Meeting Abstract
Climate change is leading to rapid changes to ecosystems worldwide. In response to accelerated temperature shifts, to survive many species must acclimate to their shifting thermal environment. We were interested in how climate change will impact a commercially and recreationally important species of fish, Atlantic salmon (Salmo salar). Native to the North Atlantic, these anadromous fish live their first few years in small streams and rivers before migrating to the ocean where they grow to adult size. As climate change alters the thermal environment of their natal streams, we asked how their muscle function will be altered by extended exposure to both warm and cold temperatures. We performed a thermal acclimation study of salmon swimming performance (Ucrit) and muscle function for groups of fish acclimated to 4, 12 and 20o. After swimming performance experiments, muscle mechanics of both fast-twitch or white and slow-twitch or red myotomal muscle bundles were investigated across a range of experimental temperatures. Ucrit did not vary with thermal acclimation when tested at a common experimental temperature (10oC). White muscle displayed modest shifts in function with thermal acclimation, while red muscle showed very little variation. Typically, the fastest contractile properties were observed in the muscle from the 12oC acclimation group. Fish from both coldest and warmest acclimation groups displayed slower kinetics when tests across a range of common experimental temperatures. Overall, Atlantic salmon appear to have limited ability to acclimate across a range of physiologically relevant temperatures, suggesting that climate change will pose of challenge to this already threatened species.
