Study: Hatcheries Can Disrupt Steelhead Navigation

Jun 3, 2014

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 may be distorted by iron pipes.

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

Lead author Nathan Putman, a federal scientist, says the results may explain why so many hatchery fish stray from their native rivers and have a lower rate of ocean survival than wild fish.

The study is published in Wednesday's edition of the journal Biology Letters.