Freshwater Mussels

We're Not Moving a Mussel (We're Moving 24,377)

In spring 2017 the Forest Preserve District began releasing native freshwater mussels cultured and reared at its Urban Stream Research Center at Blackwell Forest Preserve into the West Branch DuPage River. Throughout the year it released a total of 24,377 mussels along 13 miles of the waterway. 

Release efforts came about after extensive efforts with the U.S. Environmental Protection Agency and DuPage County Stormwater Management to improve conditions in and along the river by creating in-stream habitat for aquatic animals, combating erosion, and improving the waterway’s ability to store and handle floodwater.

True to its aquatic conservation mission, the District has led efforts to augment native freshwater mussel populations in DuPage waterways to improve water quality. Despite their size, mussels provide enormous benefits because they take in large amounts of water when they feed. In the process, they filter out bacteria, algae, detritus and many other microorganisms before passing clean water back into the river. Just one adult can filter up to 18 gallons of water in one day, and because many mussels like to live in groups, together they can filter enough water to lower overall water pollution levels.

Habitat Loss and Other Threats

Freshwater mussels comprise the most imperiled group of wildlife in North America. At one time, 80 species made their home in Illinois. Today 17 species are extinct, and 23 are listed as endangered, threatened or of special concern at the federal or state level. Man-made changes to rivers have damaged the sand-gravel habitats mussels prefer, ammonia and other contaminants threaten young mussels, and invasive species such as zebra mussels have reduced native populations.