Fig. 1. For swimming studies, a tight relationship exists between maximum oxygen uptake (_O2max) and maximum arterial oxygen transport (_O2max; the product of maximum cardiac output and arterial oxygen carrying capacity) among a variety of fish species (_O2max=0.84 _O2max–4.03; r²=0.99). These data also illustrate the modest increase in both _O2max and _O2max produced with intense exercise training in chinook salmon. C, control; Tr, exercise-trained; Co, Atlantic cod, Gadus morhua; L, leopard shark; D, dogfish; R1+R2, rainbow trout). Graph taken with permission from Gallaugher et al. (2001).