Figure 2.

Standard metabolic rate (SMR), maximum oxygen uptake (ṀO_2max), absolute aerobic scope (AAS) and factorial aerobic scope (FAS) of PFRC H-strain rainbow trout (O. mykiss) as a function of acclimation temperature. (A) SMR, ṀO_2max and AAS (difference between ṀO_2max and SMR) as a function of acclimation temperature (n = 12–16). SMR (blue square) was fitted with a polynomial quadratic function and one-way ANOVA (Y = 135.0 + 10.5^*X + 1.35^*X², R² = 0.67, F = 31.14, P < 0.0001), ṀO_2max (red circle) and AAS (green triangle) were fit with a Gaussian distribution curve and one-way ANOVA (Y = 760.2^*exp(−0.5^*((X-19.6)/9.89)2), R² = 0.22, F = 4.91, P = 0.0006; Y = 634.7^*exp(−0.5^*((X-18.6)/7.37)2), R² = 0.42, F = 15.40, P < 0.0001). ṀO_2max and SMR values were corrected to mean body mass of acclimation group, presented per unit kg. (B) Factorial of ṀO_2max/SMR (FAS) and peak SDA/SMR (n = 12–16). FAS (green circle) was fitted with a Gaussian distribution curve and one-way ANOVA (Y = 1.9^*exp(−0.5^*((X-2.0)/1.7)2), R² = 0.73, F = 43.41, P < 0.0001). (C) Critical oxygen level to maintain SMR (P_crit or C_crit) and oxygen level when fish is loss of whole animal equilibrium (ILOP or ILOC), as a function of acclimation temperature. P_crit (or C_crit) and ILOP (or ILOC) are presented as both water PO₂ (mm Hg; left y-axis) and dissolved oxygen concentration (mg O₂ l^-1; right y-axis). Curve was fit with polynomial quadratic function and one-way ANOVA (Pcrit: Y = 26.3 + 1.60^*X + 0.19^*X²), R² = 0.57, F = 22.19, P < 0.0001; Ccrit: Y = 1.54 + 0.062^*X + 0.0095^*X²), R² = 0.40, F = 11.58, P < 0.0001; ILOP: Y = 23.3 + 0.80^*X + 0.061^*X²), R² = 0.28, F = 6.41, P < 0.0001; ILOC: Y = 1.37+ 0.021^*X + 0.0031^*X²), R² = 0.57, F = 1.91, P = 0.10, (n = 12–16). Data points not sharing letters indicate significant differences between acclimation groups for that variable. All values are presented as mean ± sem and were assessed using a one-way ANOVA with Tukey’s post-hoc (α = 0.05).