AUSTIN — The Department of Natural Resources hopes the Cedar River can start flexing its muscles, or mussels, really.
On Tuesday, folks from the DNR came to East Side Lake in Austin to move more than 3,700 black sandshell mussels that had been growing in the lake to three spots in the river where black sandshells used to live and thrive.
Tim Ruzek, water plan and outreach coordinator for the Mower County Soil and Water Conservation District, said 100 years ago, Austin was nicknamed the "Pearl City" because of all the mussels in the Cedar River. But years of overharvesting and pollution decimated the mussel populations in the Cedar.
Now, after a decade of improving the Cedar River, it's time to start reintroducing mussel species to the ecosystem, said Madeline Pletta, a mussel propagation biologist for the DNR.
Pletta, who works at the Center for Aquatic Mollusk Programs in Lake City, said black sandshells are one of seven native mussels that CAMP is working to reintroduce in the Cedar below the Fourth Street dam.
The dam represents the last barrier for fish — which mussels use to move and spread their territory by catching a ride in gills during their larval stage — to move up and down river between Austin and tiny Otranto, Iowa, about 19 miles downstream. Pletta said the hope is the yearly infusion of mussels over the next decade or so will help rebuild the mussel population on this stretch of the river.
The 3,730 mussels split between three downstream sites Tuesday are added to the 1,500 mussels Pletta and her crew distributed to three spots last year.
Pletta and CAMP will begin monitoring those mussels to see if they are reproducing, building new populations and thriving in the river. The sites chosen to spread mussels present a diversity of habitats in the river so researchers can see where the mussels survive best.
"Our goal is to do five different age-class releases per each species we work with, then do the monitoring," Pletta said.
The program began in 2016, but it's taken this long for the mussels to grow big enough to transport, Ruzek said.
Pletta said the project isn't just restoring mussels to the Cedar River for old-time sake. Mussels serve as filters in the river, provide microhabitats for smaller aquatic creatures like invertebrates, and stabilize the river bottom.
"It really is about trying to bring the river back," Pletta said. "The benefits that mussels bring from an ecological standpoint is they remove bacteria like E coli, organic sediment. They are like the coral reefs of the river."