Climate change has resulted in increased global water temperatures which can have substantial negative impacts on aquatic species. These temperature changes have been documented not only in oceans and lakes, but also detected in rivers and streams which act as a natal environment for many fish species. These elevated temperatures may be negatively impacting these fish species because their early-life development is temperature-dependent, however potential mechanisms enabling them to adapt to temperature changes are poorly understood. Although maternal stress has been viewed as negatively impacting offspring performance, maternal stress has the potential to dampen the negative effects of elevated temperatures in fish offspring. Recent studies that consider the environmental and life history context of the species suggest that maternal stress may prepare offspring for harsher environments if her offspring share the same harsh environment (the environmental match hypothesis). This signal may induce phenotypic changes in the offspring, enabling an increase in offspring performance and fitness in the stressed environment.I will explore the role of prenatal stress, and the impacts of a stressful natal environment (elevated water temperatures) using the commercially and ecologically important fish species, Chinook salmon (Oncorhynchus tshawytscha). My work aims to determine whether pre-natal stress signal (cortisol, a stress hormone) can optimize offspring performance in a stressful environment (elevated temperatures due to climate change). I have exposed Lake Ontario Chinook salmon eggs to either cortisol or control (no cortisol) treatment. Eggs from both treatments were incubated at current (control environment) or future temperatures (stressful environment—increased by 3°C). I will measure offspring survival and growth and test offspring performance behaviourally and physiologically. Using an integrative approach, this study will allows us to more accurately predict how fish species will react to climate change and test the validity of the environmental match hypothesis within an ecologically relevant context.