Understanding Brook Trout Persistence in Warming Streams
Cold-water adapted Brook Trout were historically widely distributed – ranging from northern Quebec to Georgia, and from the Atlantic Ocean to Manitoba in the north, and along the Appalachian ridge in the south. However, studies show that due to factors associated with climate change, such as increased stream temperature and changing water flow, the number of streams containing Brook Trout is declining. Although efforts have been made to protect and restore this cold-water fish at local levels, the extent that temperature increases will vary within and across different streams and the ability of Brook Trout to seek cold-water refugia or adapt to these increasing stream temperatures currently remains unclear. 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. This research will be conducted in four small streams located in Western Massachusetts. However, because the work will occur across a large thermal gradient of stream temperatures, the results will be applicable across the entire range of Brook Trout. This project will allow scientists to determine whether Brook Trout are seeking out cold spots in warm streams, adapting to warming conditions, or some combination of the two. Results can help resource managers better understand how Brook Trout populations may persist as stream temperatures continue to rise.