Christopher Fulton1, John Steffensen2, Jacob Johansen3

Indo-Pacific Fish Conference, Fremantle, Western Australia, May 2009 - Talk

Abstract:
Fish living in harsh habitats often display phenotypic features that allow them to deal with extreme and/or highly variable environmental conditions. We document how relatively small changes in fin morphology has afforded some coral reef fish taxa with exceptional locomotor performance and energetic efficiency, and how this key attribute may have played a key role in the evolution and ecology of several diverse Indo-Pacific reef fish families. Using measurements of oxygen consumption in a portable respirometer, we found that fish taxa with wing-shaped fins display a metabolic scope far beyond that previously recorded for fishes (up to 10 times above resting metabolic rate), allowing them to sustain the high swimming speeds required by their wave-swept environment (up to 1 m s-1) whilst incurring a relatively low energetic cost of transport. Paddle-finned sister taxa, which have slightly more rounded fins and occupy sheltered habitats, displayed similar levels of energetic efficiency, but at swimming speeds less than half that of their wing-finned counterparts. We discuss how such differences in locomotor efficiency are pivotal to the habitat-use of these fishes, and how eco-energetic models may be used to provide new insights into spatial variations in fish demography and ecology among coral reef habitat zones.