By Bethany Wesley / Bemidji Pioneer
BENA - Pat Rooney stands along the shore of his harbor and looks across the water, noting all the areas susceptible to a zebra mussel infestation.
"It's in the back of your mind," he said. "It's something you definitely have to look at."
Rooney owns Denny's Resort on the south side of Lake Winnibigoshish, Minnesota's fourth-largest lake, a popular walleye-fishing destination.
A water sample from Lake Winnie, as it is known, was found this winter to contain zebra mussel veligers, or microscopic larvae, prompting the Minnesota Department of Natural Resources to declare the lake -- and some connected and downstream waters -- to be infested with zebra mussels, an aquatic invasive species.
ADVERTISEMENT
"The zebra mussels are in their infancy stage," said Joe Thompson, who operates Four Seasons Resort on the west side of Lake Winnie.
Nobody yet knows what the zebra mussels' impact will be on Lake Winnie, he continued, echoing a sentiment shared by many around the lake.
"It's too early to tell," Thompson said.
What are they?
Zebra mussels are small, fingernail-sized mussels that attach to solid surfaces in water, for example, rocks and dock poles.
Native to eastern Europe and western Russia, they were brought over through the Great Lakes in the ballast water of freighters, according to the DNR. They were discovered around 1988 in the Great Lakes.
Because they congregate in vast numbers on solid objects underwater, they pose potential problems, such as clogging intakes used by property owners to water their lawns with lake water. They also attach to boat motors left underwater, and they can attach to -- and kill -- native mussels, according to the DNR.
"(What) is probably our biggest concern is, What effect are they going to have on the food chain?" Kavanaugh said.
ADVERTISEMENT
'A needle-in-the-haystack kind of find'
The DNR collected Lake Winnie water samples last July to monitor plankton levels in the lake, opting at the time to also screen for veligers.
No mature zebra mussels were found, but two veligers -- not visible by the naked eye -- were found in one of 15 samples taken from the middle of the 58,544-acre lake, the DNR reported.
"That's a needle-in-the-haystack kind of find," said Joe Eisterhold, AIS specialist for the northwest region of the DNR.
The declaration of infested waters typically prompts an additional set of regulations for the lake -- such as prohibiting bait harvest from the water -- but Lake Winnie already was under those restrictions due to a previous infestation of the faucet snail, also an AIS.
Chris Kavanaugh, area supervisor of the DNR's Grand Rapids area fisheries office, said the DNR now continues to take water samples from the lake, testing for plankton and veliger densities, though those results won't be available until at least fall.
"We will track their density, if you will, throughout this summer and over the years," he said.
DNR crews also will begin diving later this month to search for mature zebra mussels in Lake Winnie and monitor their spread and abundance throughout future years, Kavanaugh noted.
ADVERTISEMENT
"Most likely, if you have veligers floating around, you're going to have adults somewhere, it's just a matter of time," Eisterhold said.
'Not the end of the world'
Lake Winnie is far from the first Minnesota lake to be infested with the zebra mussel. The DNR lists more than 100 waters infested with zebra mussels, including several of of the state's most popular and high-profile lakes such as Lake Mille Lacs in 2005 and Lake Minnetonka in 2010.
Closer to home, zebra mussels were found in 2009 in Otter Tail County's Pelican Lake.
"It was pretty surprising to me that they got zebra mussels because they have had such an active lake association," said Moriya Rufer, Pelican Lake manager.
Rufer, through her employer RMB Environmental Laboratories Inc., has been contracted since 2007 by the Pelican Group of Lakes Improvement District, a taxing authority established in 1994 long before zebra mussels were found.
The Pelican Lake Property Owners Association, a nonprofit organization, had long been working to educate its members and lake users about the importance of AIS prevention, so when Rufer received a call in 2009 from a homeowner who reported finding a possible zebra mussel, she was skeptical.
"I've seen people bring some crazy things," Rufer said. "I was expecting it to not be a zebra mussel."
ADVERTISEMENT
Indeed, it was a mature mussel, found attached to a native mussel on the bottom of a flat sandy area, a popular anchoring place for boaters. Rufer contacted the DNR, which then sent a team to confirm the find and search for others.
"You never know if the shell came from somewhere else," Rufer said. "We went over to that area and snorkeled ... and we found more zebra mussels right there."
They were about an inch long at the time, so Rufer figures they had been there a year.
"They have multiplied (since then) and there are a lot more of them now," she said.
Presumably, the numbers of zebra mussels in Pelican Lake will continue to rise.
"In theory, they'll keep increasing until they hit the carrying capacity of the lake," Rufer said. "I don't think that's happened yet."
Their presence, certainly, is unwelcome, Rufer said, but without any way yet known to eradicate the invasive species, Pelican Lake property owners and lake users have simply adapted their behaviors to the zebra mussels' presence.
"Its not the end of the world," she said.
People no longer moor their boats in the water, opting instead to put them up on a lift or shore; property owners who use the lake to water their lawns put copper mesh over their underwater pipes because zebra mussels will not attach to copper; and a select number of people have taken to wearing water shoes while in the lake because of sharp zebra mussel shells.
