Winnibigoshish is latest lake infested with zebra mussels

Deer River, Minn. — The DNR announced last week that Lake Winnibigoshish is the latest lake in the state to be infested with zebra mussels.

DNR Fisheries water-sampling efforts last summer detected two veligers, or larval zebra mussels. The samples recently were tested, and the lake and connected waters were designated as infested waters.

Additional water samples didn’t show more veligers, and adult zebra mussels haven’t been found in the 58,500-acre lake.

“The size of the lake may delay locating an adult population, but the presence of veligers suggests there is likely a reproducing population in the lake,” Rich Rezanka, a DNR invasive species specialist, said in a release.

It’s difficult to say how zebes will affect the lake, which also is home to invasive faucet snails. Gerry Albert, DNR large lake specialist for Winnie, is heartened that some lakes – such as Winnebago in Wisconsin – have had zebra mussels for decades, but “from what I understand, (there’s been) no real negative effects on fish populations,” he said.

“We’re really early yet, and I don’t know if we know the final outcome anywhere,” Albert said.

Since Winnie is upstream from other waters that have zebra mussels, DNR officials say the infestation is the result of “overland spread,” which is preventable, said Ann Pierce, DNR invasive species unit supervisor.

“Our laws are designed to prevent that,” she said. “If we all follow the laws and understand the laws and take responsibility, that is preventable,” she said.

While the lake, the fourth-largest in the state, now has two types of invasive snails – faucet snails and zebes – it’s not likely they will help or hurt one another, said Gary Montz, a DNR research scientist.

“From what I can tell right now with the biology and ecology of both of these species, I don’t see positive interaction or synergistic interaction that one would exacerbate the impacts” of the other, he said.

Though Winnie hadn’t been infested previously with zebes, the DNR did have a presence at accesses, ensuring boaters didn’t have zebes or other invasives attached to their boats or trailers. In 2011, there were 58 hours of inspector time at two public accesses on the lake. In 2012, there were 133 hours.

That’s more inspection hours than other lakes that aren’t infested, Pierce said.

“Even though the lake was not infested, we still had hours on it because it is a highly used lake, and because it’s also infested with faucet snails,” she said.

In addition to Winnie, 13 other connected waters also will be designated as infested waters.

There will be additional sampling next spring and summer, including plankton tows (which are the reason for the discovery of the veligers), dives, shoreline searches, and coordination with resource partners on the lake and downstream waters. 

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