Environmental DNA (eDNA) As a Potential Monitoring Tool: A Case Study Using An Endangered Fish (Notropis topeka)

Environmental DNA (eDNA) is genetic material from living organisms that can be recovered from the non-living environment.  eDNA is typically contained in things like shed skin, scales, mucus, excretions, or decomposing materials.  eDNA can be recovered from water, sediment, biofilm, and surface film samples, which potentially allows for less expensive, less invasive, and more efficient sampling of organisms that are fragile, difficult to capture, and/or difficult to identify.  Applications range from pathogen identification and source tracking to monitoring of invasive or endangered species.  eDNA possesses three characteristics of a good indicator: it is recoverable; it persists for a limited period of time; and it can be associated with organisms of interest.  However, the details of fate and transport of environmental DNA in freshwater systems are not fully understood, and few models exist for quantification of species parameters from recovered material.  Improved understanding of basic factors affecting degradation rates and environmental partitioning will allow better prediction of the optimal locations for sampling, general likelihood of presence, and approximate quantity of organisms for target species of interest.

The endangered Topeka shiner (Notropis topeka), which has been in culture at the University of Kansas Field Station for almost a decade, serves as a model system to address a number of basic questions regarding eDNA in aquatic systems.  For example, where does most eDNA come from?  Where does it go?  How long does it persist under various environmental conditions?  Can eDNA concentration be related to population parameters like numbers of organisms, density, or population health metrics?  Understanding of these factors is critical for development of predictive models.  Results from work in progress will be discussed

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