No bighead or silver carp captured during 2024 Seasonal Intensive Monitoring

November 5, 2024

No bighead or silver carp were captured or observed in the Chicago Area Waterway System during the Fall Seasonal Intensive Monitoring (SIM) effort involving two weeks of intensive sampling in early October 2024. One grass carp was observed but sampling crews were unable to capture it. Grass carp are occasionally captured in the Lake Calumet area during sampling.

These results are similar to those of the Spring SIM in May 2024, when no bighead or silver carp were found but two grass carp were captured and removed. The SIM is conducted in the Chicago Area Waterway System twice per year as part of an interagency effort led by Illinois Department of Natural Resources to monitor for the presence of live bighead or silver carp.

The Chicago Area Waterway System connects the Illinois River, where invasive carp are abundant in lower stretches, to Lake Michigan, representing a possible pathway for invasive carp to spread to the Great Lakes. The current invasive carp population front on the Illinois River is approximately 47 miles from Lake Michigan and is heavily monitored, with harvest efforts conducted in downstream waters to remove carp and reduce the risk of upstream movement. Furthermore, the Electric Dispersal Barrier System is active in Romeoville, 37 miles from Lake Michigan, providing an additional line of defense against upstream carp movement. Though invasive carp remain well downstream of Lake Michigan, sampling in the Chicago Area Waterway System plays a critical role in assessing any potential population changes and providing a first response capability in the event of invasive carp detections.

For the Spring and Fall SIM efforts, partner agencies under the leadership of the Illinois Department of Natural Resources sampled hundreds of sites throughout the Chicago Area Waterway System. Crews from the Illinois Department of Natural Resources, Illinois Natural History Survey, U.S. Fish and Wildlife Service, and U.S. Army Corps of Engineers conducted sampling using targeted boat electrofishing and netting; and commercial fishers, working on contract for the state, conducted gill netting and seining.

For the 2024 Spring SIM effort, crews conducted 70 hours of electrofishing at 280 locations, set 51 miles of gill net at 454 different locations and set 3,200 yards of commercial seine at 4 locations in Lake Calumet. The most concentrated sampling was conducted in the Calumet River and Lake Calumet.

For the 2024 Fall SIM effort, crews completed 70 hours of electrofishing at 280 sites and commercial fishers set 51 miles of gill net at 454 different locations. The densest sampling occurred in Lake Calumet, the Calumet River, the Cal-Sag Channel and the Little Calumet River.