Fig. 9. Relationship between body mass and (A) hypoxia tolerance (critical oxygen concentration), and (B) metabolic rate (routine oxygen consumption) in juvenile and adult coral-reef fishes (excluding pre-settlement larvae). Note that while hypoxia tolerance does not change with body mass, metabolic rate shows the `classical' scaling relationship with body mass. The dataset includes 174 individuals weighing between 40 mg and 40 g and representing 35 species from six families, and is largely the same as that presented in Table 1 [mostly from Nilsson and Östlund-Nilsson (Nilsson and Östlund-Nilsson, 2004), with additional individuals from Östlund-Nilsson and Nilsson (Östlund-Nilsson and Nilsson, 2004) and Nilsson et al. (Nilsson et al., 2007b)]. For the whole dataset, the mass-specific metabolic rate was related to mass^–0.367 (which translates into a scaling exponent of 1–0.367=0.633 for absolute metabolic rate; r=0.80). For the best represented family, Pomacentridae with 99 individuals from 14 species, the same scaling exponents were –0.347 (mass-specific metabolic rate) and 0.653 (absolute metabolic rate) (r=0.94). Temperature was 28–30°C.