The contribution of the pectoral fins, body, and the ribbon fin to turning maneuvers of a gymnotiform swimmer
Date of Award
Master of Science in Integrative Biology (MSIB)
First Committee Member
Second Committee Member
Turning is an ecologically important maneuver in fishes as it is used in prey detection, predator avoidance, and to navigate complex environments. Fishes with traditional control surfaces primarily use body bending and pectoral fins to turn. However, little is known about how fishes with atypical control surfaces facilitate turning. This study investigated the weakly electric Black ghost knifefish (Apteronotus albifrons: Apteronotidae) with an atypical control surface, namely a ribbon fin. To investigate how a fish with an atypical control surface performs turning maneuvers, A. albifrons was filmed performing small and large turns and during steady swimming using high speed videography. 3D kinematic analysis of the body, pectoral fins, and ribbon fin revealed that pitch angle, ribbon fin amplitude, and asynchronous movements of the pectoral fins dominated steady swimming while ribbon fin wavelength, frequency, wave speed, and pectoral fin flapping frequency contributed to both small and large turns. Digital particle image velocimetry (DPIV) showed that the ribbon fin generates larger counter rotating vortices during turning than is produced during steady swimming. All three control surfaces contributed to steady swimming and large turns while small turns relied mostly on movements of the pectoral and ribbon fins. Given the contribution of the ribbon fin during small and large turns in A. albifrons, the role of atypical control surfaces is likely more important than previously assumed.