Swimming plays a crucial role in the ecology and evolution of fishes. Swimming is the primary means by which fish interact and move through their environment. As such, swimming performance determines how well a fish can overcome the daily challenges of acquiring food, avoiding predators, gaining access to different habitats and conducting reproductive activities (Webb, 1994; Batty and Domenici, 2000; Plaut, 2001; Blake, 2004). Since swimming can also be one of the largest costs in the daily energy budget of fishes (Feldmeth and Jenkins, 1973; Kitchell, 1983; Boisclair and Tang, 1993), even small variations in swimming activity can have profound implications for patterns of energy allocation among growth, maintenance and reproduction (Koch and Wieser, 1983; Boisclair and Sirois, 1993). In this way, swimming can influence the evolutionary fitness of fishes and be a primary target for natural selection (Huey and Stevenson, 1979; Hertz et al., 1988).