An investigation of the geomagnetic imprinting hypothesis for salmon

作者：Bracis Chloe^*; Anderson James J

来源：Fisheries Oceanography, 2012, 21(2-3): 170-181.

DOI：10.1111/j.1365-2419.2012.00617.x

• magnetic
• magnetoreception
• migration
• Chinook
• salmon
• Onchorhynchus
• tshawytscha
• imprint
• homing
• Pacific
• fish

Although evidence indicates that salmon could use geomagnetic cues in their high seas homing migration, the underlying behavioral strategy salmon apply to navigation cues is poorly understood. In one hypothesis, salmon imprint on the magnetic field when entering the ocean as juveniles and use the difference between the local and imprinted fields to navigate home. In this paper we demonstrate that simple behaviors incorporating this cue difference, to approach the isoline matching the imprinted magnetic value and then to follow along the isoline to the river mouth, are sufficient to guide spring Chinook salmon (Oncorhynchus tshawytscha) to the Columbia River. We model homing trajectories of salmon, combining ocean currents and fish swimming behaviors. Although the magnetic field inclination angle is a more robust cue than magnetic field intensity, both are sufficient to direct fish to the river mouth from a wide region of the Northeastern Pacific. The threshold defining the transition between the isoline approach and follow behaviors is the main factor determining successful homing trajectories. Small thresholds are more successful, meaning the approach behavior predominates until the fish is near the isoline intersecting the river mouth. The follow behavior swim heading can compensate for magnetic field changes, and the directed migration start date determines the longitudinal center of successful starting locations. This analysis suggests that salmon from ocean habitats may approach their home river in a narrow migration corridor along a magnetic field isoline.

• 出版日期2012