Fig. 7. Pelvic fin kinematic timing during steady swimming. Complete pelvic oscillation cycle of left fin represented in a polar plot. 0 deg. arbitrarily represents the start of the stroke when fin is held against body. 180 deg. represents mid-stroke when the pelvic fin's lateral tip is maximally abducted. Each rectangle represents the 95% confidence interval around the mean peak kinematic variable with error bars depicting angular variance s² (Batschelet, 1965; Batschelet, 1981). Bar colours define the following: black, maximum amplitude of body at fin attachment site; green, fin area; red, body velocity; yellow, fin velocity; dark blue, fin angle with transverse plane; light blue, fin angle with sagittal plane. Thick bars represent maximum values for each variable and thin bars represent minimum values. The data represent left pelvic fins of all fish during all swimming trials.