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Follow-up eDNA results announced for Bubbly Creek, Chicago

2020 results are now posted for the eDNA sampling done in follow-up to the high number of positive Asian carp eDNA samples found in the South Fork of the South Branch of the Chicago River in 2019.

September 17, 2020

A red brick building with grass on the roof sits on the edge of a small river. A city skyline is seen in the distance.
The Racine Avenue Pumping Station in Chicago. Photo courtesy of Justin Brown/Metropolitan Water Reclamation District of Greater Chicago.

The U.S. Fish and Wildlife Service confirmed an unusually high number of positive Asian carp eDNA samples in the South Fork of the South Branch of the Chicago River, also known as Bubbly Creek, in the fall of 2019. The samples were collected downstream of the Racine Avenue Pump Station around the time of a pumping event due to a storm. The 2019 eDNA results triggered two weeks of intensive monitoring in the Bubbly Creek area completed by the Illinois Department of Natural Resources and Asian Carp Regional Coordinating Committee partners using traditional fish sampling gears, including nets and electrofishing. During that time biologists found no evidence of Asian carp in the area, but observations were made about the proximity of Bubbly Creek to the pumping station, which resulted in it being considered as a potential source of the Asian carp eDNA being detected.

Water samples were subsequently collected by the Service in cooperation with the Metropolitan Water Reclamation District of Greater Chicago and the Illinois Department of Natural Resources in February of 2020 to determine if Asian carp eDNA was present in the four sewer lines feeding into the Racine Avenue Pumping Station. In total, 192 samples were collected and transported to the Service’s Whitney Genetics Lab in Onalaska, Wisconsin for processing. The subset of samples tested revealed the presence of Asian carp eDNA at all sewer line sampling locations.

View the recent eDNA sampling results from Bubbly Creek.

Due to the presence of Asian carp eDNA in the sewer lines leading into the pumping station, along with the degraded water quality of Bubbly Creek making it unlikely to sustain fish, the Service recommends it cease eDNA sampling in Bubbly Creek. Following the February eDNA sampling, the Service was not able to collect additional eDNA samples in Chicago due to COVID-19 restrictions, but plans to resume eDNA sampling in the Chicago Area Waterway System in the spring of 2021. The Service continues to coordinate with the Illinois Department of Natural Resources, the Metropolitan Water Reclamation District of Greater Chicago and the U.S. Geological Survey to plan and implement Asian carp eDNA surveillance in the CAWS.

Visit our eDNA page to learn more about the science of environmental DNA.