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The relationship between mosaic muscle fibres and size in rainbow trout ( Salmo gairdneri )
Author(s) -
Weatherley A. H.,
Gill H. S.,
Rogers S. C.
Publication year - 1980
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.1980.tb02792.x
Subject(s) - rainbow trout , salmo , biology , trout , zoology , anatomy , fish <actinopterygii> , muscle fibre , fishery , skeletal muscle
The dynamics of increase of the mosaic muscle in hatchery reared rainbow trout (2·3 to 61·3 cm fork length) are investigated. In trout <5 cm, all fibres are <40 μm in diameter; from 5 to 20 cm the diameter mode remains in the 0–39·9 μm class and there is some extension in range of diameter, thereby suggesting that mosaic muscle increase up to 20 cm is mainly by recruitment of new (small) fibres. When trout exceed 20 cm, mode of fibre diameter shifts to the 40–79·9 um class and fibres of larger diameter (> 100 μrn) appear but the subsequent overall fibre diameter frequency distribution changes little until 50 cm. Increase in muscle during the phase 20–50 cm seems partly attributable to increase in fibre diameter, but remains largely the result of recruitment of small fibres, although the mechanism of the latter process appears less clear than in fish of <20 cm. The recruitment of new fibres stops at 55 cm and further increase in mosaic muscle evidently depends upon the ability of existing fibres to increase in diameter. Possible means by which increasing muscle fibre diameter may limit the ultimate size which trout may achieve are discussed. A phenomenon of apparent reduction in fibre diameter in winter among fish 20–39·9 cm long is noted and its significance is considered.