GF&P officials confirm presence of Zebra mussels in Lake Mitchell

Mitchell Mayor Bob Everson said a social media post he saw showing a zebra mussel attached to a twig that the individual who posted the photo claimed the twig was found in Lake Mitchell is what led him to investigate.

Adult zebra mussels are pictured attached to a dock in the Lewis and Clark marina. Game, Fish and Parks has modified its aquatic invasive species regulations to stop their spread and ease boat travel between infested waters. (Photo courtesy of the South Dakota Department of Game, Fish and Parks)

Zebra mussels have hit Lake Mitchell.

According to Dave Lucchesi, area fisheries supervisor for the southeast portion of the state with the South Dakota Game, Fish and Parks, several zebra mussels were discovered this week at different portions of the lake, including the spillway dam, the west end boat launch and the Sportsman’s Club access along the west side of the lake.

“We sent a crew out there to examine the area where this zebra mussel was found. They went to the Sportsman’s access as well and found zebra mussels both in and out of the water on parts that have been exposed by the declining water levels,” Lucchesi said Friday in an interview with the Mitchell Republic.

Mitchell Mayor Bob Everson said a social media post he saw showing a zebra mussel attached to a twig that the individual who posted the photo claimed the twig was found in Lake Mitchell is what led him to investigate. Everson contacted the state’s GF&P and showed an official the photo.

Lake Mitchell is now one of several lakes around South Dakota that zebra mussels have been detected, joining Lake Sharpe and Lake Francis along the Missouri River, which are located in central South Dakota near the Chamberlain-Oacoma area. The small mussels, which have sharp shells, are known to damage and destroy boats by clogging water systems used in boat motors and make fishing more difficult.


As of now, zebra mussel infestations haven’t been found to destroy fisheries, but the potential does exist, according to GF&P Chief of Aquatic Resources John Lott.

A pair of South Dakota conservation officers inspect Pierre resident Jeff Carr’s boat July 14 as part of a temporary law enforcement check station near Oahe Dam a few miles north of Pierre. Carr had been fishing on Lake Oahe and officers checked to make sure the boat’s drain plug was out, which is required under the state’s aquatic invasive species rules. Regional Conservation Officer Supervisor Steve Rossow said enforcement of the rules has taken on new urgency as Lake Sharpe was confirmed to be infested with invasive zebra mussels on July 12. (Nick Lowrey / South Dakota News Watch)

After GF&P officials went to investigate, Lucchesi said several of the invasive species were discovered. As GF&P officials continued examining more parts of Lake Mitchell, Lucchesi said several more of the mussels were found, which has led the GF&P to declare the lake as “infested”with the invasive mussels.

“Even when we find one or two, they become established down the road and usually that’s the tip of the iceberg,” he said.

Lucchesi believes that zebra mussels have been in Lake Mitchell for about one to two years.

Zebra mussels feed on a wide variety of algae, Lucchesi noted. Considering the algae woes that have been plaguing Lake Mitchell’s water quality for several decades, Everson said the mussels could potentially help in that regard. However, he said it’s vital to mitigate the mussels as much as possible to protect the lake.

“They will help clean the algae in the lake, but the problem is they are virtually impossible to get rid of,” Everson said. “With the sharp shells, I’d urge people to wear some type of cover on their feet like water shoes if they are walking along rocks submerged in the lake. We are going to work with the GF&P closely on this, as this is their expertise.”


With the recent discovery of the species, Lucchesi said the GF&P will be posting signs in the coming weeks along the lake to warn users of the mussels’ presence in the city-owned body of water. In addition, Lucchesi said people who used a boat in the water will be asked to closely inspect their watercraft for zebra mussels.

As for how the mussels found their way into the lake, Lucchesi pointed to boats that may have came from another body of water infested with the mussels.

“Honestly, we aren’t surprised, since the close proximity of Lake Mitchell to Lake Sharpe. We believe most of the transfers occur by a recreational boat,” he said.

Sam Fosness joined the Mitchell Republic in May 2018. He was raised in Mitchell, S.D., and graduated from Mitchell High School. He continued his education at the University of South Dakota in Vermillion, where he graduated in 2020 with a bachelor’s degree in journalism and a minor in English. During his time in college, Fosness worked as a news and sports reporter for The Volante newspaper.
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