Analysis Complete of Silver Carp Captured in Lake Calumet

May 16, 2023

Contact:
Tim Patronski, Tim_Patronski@fws.gov, 612-418-9148

Laboratory analysis of a silver carp collected this past August in Lake Calumet within the Chicago Area Waterway System found that the fish was an adult that originated in the Illinois River watershed. The silver carp was determined to be at least four years old, measured 38 inches in total length, and weighed 22 pounds. Analysis showed that the fish was likely a relatively recent arrival to the Chicago Area Waterway System, though it is not known how the fish arrived at Lake Calumet. The analysis of the silver carp was completed by Southern Illinois University, the U.S. Fish and Wildlife Service and the U.S. Geological Survey.

The live capture of the silver carp on August 4, 2022, in Lake Calumet triggered two additional weeks of intensive sampling in the area between August 5 and August 19, as outlined in the Invasive Carp Regional Coordinating Committee’s Contingency Response Plan. The multi-agency response included electrofishing by agency crews and netting by contracted commercial fishers in Lake Calumet and adjacent waters within the Chicago Area Waterway System. No additional bighead or silver carp were caught or seen. The response effort produced many native fish, which were returned to the lake unharmed. In addition, four grass carp were collected and removed.

Additionally, seasonal intensive monitoring, which is conducted bi-annually by the ICRCC in the spring and fall, was completed between October 3 and 14, 2022. Due to the August 4 silver carp capture, monitoring efforts were conducted in Lake Calumet, the Calumet River, and the Little Calumet River as a precautionary measure, in addition to other areas of the Chicago Area Waterway System. Crews from the Illinois Department of Natural Resources, Illinois Natural History Survey, U.S. Fish and Wildlife Service, U.S. Army Corps of Engineers, and state-contracted commercial fishers focused agency electrofishing and commercial gill netting actions on the detection of any bighead or silver carp potentially in the sampling locations. No bighead or silver carp were caught or seen. The response effort produced many native fish, and one grass carp was collected and removed.

A separate analysis showed that the adult silver carp found dead on the banks of the Calumet River on May 24, 2022 during the spring 2022 seasonal intensive monitoring period was approximately 12 years old and originated in the Illinois River Watershed. It was also determined to be a recent arrival to the Chicago Area Waterway System; however, it is not known how the fish arrived in the Calumet River. Moving forward, the Illinois Department of Natural Resources will continue responding to reported sightings, while regularly searching for and removing invasive carp through seasonal intensive monitoring conducted in the Chicago Area Waterway System with support from the Invasive Carp Regional Coordinating Committee.