Application of eDNA as a tool for assessing fish population abundance

Abstract

Estimating the abundance of organisms is fundamental to the study and management of ecological systems. However, accurately and precisely estimating organism abundance is challenging, especially in aquatic systems where organisms are hidden underwater. Estimating the abundance of fish is critical for the management of fisheries which relies on accurate assessment of population status to maximize yield without overharvesting populations. Monitoring population status is particularly challenging for inland fisheries in which populations are distributed among many individual waterbodies. Environmental DNA (eDNA) may offer a cost‐effective way to rapidly estimate populations across a large number of systems if eDNA quantity correlates with the abundance of its source organisms. Here, we test the ability of quantities of eDNA recovered from surface water to estimate the abundance of walleye (Sander vitreus), a culturally and economically important sportfish, in lakes in northern Wisconsin (USA). We demonstrate a significant, positive relationship between traditional estimates of adult walleye populations (both number of individuals and biomass) and eDNA concentration (R2 = .81; n = 22). Our results highlight the utility of eDNA as a population monitoring tool that can help guide and inform inland fisheries management.

A statistical model for calibration and computation of detection and quantification limits for low copy number environmental DNA samples

“…It is applied to a number of technical replicates to ascertain whether a given gene or DNA fragment is present in a sample and to infer biomass or abundance. While eDNA assessments have so far largely been used for species detection, one ultimate goal of eDNA studies is to quantitate the copy number or concentration of a specific gene or DNA fragment in an environmental sample (Doi et al, 2015, 2017; Goldberg et al, 2016; Klobucar et al, 2017; Lacoursiere‐Roussel et al, 2016; Pilliod et al, 2013; Salter et al, 2019; Spear et al, 2020; Yates et al, 2019).…”

The future of biodiversity monitoring and conservation utilizing environmental DNA

“…Spear et al. (2021) make progress on using the quantities of eDNA measured from water samples of a culturally and economically important sportfish, walleye, from 22 lakes in Wisconsin. Their observed correlation is among the best yet in natural systems and compares with adult population abundance and biomass estimated from mark–recapture surveys.…”

Maturation in Atlantic salmon (Salmo salar, Salmonidae): a synthesis of ecological, genetic, and molecular processes

“…Advances in stable isotope composition analysis can provide more detailed insights into long distance migrations without the need for tagging (Matsubayashi et al, 2020), while decreasing costs for genetic tagging offer opportunities for improving sample sizes via "close-kin mark-recapture" (Bravington, Grewe, & Davies, 2016). Finally, eDNA techniques may be used to determine kinship, sex ratios, population size, and density, although its application for longitudinal studies at the individual level is unclear based on current practices (Adams et al, 2019;Spear, Embke, Krysan, & Vander Zanden, 2020). In the future, studies that incorporate such technological advances should help to reveal how genetic and environmental factors influence maturation over the course of an individual's lifetime.…”