Meeting Abstract
Maneuvering turns are used by many fishes to navigate complex environments. Despite their prevalence in real-world situations little is known about the kinematics and mechanics of this behavior. We examined turning in zebrafish, a species that, as a model organism, can be investigated with a wide range of genetic and molecular approaches. We used high-speed imaging to film the fish from dorsal and lateral views as they turned around a 90° corner in a filming tank. Turns had two distinct kinematic stages. During stage 1 the body curved to one side and the head rotated. Often at the beginning of this stage the fish pivoted around the pectoral fin on the inside of the turn. In many trials stage 1 included a downward motion of the fins, which was associated with the fish rising in the water. During stage 2 the body straightened and propelled the fish out of the turn while the head held the orientation achieved at the end of stage 1. We found that turns could be categorized into three classes based on gaps in the distribution of turn angles. In shallow turns (below approximately 20°) the pectoral fin on the inside of the turn always adducted first and its pivot duration was short. The majority of turns fell into the intermediate class (between 20° and 45°). The coordination of fin movements in this class was more variable than in the others and the pivot duration was longer. Rising during both shallow and intermediate turns was common. Fish performing tight turns (above approximately 45°) had the shortest pivot durations and we did not observe rising in association with pectoral fin movement. Otherwise, the fin movement was similar to that of the intermediate trials. This study provides evidence that turning can be divided into classes based on turn angle, and that these classes differ in pectoral fin and body movements.
