Dr Jaret Bilewitch1, Dr Gustav Kessel1, Dr Daniel Leduc1, Ms Sadie Mills1, Dr Judy Sutherland1
1National Institute of Water & Atmospheric Research Ltd., Wellington, New Zealand
The marine environment poses challenges for assessments of species diversity using eDNA-metabarcoding due to insufficient reference data for the breadth of taxonomic groups that are present in any sample. Although reference sequences for marine vertebrates have advanced considerably, in Aotearoa/New Zealand many invertebrate and algal taxa have not been extensively sequenced or available sequence data has not been curated for use in sequence assignments. Furthermore, many eDNA reference libraries are constructed from public repository sequences that may be incorrectly identified, due to insufficient taxonomic expertise and the challenging nature of identifying cryptic groups. The recognition of misidentified reference sequences becomes difficult when associated specimens are not archived, preventing morphological or genetic re-examinations that could confirm or revise their taxonomic identity. Together, these sources of error hinder eDNA-based biodiversity monitoring and assessments.
We advocate for curated eDNA reference libraries that are founded upon collections of specimens that have received expert identifications, particularly for those invertebrate and algal groups that are cryptic, speciose or poorly sequenced. To this end, we have engaged a large assemblage of marine invertebrate and algal specialists, a nationally significant collection of marine invertebrates, and a well-curated national collection of marine algae. We give examples of how these resources are being used to produce reliable, replete, and reproducible reference libraries on both regional and national scales for the marine environments of New Zealand. While reference database development is already a priority for eDNA research, linkages to curated permanent collections should be established as standard practice, to future-proof reliability.
Biography:
Dr. Jaret Bilewitch is a molecular biologist at the National Institute of Water and Atmospheric Research (NIWA) in Wellington, New Zealand, where he specialises in genetic and genomic applications for the research and management of fisheries, marine biosecurity and biodiversity. He and his team are responsible for the development and delivery of custom solutions, with technical expertise in assay development, optimisation and validation. Jaret has over five years of experience with genetic and genomic surveys of NZ invertebrates, including molecular systematics for biodiversity discovery and protected species conservation, molecular diagnostics, eDNA metabarcoding, and ddPCR and qPCR applications for detecting, quantifying and genotyping target organisms