SZYMIK, Brett G*; SATTERLIE, Richard A; Arizona State University; University of North Carolina at Wilmington: A Three-dimensional Kinematic Analysis of Pteropod (Clione limacina) Swimming at Different Speeds

The pteropod mollusk Clione limacina swims by flapping a pair of wing-like parapodia. Clione is negatively buoyant, and in order to keep from sinking, it demonstrates a tonic swimming behavior (“slow swimming”) whereby it rhythmically flaps its parapodia. Since it orients the long axis of its body perpendicular to the surface of the water, Clione‘s slow swimming is effectively a hovering behavior. Increases in swim speed (to “fast swimming”) are observed as an escape response as well as during feeding and can be elicited by a touch to the tip of the tail. This change in speed is abrupt, and the increase in locomotory speed from slow swimming to fast swimming has been described as a “change of gears”. With the apparent existence of two distinct locomotory behavioral states, we have looked to Clione as a model animal to study the neural and biomechanical aspects behind changes in locomotory speed and changes in gait. Our interest in Clione‘s rather unique form of swimming–a veritable underwater flight–has fueled this as well. Here, we present three-dimensional kinematic data of slow and fast swimming Clione limacina. Data were taken from high-speed videos of tethered animals.