Meeting Abstract
Fishes exhibit a range of body shapes, with each different shape having its own hydrodynamic effect on swimming performance. However, morphology alone does not drive performance; rather, performance emerges from the integration of morphology with kinematics. Thus, in order to determine how fishes with different body shapes perform and what causes performance differences, it is important to examine kinematics and morphology along with metrics of swimming performance. I recorded fin and body kinematics of three differently shaped species of neotropical cichlids: Cichla ocellaris, a fish with stereotypical cruising morphology; Symphysodon aequifasciatus, a laterally-compressed species with stereotypical maneuvering morphology; and Crenicichla saxatilis, a torpedo-shaped fish with stereotypical acceleration-specialist morphology. Kinematics were recorded at a range of speeds starting from 0.5 L/s and increasing by 0.2 L/s every 15 minutes until burst and coast swimming was observed. As measures of performance, gait transition (where observed) and maximum sustainable speeds were recorded. The different species used different kinematic strategies for increasing speed. Cichla used a typical subcarangiform transition from labriform to undulatory swimming, decreasing pectoral fin beat frequency and increasing caudal fin beat frequency with speed. Symphysodon and Crenicichla increased both caudal and pectoral fin beat frequency to increase speed, without ever exhibiting a clear gait transition. These results reinforce the idea that there is no one-to-one mapping between morphology and kinematics. Even very differently shaped fishes can use similar kinematics, as is the case for Symphysodon and Crenicichla.
