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Scientists have confirmed the previous theory that suggested a correlation between the migration patterns of ocean salmon and Earth's magnetic field. The findings carry the potential explanation of how fish can navigate across thousands of miles of water to find their river of origin. 

In a series of experiments conducted at the Oregon Hatchery Research Center in the Alsea River basin, researchers exposed hundreds of juvenile Chinook salmon to different magnetic fields. These magnetic fields existed in the latitudinal extremes of their oceanic range. 

They observe that fish responded to the simulated magnetic displacements" by swimming in the direction that would bring that toward the center of their marine feeding grounds. 

"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," said Nathan Putman, a postdoctoral researcher at Oregon State University and lead author on the study, in a press release. 

"These fish are programmed to know what to do before they ever reach the ocean," he added.

Researchers constructed a large platform with copper wires that ran horizontally and vertically around the perimeter that created a magnetic field when electric current ran through. When fish were presented with a magnetic field characteristic, they seemed to posses the "map sense" that determined where they are and which way to swim. 

"The evidence is irrefutable," said co-author David Noakes of OSU, senior scientist at the Oregon Hatchery Research Center and the 2012 recipient of the American Fisheries Society's Award of Excellence, according to News Medical. "I tell people: The fish can detect and respond to the Earth's magnetic field. There can be no doubt of that."

"What is really surprising is that these fish were only exposed to the magnetic field we created for about eight minutes," Putman added. "And the field was not even strong enough to deflect a compass needle."

The study will be published in the forthcoming issue of Current Biology.