The effect of lake morphometry on thermal habitat use and growth in Arctic charr populations: implications for understanding climate‐change impacts

Abstract

Oxygen stable isotope temperature reconstruction methods were used to estimate mean experienced summer temperatures from growth zones within individual Arctic charr otoliths sampled from lakes with contrasting morphologies but proximate locations. For either lake, otolith‐estimated temperatures were not significantly related to back‐calculated growth. Fish in the smaller lake evidenced an increase in growth with age related to increasing use of cooler thermal habitats, with the use of thermal habitat possibly governed by predation risks. No relationships between age, growth or temperature were observed in the larger lake. Significant negative effects on back‐calculated growth were observed due to increasing air temperatures in the smaller and shallower lake, possibly owing to warmer surface and littoral waters and a limited amount of preferred cool‐water habitat. A similar relationship was not observed in the larger and deeper lake and indicated that resident Arctic charr were not as vulnerable to the impacts of temperature warming, possibly because of better behavioural thermoregulation opportunities in the cooler, deeper lake. Results provide evidence for differing climate‐influenced growth outcomes among proximately located populations, with outcomes likely to depend on the differences among habitats, including lake size and morphometry which may act to influence fish densities in available preferred thermal habitats.

Threats to Freshwater Fisheries in the United States: Perspectives and Investments of State Fisheries Administrators and Agricultural Experiment Station Directors

“…This notion has some scientific support in that climate change is exerting negative effects (e.g., decreased growth and abundance, range contraction) on certain coldwater fishes (e.g.., Bull Trout S. confluentus , Arctic char S. alpinus , Cisco Coregonus artedi ) in northern latitudes (Jacobson et al. ; Murdoch and Power ; Eby et al. ).…”

“…For instance, climate change could have greater impacts on northern fisheries where coldwater/coolwater, climate-vulnerable fishes are relatively prevalent compared to southern states, where water bodies are already relatively warm, fish communities are primarily warmwater, and other concerns (e.g., hatchery-fish production, need for more research) predominate. This notion has some scientific support in that climate change is exerting negative effects (e.g., decreased growth and abundance, range contraction) on certain coldwater fishes (e.g.., Bull Trout S. confluentus, Arctic char S. alpinus, Cisco Coregonus artedi) in northern latitudes (Jacobson et al 2012;Murdoch and Power 2013;Eby et al 2014). In contrast, effects of climate change are neutral or positive (e.g., increased abundance, range expansion) for certain warmwater species (e.g., black bass) in the southern United States (Robillard and Fox 2006;Lynch et al 2016b).…”

Latitudinal variation in growth and otolith‐inferred field metabolic rates of Canadian young‐of‐the‐year Arctic charr

“…Questions remain as to how Arctic charr may ultimately respond to the rate of temperature change associated with climate warming (e.g. Lehtonen 1996;Murdoch & Power 2013;Sinnatamby et al 2013). Nevertheless, the marked phenotypic variation exhibited by the species suggests that phenotypic plasticity is likely to play a key role in defining Arctic charr responses to climate change and may ultimately facilitate genetic adaptation by buffering populations against the immediate negative consequences of environmental change (Fuller et al 2010;Fierst 2011).…”

Fresh Waters, Climate Change and UK Nature Conservation

“…In the UK, coregonid fishes may not survive because the lakes where they occur are too small and vulnerable (Elliott & Bell, 2011;Murdoch & Power, 2013) though translocations to higher and more northern lakes may help (Winfield et al, 2012). Charr may survive only in the cooler Scottish lochs (Winfield et al, 2010a).…”