Using thermal limits to assess establishment of fish dispersing to high-latitude and high-elevation watersheds

Abstract

Distributional shifts of biota to higher latitudes and elevations are presumably influenced by species-specific physiological tolerances related to warming temperatures. However, it is establishment rather than dispersal that may be limiting colonizations in these cold frontier areas. In freshwater ecosystems, perennial groundwater springs provide critical winter thermal refugia in these extreme environments. By reconciling the thermal characteristics of these refugia with the minimum thermal tolerances of life stages critical for establishment, we develop a strategy to focus broad projections of northward and upward range shifts to the specific habitats that are likely for establishments. We evaluate this strategy using chum salmon (Oncorhynchus keta) and pink salmon (Oncorhynchus gorbuscha) that seem poised to colonize Arctic watersheds. Stream habitats with a minimum temperature of 4 °C during spawning and temperatures above 2 °C during egg incubation were most vulnerable to establishments by chum and pink salmon. This strategy will improve modelling forecasts of range shifts for cold freshwater habitats and focus proactive efforts to conserve both newly emerging fisheries and native species at northern and upper distributional extremes.

Tundra be dammed: Beaver colonization of the Arctic

“…Pacific salmon, notably Chum salmon ( O. keta ) and Pink salmon ( O. gorbuscha ), have been observed in many rivers across the North Slope of Alaska. However, it appears that most arctic freshwater ecosystems are too cold for successful salmon reproduction and egg incubation; juveniles are extremely rare (Craig & Haldorson, ; Dunmall et al., ). Rivers on the western North Slope have few perennial water sources, but perennial groundwater sources on the eastern North Slope into northwestern Canada raise winter stream temperatures and locally permit Dolly Varden ( Salvelinus malma ) spawning and reproduction (Craig & McCart, ; Daum, Rost, & Smith, ).…”

“…However, it appears that most arctic freshwater ecosystems are too cold for successful salmon reproduction and egg incubation; juveniles are extremely rare (Craig & Haldorson, 1986;Dunmall et al, 2016).…”

“…Pacific salmon (Oncorhynchus spp.) are shifting their distribution northward, though they have not successfully reproduced in most of Arctic Alaska (Dunmall, Mochnacz, Zimmerman, Lean, & Reist, 2016;Grebmeier et al, 2006;Nielsen, Ruggerone, & Zimmerman, 2013).…”

Growth and reproductive characteristics of rarely observed resident female Dolly Varden (Salvelinus malma malma) in North America

“…obs.) are indicative of salmon accessing and potentially colonizing these Arctic river systems in response to the warming of Arctic marine habitats (see Dunmall et al, 2013Dunmall et al, , 2016. We hypothesize that if Pacific salmon become more frequent in these river systems, they may provide enough allochthonous sources of energy to increase the prevalence and abundance of life-long resident females in Dolly Varden populations that do not currently co-exist with salmon.…”

Warm northern river temperatures increase post‐exercise fatigue in an Arctic migratory salmonid but not in a temperate relative

“…pink and Atlantic salmon; Dunmall et al, 2012;Jonsson & Jonsson, 2009) indicate that they have greater warm tolerance (Clark et al, 2008;Eliason et al, 2011;Penney et al, 2014;Richter & Kolmes, 2005) and capacity for aerobic exercise (Beamish, 1980;Clark, Jeffries, Hinch, & Farrell, 2011) than Arctic char in the present study, While river migration is an essential life-history event for anadromous salmonids, our results taken together with this previous research suggests that current migratory conditions are not likely to restrict range expansion of temperate salmonids. Rather, other critical life-history stages such as early life survival and marine residency will likely be limiting (Dunmall et al, 2016). supervised the progression of the study.…”