However, nobody knew how salmon managed to know where they were going. Until now that is as biologists this week at Oregon State University's Department of Fisheries produced a new study suggesting that B.C. salmon use magnetic fields in their heads to find their way home in Frazier River spawning grounds.
It's kind of like an internal GPS system. Salmon have a magnetic map in their brains that allow them to sense and navigate where they're going by reading the Earth's magnetic fields. This ability has been found in birds, sea turtles, and even pooping dogs previously. Salmon utilize the ability even if they're juveniles. They're able to sense the intensity and inclination of the magnetic field guiding them on their journey to feeding areas and spawning grounds.