Mussels regaining a foothold in the upper Mississippi River after decades of decline

At first glance, the boat’s crew looks ready to embark on a fishing trip. Their boat is equipped with a hefty rectangular cooler, a couple of white buckets and neon orange life jackets. They chat idly with one another from the boat’s helm, remarking on the September day’s balmy weather and the dogs that bound along the riverbanks across from them. 

But this is no fishing expedition. Their cooler is filled with about 400 mucket and Higgins eye mussels, each a little over an inch in diameter. Their brown striped shells gleam in the late summer sun. By the end of the afternoon, each of these mussels will be sitting at the bottom of a stretch of the Mississippi River between St. Paul and Minneapolis, Minnesota. 

The operation is led by biologists at the Minnesota Department of Natural Resources. Since 2001, the agency has been reintroducing native freshwater mussels into this section of the Mississippi, returning every year...