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Veilleux, H., McPherson, M.*, Cott, P., Poesch, M., S., Glover, C., and G. Goss. (In Press) Environmental DNA as a tool to detect Arctic grayling and their habitat preferences in the Northwest Territories, Canada. Arctic Science.

Abstract: 

Environmental DNA (eDNA) assays represent a non-invasive approach for biomonitoring. To assess Arctic grayling (Thymallus arcticus) populations in the Little Nahanni watershed of Northwest Territories (NWT), Canada, an eDNA assay that has been previously validated for use in fish of the Beringia lineage was used in conjunction with traditional survey methods (i.e., electrofishing). Forty-six 100-metre reaches of streams were assessed in August 2015. The assay successfully detected Arctic grayling of the Nahanni lineage, with an eDNA signal recorded at each of the 17 sites in which Arctic grayling were observed by traditional fish surveys, but also at 3 of the 29 sites where Arctic grayling were not observed. The presence of eDNA was related to habitat metrics via Random Forest and correlation analyses. Riffles and water temperature were identified as being predictive of Arctic grayling eDNA abundance; however, no significant relationship between eDNA abundance and biomass proxies (fish abundance and fork length metrics) could be established. The high congruence between traditional approaches and eDNA surveys suggests adoption of the latter method will enhance the temporal and spatial acuity of biomonitoring, thereby improving field assessment of Arctic grayling populations and contributing towards more effective conservation management of this species.

Citation: Veilleux, H., McPherson, M., Cott, P., Poesch, M., S., Glover, C., and G. Goss. (In Press) Environmental DNA as a tool to detect Arctic grayling and their habitat preferences in the Northwest Territories, Canada. Arctic Science.

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McPherson, M.*, Lewis, J.B., Cott, P.B., Baker, L.F., Mochnacz, N.J. Swanson, H.K., and S. Poesch. (2023) Habitat use by fluvial Arctic Grayling (Thymallus arcticus) across life stages in northern mountain streams. Environmental Biology of Fishes 106: 1001-1020.

*Lab members: Morag McPherson and Mark Poesch. Check out opportunities in the lab!

McPherson, M.*, Lewis, J.B., Cott, P.B., Baker, L.F., Mochnacz, N.J. Swanson, H.K., and S. Poesch. (2023) Habitat use by fluvial Arctic Grayling (Thymallus arcticus) across life stages in northern mountain streams. Environmental Biology of Fishes 106: 1001-1020.

Abstract:

Northern aquatic ecosystems face increasing pressures from climate change and natural resource development.  The Arctic Grayling (Thymallus arcticus) is a widely distributed, northern freshwater fish which can be vulnerable to such pressures. There remains a paucity of information on life stage requirements through most of the species’ range to reliably map and manage habitat to protect populations into the future. We sought to characterize fluvial Arctic Grayling distribution among mountain streams and determine habitat characteristics that habitat use across life stages. Sampling was conducted at 183 sites across the Little Nahanni River watershed to collect information on fish distribution and reach-scale habitat parameters. Arctic Grayling were collected for biological analyses of age, size, weight, and reproductive development. Based on age and size-classes there were four distinct post-emergence life stages: YOY, juvenile, sub-adult and adult. YOY Arctic Grayling were found exclusively in low elevation (<1000 m) streams, flat-water habitat dominated by silty-sand substrate with average water temperatures >10oC. Similarly, juvenile Arctic Grayling occupied low elevation, warm water stream habitat, but associated strongly with run habitats. Sub-adult Arctic Grayling, the most widely distributed life-stage, were found associated with riffle, pool, and cascade-boulder habitats. Adults occupied high elevation (>1200 m) habitats that were cold (mean stream temperature = 7oC), and had higher proportions of pool and boulder habitat. The dynamic nature of Arctic Grayling habitat use in mountain streams highlights the need to consider habitat complexes at the watershed scale when defining species life stage requirements, managing habitats, monitoring populations, and assessing potential impacts. Keywords: Climate Change; Water Stress; Biodiversity; Preservation.

Citation: McPherson, M., Lewis, J.B., Cott, P.B., Baker, L.F., Mochnacz, N.J. Swanson, H.K., and S. Poesch. (2023) Habitat use by fluvial Arctic Grayling (Thymallus arcticus) across life stages in northern mountain streams. Environmental Biology of Fishes 106: 1001-1020. 

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Pandit, S.N.*, Koriala, L., Maitland, B.M*, Poesch, M.S., and E. Enders. (2017) Climate change risks, extinction debt, and conservation implications for an endangered freshwater fish Carmine Shiner (Notropis percobromus). Science of the Total Environment 598: 1-11.

*Lab members: Morag McPherson and Mark Poesch. Check out opportunities in the lab!