Meeting Abstract
As climate change alters the thermal environment of the planet, interest has grown in how animals may mitigate the impact of a changing environment on physiological function. My students and I have been examining how thermal acclimation alters swimming performance, muscle contractile properties and the gene expression and protein content of myotomal muscle in several cold-water fishes. Thermal acclimation to a warm environment may, for instance, blunt the impact of a warming environment on metabolism by allowing a fish to shift to slower isoforms of metabolically significant proteins such as myosin heavy chain. Our studies of rainbow smelt (Osmerus mordax) and three salmonids – Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis) – reveal a range of responses to thermal acclimation that suggest that the impact of climate change will be highly variable, even amongst related species. Smelt show a substantial thermal acclimation response, with significant shifts in swimming performance, muscle contractile properties and gene expression with changes in environmental temperature. Alternatively, young salmon displayed very little thermal acclimation response, suggesting they may be more substantially impacted by climate change. Brook trout and rainbow trout show intermediate thermal acclimation responses compared with smelt and salmon, with modest changes in muscle function with changes in thermal environment. How variations in thermal acclimation capacity will relate to species survival in the face of climate change remains an open question.
