Mussel research setting the tone for the future of a cleaner Cedar River

Published 6:30 pm Friday, August 30, 2024

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Officials from the Minnesota Department of Natural Resources were back in Austin Thursday and Friday to continue a survey of mussels in the Cedar River.

Part of a project to reintroduce the mussels to the river that started in 2019, these officials were back in order to check the progress of the reintroduction and to highlight any changes to the river, as well as help determine the future.

“Coming back annually allows us to put that data into models to get recapture estimates and survival estimates,” said Lindsay Ohlman, freshwater mussel senior propagation biologist for the DNR. “That gives us information for each site.”

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By reviewing the data and comparing them to the three other sites, Ohlman and her team can learn what sorts of things are influencing the populations in terms of habitat and to make better management decisions in the future.

The DNR established two different species of mussels in the river — the mucket and the black sandshell — freshwater species that work as a filtration system for the river by filtering algae, bacteria and e-coli.

In turn they expel little packets of nutrient-rich food for smaller fish and invertebrates. This creates a cycle that then draws fish like minnows, darters and larger fish.

“They kind of create their own sort of ecosystem,” Ohlman said.

What’s more, the shells of the mussels can also be habitat for fish spawning and for snails and aquatic insects, which are food for river otters and more.

Their presence along the bottom can also help stabilize the substrate to make the river more resilient to flooding.

So far, the reintroduction has reflected some positive results and has shown a progression of mussels in the Cedar, including reproduction.

“The females are getting fertilized naturally,” Ohlman said. “We’re at a point now where in the next couple years we will be coming back to do surveys to look for offspring of the mussels we’ve put into the system.”

This work is made possible through funding from the Environmental and Natural Resources Trust Fund, which have driven Ohlman and her team for the last 10 years.

“We’re very appreciative of the funding they give us that allows us to do this type of conservation work,” she said.