Fig. 1. Relationship between caudal fin beat frequency and swimming speed in bluegill sunfish at a range of water temperatures. All data were collected in air-saturated water except for the high O₂ condition at 30°C where oxygen levels were elevated to 12 mg l^–1, using 100% oxygen. Data are shown as mean ± s.e.m. (N=6, air saturated oxygen concentrations; N=5, elevated oxygen concentration 30°C).