The goal of this project is to examine to what degree Brook Trout utilize cold-water refugia in warming streams. Stream temperatures will be monitored, and individual fish will be implanted with a tag that records the water temperature fish are experiencing in both historically cold and warm streams. After collecting temperature data fish experience in the streams, the fish will be thermally challenged in a laboratory setting to measure tolerance and stress response to determine if past thermal experience in the wild affects subsequent thermal performance.