Pacific salmon that were raised in hatcheries demonstrate the same sense of direction as salmon born in the ocean and adult salmon according to new research conducted by Nathan Putman and colleagues at Oregon State University published in the Feb. 6, 2014, edition of the journal Current Biology.
Salmon that have never been in the ocean were shown to orient themselves in the direction of the native feeding grounds of ocean born salmon based on the Earth’s magnetic field. The salmon are born with a sense of direction that is based on the angle of inclination and magnetic intensity of the Earth’s magnetic field that allows the fish to orient themselves toward the historic feeding grounds that have been used by salmon for thousands of years.
The researchers also found that salmon are sensitive to changes in the Earth’s magnetic field that are undetectable with a compass and could be interfered with by the type of metal used in fish hatcheries.
The research can be used to predict the behavior of salmon and other species that migrate using the Earth’s magnetic field because the Earth’s magnetic field changes relatively slightly.