The contribution of the body, pectoral fins and ribbon fin to turning in a gymnotiform swimmer


SOCIETY FOR INTEGRATIVE AND COMPARATIVE BIOLOGY
2021 VIRTUAL ANNUAL MEETING (VAM)
January 3 – Febuary 28, 2021

Meeting Abstract


105-2  Sat Jan 2  The contribution of the body, pectoral fins and ribbon fin to turning in a gymnotiform swimmer Hawkins, OH*; Ortega-Jimenez, V; Sanford, C; Kennesaw State University, Kennesaw, GA; Kennesaw State University, Kennesaw, GA; Kennesaw State University, Kennesaw, GA ohawkin1@students.kennesaw.edu

Turning is an ecologically important maneuver in fishes as it is used in prey detection, predator avoidance, and the navigation of complex environments. Fishes with traditional control surfaces mostly use body bending and pectoral fins to turn. Less well known is how fishes with atypical control surfaces facilitate turning. We investigated the weakly electric Black ghost knifefish (Apteronotus albifrons: Gymnotidae) with an atypical control surface, the anal or ribbon fin. This fish is well known for maneuvering easily using this ribbon fin. To investigate how a fish with an atypical control surface performs turning maneuvers, we filmed A. albifrons using high speed videography. We captured three classes of maneuvers: steady forward swimming, small turns, and large turns. To assess which control surfaces (i.e., the body, ribbon fin, pectoral fins) contribute to turning maneuvers, we used 3D kinematic analysis. The body of turning individuals exhibits less pitch on average than steady forward swimmers. As expected, the average body bending coefficient is higher during turning compared to that of straight swimming individuals . The average pectoral fin flapping frequency, pectoral fin amplitude, ribbon-fin wave speed, and ribbon-fin frequency for turning individuals are higher than individuals swimming straight. All three control surfaces contribute to turning maneuvers. The increased frequency of pectoral fin flapping as well as the high ribbon-fin frequency and wave speed suggest they are critical drivers for turning maneuvers.

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