Information on the effect of increased temperature on freshwater and anadromous species is critical in order to understand and mitigate the impacts of climate change. The long-term persistence of coldwater fish species will depend upon their ability to cope with and adapt to increasing temperatures. Our current studies are focusing on the iconic cold-water species, the Eastern brook trout (Salvelinus fontinalis) in which we examine (1) thermal tolerance of trout at the individual and populations level raised under increased thermal regimes using critical thermal maximum (CTmax), (2) the physiology of heat stress using blood parameters, heat shock protein regulation and cardiac characteristics, (3) investigation of acclimation timing and potential for development of “thermal memory”.

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Anadromous salmon are susceptible to changes in river conditions due to the physiological challenge of migrating upriver to spawn. Thermal stress has been implicated in the decline of migrating Alaskan Sockeye and Chinook salmon by increasing pre-spawning mortality. We have developed biomarkers to provide evidence of heat stress in Alaskan salmon populations. Heat shock proteins (HSPs) are highly conserved proteins that help maintain cellular function under conditions of stress, especially warm temperatures, and increase in all tissues in response to thermal stress. While HSPs have been established as a useful marker for thermal stress in laboratory studies, their application to salmonids in the wild is rare. We are also developing methods for measuring cortisol in scales that will be useful for monitoring stress in response to elevated temperature and other environmental stressors.