Scientists have found that sharks use the Earth’s magnetic field as a natural Global Positioning System to navigate journeys that take them great distances across the world’s oceans. This study was published in the Journal Current Biology.Researchers said in their marine laboratory experiments with a small species of shark confirm the long-held assumption that sharks use magnetic fields as aids to navigation behaviour observed in other marine animals such as sea turtles.
Bryan Keller, one of the study authors, said that the study also focuses on why sharks can travel seas and find their way back to feed, breed and give birth, said marine policy specialist. Sharks respond to the magnetic fields. Scientists were not aware that they used it as a natural Global Positioning System. Sharks can travel 20,000 kilometers and return to the same spot again.
Researchers exposed 20 bonnetheads to magnetic conditions that simulated areas hundreds of miles away from where they were caught off Florida. Sharks began to swim north when the magnetic cues made them think they were south of where they should be. Robert Hueter, senior scientist emeritus at Mote Marine Laboratory & Aquarium, who was not involved in the study said that the finding is compelling.
Keller said the study could help inform the management of shark species, which are in decline. A study this year found that the worldwide abundance of oceanic sharks and rays dropped more than 70% between 1970 and 2018.Researchers say the bonnethead’s reliance on Earth’s magnetic field probably is shared by other species of sharks, such as great whites, that make cross-ocean journeys. Scientists said that bonnetheads evolved with a magnetic sensitivity and other traveling sharks did not.