Secret agent fish? Robot infiltrates aquatic schools, influences their behavior

Robots may be getting more realistic but most of us can still discern a human from a humanoid. Fish, on the other hand, seem easier to fool.

Researchers at École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland have developed an aquatic robot that can infiltrate schools of zebrafish, going so far as to influence their activities. By designing robots to integrate with animal communities, the roboticists hope to unravel these animals’ behavioral and social structures by learning more about how they communicate.

“We wanted to study how a robotic agent can be inserted in a fish shoal, and, when inserted, how this robotic agent could learn how the fish interact, communicate, and take decisions,” Frank Bonnet, an EPFL postdoctoral researcher who worked on the project, told Digital Trends.

The robot has two parts — a magnetic fish and a motor, which is positioned underneath the aquarium and helps propel the robot through the water.

To infiltrate the school, the EPFL team identified characteristics that real fish use to distinguish themselves and designed the robot accordingly. These included physical traits (such as shape, color, and markings) and behavioral traits (including acceleration speeds, size of schools, and how the fish move their tails in transit). Taking the project one step further, the researchers designed the robot to learn and adapt from the behavior of the real fish.

“In somes studies, we compared groups composed of only fish with groups composed of fish and robots,” Bonnet said. “We could show that the two are behaving similarly, which shows that the robots are able to act like fish, and integrate groups of fish. We also used other setups, such as a ring-shaped setup, to show that the robotic agents can influence on the swimming direction preference of the fish.”

EPFL researchers have previously done similar work on cockroach communities, which are willing to accept practically anything that emits specific cockroach pheromones. Fish posed a much more difficult task, but Bonnet already sees how the work will shed light on the nuances of their societies.

“We could already learn which features are relevant for the fish for social integration,” he said. “We can also learn the hierarchy in fish societies, if for instance there are some leaders, and what are the important aspects to become a leader in fish groups, and how the fish are collectively taking decisions.”

A paper detailing the research was recently published in the journal Bioinspiration & Biomimetics.