great Lakes on ocean going shipping vessels during the 1980s.
In the early 1990s, they were discovered in the Mississippi River in northern Minnesota. The first Minnesota inland water they were found in was Lake Zumbro in southeastern Minnesota in 2000.
Montz explained that there are basically only two ways for zebra mussels to migrate. He said, “They either hitch a ride on boats and trailers, or simply float downstream.”
Adult zebra mussels attach themselves to underwater structure such as rocks, docks, bridge pilings, and wood snags. “They do best in slow moving waters such as lakes. They are not a good river animal because the current is generally too strong for developing veligers to settle and attach themselves to an object,” Montz said.
Zebra mussels are a nuisance to humans. In addition to attaching themselves to docks and dock ladders, they will occasionally attach to boats that are left in the water for extended periods. Their shells are sharp and can easily cut or scrape swimmers and waders.
The big problem with zebra mussels, said Montz, is that they are prolific reproducers. “An individual female mussel can produce 200,000 to 400,000 eggs in a single season,” he said.
The sheer number of larvae produced by zebra mussels make them difficult to eradicate from an infested body of water. “There are control products available, but they are expensive and have detrimental environmental side effects,” said Montz.
Scott Williams, director of the Chippewa County Land and Resource Management department, is concerned about the Infested Waters designation for the Minnesota River. “The biggest thing is awareness. it’s an education issue,” he said.
Chippewa County, along with other counties in the state, receives money from the state of Minnesota to fund efforts to raise awareness about zebra mussels. “The money we’ve received has been spent on education signage at public water access sites along the Minnesota River.
“One of the things we are looking into is building a wash station at county park in Wegdahl,” said Williams. “We’d also like to put a wash slab at Volden’s Pit, but since there is no electricity there, we are considering a solar powered well pump to be installed there,” he added.
Williams mentioned that the Infested Waters designation means that there will also be a small, local economic impact. “Bait dealers can no longer harvest bait from the Minnesota River.”
Jennifer Hoffman of the Chippewa river Watershed Project, pointed out that the Chippewa River and other tributaries of the Minnesota River are not included in the Infested Waters designation. “That being said, we should assume all of our waters are infested and take appropriate precautions,” she said.
Hoffman stressed the importance of carefully cleaning boats, dry wells, bait buckets, and basically anything coming into contact with the water. They should be thoroughly washed out and allowed to dry for at least five days. It is important to be vigilant and understand what we can do,” Hoffman said.
From an ecological standpoint, Peg Furshong, Operator and Program Director of CURE, is deeply concerned about the future of native freshwater mussel species. “Most freshwater mussel species are endangered in Minnesota,” she explained. “Zebra mussels often attach themselves the shells of native mussel species and kill them by suffocating them.”
“One of the biggest problems with zebra mussels is that the larvae are microscopic,” explained Furshong. “Once adults are discovered, they have been in the lake or river for one to two years. This makes it difficult to monitor them.”
Recreational users of the Minnesota River need to be aware of that the river is now listed as an Infested Water. Precautions that have been common on infested lakes should now be put into practice on the river.
Boats, canoes, kayaks, and bait buckets should all be washed off after being on the river. Swimmers need to be wary of the dangers posed by the sharp shells of the zebra mussels.
For more information about zebra mussels, contact the Minnesota DNR at 651-296-6157, or <ww.,dnr.state.mn.us>, or email at email@example.com.
To learn more about zebra mussels and native mussles, contact the Montevideo CURE office at 320-269-2984, or toll free at 877-269-2873 or <www.cureriver.org>
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