SEATTLE, WA - Scientists have long known that spawning salmon use their sense of smell to home in on the exact stream where they WERE born years before. But chemical clues alone cannot explain how salmon find their way home through the vast ocean. Correspondent Tom Banse reports on some marine biologists who theorize that salmon have magnetic sensing ability.

Ken Lohmann is a marine biologist at the University of North Carolina. His specialty is sea turtle migration. His team previously proved sea turtles have an internal compass that they use to navigate back to a nesting area. Now he suggests Pacific Northwest salmon have a similar kind of internal GPS to perform the similar homing feat.

Lohmann: “What we're proposing is that salmon and sea turtles, at the beginning of their lives, learn the magnetic field of their home area, and then retain this information as they migrate far away across thousands of kilometers of ocean. And finally, when it's time for them to return, they can exploit this information to help guide themselves back into the correct part of the world.”

Lohmann and his colleagues detail their theory in a paper published this week in the Proceedings of the National Academy of Sciences. In it, they invite other scientists to suggest ways to prove whether salmon use magnetic navigation.

Copyright 2008 KUOW

Web Extra: Proceedings of the National Academy of Sciences

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