Thermal performance covaries with environmental temperature across populations of Atlantic salmon (Salmo salar)

Global climate change is projected to have widespread effects that could threaten the viability of natural populations. Physiological processes of aquatic ectotherms critically depend on their thermal environment, such that the optima for performance often correspond to environmental temperatures. G...

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Bibliographic Details
Main Author: Harding Gradil, Kayla J
Format: Text
Language:English
Published: Scholarship@Western 2015
Subjects:
Online Access:https://ir.lib.uwo.ca/etd/3102
https://ir.lib.uwo.ca/context/etd/article/4516/viewcontent/auto_convert.pdf
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Summary:Global climate change is projected to have widespread effects that could threaten the viability of natural populations. Physiological processes of aquatic ectotherms critically depend on their thermal environment, such that the optima for performance often correspond to environmental temperatures. Given predicted changes in aquatic thermal environments, it is increasingly important to understand organism’s underlying physiological mechanisms utilized to cope with these changes. Here, I show that three populations of Atlantic salmon (Salmo salar) are narrowly adapted to their native summer temperatures, such that thermal tolerance is optimized near average temperatures and collapses near peak temperatures. Further, I found evidence of various physiological mechanisms that drive thermal tolerance at the level of the heart, at both the individuals and population level. These results enhance our understanding of thermal adaptation in an ecologically, economically, and culturally important fish.