In this paper, we present a bioinspired robotic fish designed to modulate the behavior of live fish. Specifically, we experimentally study the response of zebrafish to a robotic fish of varying size, color pattern, tail beat frequency, and acoustic signature in a canonical preference test. In this dichotomous experimental protocol, focal fish residing in the center focal compartment of a three-chambered test tank are confronted with pairs of competing stimuli, including various robots and the empty compartment, and their position is observed over time to measure preference. Fish behavior is classified into three main locomotory patterns to further dissect the complex behavior of zebrafish interacting with robots. A total of twelve experimental conditions is studied to isolate the effect of different elements of the robot design and provide general techniques for enhancing the attraction of zebrafish. We find that matching the aspect ratio and the visual appearance of the robotic fish with the target species increases the attraction experienced by zebrafish. We also find that the robot's tail beat frequency does not play a dominant role on fish attraction, suggesting that this parameter could be optimized based on engineering needs rather than biological cues. On the other hand, we find that varying the aspect ratio and coloration of the robot strongly influences fish preference.
"These conditions comprised a single robot swimming by itself, two robots swimming close to each other, and two robots swimming diametrically opposite to each other, all in circular trajectories of fixed size and at three different speeds from a tail-beat frequency of 1 Hz, 2 Hz, and 3 Hz. These tail-beat frequencies corresponded to robot speeds of approximately 2 cm s −1 , 3 cm s −1 , and 4 cm s −1 , respectively, and were selected to explore variations in the reference condition corresponding to 2 Hz, which was considered in the preference tests described in    . Two more conditions to control for the effect of robot presence (NoRobot) and robot movement (0 Hz) were also tested. "
[Show abstract][Hide abstract] ABSTRACT: In animal studies, robots have been recently used as a valid tool for testing a wide spectrum of hypotheses. These robots often exploit visual or auditory cues to modulate animal behavior. The propensity of zebrafish, a model organism in biological studies, toward fish with similar color patterns and shape has been leveraged to design biologically inspired robots that successfully attract zebrafish in preference tests. With an aim of extending the application of such robots to field studies, here, we investigate the response of zebrafish to multiple robotic fish swimming at different speeds and in varying arrangements. A soft real-time multi-target tracking and control system remotely steers the robots in circular trajectories during the experimental trials. Our findings indicate a complex behavioral response of zebrafish to biologically inspired robots. More robots produce a significant change in salient measures of stress, with a fast robot swimming alone causing more freezing and erratic activity than two robots swimming slowly together. In addition, fish spend more time in the proximity of a robot when they swim far apart than when the robots swim close to each other. Increase in the number of robots also significantly alters the degree of alignment of fish motion with a robot. Results from this study are expected to advance our understanding of robot perception by live animals and aid in hypothesis-driven studies in unconstrained free-swimming environments.
Behavioural Brain Research 09/2014; 275. DOI:10.1016/j.bbr.2014.09.015 · 3.03 Impact Factor
"Specifically, several phenotypic varieties of zebrafish, taxonomically listed in the Cyprinidae family together with golden shiner, are known to react differently to computer animations of their conspecifics depending on the similarities of their stripe pattern ,  and color pigmentation . Further studies have corroborated the evidence that zebrafish shoaling preference is affected by visual cues incorporated by both live  and robotic , ,  stimuli. "
[Show abstract][Hide abstract] ABSTRACT: The possibility of integrating bioinspired robots in groups of live social animals may constitute a valuable tool to study the basis of social behavior and uncover the fundamental determinants of animal functions and dysfunctions. In this study, we investigate the interactions between individual golden shiners (Notemigonus crysoleucas) and robotic fish swimming together in a water tunnel at constant flow velocity. The robotic fish is designed to mimic its live counterpart in the aspect ratio, body shape, dimension, and locomotory pattern. Fish positional preference with respect to the robot is experimentally analyzed as the robot's color pattern and tail-beat frequency are varied. Behavioral observations are corroborated by particle image velocimetry studies aimed at investigating the flow structure behind the robotic fish. Experimental results show that the time spent by golden shiners in the vicinity of the bioinspired robotic fish is the highest when the robot mimics their natural color pattern and beats its tail at the same frequency. In these conditions, fish tend to swim at the same depth of the robotic fish, where the wake from the robotic fish is stronger and hydrodynamic return is most likely to be effective.
PLoS ONE 10/2013; 8(10):e77589. DOI:10.1371/journal.pone.0077589 · 3.23 Impact Factor
"In this study, we hypothesize that a robotic fish inspired by mosquitofish in its shape and colouration can be used to influence the behaviour of mosquitofish shoals. To assess this hypothesis, we adopt the canonical choice test considered in    to study zebrafish response to robotic fish, see also   . Specifically, we study the spatial preference and group cohesion of small shoals of mosquitofish confronted to a robotic fish whose position is systematically varied in the water column of the experimental tank and whose aspect ratio is changed from curbed shapes, mimicking a well fed/fertile individual   , to elongated shapes typical of predator species  . "
[Show abstract][Hide abstract] ABSTRACT: 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.
Behavioural brain research 05/2013; 250. DOI:10.1016/j.bbr.2013.05.008 · 3.03 Impact Factor
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