Federal agencies have been adopting as surveillance or monitoring the approach of sampling aquatic environments for DNA fragments (environmental DNA or eDNA) that are shed via slime, skin, scales, blood or feces to the environment to then match those fragments to aquatic species (animals or pathogens) and then assume the animal or pathogen presence can be interpreted as being in that location or posting a disease risk. The National Aquaculture Association (NAA) has pushed back on this approach because the DNA compound can persist in water or sediments, is moved around by currents or wind as a bioaerosol, or can be moved around by other animals (mammals, reptiles or birds) on their surfaces or in their feces having eaten the target animal.

We have suggested a recent National Invasive Species Council (a federal coordinating council created by Executive Order and housed within the Secretary of the Interior’s Office) published white paper, nisc-edna-white-paper-2022-final-2-17-23.pdf (doi.gov), include a section to present these uncertainties, letter attached, which they have declined to do. A recent paper, Whitmore et al. 2023, focused on human DNA being ubiquitous to aquatic environments, paper attached, and described the ethical implications of collecting, analyzing and archiving samples that may reveal considerable information to the individual person level. See Box 1 on page 8 of the paper.

We have informed the National Invasive Species Council of this new issue and requested again their white paper be amended to include an uncertainties discussion and a new section dedicated to the issues raised in the Whitmore et al. 2023 paper.

View NAA's Response Letter

We are also leading a tour of Arkansas fish farms next week that use outdoor pond production systems for U.S. Fish and Wildlife and U.S. Geological Survey representatives to demonstrate and educate the ease in which eDNA an enter farms from the surrounding terrain via animals, wind or water; move about within a farm; “contaminate” live haul trucks or shipping boxes; or be retained in pond sediments from prior production of aquatic animals that are now prohibited or restricted.

Why are we bringing our efforts to your attention?

At least one state natural resource agency has proposed sampling aquaculture farm effluent for eDNA to determine, in their estimation, the presence of invasive aquatic species and pathogens. The NAA opposed this effort and the agency decided not to pursue the sampling. However, the interest in eDNA sampling is very strong (cheap, fast, nondestructive to the environment or disruptive to aquatic animals, and sampling can be completed by anyone with very simple training). This information should be helpful if your state agency decides to adopt a eDNA sampling effort or to inform the NAA so that we may comment in opposition to the adoption of this sampling methodology.