Does the Journey Affect the Destination? eDNA Metabarcoding Methods and Their Influence on Downstream Results.

O'Donnell, Tim¹, Carly McCall¹, Amanda Davis², John Logan² , Dylan Comb¹, ¹Gloucester Marine Genomics Institute, Gloucester, MA, ²MA Division of Marine Fisheries, New Bedford, MA

The concept of environmental DNA (eDNA) metabarcoding is simple: by taking a water sample, one can generate an estimate of biodiversity by detecting multiple species based on the DNA present. While the concept is simple, the process of going from a water sample to a list of species involves many steps, each requiring researchers to makes choices that can ultimately influence the results. When targeting marine fish, the eDNA metabarcoding workflow involves choices related to 1) water collection; 2) Filtration; 3) DNA extraction; 4) DNA amplification; and 5) Data analysis, all of which are continuously evolving given that eDNA metabarcoding has only been in use for about a decade. The rising popularity of eDNA in a short time has generated many methodological options and sophisticated tools. We are exploring the effects of altering several methodological choices in the eDNA metabarcoding workflow for fish biodiversity surveys in coastal New England marine ecosystems and present preliminary results on two aspects: filter pore size and PCR replication during DNA amplification. Results will help guide future projects in the region as we continue to expand the use and integration of eDNA metabarcoding into traditional fisheries surveys.