'Not cute and fuzzy' endangered mussels to be released in DuPage River

Roughly 9,000 freshwater mussels will be released into the West Branch of the DuPage River over the next six months with an eye toward improving water quality and giving new hope to an endangered species.

“Freshwater mussels are the most endangered animals in America,” said Jessi DeMartini, aquatic research center coordinator for the Forest Preserve District of DuPage County. “But nobody knows it because they're not cute and fuzzy.”

While they may be small, DeMartini said freshwater mussels play a crucial role in the overall health of aquatic habitats in urban waterways by acting as filter feeders. They take in large amounts of water and filter out bacteria, algae, or decaying plant or animal matter before passing clean water back into the river.

A single adult mussel can filter more than 18 gallons of water a day, officials said. Because they live en masse, a group of mussels can filter enough water to lower overall pollution levels.

“They provide incredible ecosystem services for our water - our rivers, our streams, our lakes - by cleaning it and filtering it,” DeMartini said. “They do all kinds of other things for other organisms in the aquatic systems.”

But native freshwater mussel populations have been declining for a number of reasons, including sedimentation, stormwater runoff, chemicals, pollutants and competition from invasive species such as the zebra mussel.

DeMartini said zebra mussels are a huge problem for native mussels because they compete for the same food sources and attach themselves to the shells of native mussels, which can cause the animals to suffocate and die.

In addition, zebra mussels can be a costly problem for cities and power plants because they can clog water intake systems.

So DeMartini and other experts at the district's Urban Stream Research Center spent 2½ years working to raise freshwater mussels in the facility at Blackwell Forest Preserve near Warrenville. They succeeded in cultivating three species native to DuPage - the plain pocketbook mussel, fat mucket mussel and white heelsplitter mussel.

“One of the missions of the forest preserve is to conserve and to protect,” DeMartini said. “What we're doing here is keeping our common freshwater mussels common.”

By adding thousands of native freshwater mussels to the West Branch, officials are hoping to augment and boost the existing populations.

“They're very diminutive right now,” she said.

The 9,000 mussels slated for release this year all were propagated in the lab before being moved to floating baskets in a local pond so they could grow. Today, they're more than a year old and one to two inches long.

Under the district plan, the mussels will be released at a dozen locations along a 13-mile stretch of the West Branch between Gary's Mill Road in Warrenville and 87th Street in Naperville.

An initial release of 500 to 1,000 mussels was scheduled last weekend at McDowell Grove Forest Preserve near Naperville, but it had to be scrapped because of rain and flooding. Officials now plan for the first release later this month.

In the meantime, roughly 1,900 mussels pulled from the baskets in the pond have been tagged and are being kept at the aquatic research center until they're released into the river.

“They're all dressed up and ready to go,” DeMartini said.

Forest preserve officials said the release comes on the heels of extensive work by the district, the U.S. Environmental Protection Agency and the county's stormwater management department to improve conditions in and along the West Branch by creating in-stream habitat, preventing erosion, and improving the river's ability to store and handle floodwater.

“I see opportunity,” DeMartini said. “The river is more functional and can support the species that we're augmenting.”