Asian Carps have become invasive species in the US. Originally from Asia, these fish (namely Bighead, Silver, Black and Grass carp) were brought to the US in the 1970’s for water quality control of aquaculture facilities. Unfortunately, they escaped the aquaculture facilities and have been swimming up the Mississippi River. Asian carps may out compete native species for food and habitat resources and are even a hazard to recreationists, as Silver carp will jump three meters out of the water when disturbed. There is concern that the fish will enter the Great Lakes from the Mississippi and Illinois Rivers via the Chicago Area Waterways System.
Currently managers are using eDNA (or environmental DNA) to monitor the presence or absence of these fish in the CAWS. The tool uses PCR (polymerase chain reaction) to amplify specific DNA strands shed by these fish into the environment, producing a measurable amount of DNA. Although likely to be more sensitive than traditional surveying tools (netting, etc.), a lot is still unknown about what a positive eDNA hit means in regards to actual live fish presence and abundance. I worked on a project with the US Geological Survey, US Army Corps of Engineers, US Fish and Wildlife Service, and the Missouri Cooperative Fish and Wildlife Research Unit to assess the information we can gain from eDNA in order to better understand and interpret eDNA results. Understanding where these fish are is of vital importance for their management and eradication.