Trout Passage of Beaver Dams in Two Northern Utah Tributaries

Dams created by North American Beaver (Castor canadensis) have numerous effects on the habitat use of in-stream fish . Pond habitats slow water velocities, provide refugia, and increase the habitat heterogeneity of the stream environment. Whether dams act as movement barriers to salmonids is a topic in need of further research. This study investigates the passage of beaver dams in two northern Utah tributaries by three species of trout. Trout fitted with passive integrated transponder tags were located above and below known beaver dams indicating that passage had taken place. Dam passage for each species revealed that native Bonneville cutthroat trout (Oncorhynchus clarki utah) passed dams more frequently than non-native brown trout (Salmo trutta) or brook trout (Salvelinus fontinalis). Cutthroat trout were identified as being more mobile than the other two species of trout which may help to explain their higher passage numbers. Seasonal patterns revealed that spawning timing appeared to play a role in dam passage. Physical characteristics of individual beaver dams also played a role in the passage of each species. This data suggests that beaver dams are not acting as barriers to movement for cutthroat and brook trout which have both coevolved with North American beaver