Fig. 2. Frequency distribution of fish orientation relative to the oncoming flow at 0 cm s^-1 (A), 4 cm s^-1 (B) and 8 cm s^-1 (C). An orientation angle of 0° represents perfect positive rheotaxis (fish facing directly upstream). Each dotted line represents the distribution of orientation angles for one of four individuals, while the solid line indicates the mean distribution for all four individuals. Bin width=10°.