Fulton, C.J., Johansen, J. L. and Steffensen, J.F.

Abstract: Shallow wave-swept habitats are a major challenge for fish locomotion, where crashing waves produce water flows equivalent to cyclone-force winds. Here we document the exceptional locomotor energetics of Bluelined wrasse (Stethojulis bandanensis), which maintain tuna-like optimum swimming speeds (7.5 lengths per second) while using no more energy than a similar-sized fish swimming four times slower. Such high performance in S. bandanensis arises from their exceptional aerobic scope (22 times above RMR), streamlined rigid-body posture, and wing-like fins that generate lift-based thrust at high speed. Literally flying underwater, Stethojulis and other winged-fin species are the most abundant fish in wave-swept coral reef habitats. We discuss the extreme swimming performance of these reef fishes within the context of other non-scombrid and scombrid fishes, and illustrate how such performance has contributed to their domination of shallow coral reef habitats worldwide.