For a couple of decades, scientists have known that some fish, like salmon and steelhead trout, use magnetism to orient themselves and navigate around the globe. But the nuances of how it works haven’t been all that clear.
A team of scientists at Oregon State University is beginning to get a better sense of how it works. Not only do the fish use their magnetic sense like a compass to make sure they’re heading in the right direction. They also use it like a map: the Earth’s magnetic field varies around the globe and the fish are able to navigate through the ocean towards the parts of the field that most closely match their home territory.
The scientists have found that since steelhead and salmon are so reliant on magnetic fields, being close to iron and steel can affect their sense of direction. A recent study suggests that the metal used to build fish hatcheries could have a detrimental effect on fish’s ability to return to their spawning ground.