Thus, to better understand the bases of inter-individual variation
in environmental adaptation performance, the present study
examined some morpho-functional determinants of hypoxia and
heat tolerance in fish.This examination was conducted using a
methodology based on two standardized challenge tests aimed at
assessing individual incipient lethal oxygen saturation (ILOS) and
incipient upper lethal temperature (IULT). Results to these tests
were then cross-correlated with swim tests during which indivi-
dual critical swimming speed and standard and active metabolic
rates were measured. Measurements of permeabilized ventricular
myofibers oxygen consumption were also conducted, as well
as various organ-to-body-mass ratios.Two strains of rainbow
trout (O. mykiss) were used for this experiment, a fast growing
strain and a slow growing strain