FARGO -- With zebra mussels now present in the Red River Basin, water managers in the U.S. and Canada are bracing themselves for the potential impacts.

There are a lot of unknowns, but if the invasion in other watersheds is any indication, zebra mussels could mean big changes, both to the natural environment and to cities and water users along the river.

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The invasive mollusks are prolific and can choke out native mussels, out-compete native fish species and clog the intake structures of city water systems and power plants.

Zebra mussels were a prominent topic Wednesday afternoon during a presentation held as part of the 28th annual Red River Basin Land and Water International Summit Conference in Fargo. The conference began Tuesday and wrapped up Thursday.

Titled, "What You Really Need to Know About Aquatic Nuisance Species and Then Some -- You Best Be Prepared Now!" the panel presentation included speakers from the North Dakota Game and Fish Department; the Minnesota Department of Natural Resources; Manitoba Water Stewardship; Fisheries and Oceans Canada; and the South Dakota Department of Game, Fish and Parks."

Matter of time

While the presentation offered an overview of aquatic invasive species from Asian carp to Eurasian milfoil, zebra mussels garnered the most attention.

Discovered in 2009 in Pelican Lake in Otter Tail County, zebra mussels quickly spread downstream through the watershed, and last summer, larval zebra mussels, or "velagirs," were confirmed in the Red River near Wahpeton-Breckenridge.

It's just a matter of time, then, before zebra mussels work their way downstream through Grand Forks and into Manitoba.

"I call zebra mussels 'ecological Armageddon,'" said Candace Parks, water quality specialist for Manitoba Water Stewardship in Winnipeg. "I don't know how to sugarcoat it."

Parks said the province last year sampled the Red River near Emerson, Man., weekly from mid-April -- when Pelican Lake hit 50 degrees -- until Nov. 1 checking for zebra mussels.

"So far, knock on wood, we haven't found anything," Parks said.

She concedes, though, that the mussels will show up eventually. And the significant flooding that's expected this spring in the Red River Basin could accelerate the invasion.

"We don't know for sure -- it's just kind of a best guess -- but with the potential flooding and perhaps warm temperatures, we could possibly get them as soon as next summer," Parks said. "Most of North America is watching what's happening on the Red River."

No impact -- yet

Minnesota has designated about 85 bodies of water, including popular fisheries such as Mille Lacs and Lake Superior, as infested with zebra mussels. According to Nathan Olson, an aquatic invasive species specialist with the DNR in Fergus Falls, Minn., there hasn't been a negative impact on fish populations in any of the infested waters -- to this point, at least.

It's too soon to say, he said, how zebra mussels will impact the Red River. The river doesn't have a lot of "pelagic" fish species such as tullibees that cruise the water column feeding on zooplankton. But it's possible, he said, that there could be some "major effects" on larval fish production.

Parks of Manitoba Water Stewardship said the province conducted a study in 1997 looking at the potential for zebra mussels to colonize Manitoba lakes and rivers. The Red River, she said, offered the best potential for zebra mussels to colonize, based on factors such as water quality and bottom substrate.

And a competing invasive known as the quagga mussel -- which is actually outcompeting zebra mussels in parts of the Great Lakes -- would thrive in the substrate of Lake Winnipeg, which generally has a softer bottom conducive to quagga mussels.

"If we get both critters, it definitely would not be good news," Parks said.

The goal now, Parks said, is to further educate boaters and other users of the river to do what they can to minimize the spread of zebra mussels, which can survive out of the water for up to 15 days.

"Now that it's in the Red River, there's no silver bullet," she said in an interview. "I truly believe people do the right thing if they know what the right thing is. That's my goal. That's the best we can do."

Dokken reports on outdoors. Reach him at (701) 780-1148; (800) 477-6572, ext. 148; or send e-mail to bdokken@gfherald.com.