Fig. 6. The effect of increasing the duration of severe hypoxia on maximum cardiac performance of in situ rainbow trout hearts. Hearts were exposed to 0 min (control), or 10 min, 20 min and 30 min of severe hypoxia (N=7–8 in each group). (A) Comparison of maximum cardiac performance between _max1 and _max2; *significant difference (P<0.05) as determined by repeated-measures ANOVA. (B) The percent change in maximum cardiac performance at _max2 relative to _max1. Dissimilar letters indicate a significant difference (P<0.05) between treatments, as determined using one-way ANOVA.