Freshwater Mussels to be Released into West Branch DuPage River

News Release

District to Release More Than 24,000 Freshwater Mussels into West Branch DuPage River

(April 25, 2017) — Between April and October the Forest Preserve District of DuPage County will release 24,377 native freshwater mussels along 18 miles of the West Branch DuPage River to serve as water filters.

“We cultivated three native species of the mussels at the Forest Preserve District’s Urban Stream Research Center at Blackwell Forest Preserve in Warrenville, the only facility of its kind in Illinois,” said Jessi DeMartini, the District’s aquatic research center coordinator.

Over the next six months the District will place 24,377 mussels at 11 locations along the West Branch between Gary’s Mill Road in Warrenville and 87th Street in Naperville. The goal is to boost natural populations of these animals, which play vital, irreplaceable roles in the overall health of aquatic habitats, in urban waterways.

“Freshwater mussels are what we call a ‘keystone species,”’ DeMartini explained. “They may be small, but they have enormous beneficial effects on the lives of other organisms.”

Mussels act as filter feeders by taking in large amounts of water, filtering out bacteria, algae, or decaying plant or animal matter before passing the clean water back into the river. Just one adult mussel can filter more than 18 gallons of water in one day.

“Because mussels often live en masse, together they can filter enough water to lower overall water pollution levels,” DeMartini said.

Freshwater mussels make up the most imperiled group of wildlife in North America. Over a century of manmade changes to rivers have damaged mussels’ preferred sand-gravel habitats. Ammonia and other contaminants are life threatening to juveniles, and competition from invasive species like the zebra mussel has further reduced native populations. As a result, of the 297 known species of native freshwater mussels in the U.S., 213 are listed as endangered, threatened or species of special concern at federal or state levels. Once home to 80 species, Illinois now has 63, 17 extinct and 23 that are federally or state-listed.

The release of mussels into the West Branch comes after extensive work by the Forest Preserve District in conjunction 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, preventing erosion, and improving the waterway’s ability to store and handle floodwater.

“We are thrilled to lead efforts to augment native freshwater mussel populations in DuPage waterways to improve water quality in support of our aquatic conservation mission,” said Forest Preserve District of DuPage County President Joe Cantore.

The Forest Preserve District of DuPage County has been connecting people to nature for more than 100 years. More than 4 million people visit its 62 forest preserves, 145 miles of trails, five education centers and scores of programs each year. For information, call 630-933-7200 or visit, where you can also link to the District’s e-newsletterFacebookTwitter and Instagram pages.
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Deb Humiston
630-871-6402 | 

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