Mystery Solved: Salmon Navigate Using Magnetic Field
by Carrie Arnold
Whoever said you can’t go home again has never met a sockeye salmon, which navigates more than 2,485 mi (4,000 km) to spawn in the same stream in which it hatched.
Now, scientists have finally solved how the species accomplishes its navigational feat—the fish uses Earth’s magnetic field to steer itself home.
“To find their way back home across thousands of kilometers of ocean, salmon imprint on [i.e. learn and remember] the magnetic field that exists where they first enter the sea as juveniles,” study leader Nathan Putman, of Oregon State University, said in a statement.
“Upon reaching maturity, they seek the coastal location with the same magnetic field.”
Like several other species of salmon, sockeye hatch in many of the streams and tributaries of the U.S. Pacific Northwest. After hatching, they live and mature in the gravel beds of these freshwater streams for one to three years. Then, the salmon make their way from their freshwater nurseries to the open waters of the Pacific Ocean, where they spend another several years feeding. Eventually the fish make their way back to the streams in which they were born to spawn and begin the cycle anew…
(read more: National Geo)
(photos: T - Tom Quinn, Univ. of Washington; B - Todd Mintz, Your Shot)