Global environmental change threatens the biodiversity and function of all ecosystems (Sala et al., 2000), and Arctic ecosystems are no exception (Meltofte, 2013). Maintenance of freshwater biodiversity is crucial to the healthy function of Arctic ecosystems and to the preservation of ecosystem services provided to humans (Culp et al., 2012; Socolar, Gilroy, Kunin, & Edwards, 2016; Wrona et al., 2013). However, Arctic freshwater ecosystems are vulnerable to multiple global and localised stressors, including climate warming, biological invasions, and direct anthropogenic disturbance (Rolls et al., 2018; Wrona et al., 2013). Scenario analyses of changing biodiversity show that Arctic ecosystems are currently overwhelmingly influenced by climate change when compared to other factors (e.g. land use, biotic exchange, carbon dioxide, and nitrogen deposition), but this may change as global economic interests increase in Arctic regions (Hovelsrud, Poppel, van Oort, & Reist, 2011; Huntington et al., 2007). The effects of each of these stressors alone and in combination, although often difficult to determine (Hayden, Myllykangas, Rolls, & Kahilainen, 2017; Schindler & Smol, 2006; Wrona et al., 2006), may impact the fishes living in Arctic streams and lakes. Ongoing and future changes in climate and land use will probably have profound effects on fish biodiversity (Rolls et al., 2018; Wrona et al., 2006).