The behaviour and physiology of bull trout (Salvelinus confluentus) and mountain whitefish (Prosopium williamsoni ) relative to short-term changes in river flo

The purpose of this thesis was to evaluate the sub-lethal responses of bull trout (Salvelinus confluentus) and mountain whitefish (Prosopium williamsoni) relative to unsteady river flows. Within-hour changes in river flow did not elicit hyperactive responses in either fish which suggested that hydropeaking was no more energetically costly than a stable flow regime. Considering that bull trout were able to maintain position for periods of time without beating their tail and reach-scale movements were depressed at high discharge, they were not at risk of washing out of the study reach. The majority of the variance in mountain whitefish swimming muscle activity was not related to the discharge hydrograph and blood physiology provided no evidence of a stress response or anaerobic swimming. Taken together, these results suggested that the activity metabolism portion of the energy budgets of these fish are not modulated by hydropeaking; further studies should examine feeding and growth.