Meeting Abstract
Maneuvering is an important component of routine swimming, playing important roles in predator avoidance, prey capture, and navigation. In many squid, multiple propulsive systems and control surfaces are used independently or in concert to perform impressive unsteady maneuvers, such as rapidly changing swimming direction and quickly adjusting trajectory or orientation according to predator or prey behavior. Despite its ecological significance, little is known quantitatively about turning performance in squid, especially metrics like angular velocity and turning radius and the linkage between propulsor/control surface movements and hydrodynamics. To better understand maneuvering in squid, we studied brief squid Lolliguncula brevis and longfin squid Doryteuthis pealeii as they performed turns in an observation tank using high-speed videography and volumetric (3D) velocimetry. A range of turning categories were identified, ranging from tight rotational (short turning radius) maneuvers with prominent vortex ring flows to broader translational (large turning radius) turns associated with longer, often less-defined regions of concentrated vorticity. Both the fins and pulsed jet were integral for turning, but their relative contributions to rotational torque changed with turning category. Differences in propulsor and control surface usage between the two species correlated with performance metrics, such as angular turning velocity and length-specific turning radii. Our results suggest that the fins and jet work in tandem to achieve a wide diversity of turns and interspecific differences in propulsive/stabilizing systems can affect turning performance.
