Progress of migrating Atlantic salmon (Salmo salar) along an estuary, observed by ultrasonic tracking

Adult Atlantic salmon were captured in the Miramichi esturary, tagged with ultrasonic transmitters, and released. Nine fish were tracked for a total of 425 h, spanning 71 flood and ebb tides. There was drifting with the tidal currents, and holding of position relative to land. Fish that achieved overall upstream progress did so by drifting with flood tidal currents and by stemming the ebb currents. Fish which did not achieve upstream progress also drifted with flood tidal currents, but these fish did not stem the ebb currents and dropped back downstream during ebb tides. No differences in movement patterns were apparent for different times of day or wind conditions.