Scientists Begin to Unravel Mystery of Marine Animals’ Migration

Hatchling loggerhead turtles, such as this one, imprint on the magnetic field of their birthplace. (Photo credit: Ken Lohmann, University of North Carolina at Chapel Hill)

Scientists at the University of North Carolina-Chapel Hill are working to unravel the mystery of how (and why) some marine animals return to where they were born to reproduce. For example, some salmon migrate over 1000 miles from the ocean upriver to their spawning grounds. Young loggerhead turtles from the North Atlantic migrate over 9000 miles before returning to the North American coast to reproduce.

Dr. Kenneth Lohmann, a professor of biology in the College of Arts and Sciences, and his team of researchers theorize that marine animals imprint on the magnetic field of the home area where they are born, and use differences in Earth’s magnetic field to return to their birthplace when it comes time to reproduce. Earth’s magnetic field differs across the globe, meaning that different areas of Earth have a different magnetic “fingerprint.” In addition, different regions of the ocean have slightly different magnetic fields, which allows migrating marine animals to home in on their place of birth.

Scientists think that learning more about how and when marine animals imprint on Earth’s magnetic field will help in future conservation projects. For example, scientists might be able to use knowledge of magnetic fields to direct sea turtles to protected areas, or re-establish salmon populations in rivers.

The full results of the scientists’ research are reported in latest edition of Proceedings of the National Academy of Sciences. Lohmann co-authored the paper along with UNC researchers Dr. Catherine Lohmann, a biology lecturer, and Nathan Putman, a graduate student in the biology department. The study was funded by the National Science Foundation.

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  1. Freddy Macpherson says

    but what does it all mean???

  2. i heart marine life

  3. what happens if they don’t come back to the same place to reproduce?

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