ABSTRACT
Residing within the immense diversity of fishes on earth is an equally impressive array of locomotor abilities. Owing to a strong foundation that has grown in the realm of biomechanics of fish locomotion, the time is ripe for an explosion of ecological and evolutionary work on fish swimming performance. Most research on the ecology and evolution of fish has centered on features of fish design, rather than aspects of locomotor performance. Unsteady swimming refers to more complicated locomotor patterns in which changes in velocity or direction occur, such as fast-starts, rapid turns, braking, and burst-and-coast swimming. External, non-retractable copulatory organs represent obvious alterations of morphology, and can affect swimming performance. Existing evidence for the interaction between the evolution of life histories, diet, body shape and swimming performance suggest that the evolution of locomotor ability does not happen independently of other adaptations.
