Fig. 6. Aerobic swimming performance in juvenile rainbow trout exposed to 394 µg Ni l^–1. (A) Basal oxygen consumption rate (). (B) Maximal oxygen consumption rate (). (C) Aerobic scope for activity. (D) Critical swimming speed (U_crit). Values are means ±1 S.E.M. (N=5–8). Asterisks indicate significant difference (P<0.05) from simultaneous control mean by an unpaired two-tailed Student's t-test. Bars to the right of the broken vertical line represents measurements made after 38 days of exposure to clean water (C 38). BL, body lengths.