Figure 9.

Number of voluntary ascents made by smallmouth bass (Micropterus dolomieu) against different water velocities in either a 25 m (open symbols) or a 50 m (closed symbols) raceway. The willingness of fish to ascend the raceway decreased dramatically after the fish switched swimming gait (indicated by the vertical broken line). One hundred and thirty-one fish (mean fork length: 35.3 cm) were used in the 25 m raceway, while 148 individuals (mean fork length: 36.8 cm) were used in the 50 m raceway. All fish were naive to the raceway. Ascent rate was calculated by dividing the number of complete ascents by the exposure period. Gait transition speed was assessed using video recordings of fish as they swam past an observation window.