Meeting Abstract
Triggerfishes and filefishes in the superfamily Balistoidea power slow steady swimming using oscillations or undulations of their median dorsal and anal fins in a gait termed balistiform locomotion. Most balistoid fishes undergo a gait transition with increasing speed from balistiform locomotion to a gait dominated by body and caudal fin (BCF) contribution. The goal of this study was to examine trends between balistoid morphology, swimming performance and kinematics across this gait transition. In order to explore these patterns, we analyzed endurance swimming performance and gait transition speeds of 13 balistoid species. This study revealed that the initiation of the gait transition from balistiform to BCF locomotion ranged from 44% to 94% of the maximum achieved swimming speed. We then conducted geometric morphometric analyses of the fins and bodies of the 13 balistoid species and found that species with large median fins and wide caudal peduncles tend to use the balistiform gait for a larger percentage of their maximum swimming speed. Finally, we performed 3D kinematics experiments on 4 balistoid species spanning the range of observed gait transition speeds. These fishes were filmed with 3 high-speed cameras while swimming at multiple speeds in order to quantify diversity in dorsal, anal and caudal fin kinematics across the gait transition using a recently described method in which propulsive contribution of each fin is calculated as a function of its frequency and amplitude at each swimming speed. We found multiple distinct gait transition patterns and differences in fin kinematics and coordination between species, indicating that balistoid fishes adopt several gait transition strategies to achieve efficient, high-speed locomotion. NSF GRFP and NSF 1541547.
