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Optimizing eDNA methods for fish community assessment in Minnesota lakes
Citation:
Larson, C., C. Hatzenbuhler, G. Peterson, E. Pilgrim, J. Hoffman, AND A. Trebitz. Optimizing eDNA methods for fish community assessment in Minnesota lakes. Minnesota Chapter of the American Fisheries Society, St. Cloud, MN, February 11 - 13, 2025. https://doi.org/10.23645/epacomptox.29538008
Impact/Purpose:
The work described in this presentation is motivated by a growing interest in bringing eDNA methods into broad-scale natural resource surveys such as NARS and those conducted by the MN DNR. The target outcome is to determine streamlined sampling methods and data analysis streams that can then be incorporated into larger survey designs.
Description:
Environmental DNA (eDNA) may supplement conventional methods for fish community assessment by measuring fish-specific DNA shed by the fish community in the water of a given ecosystem, enhancing rare species detection and reducing field effort. However, eDNA is not typically paired with physical catch surveys because molecular methods remain under-studied in management contexts and it is unknown how they fit with existing protocols. Therefore, we are developing efficient, scalable methods for eDNA fish surveys in lakes to illuminate fish biodiversity over different habitats and spatial scales. We conducted eDNA fish surveys of 9 lakes in the northern Minnesota with varying habitat complexity and species diversity to determine the number and spatial distribution of samples required to detect maximal species richness compared to conventional approaches. Our 2021 survey (1093 samples from 318 sites) indicated certain species were missed with either conventional or eDNA methods, although there was considerable overlap. In small (26-40 ha) and medium (92-124 ha) lakes, eDNA methods detected as many or more species than conventional methods, with eDNA detecting 88-100% of species from historical observations and physical methods from one year’s field effort detecting 50-100% of species from historical observations. Additionally, eDNA detected 10 species per lake on average that neither ongoing nor historical collection techniques have observed, increasing the probability of detecting new invaders and rare species. The views expressed in this presentation are those of the author(s) and do not necessarily represent the views or policies of the U.S. Environmental Protection Agency.
URLs/Downloads:
DOI: Optimizing eDNA methods for fish community assessment in Minnesota lakes
PRESENTATION.PDF (PDF, NA pp, 2289.124 KB, about PDF)