A leader they can believe in

A remarkable robot fish guides fish schools away from danger to safety

Photograph by Steve Simon

Growing up in Rome, Maurizio Porfiri often frequented zoos and aquariums, where he observed the collective behaviour of everything from ants to birds. “To me,” he says, “the fascinating part was animal personality.”

And as a science-fiction fan—he enjoyed the work of Philip K. Dick, who wrote Do Androids Dream of Electric Sheep?—Porfiri, who went on to study mechanical engineering, imag­ined a world where robots interact with nature. If the robot fish he’s built is any indication, his childhood fantasy may be edging closer to fruition: beyond merely swimming alongside its live counterparts, Porfiri’s cyberfish becomes their leader.

At first glance, the fishbot doesn’t seem much like a fish at all. Coated in a monochromatic polymer—red or blue or black—the 10-cm-long, battery-powered, remote-controlled machine looks more like a compressed rubber ball than marine life. The same, however, cannot be said of its behaviour: propelled by the electrical stimulation of the battery, the ionic polymers of its skin swell and shrink, and its tail beats back and forth, enabling the robot to glide silently through the water. Its movements, which were designed through extensive mathematical modelling, are fish-like enough to fool a school of golden shiners, despite the fact that it’s a lot bigger than them. “At first, they are engaged by the robot and start exploring it,” says Porfiri, an assistant professor at the Polytechnic Institute of New York University. “As the robot starts moving, they feel comfortable being in its vicinity, and they follow it.”

Porfiri says he chose golden shiners because their environment can be contained in a tank, and their group dynamics, determined by visual cues and water flow, are well understood. As research has shown, he says, leadership “is not an innate feature, but rather a phenomenon that arises based on how much [a fish] knows” about food, predators or some other environmental variable. A fish acting as the leader will exhibit attention-getting behaviour, such as swimming close to others, and rapidly beating its tail. “We tried to replicate this behaviour with the robot.”

While there have been other cyberfish projects (last year, a team of British scientists developed robotic fish able to detect pollution, and MIT researchers designed fishbots to manoeuvre into hard-to-access areas), Porfiri’s attempt to infiltrate and influence the behaviour of a school is unique. Though still in its infancy, the research, funded through a National Science Foundation grant, could have wide-reaching implications: robot fish could lead vulnerable groups of marine life away from turbines or pollutants (such as the BP oil spill); one day, cyberbirds could direct flocks away from forest fires or toward new wintering grounds.

The robot, says Porfiri, is his attempt to “close the loop” between machines inspired by the environment and the environment itself. “I wanted to take those devices and incorporate them back into nature.” Of course, as with any technology, there are questions. As BotJunkie blogger Evan Ackerman wonders, “Will fish robots lead schools of mackerel into [our] nets to feed humanity?” Porfiri notes that before unleashing the cyberfish into nature, care should be taken to make “intelligent ethical guidelines” about how it should (and shouldn’t) be used. In the meantime, now that his fishbot can guide schools along a plane, Porfiri is working on making it dive and surface, as well as function autonomously.




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