DNA Shedding Rates of Asian Carps, for Use in Understanding Field Collections of Edna

The use of environmental DNA (eDNA) as a tool for species detection has come to the forefront in the fight against aquatic invasive species. The technique works by extracting DNA shed into an organism’s environment and using polymerase chain reaction (PCR) to identify species specific DNA. The sensitivity of the technique is higher than that of more traditional methods (surveys) of species detection. This increased sensitivity is especially important because invasive species likely exist in low densities at the beginning of an invasion. Currently, eDNA is being used to detect Asian Carp, (Silver carp, Hypophthalmichthys molitrix, and Bighead carp, H. nobilis) in the Chicago Area Waterways (CAWS). Positive eDNA samples have been found in the CAWS, but intense fishing in the area has only found one Bighead and no Silver carp. We aim to better understand the information that this tool provides by examining how DNA of Asian Carps gets into the environment and how quickly it degrades. In a controlled laboratory setting, we first measured how much DNA a single fish sheds and investigated the variability of these measurements using quantitative PCR (qPCR). In a series of manipulative lab experiments, we studied how temperature, biomass, and diet affect the shedding rate of eDNA by these fish. Ultimately this data will inform a probabilistic model that can be used by resource managers as a way to statistically infer the presence of live Asian Carps from positive eDNA hits.