Assessing the potential of environmental DNA for quantitative monitoring of northern pike (Esox lucius) populations

Abstract

Environmental DNA (eDNA) has emerged as a useful tool for species detection and assessment of biodiversity and hold promise for quantitative estimates. This development is of particular interest for species such as northern pike (Esox lucius), an ecologically and socio-economically important apex predator in freshwater and coastal ecosystems, for which suitable monitoring techniques is lacking due to low catchability with traditional monitoring methods.

In this thesis I explore the potential of eDNA to enhance the understanding of pike ecology and provide reliable data on abundance needed for informed management decisions. Relationships between eDNA and biomass of pike were first established under controlled conditions, revealing strong positive linear relationships between eDNA and biomass of juvenile and adult pike. Subsequent field experiments investigating eDNA relationship with pike further found that abundance of pike together with temperature and size of sampled area could explain considerable variation in eDNA concentrations. The temporal eDNA dynamics of spawning run was investigated in an additional field study, demonstrating strong positive linear relationship between eDNA levels and amount and biomass of migrating pike and eDNA levels. Furthermore, I evaluated eDNA methodologies and developed a genetic marker targeting highly repetitive nuclear DNA, providing a stronger eDNA signal compared to mitochondrial assay.

The results from this thesis provide important knowledge and advances towards achieving quantitative estimates of fish populations through eDNA-based monitoring. In addition, the method developments achieved within the thesis through improved sensitivity of eDNA assays enhances detection accuracy of aquatic species. Together, the findings of this thesis will have significant implications for conservation and management of aquatic ecosystems.

Keywords

real-time PCR; chelex; Baltic Sea; abundance; biomass; spawning; temperature; COI; 5S rDNA

Published in

Acta Universitatis Agriculturae Sueciae
2024, number: 2024:85ISBN: 978-91-8046-376-8, eISBN: 978-91-8046-412-3Publisher: Swedish University of Agricultural Sciences

SLU Authors

• Karlsson, Erik

  • Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Ecology
Fish and Aquacultural Science


Publication identifier

DOI: https://doi.org/10.54612/a.7hrsveo886

Permanent link to this page (URI)

https://res.slu.se/id/publ/130480