1. Introduction As global temperatures, as well as the incidence of aquatic hypoxia [1,2], are on the rise, the tolerance of fishes to these stressors is expected to dictate future species distribution [3–5]. The physiological responses to increased temperature and hypoxia are interconnected from the cellular to the whole-organismal level [6–9] and it has been suggested, albeit not without controversy [10–12], that oxygen supply capacity limits thermal tolerance (OCLTT) in fishes [13–16].
