Robotic Predator Fish Hunt Invasive Species.

• Author: Hamilton, Kathleen

Invasive species control is notoriously challenging, especially in lakes and rivers where native fish and other wildlife have limited options for escape. In his laboratory's latest foray into using biomimetic robots to understand and modify animal behavior, Maurizio Porfiri, professor in the School of Engineering at New York University, led an interdisciplinary team of researchers from NYU and the University of Western Australia toward demonstrating how robotic fish can be a valuable tool in the fight against one of the world's most problematic invasive species, the mosquitofish.

Found in freshwater lakes and rivers worldwide, soaring mosquitofish populations have decimated native fish and amphibians, and attempts to control the species through toxicants or trapping often fail or cause harm to local wildlife.

Porfiri and a team of collaborators have published the first experiments to gauge the ability of a biologically inspired robotic fish to induce fearrelated changes in mosquitofish. Their findings indicate that even brief exposure to a robotic replica of the mosquitofish's primary predator--the largemouth bass--can provoke meaningful stress responses, triggering avoidance behaviors and physiological changes associated with the loss of energy reserves, potentially translating into lower rates of reproduction.

"To the best of our knowledge, this is the first study using robots to evoke fear responses in this invasive species," notes Porfiri. 'The results show that a robotic fish that closely replicates the swimming patterns and visual appearance of the largemouth bass has a powerful, lasting impact on mosquitofish in the lab setting."

The team exposed groups of mosquitofish to a robotic largemouth bass for one 15-minute session per week for six consecutive weeks. The robot's behavior varied between trials, spanning several degrees of biomimicry. Notably, in some trials, the robot was programmed to incorporate realtime feedback based on interactions with live mosquitofish and to exhibit...