Tradeoffs of a portable, field-based environmental DNA platform for detecting invasive northern pike (Esox lucius) in Alaska

Environmental DNA (eDNA) has improved detection probabilities of aquatic invasive species but lab-based analytical
platforms for eDNA analyses slow opportunities for rapid response. Effective approaches that address this analytical
bottleneck and improve capacity for rapid response are urgently needed. We tested the sensitivity of a portable, field-based
eDNA platform relative to widely used lab-based eDNA approaches for detecting invasive northern pike (Esox lucius) in
eight lakes on Alaska’s Kenai Peninsula. The portable, field-based platform takes ~ 1 hr from sample collection to final results
and uses a field-based DNA extraction kit, a shelf-stable assay, and a portable real-time PCR thermocycler. Lab-based
approaches take days to weeks to months for final results and use lab-based DNA extraction kits, lab-bound assays, and
benchtop real-time thermocyclers. We found that the portable, field-based approach was less sensitive than lab-based
approaches and was more prone to inhibition, thus increasing potential for false-negatives. Until sensitivity and inhibition
issues can be resolved, this portable, field-based approach is best viewed as a complement to rather than a replacement of
standard eDNA lab-based approaches.