Wall obstacles impact escape response latency and directionality in Pacific staghorn sculpin

Abstract

Effective escape maneuvers are critical for prey fishes, as fast-start performance has a direct impact on survival in predator-prey interactions. For fish living in structurally complex environments, physical obstacles – such as rocks for bottom-dwelling fishes – may impact fast-start behaviors and overall performance. Incorporating proxies for such obstacles in escape response studies will improve their ecological relevance and offer better insight into the predator evasion tactics employed by these fishes. In this study, we investigated the effects of wall obstacles on escape response in Pacific staghorn sculpin (Leptocottus armatus). We used a mechano-acoustic stimulus to trigger fast-start behaviors and used a high-speed camera to film fish with and without a wall barrier located parallel to the body. We analyzed various kinematic and performance metrics, including responsiveness, escape directionality, turning angle, and turning rate. Preliminary results confirmed a trend observed in previous studies for the escape directionality toward the stimulus to be higher when the obstacle was present. It also highlighted a greater reaction latency in obstacle trials. Additionally, further investigating the impact of fish size, obstacle experience, and stimulus positionality (left versus right) will provide a more holistic understanding of predator evasion for these bottom-dwelling fish.