In the early 1950s it was made illegal to “phone catfish” in Alabama. Game wardens had discovered that catfish populations were being decimated using a novel fishing technique. Locals had discovered that they could repurpose the magneto component of old crank-style telephones to send an electric shock through the local fishing holes. The shock stunned fish in the vicinity, causing them to float to surface where they could easily be netted. Catfish were particularly susceptible and populations were being quickly decimated, a testimony to the efficacy of “electrofishing.”

Although now illegal as a method for private or commercial fishing, electrofishing remains an important scientific technique used by ecologists and fish stock managers. Armed with electronic packs, wired poles, nets, and non-conductive rubber boots, ecologists can send an electric charge through confined bodies of fresh water. The fish, rendered temporary immobile, can easily be caught, weighed, and measured. Eventually the effect wears off and the fish swim off unharmed.

Electrofishing has a long and complex history stretching back to the late 19th century. Perhaps the most interesting aspect of this history, at least for historians of oceanography, is that electrofishing has not always been confined to fresh water. In the 1950s and 60s, sea trial experiments were conducted in Germany and in the U.S.S.R. to determine the viability of commercial electrofishing at sea.

In the late nineteenth century, physiologists discovered that electric currents could be used to affect the orientation and movement of fish. It was believed that this discovery might facilitate commercial fishing. In Germany, the effort was led by Jurgen Dethloff, in Russia, by Ivan Vasilevich Nikonorov. Both experimented at sea with the use of electric currents to direct fish schools towards the opening of large suction pipes – essentially enormous vacuum tubes that brought fish directly into a vessel’s hold. It is unclear what became of Dethloff and Nikonorov’s experimental work. Nikoronov went on to co-author a book titled “Electrical fishing: Theory and practice”, while Dethloff seems to have changed career paths. In 1969 Dethloff, along with former V-2 rocket engineer Helmut Gröttrup, co-invented the smart card – now found in everything from bus passes to credit cards, and yes… phone cards. So, next time you make a phone call, consider the strange historical connection between phones and fish.

Click here for a video of electric fishing in England in 1958.