New Research Develops Reliable eDNA Methodology for Monitoring Aquatic Species Upstream of Water Delivery Facilities

 
Sacramento, CA 2021
 

A new research project aimed at developing an environmental DNA (eDNA) methodology has successfully monitored listed aquatic species upstream of water delivery facilities, improving water supply reliability. The eDNA methodology can detect listed species without capture, handling, and “take” by only using water samples.
 

The project’s central research question was whether monitoring for eDNA in a hydrodynamically complex environment could be used as a tool for determining presence of listed fishes such as Delta Smelt and steelhead. The methods employed included developing a quantitative tool to design sampling and analyzing eDNA data, as well as conducting caged Delta Smelt and steelhead field experiments in a tidal environment to evaluate the effects of tidal action and distance from the DNA source on the quantity of eDNA in a water sample.
 

The quantitative tool developed as part of the project, {artemis}, was written in R and has been made publicly available. It produced less bias than commonly used regression approaches, and the caged fish experiments showed that the natural log of DNA quantity decreased with sampling distance from the cage just as expected.
 

However, the project also highlighted the need to increase the number of samples in tidal-environment applications to compensate for the phenomenon of eDNA plume not being homogenously mixed throughout the water column. Under the range of conditions in which the project worked, Delta Smelt biomass was directly related to the probability of eDNA detection.
 

The eDNA methodology and the validated quantitative tool {artemis} have the potential for field applications such as using eDNA sampling to guide target species capture or identification of listed species approaching a water intake.
This research project is a significant step forward in developing a reliable eDNA methodology for monitoring aquatic species upstream of water delivery facilities, ensuring better water supply reliability.
 

GitHub site: { artemis package }

Publication: doi/full/10.1002/edn3.277