Does the eel use electric fields to navigate? — Science News, 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.
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.