Perhaps for centuries, people have marveled at the abilities of trout and salmon to navigate long distances. Scientists have theorized the presence of some sort of internal compass in addition to a finely-honed sense of smell as the means to cross open water and return to spawning streams. Now, a team of scientists from Munich, Cambridge and Cal Tech have combined to isolate magnetite-based sensory structures from the nasal passages of rainbow trout.
Magnetite is essentially an iron-rich crystal inside the trout’s nasal cells that orient to magnetic fields just like a compass. The crystal’s magnetic response supports the contention that these fish have a” magnetic sense” that enables them to judge their movement and direction in response to the earth’s weak magnetic field. Salmonids, tuna and some other fishes are likely to have this magnetic sense. This may also help explain how power lines or other sources of magnetic fields could disrupt trout and salmon migrations.
Jack Williams , TU’s Senior Scientist