Depth and temperature preference of anadromous Arctic char Salvelinus alpinus in the Kitikmeot Sea, a shallow and low-salinity area of the Canadian Arctic

Population structure and genomic evidence for local adaptation to freshwater and marine environments in anadromous Arctic Char (Salvelinus alpinus) throughout Nunavik, Québec, Canada

“…Furthermore, Spares et al (2012) maintained that Arctic Char’s diving behavior in Frobisher Bay (Nunavut) could be linked to optimal digestion temperature, suggesting behavioral thermoregulation, a plastic response that could limit local adaptation to temperature (Buckley, Ehrenberger & Angilletta, 2015). Nevertheless, Harris et al (2020) showed seasonality in Arctic Char diving behavior that followed the warming of surface waters in Cambridge Bay (Nunavut), but little year-to-year variation in thermal habitat use despite annual differences in climatic conditions, which could suggest limited plasticity. Sampling sites across our study area displayed considerably different SST conditions: while coastal waters surrounding sampling sites in Hudson Bay reached mean summer SSTs ranging from 5.5 – 7.5°C, Hudson Strait stayed closer to the freezing point (0.5 – 2°C).…”

“…Clucas, Lou, Therkildsen & Kovach, 2019). Arctic Char is expected to use preferred habitats based on temperature, salinity, and prey availability (Spares et al, 2012, 2015; Harris et al 2020). As we averaged near-shore marine conditions around river mouths, this study is limited to broad-scale environmental heterogeneity, which is in line with Fraser et al (2011), who suggest that local adaptation of anadromous salmonids to the marine environment should occur at a larger spatial scale that in fresh water.…”

“…In marine environments, Arctic Char tend to stay near the surface (< 3m), with occasional dives up to 50m (Harris et al 2020; Spares, Stokesbury, O’Dor & Dick, 2012) and preferably use nearshore habitats within 100 km from their natal river’s mouth (Dempson & Kristofferson, 1987; Layton et al, 2020; Moore et al 2016). Thus, one could expect this behaviour to lead to Arctic Char populations experiencing more diverse marine conditions than other anadromous species.…”

Anadromy and marine habitat use of Lake trout (Salvelinus namaycush) from the central Canadian Arctic

“…From 2014-2019, we recorded 77,451 detections, 16,920 of which were considered estuary/marine detections (Table 2 and Supporting Information Figure S2). Ekalluk River S. namaycush were only detected at two estuary stations (stations 07 and 08) and one marine station (station 19 located~9 km from the Ekalluk River estuary, Figure 1b; see Harris et al, (2020) individuals (Figure 2). Mean temperature calculated across all detections was 6.51 C (±2.04S.D.…”

“…On southern Victoria Island in Canada's Central Arctic, there have been accounts of S. namaycush in brackish and marine waters (Coad & Reist 2018) that are characterized by shallow depths and low salinities compared to other marine areas of the Canadian Arctic (Harris et al 2020). It is therefore reasonable to predict that the frequency of S. namaycush anadromy in this region might be higher than that in other Canadian Arctic regions.…”