Limits to the acclimation of fish muscle

Some of the factors which lead to acclimational changes in fish axial muscle are reviewed and discussed: these are temperature, hypoxia, training and habitat. On the fine structural level, the morphological adaptations are seen mainly in mitochondrial and intracellular lipid content and capillary supply of swimming muscle. Cold acclimation, hypoxic conditions and an endurance training programme show a general trend for transition to more aerobic fibre types and a more aerobic type of muscle.