Study of microscopic structural changes of red and white muscle of coho salmon, Oncorhynchus kisutch, through different developmental stages and through transition from parr to smolt revealed developmental variation in fibre size where white fibres were larger than red ones. The increase in fibre area, characterizing all stages of development, was associated with reduction in both fibre and capillary densities. In large fish the reduction in red muscle capillary density was 10 fold lesser than that of white muscle. |