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Loss of muscle fibres in a landlocked dwarf Atlantic salmon population

2005; Royal Society; Volume: 1; Issue: 4 Linguagem: Inglês

10.1098/rsbl.2005.0377

1744-957X

Ian A. Johnston, Marguerite Abercromby, Øivind Andersen,

Aquaculture Nutrition and Growth

Growth of fast myotomal muscle in teleosts involves the continuous production of muscle fibres until some genetically pre-determined length. The dwarf landlocked (Bleke) population of Atlantic salmon (Salmo salar L.) from Byglands-fjord, Southern Norway mature at about 25 cm fork length and reach a maximum size of only 30 cm in the wild. The maximum diameter (D(max)) of fast muscle fibres in 4-year-old Bleke salmon (25-28 cm fork length) was 118 microm and not significantly different from that found in immature migratory salmon of a similar size. In contrast no evidence for active fibre recruitment was found in the Bleke salmon, such that the maximum fibre number, FN(max), was only 21-30% of that reported in typical farmed and wild migratory populations, respectively. We hypothesise that, once established, the physiological consequences of the dwarf condition led to rapid selection for reduced fibre number, possibly to reduce the maintenance costs associated with ionic homeostasis.