Fig. 4. The change in (A) blood pH (solid line), plasma HCO₃^– (mmol l^–1, dashed line) and (B) the partial pressure of CO₂ (P_CO2), over the duration of the experiment when fish fed voluntarily on a 1% of body mass ration. Values are means ± s.e.m. (N=8). An asterisk denotes a significant difference when compared with pre-feed levels [adjusted P<0.05; RM-ANOVA followed by a multiple pairwise control (pre-feed) comparisons versus post-feed groups using the Bonferroni t-test method], whereas a dagger indicates a significant difference in pH when compared with catheter-fed fish (P<0.05; paired t-test).