Extended Data Fig. 1: Dosidicus gigas: Temperature and mass effects on metabolic traits.

a. The temperature dependence, E (eV), of each metric (SMR, MMR, P_cSMR and α, was determined from the slope of the linear regression of 1/kBT versus the natural logarithm of each metric (for Dosidicus gigas), where T is absolute temperature (K) and k_B is the Boltzmann constant. Note that, to avoid the confusion when using inverse temperature plots, the sign for each temperature coefficient is reversed (that is temperature coefficients are positive when a metric increases with temperature). b. Oxygen-consumption rates recorded at rest (blue, mass-normalized, SMR) and during exercise (MMR, red). The effect of temperature between 10 and 20 °C is similar for MMR and SMR. The effect of temperature is much higher for MMR compared to SMR between 20 and 25 °C. The metabolic rates are normalized to a common body mass (100 g) using the scaling coefficients in panel C. c. SMR and P_cSMR as a function of body mass (M) at 10 °C (SMR = 13.03 M^−0.12 and P_cSMR = 2.44 M^−0.03). d. The effect of temperature coefficient on MMR in the Gulf of California (solid lines) and in the California Current System (dashed lines) at different temperatures. The difference between dashed and solid lines at a given temperature (arrows) is due to oxygen limitation in the Gulf of California and the lack of oxygen limitation in the California Current. The measured rates are indicated by black dashed lines. This figure indicates that a temperature coefficient for MMR less than 1.0 eV results in oxygen limitation of maximum metabolic rate whereas a coefficient greater than 1.0 eV results in temperature depression of metabolism at cold temperatures and no effect of low oxygen except at the coldest, deepest daytime depths (~300 m, 10 °C, PO₂ < 0.5 kPa).