Fig. 3. The maximum cardiac output (A) and maximum cardiac power output (B) of perfused rainbow trout hearts at 10°C under hypoxic perfusate. The grey line indicates the level of recovery during a subsequent exposure to normoxic conditions. Individual groups of hearts were exposed to specific hypoxia levels as indicated on the x-axis. Results shown are from two different series of experiments, as indicated by the separate (and discontinuous) line segments; however, experimental protocols were identical up until this point. The number of hearts used for each experiment was in series III: 12.6 kPa (N=6), 10 kPa (N=10), 6.7 kPa (N=6), and in series IV: 5.0 kPa (N=7), 3.3 kPa (N=8), 2.7 kPa (N=5). Values are reported as percentage change from an original assessment under normoxic conditions. One-way repeated-measures ANOVA and Holm–Sidak multiple comparisons tests were used to compare treatment means and each heart acted as its own control. Values shown are means ± s.e.m. *Significant difference from normoxia (P=0.05).