Fig. 6. Instantaneous shortening velocity relative to peak gape from three individuals are displayed. This figure shows the change in normalized length between each sampling period, averaged within individuals and smoothed. Fish 1 showed roughly isometric contraction during fast lower jaw depression, while fish 5 showed lengthening during fast lower jaw depression. These fish also displayed less than 40% fascicle strain prior to peak gape. Fish 1 showed a gradual increase in shortening velocity prior to peak gape. This pattern was also found in fish 2 and 4. Maximum instantaneous speed was variable between individuals.