Growth of striated muscle fibres in the M. lateralis of the European eel Anguilla anguilla (L.) (Pisces, Teleostei).

Diameters of red and white muscle fibres were measured in the M. lateralis of eels cultured under laboratory circumstances over a period of 2 years, starting from the glass eel stage. The red fibres of eels less than 10 cm are unique in that their growth involves increase in diameter only. Growth of the red fibres in eels greater than 10 cm, and of the white fibres in eels at all lengths considered, is characterized by an increase in number as well as diameter, the relative importance of these two methods of growth being related to factors other than the length of the animal. Satellite cells may play an important part in the addition of new, small muscle fibres.