Study: Steelhead 'Map Sense' Thrown Off By Iron

"GRANTS PASS, Ore. — A new study suggests steelhead trout can have trouble using the Earth’s magnetic field to navigate if they were raised in a hatchery, where the field can be distorted by iron pipes.

Scientists at the Oregon Hatchery Research Center in Alsea raised two sets of fish: one outside the hatchery with a natural magnetic field, and one inside the hatchery, where instruments showed the field was distorted.

Fish raised outside the hatchery oriented themselves to changes in the magnetic field, but fish raised in the hatchery’s distorted magnetic field did not."

Jeff Barnard reports for the Associated Press June 4, 2014.