Environmental DNA

Environmental DNA (eDNA) is the genetic material from a plant or animal that is found in the air, water or soil. Fish, such as invasive carp, release DNA into the environment in the form of skin cells, secretions, and feces. This DNA can be collected from water samples in the field and be used to indicate the potential presence of an individual species.

A positive eDNA hit does not necessarily indicate the presence of a live carp. eDNA evidence cannot verify whether live invasive carp are present, whether the DNA may have come from a dead fish, or whether water containing Asian carp DNA may have been transported from other sources, such as bilge water.

eDNA testing is useful as a potential early indicator of invasive carp presence and was developed to improve monitoring of such aquatic invasive species. All fish release DNA into the environment and scientific sampling can detect and identify species-specific organisms (bighead and silver carp). However, as there remain many uncertainties about what a positive eDNA sample indicates, it is used in conjunction with other detection tools. This comprehensive approach includes electro-fishing, netting, the operation of electric barriers, and the construction of fencing to prevent carp from crossing between waterways, among dozens of other measures.

The Great Lakes Region of the U.S. Fish and Wildlife Service has been conducting eDNA testing since 2013 within the Chicago Area Waterway System and other areas of concern within the Upper Mississippi River, Ohio River and Great Lakes. To ensure reliable results the Service maintains the Quality Assurance Project Plan (QAPP) for eDNA monitoring of bighead and silver carps which details the eDNA monitoring process, including methods and quality control.

The U.S. Fish and Wildlife Service processes eDNA samples at the Whitney Genetics Lab in Onalaska, Wisconsin. View eDNA results from current monitoring efforts.

eDNA Calibration Study

In late 2011, the ICRCC funded a study to better understand eDNA. This study was referred to as the eDNA Calibration Study, or ECALS. The main purpose of ECALS was to improve the application of eDNA methodology to assess and mange uncertainty.