Physiological responses to a short-term, environmentally realistic, acute heat stress in Atlantic salmon, Salmo salar

• Published in: FACETS
• Main Authors: Gallant, Melanie J., LeBlanc, Sacha, MacCormack, Tyson J., Currie, Suzanne
• Other Authors: Kidd, Karen
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2017
• Subjects: Atlantic salmon; Salmo salar
• Online Access: http://dx.doi.org/10.1139/facets-2016-0053; http://www.facetsjournal.com/doi/pdf/10.1139/facets-2016-0053

Atlantic salmon populations are declining, and warming river temperatures in the summer months are thought to be a significant contributing factor. We describe the time course of cellular and metabolic responses to an ecologically relevant short-term thermal cycle in juvenile Atlantic salmon. We then examined whether this heat event would affect tolerance to a subsequent heat shock in terms of critical thermal maximum (CT max ). Fish induced heat shock protein 70 in red blood cells, heart, liver, and red and white muscle; whole blood glucose and lactate transiently increased during the heat cycle. In contrast, we observed no significant effect of a prior heat shock on CT max . The CT max was positively correlated with Fulton’s condition factor suggesting that fish with greater energy reserves are more thermally tolerant. Atlantic salmon activate cellular protection pathways in response to a single thermal cycle and appear to cope with this short-term, ∼1 d heat shock, but this challenge may compromise the ability to cope with subsequent heat events.