ADVERTISEMENT
"People have just adapted their activities a little bit and it doesn't seem to be a big problem," Rufer said.
Tracking behaviors
The Pelican Lake Property Owners Association, with an 82 percent membership rate of all shoreline property owners, worked constantly to educate lake users and boaters to fight the spread of AIS, Rufer said.
"There's no way to 100 percent prevent them from coming in and they were doing everything they could," she said.
But, once zebra mussels arrived, the lake did have the benefit of having a lake improvement district in place, meaning funds were available.
"That's one of the advantages they have, to be able to do some of these programs," Rufer said.
Those programs benefit not only Pelican Lake residents, but the entire state.
RMB is the only lab in Minnesota, outside of the DNR, that can test for veligers. Rufer said her team has been testing and netting veligers every other week to monitor their density and track their behaviors.
ADVERTISEMENT
Those tests revealed that veligers start to appear in early summer when water temperatures reach the low 60s and seem to be the most dense in July during the warmest water temperatures, she said.
Mature zebra mussels appear the most dense, in Pelican Lake, near the Pelican River inlet, which could be due to the inflow of nutrient-rich water providing a food source, Rufer said, noting that such findings are shared with the DNR.
"Pelican Lake is paying for this monitoring to be done, yet it's a good service to the general public," she said.
Pelican Lake also continues to work with the DNR and host inspectors at its accesses to prevent further spread of AIS to other waters. Rufer pointed out that despite other large, popular lakes neary -- such as Detroit Lake -- those waters have not become infested.
"Even though they have zebra mussels, they're helping to prevent it from spreading to other lakes," she said.
'No one really knows'
Michael Kellin, owner/broker of Coldwell Banker Northwoods Realty in Grand Rapids, said he does not have any direct evidence that an AIS infestation negatively affects property values.
"It is new," he said of the zebra mussel discovery in Lake Winnie. "When it's new, no one really knows yet" what will happen.
Kellin has had buyers who have requested shoreline property along a lake free of mussels -- one specifically said he was not interested in waters containing any of the three Ms: milfoil, mercy and mussels -- but it's not the norm.
Whether AIS will actually prompt a decline in property values, he said, it was too soon to say.
"It's not going to help anything," he said. "Is it going to add value? No. But just how much or when will it have an effect, we just don't know yet."
Ken Grob, a member of the DNR's AIS advisory committee and the Hubbard County Coalition of Lake Associations, said a COLA member examined the economic impact of lake property in the county.
"What it discovered was 60 percent of all the taxable market value of property in Hubbard County is water-related," he said.
The top township is Lake Emma, Grob reported, with more than $357 million in water-related taxable market value, or 87.5 percent of its its total taxable market value.
That township, home to Big Sand Lake, has $100 million more in taxable market value than the cities of Park Rapids, Nevis, Akeley and Laporte combined, Grob noted.
"You just see (that information) gets their attention," he said, discussing the importance of protecting Minnesota waterways.
He said a Wisconsin study into the effects of AIS on market value -- done before the Great Recession -- showed a 13 percent decrease in property values for land bordering Eurasian watermilfoil-infested lakes, but to his knowledge, Minnesota has not done its own study.
'The bigger threat'
Rooney, Denny's Resort owner, used to charter on Lake Michigan and is quite familiar with zebra mussels.
Standing beside his private harbor, filled with boats and docks, he held handsful of Chinese and banded mystery snails, non-native species long established in Lake Winnie. The snails are invasive, but are less threatening, in a lower class of invasives as compared to, for example, the faucet snail, which can kill ducks.
"At this point, we're not aware of any ecological harm that (banded mystery snails) do," said Kavanaugh, the Grand Rapids fisheries supervisor.
Rooney pointed to dock poles and weeds hosting dozens of the snails, but he shrugged them off, saying they make the water clearer but have not done any harm..
What concerns him, he said, is that the snails, like zebra mussels, feed off plankton in the water.
"Where you see the snails at is right where the zebra mussels will start to establish," he said.
Rooney is concerned for his harbor. Whereas the main shoreline of Lake Winnie is unlikely to have any huge infestations of the zebra mussel -- the slow, gradual slope of its shoreline, its summer wave action, and wintertime draw-down will make such colonization difficult -- Rooney said his harbor, and others like it, could become a hotspot for the invasive species.
"Those are the places where you could have the hardest infestations," he said.
So he, along with the DNR, countless volunteers and lake associations, continue to spread awareness and increase education about the necessary steps to prevent further AIS spread: pull the boat plug, drain the boat of water, and wash it down, if needed.
"Twenty, 30 years ago, people didn't believe in catch-and-release either," he said.
Eisterhold, the AIS specialist in Park Rapids, said he believes that effort has taken hold. He now fields inquiries from prospective out-of-state visitors, wanting to know the AIS regulations in advance of a planned fishing trip.
"I'm getting calls and emails trickling in here and there," he said. "I don't think I can say I had very many of these emails and phone calls in the past."
Getting lake users accustomed to such best practices likely will come in handy in the future, when a new, potentially more threatening AIS makes it way to Minnesota lakes.
"The bigger threat is what other invasive species are knocking on the door," Kavanaugh said.
