Winter 2003

Sentenced to Desk, Mussel Granted Eleventh-Hour Pardon

Inspecting a future restoration site along the West Fork of the Chicago River in Glenview, Friends of the Chicago River staffers Nathan Aaberg and John Quail discovered a mussel they didn't recognize. Judging it had passed on, Aaberg brought the mussel back to the Friends office.

Aaberg later took the mussel to Roger Klocek, senior conservation biologist at the John G. Shedd Aquarium, who revealed that the specimen was the uncommon pondhorn mussel, Uniomerus tetralasmus. To Aaberg's surprise, Klocek called him two days later to say that the pondhorn had recovered fully in Klocek's office aquarium. This, despite the fact that it had spent the prior seven days being shuffled between reports and memos on Aaberg's desk.

"I've only seen one live example from the streams I've sampled in northern Illinois, and perhaps a half dozen dead examples," said Klocek. "I'm pretty surprised, but happy, to see one in the Chicago River." The pondhorn mussel has never been recorded in the Chicago River. Its discovery suggests a river regaining its health.

Friends staff and Klocek returned to the West Fork on October 30 to release the pondhorn and to search the river for other mussels. They found several recently dead mussels (a giant floater, a squawfoot, and a paper pondshell) as well as one live paper pondshell, also a new Chicago River record. Friends and the Shedd Aquarium hope to launch a comprehensive mussel survey of the Chicago River in 2003.