Salmonids in hot water: are physiological constraints causing salmonids to die?

The objective of the project is to determine whether physiological constraints are causing salmonids to die in the era of climate change. Human-induced climate change affects species distribution and abundance, with adverse ecological impacts predicted to increase in intensity and frequency in the next century. This increased temperature has direct consequences on the performance of ectotherms, such as fish, which are threatened worldwide due to warming oceans and rivers. When faced with environmental change, organisms may respond by moving, acclimating, or adapting. If acclimation processes do not meet the demands of the new environment, an organism’s vulnerability to this environment is ultimately determined by its adaptive capacity. However, adaptation can be challenging to measure directly in long-lived species. In this case, adaptive capacity may be inferred by comparing important phenotypic traits across reproductively isolated populations of the same species, such as intraspecific variability in thermal tolerance. The mechanisms that create and support these phenotypic differences can also provide insight into the adaptive capacity of the species.