Behavior and Growth of Juvenile Atlantic Salmon (Salmo salar) and Three Competitors at Two Stream Velocities

In a laboratory stream juvenile Atlantic salmon (Salmo salar), common shiners (Notropis comutus), blacknose dace (Rhinichthys atratulus), and white suckers (Catostomus commersoni) apparently preferred habitats that simulated their natural ones. Only salmon and one sexually mature male shiner defended territories. Dace were gregarious and nomadic, shiners tended to school in open water, and suckers were asocial bottom browsers.No competitive advantage or disadvantage was apparent between species in capturing drift food and growing at fast and slow stream velocities. However, salmon, because of their aggressive territorial behavior, successfully competed for and reduced presence of other species in their preferred boulder habitat.