Arctic char occurrence and abundance using environmental DNA

• Published in: Freshwater Biology
• Main Authors: Seymour, Mathew, Smith, Antony
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2023
• Subjects: Arctic; Climate change; Salvelinus alpinus
• Online Access: http://dx.doi.org/10.1111/fwb.14063; https://onlinelibrary.wiley.com/doi/pdf/10.1111/fwb.14063; https://onlinelibrary.wiley.com/doi/full-xml/10.1111/fwb.14063

Abstract Our ability to rapidly monitor species is essential for effective resource management and for establishing conservation practices. Current monitoring practices for many fish species are not effective across multiple habitats due to limited resources, permit restrictions, etc. In response, environmental DNA (eDNA)‐based surveying and monitoring programmes are increasingly being developed and applied to meet the growing demands of local regulators and resource managers. The management of Arctic char ( Salvelinus alpinus ), a fish species of economical and societal importance, is a prime candidate for eDNA surveillance as many existing and endemic populations are increasingly threatened by human activity and climate change. Here we applied and tested the effectiveness of using eDNA to survey endemic and transplanted Arctic char populations across north Wales, which represents the southern extent of the Arctic char geographic range. We used a species‐specific quantitative polymerase chain reaction (qPCR) method to assess Arctic char occurrence and estimated the biomass (e.g., abundance) of Arctic char populations for each of the sampled lakes. We found Arctic char present in four of the five lakes with eDNA detection increasing with increasing lake depth. Spatial distribution of Arctic char eDNA detection was not found to be related to spatial location or distance from inlet or outlet for each sampled lake. Arctic char biomass was estimated from eDNA using a range of previously documented eDNA concentrations to biomass measures. Following biomass validation from one lake, we suggested that a mid‐range measure of eDNA to biomass estimate (from the currently available literature) is most likely, resulting in a range of 3,002–42,614 g/ha for our biomass estimates across all sites. Environmental DNA sampling is an effective method for assessing Arctic char populations and offers an informative base for estimating population densities. DNA detection was not spatially structured, which might indicate that the ...