Red swamp crayfish found in Chicago River could wreak havoc on local ecosystems

Crayfish is a popular dish, including at this market hall in Germany. But experts warn not to eat the red swamp crayfish found in the Chicago River because of their proximity to a sewage treatment plant. (Markus Schreiber/AP)

If you’ve ever kayaked down the Chicago River or relaxed along any of the waterways in the area, you may have encountered all sorts of creatures — an enormous snapping turtle, a stray alligator or maybe something that looks a lot like a lobster.

It turns out a lobster-like creature spotted swimming around the city was a red swamp crayfish, and its presence in Chicago waterways is a warning sign.