Onset of air breathing and development of accessory breathing organs in relation to temperature in the African catfish,Clarias gariepinus(Burchell)

摘要

AbstractThe timing of the onset of air breathing in young African catfish,Clarias gariepinus(Burchell) was investigated and demonstrated to vary as a power law function in relation to constant water temperatures between 20 and 35°C. In addition, the development of the accessory breathing organs on the second and fourth gill arches are examined and examples of scanning electron micrographs of the early developmental stages presented. The appearance of accessory breathing organs appears not to be prerequisite for the onset of air breathing and possible reasons for this are discussed. The value of the development of air breathing versus temperature relationship is considered in relation to hatchery management