12-year-old discovers invasive clams in Minnesota lake

A budding young scientist made an unusual discovery in a Sherburne County lake last summer.

Twelve-year-old William Guthrie of Big Lake, Minn., was volunteering with his family to comb lakes for aquatic invaders when he discovered a golden clam — an invasive species not previously found in Minnesota lakes — in Briggs Lake, southeast of St. Cloud.

Experts with the Minnesota Department of Natural Resources confirmed the discovery, said Megan Weber, an educator with the University of Minnesota Extension and Minnesota Aquatic Invasive Species Research Center.

Golden clams are a bivalve mollusk that can block intake pipes for power plants and water treatment facilities. They have been found previously in Minnesota, but mainly in rivers where a power plant is discharging its cooling water so the river stays warmer year round, Weber said. 

William’s family, including parents Becky and Korby Guthrie and two siblings, were participating in StarryTrek, a one-day event in August in which trained volunteers fan out across the state to sample lakes for invasive species. 

They watched training videos that taught them how to identify invasive aquatic species, Becky Guthrie said. Then, they used a dredging rake to pull up plant matter from four different lakes and tried to identify what they found. 

Mainly, they were looking for starry stonewort, a non-native plant that has infested several Minnesota lakes, Guthrie said.

“Really, that’s all we were looking for, but Will has such a keen eye,” she said. “So when we pulled up some plant matter and I was sorting through, he latched on to the golden clams that came up and said, ‘These are not supposed to be here.’”

William, who’s interested in science and enjoys reading about and exploring nature, said it was the clam’s golden color that caught his attention.

A water resource specialist at the Sherburne County Soil and Water Conservation District sent the clams to the DNR, which confirmed that they were the species Corbicula fluminea, also known as golden or Asian clams.

The Guthries later returned to the lake and found about 20 additional golden clams, which could indicate the population survived the winter and is reproducing.

The finding raises questions about whether Minnesota lakes could be more at risk for invasive species as lake temperatures warm due to climate change, Weber said.

The golden clam is not currently regulated in Minnesota. The DNR is proposing to list it as a prohibited invasive species.

Weber said William’s discovery highlights the importance of people getting involved in the early detection of invasive species.

“I think it says a lot about what just anyone can do, just by kind of looking at their surroundings and asking questions,” she said.

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