The Effects of Flow Speeds on Smooth Pursuit Tracking and Active Sensing Movements of Weakly Electric Fish

Weakly electric fish employ refuge-tracking behavior to survive, seeking and utilizing hiding places to shield themselves from predators and unfavorable environmental conditions. This adaptive mechanism enables them to minimize the risk of predation, maintain optimal electrocommunication, and adapt to changing surroundings. While studies have explored smooth pursuit tracking and active sensing movements of these fish in stationary environments, limited emphasis has been given to how varying flow speeds in their natural habitats may impact these behaviors. This study addresses this gap by investigating the effects of different flow speeds on smooth pursuit tracking and active sensing movements in weakly electric fish. Active sensing provides sensory data and multisensory integration processes and combines this data to create a holistic perception of the environment. The synergy between these processes is fundamental for enhancing an organism's sensory capabilities and enabling it to adapt and interact effectively with its surroundings. For this study, a specialized experimental setup was designed and built to facilitate refuge-tracking behavior under controlled flow conditions. The experiments involved Apteronotus albifrons fish exposed to visual and complex electrosensory stimuli, which consisted of a sum of sine signals. Data was recorded for different sensory conditions, including variations in flow speeds, illumination levels, and refuge structures. The analysis revealed that increased flow speeds correlated with reduced tracking gain and phase lag in the fish. Additionally, it was observed that active sensing movements were more pronounced in dark conditions. These findings highlight the significant impact of flow speeds on smooth pursuit tracking and active sensing movements and emphasize the importance of studying these behaviors within the context of water flow. Understanding the biological motivations underlying these effects is vital for their potential application in engineering fields. ### Competing Interest Statement The authors have declared no competing interest.