open access

https://hdl.handle.net/2115/39887

First record of the at-sea swimming speed of a Pacific salmon during its oceanic migration

英語

Foraging behavior

2005-04-28

Inter-Research

Marine Ecology Progress Series

291

307-312

The swimming behavior of the chum salmon Oncorhynchus keta was studied for 53 d of its 67 d oceanic migration from the central Bering Sea to the Japanese coast. We provide the first data on swimming speeds by a homing salmon, recorded at 5 s intervals by a fish-borne time-speed, depth, and temperature logger. Swimming speed rarely exceeded 1.0 m s^[-1], and horizontal swimming speed was 36.4 ± 15.2 km d^[-1]. Cumulative horizontal swimming distance was approximately 2500 km, equivalent to 90% of the minimum distance between the release and recovery sites (2760 km). Swimming depth and speed peaked around dawn and dusk, and there was a smaller peak around midnight. The fish showed sequential up-and-down movement near the thermocline during daytime. Diurnal patterns of movement suggest that homing chum salmon spend a considerable time foraging, and the strategy is different between daytime and nighttime. Our findings indicate that over large distances of ocean, a homing salmon maintains a strong homeward orientation, but that passive transport by favorable water currents may help the migration.

学術雑誌論文

Version of Record

© 2005 Inter-Research

0171-8630

1616-1599

AA10608952