Fig 5. An example of the oxygen consumption rate during an experiment and the determination of standard metabolic rate.

Upper panel: Open circles represent oxygen consumption rate (ṀO₂) and solid circles represent the corresponding R². The values were recorded at 25 PSU and 18°C. Lower panel: a histogram of all ṀO₂ values with an R² above 0.95, fitted to a double Gaussian distribution (solid line). The standard metabolic rate is shown in both panels by punctuated lines, and was determined as the lowest mean of the two Gaussian distributions.