Finding just one zebra mussel in a lake doesn't mean they aren't there

OTTER TAIL CITY, Minn.-There was only one zebra mussel found so far in Otter Tail Lake in western Minnesota and four in Detroit Lake.Yet, they are labeled "infested waters."It's a precautionary measure, said Minnesota Department of Natural Resour...
A zebra mussel is on the list of aquatic invasive species that is the focus of an effort to keep them out of lakes and rivers in the region. Forum News Service file photo.

OTTER TAIL CITY, Minn.-There was only one zebra mussel found so far in Otter Tail Lake in western Minnesota and four in Detroit Lake.

Yet, they are labeled "infested waters."

It's a precautionary measure, said Minnesota Department of Natural Resources official Ann Pierce, but there are probably more of the pesky mussels there.

"Looking for a quarter inch to 1.5 inch animal in any lake is like looking for a needle in a haystack, so just because we didn't find any additional zebra mussels doesn't mean they are not there," said Pierce.

And Otter Tail lake was a perfect example as DNR dive teams searched for days looking for any more of the mussels, but they didn't find any in taking over 3,000 samples.

That leads Otter Tail Property Owners Association director Bernie Steeves to wonder if there are really zebra mussels in the lake.

"We question it," he said.

DNR officials are sure about one thing, however, "it's us" that are spreading the somewhat dangerous invasive species from lake to lake, Pierce said.

With the mussels now found in Otter Tail and Detroit lakes-two of the most popular lakes in western Minnesota-officials are continuing to urge boat and other watercraft owners to follow the new laws that require them to be cleaned thoroughly when removing them from the water, with drain plugs pulled and old bait thrown away.

Out of more than 11,300 Minnesota lakes, less than 2 percent are listed as infested for a total of about 206.

However, officials said by cleaning watercraft, people can certainly prevent a rapid spread of the mussels.

It's certainly something lake users don't what to see.

Heidi Wolf, invasive species unit supervisor for the DNR, said the mussels-who likely came from Asia on ships-can disrupt a lake or river's ecosystem, kill off native clams, affect some of the nutrients that fish eat, hurt water clarity, be harmful to swimmers because they are sharp-edged, can cause a severe odor when they die off and can get inside boat motors and cause damage.

"They really are a big nuisance," Wolf said.

Steeves said the lake association is meeting Thursday in Otter Tail City to talk about a possible response to the zebra mussels after hearing from the DNR and the Otter Tail County Aquatic Invasive Species task force, which Steeves chairs..

"We are going to do something. We're not going to just sit back," Steeves said.

Wolf said a copper pesticide treatment program to try to ride the mussels from Ruth Lake in Crow Wing County near Brainerd is under way, with some promising results so far.

"I really hope it can work until we figure out what next do do," Wolf said, noting that a University of Minnesota study is also under way.

A barrier is put around where the zebra mussels are and the treatment is applied in the pilot program.

The best preventative step, however, is for owners to clean their watercraft each and every time they move them from lake to lake.

Lake association and community members around lakes across Minnesota are trying to help the cause, too, by volunteering at boat accesses. They can help people understand the dangers and give advice on cleaning to help prevent the spread, Wolf said.

"It's a great tool," in the fight, she said.

Steeves said they also have inspectors checking boats at the accesses around the county. Cameras have also been set up at some accesses to check to make sure watercraft owners are pulling their drain plugs and that they are clean.

Steeves also said $100 fines or "putting some teeth into the laws" is probably necessary.

"I guess there will always be some that won't obey the laws," he said.

"I don't know if we can stop it, but we are going a great job so far and we are going to keep going," Steeves said.