NAMERS: a purpose-built reference DNA sequence database to support applied eDNA metabarcoding

Applied eDNA metabarcoding is increasingly being considered as a tool to inform management decisions, regulations, or policy development. Because these downstream considerations are coming to the forefront of eDNA applications, optimizing workflow elements is essential to increasing standardization, efficiency, and competency of metabarcoding results. Reference DNA sequences are critical workflow elements that currently lack consistent approaches to generating, curating, or publishing. We present a complete mitochondrial genome and nuclear ribosomal DNA cistron reference DNA sequence library for 92% of the freshwater fish species of British Columbia, Canada. This resource is published as the Novel Applied eDNA Metabarcoding Reference Sequences (NAMERS) repository (https://namers.ca), a user-friendly and interactive website for specialists and non-specialists alike to explore and generate custom reference libraries for taxa and genes of interest. We demonstrate the power of NAMERS for optimization of applied eDNA metabarcoding study design by analyzing the number of primer mismatches and species resolution power of existing metabarcoding markers. NAMERS demonstrates that high quality curated genomic information is within a reasonable reach to meet the increasing demand for actionable eDNA metabarcoding applications. The framework used here incorporating the pillars of accuracy, completeness and accessibility can be applied for new iterations of other reference sequence databases to bring DNA-based monitoring into a new era.