| Summary: | Chapter 1 - General Introduction : The general introduction sets out the rationale for the study and it's applicability to aquaculture. A description of the life history of the Atlantic salmon {Salmo salar L.) is given, together with a description of the origin and current status of fish farming. The structure and function of fish muscle is explained in addition to its growth, development and inherent plasticity. Finally, the environmental influences on muscle growth in fish are discussed and this is followed by the aims of the thesis. Chapter 2 - Egg incubation temperature influences muscle fibre recruitment during seawater stages of Atlantic salmon (Salmo salar L.) : Eggs of Atlantic salmon {Salmo salar L.) were incubated in either heated or ambient water temperatures. The comparative whole animal and muscle growth performance of the two groups was monitored for 26 months. The number of white muscle fibres per myotome was significantly higher at hatch in the ambient group, resulting in a greater muscle cross sectional area. However, muscle fibre number was almost four-fold higher in the heated group at the SI parr stage relative to the ambient group. Six months following seawater transfer the number of fast white muscle fibres was not significantly different between groups. The 5th and 10th percentile fibre diameters decreased significantly in both groups during winter and spring, indicating a relative increase in the contribution of new fibre recruitment which was correlated with seasonal lows in water temperature and day-length. The results indicate that egg incubation temperature has persistent effects on muscle cellularity throughout the freshwater and early seawater stages of Atlantic salmon. Chapter 3 - Advanced photoperiod treatment affects smoltification and muscle growth in Atlantic salmon (Salmo salar L.) : Juvenile Atlantic salmon {Salmo salar L.) were reared under three different photoperiod regimes: constant light (CL), simulated short winter (SW) and simulated long winter (LW) from July to ...
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