Meeting Abstract
The agility of shark maneuvering is often referred to but remains understudied, likely due to challenges associated with calibrating large volume environments for 3D analyses. Studies documenting yaw maneuvering in the horizontal plane (2D) note asynchronous pectoral fin movements during turns in bonnethead sharks and Pacific spiny dogfish, but lack 3D fin kinematics. Previously, we adapted marker-based Video Reconstruction of Moving Morphology (VROMM) for use with two fully submerged cameras in a large volume environment (greater than 1m3) and found that Pacific spiny dogfish predictably protract, supinate, and depress their pectoral fin inside to body curvature while yaw turning. The goals of this study were to further innovated VROMM methods by: 1) expanding the calibrated volume of interest and 2) examining the 3D kinematics of both pectoral fins in the context of maneuvering kinematics during turning. We predict both pectoral fins will rotate with three degrees of freedom, and the inside fin is protracted, supinated, and depressed whereas the outside fin is elevated and retracted. Three Go-Pro Hero5 cameras were fully submerged at a depth of 1.5m with overlapping fields of view. Bonnethead sharks (Sphyrna tiburo) were outfitted with hemi-spherical black bead markers and enticed to maneuver in the filming volume (approximately 3.5m3). The movements of the fin and body were tracked in 3D and reconstructed. We found that bonnethead sharks rotate their pectoral fins in three planes during yaw turns. In all trials, the inside pectoral fin was supinated up to 28o; however, rotation in the other two planes were less consistent. By demonstrating consistently low errors with increasing filming volumes, we propose that development of this technique will lead to precise 3D analyses of larger animals and wild behaviors in the field.
