Meeting Abstract
Locomotion dominates energy budgets of animals, and selection should favor behaviors that minimize transportation costs. Recent field work has altered our understanding of the preferred modes of locomotion in fishes. For instance, bluegill employ an intermittent swimming form with 2-3 tailbeats alternating with short glides. Volitional swimming studies in the laboratory with bluegill suggest that the propulsive phase reflects a fixed-gear constraint on body-caudal-fin activity. Anecdotal observations of another centrarchid, the largemouth bass (Micropterus salmoides), suggests they also routinely employ intermittent propulsion in nature. We examined swimming by bass in a static tank in the laboratory to quantify the parameters of volitional locomotion including tailbeat frequency and glide duration across a range of swimming speeds. We found that tailbeat frequency was not related to swimming speed at low swimming speeds. Instead, swimming speed was a function of glide duration between propulsive events, with increasing swimming speed associated with decreasing glide duration. Analysis of the Strouhal number of bass locomotion in the static tank suggests they operate outside of the Strouhal range of peak efficiency. The results offer support for a new perspective on fish locomotion – intermittent swimming is key to understanding minimization of cost of transport.
