Cardiorespiratory responses of seawater-acclimated adult Arctic char ( Salvelinus alpinus ) and Atlantic salmon ( Salmo salar ) to an acute temperature increase

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Authors: Penney, Chantelle M., Nash, Gordon W., Gamperl, A. Kurt
• Other Authors: Tierney, Keith
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2014
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; Arctic; Atlantic salmon; Climate change; Salmo salar; Salvelinus alpinus
• Online Access: http://dx.doi.org/10.1139/cjfas-2013-0569; http://www.nrcresearchpress.com/doi/full-xml/10.1139/cjfas-2013-0569; http://www.nrcresearchpress.com/doi/pdf/10.1139/cjfas-2013-0569

In this first study examining the thermal tolerance of adult Arctic char (Salvelinus alpinus) acclimated to seawater, we measured their critical thermal maximum (CT Max ) and several cardiorespiratory parameters (oxygen consumption (MO 2 ), heart rate (f H ), stroke volume (S V ), cardiac output (Q), ventilatory frequency (V F ), opercular pressure (P O ), and ventilatory effort (V E )) when exposed to a temperature increase of 2 °C·h −1 . Further, we directly compared these results with those obtained for the eurythermal Atlantic salmon (Salmo salar) under identical conditions. There was no significant difference in cardiorespiratory values between the two species at their acclimation temperature (9.5–10 °C). In contrast, the slope of the MO 2 –temperature relationship was lower (by 27%) in the char as compared with that in the salmon, and the char had significantly lower values for maximum f H (by 13%), maximum MO 2 (by 35%), absolute metabolic scope (by 39%), and CT Max (approximately 23 versus 26.5 °C, respectively). Although not a focus of the study, preliminary data suggest that interspecific differences in mitochondrial respiration (oxidative phosphorylation), and its temperature sensitivity, may partially explain the difference in thermal tolerance between the two species. These results provide considerable insights into why Atlantic salmon are displacing Arctic char in the current era of accelerated climate change.