Fig. 8. Vorticity and vector plots during a manoeuvre at 0.5 L s^-1. The fish is manoeuvring away from the stimulus located beyond the top of each image. Top panel, dorsal fin during pause at maximum excursion as is commonly seen in lateral yawing manoeuvres. Bottom panel: anal fin returning to midline after the pause at maximum excursion. Shear layers can be seen on dorsal and anal fins. Formation of the second counterclockwise vortex appears early causing the formation of an imbalance in contralateral jet magnitude. Note that x and y axes represent the scale of the video image.