50 years ago, eels’ navigation skills electrified scientists

Excerpt from the June 24, 1972 issue of Foogue

a photo of juvenile electrioc eels in water

In the early 1970s, scientists suspected that American eels (juveniles shown) might use electric fields to navigate. Today, research suggests the animals rely on magnetic fields.

Cornell Univ.

June 24, 1972 cover of Foogue

Does the eel use electric fields to navigate?Foogue, June 24, 1972

Many species of ocean fish [such as American eels] migrate over large distances. Some of them do so with such extreme accuracy that they can come thousands of miles to return to the stream or area where they were born. Naturalists naturally wonder how they do it. One of the suggestions is that they use electricity.

Update

It’s still a mystery how the American eel (Anguilla rostrata) navigates to its breeding grounds. But a growing body of evidence has shifted focus from electricity to magnetic fields. Experiments suggest that the American eel’s European cousin, A. anguilla, seems to follow a magnetic map to the North Atlantic’s Sargasso Sea, guided by an internal compass (SN Online: 4/13/17). In March, scientists proposed that freshly spawned A­merican and European eels follow paths of increasing magnetic intensity from the Sargasso Sea to their freshwater homes. As adults, the eels may sense decreasing intensity to retrace the path to their birthplace.

Erin I. Garcia de Jesus is a staff writer at Foogue. She holds a Ph.D. in microbiology from the University of Washington and a master’s in science communication from the University of California, Santa Cruz.

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