Research reportMosquitofish (Gambusia affinis) responds differentially to a robotic fish of varying swimming depth and aspect ratio

- The response of mosquitofish shoals to a robotic fish is studied.
- Mosquitofish are not attracted by bioinspired robotic fish.
- A robot with elongated aspect or swimming at a middle-depth repels mosquitofish.
- Fish cohesion is not influenced by the robot' visual features.
- The behaviour of social invasive fish species can be modulated using robots.

In this study, we explore the feasibility of using bioinspired robotics to influence the behaviour of mosquitofish (Gambusia affinis), a social freshwater fish species that is extensively studied for the ecological issues associated with its diffusion in non-native environments. Specifically, in a dichotomous choice test, we investigate the behavioural response of small shoals of mosquitofish to a robotic fish inspired by mosquitofish in its colouration, shape, aspect ratio, and locomotion. Our results indicate that the swimming depth and the aspect ratio of the robotic fish are both determinants of mosquitofish preference. In particular, we find that mosquitofish are never attracted by a robotic fish whose colouration and shape are inspired by live subjects and that the degree of repulsion varies as a function of the swimming depth and the aspect ratio.