A new study has found that salmon use the Earth's magnetic field to migrate.
A team of scientists presented last year evidence of a correlation between the migration patterns of ocean salmon and the Earth's magnetic field, suggesting that it may help explain how the fish can navigate across thousands of miles of water to find their river of origin.
This week, scientists confirmed the connection between salmon and the magnetic field following a series of experiments at the Oregon Hatchery Research Center in the Alsea River basin.
Researchers exposed hundreds of juvenile Chinook salmon to different magnetic fields that exist at the latitudinal extremes of their oceanic range. Fish responded to these "simulated magnetic displacements" by swimming in the direction that would bring that toward the center of their marine feeding grounds.
The study was funded by Oregon Sea Grant and the Oregon Department of Fish and Wildlife.
"What is particularly exciting about these experiments is that the fish we tested had never left the hatchery and thus we know that their responses were not learned or based on experience, but rather they were inherited," Nathan Putman, a postdoctoral researcher at Oregon State University and lead author on the study, said.
"These fish are programmed to know what to do before they ever reach the ocean," he added.
In essence, fish possess a "map sense" determining where they are and which way to swim based on the magnetic fields they encounter.
The study is set to be published in the forthcoming issue of Current Biology.
