Silver carp that were brought to the US in the 1970s for aquaculture and water-treatment facilities have spread across the Mississippi River basin and are now raising concerns about the Great Lakes. Hundreds of the invasive fish have been detected in the Illinois River about 80 miles from Lake Michigan, while their established population front is even closer.
The discovery has renewed concerns about what could happen if silver carp establish a reproducing population in the Great Lakes. The fish consume large amounts of microscopic plankton that form the base of aquatic food webs, potentially putting pressure on native fish populations.
