Winter Movement of Radio-Tagged Juvenile Atlantic Salmon in Northeast Brook, Newfoundland

In winter, juvenile Atlantic salmon Salmo salar move to habitat with increased water depth, reduced water velocity, and larger substrate than in their preferred summer habitat and become predominantly nocturnal. However, knowledge of their behavior within wintering habitat is limited. In this study, radiotelemetry was used to investigate winter movement, activity, and habitat preference of juvenile Atlantic salmon. Data on fish position, corresponding habitat variables, and fish activity (i.e., active or nonactive) were collected on 14 d and 9 nights between 21 January and 10 February 1999. Due to mild winter air temperature, the river remained ice free during sampling, and water temperature ranged from 0.5°C to 1.4°C. Habitat preference differed between active and nonactive states. Fish were observed in an active state only at night and preferred smaller substrate and higher water velocity than the same fish in a nonactive state. Selecting higher water velocity while active may give fish access ...