Chicago River - Pollution

Pollution

The Chicago River has been highly affected by industrial and residential development with attendant changes to the quality of the water and riverbanks. Several species of freshwater fish are known to inhabit the river, including largemouth and smallmouth bass, rock bass, crappie, bluegill, catfish, and carp. The river also has a large population of crayfish. The South Fork of the Main (South) Branch, which was the primary sewer for the Union Stock Yards and the meat packing industry, was once so polluted that it became known as Bubbly Creek. Illinois has issued advisories regarding eating fish from the river due to PCB and mercury contamination, including a "do not eat" advisory for carp more than 12 inches long. There are concerns that silver carp and bighead carp, now invasive species in the Mississippi and Illinois Rivers, may reach the Great Lakes through the Chicago River. Despite the pollution concerns, the Chicago River remains a very popular target for freshwater recreational fishing. In 2006, the Chicago Park District started the annual "Mayor Daley's Chicago River Fishing Festival", which has increased in popularity with each year.