Popular Northern Minnesota Lakes Now Named ‘Infested Waters’

The Minnesota DNR has named a handful of very popular Northern Minnesota lakes to an unfortunate list: zebra mussel-infested waters.

All four new bodies of water now categorized as infested are in Northern St. Louis County, and all three of them are busy and popular lakes for fishing and other water-based recreation. While these lakes are being classified as infested, the Minnesota DNR says they haven't found any adult zebra mussels in these lakes yet.

The Minnesota DNR says Lake Vermilion, Lake Kabetogama, Crane Lake, and Namakan Lake have been found to contain zebra mussel larvae.

As the DNR explains, the presence of larvae indicates that the lakes contain reproducing adult zebra mussels. They just haven't seen any adult zebra mussels in any of these lakes to this point.

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The DNR says that the levels of larvae found in these lakes are "small but measurable," and even though there haven't been any adults found, the presence of larvae and suspected adult populations reproducing means these lakes will now be classified as infested waters.

How abnormal is it for larvae to be found without any known reports of adult zebra mussels?

It might seem kind of weird for there to be larvae without any known adult zebra mussels in these lakes, but the Minnesota DNR says it isn't unusual, at least for large lakes like the ones we're talking about.

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In a news release announcing the addition of these four lakes to the list of zebra mussel-infested waters, the DNR highlights a similar situation on Rainy Lake. Back in 2021, zebra mussel larvae were discovered in Rainy Lake, but no confirmed presence of adults has been identified.

Why are zebra mussels bad?

If you don't know much about these invasive species, the Minnesota DNR explains that their presence can have a number of impacts.

Among those impacts are that zebra mussels can compete with native species for food and habitat while also having other impacts on the waterway's ecosystem. In addition, their presence can also cause issues for humans.

Their presence in lakes can cause a buildup of the creatures on structures like dock posts, while also cutting the feet of swimmers, causing expensive damage to water intake systems, and also impacting boat motors and other watercraft.

Now what?

This highlights the overall need for increased care and vigilance when removing watercraft and trailers from a body of water.

The general rule of thumb is the "Clean, Drain, Dry, (and Dispose)" method.

Inspecting and removing plants and other items, removing all drains and not transporting water, allowing for at least 5 days of drying after a thorough cleaning before heading to your next lake, and properly disposing of unused/unwanted bait are all part of this procedure.

If you suspect there is a new infestation of some aquatic invasive plant or animal, the Minnesota DNR asks that you note the exact location, take a photo or keep a specimen, and then contact a Minnesota DNR aquatic invasive species specialist.