Fig. 5. The number of fast muscle fibres per trunk cross-section (FN) for the ambient (open circles) and heated (filled circles) treatment groups of Atlantic salmon. (A). The relationship between FN and age post-fertilisation for the randomly sampled fish. The numbers in brackets represent the number of fish sampled for the ambient and heated groups, respectively. The arrow shows the age at which smolts were transferred to seawater cages (SWT). (B) The relationship between FN and the total cross-sectional area (TCA) of fast muscle at the level of the first dorsal fin ray. The values represent means ± S.E.M. Fish were selected at random, except for the last two samples (box), which represents a selection of the largest individuals available in each cage. The numbers in brackets represent the number of fish sampled for the ambient and heated groups, respectively.