Adaptive divergence in embryonic thermal plasticity among Atlantic salmon populations

• Published in: Journal of Evolutionary Biology
• Main Authors: Côte, J., Roussel, J.‐M., Le Cam, S., Guillaume, F., Evanno, G.
• Other Authors: Plan Loire Grandeur Nature
• Format: Article in Journal/Newspaper
• Language: English
• Published: Oxford University Press (OUP) 2016
• Subjects: Atlantic salmon
• Online Access: http://dx.doi.org/10.1111/jeb.12896; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjeb.12896; https://onlinelibrary.wiley.com/doi/pdf/10.1111/jeb.12896

Abstract In the context of global changes, the long‐term viability of populations of endangered ectotherms may depend on their adaptive potential and ability to cope with temperature variations. We measured responses of Atlantic salmon embryos from four populations to temperature variations and used a Q ST – F ST approach to study the adaptive divergence among these populations. Embryos were reared under two experimental conditions: a low temperature regime at 4 °C until eyed‐stage and 10 °C until the end of embryonic development and a high temperature regime with a constant temperature of 10 °C throughout embryonic development. Significant variations among populations and population × temperature interactions were observed for embryo survival, incubation time and length. Q ST was higher than F ST in all but one comparison suggesting an important effect of divergent selection. Q ST was also higher under the high‐temperature treatment than at low temperature for length and survival due to a higher variance among populations under the stressful warmer treatment. Interestingly, heritability was lower for survival under high temperature in relation to a lower additive genetic variance under that treatment. Overall, these results reveal an adaptive divergence in thermal plasticity in embryonic life stages of Atlantic salmon suggesting that salmon populations may differentially respond to temperature variations induced by climate change. These results also suggest that changes in temperature may alter not only the adaptive potential of natural populations but also the selection regimes among them.