Fig. 4. Relationship between the cost of transport (COT) and swimming speed for bluegill sunfish. Filled symbols, COT_gross; open symbols, COT_net; black symbols, labriform swimming; red symbols, undulatory swimming. Data are fitted with the following relationships: labriform COT_gross=5.73–10.1U; undulatory COT_gross=3.59+76.3U^3.96; labriform COT_net=1.9+0.13U; undulatory COT_net=1.83+39.2U^2.84. The broken lines show 95% confidence intervals for the fitted relationships. Values are means ± s.e.m., N=9, except where the speed ranges for labriform and undulatory swimming overlap at 0.25 m s^–1, where N=4 for labriform swimming and N=5 for undulatory swimming.