Abstract
A general review of the basis and measurement of respiratory metabolism in fish is presented, with particular reference to sources and magnitudes of influence (error) which various major factors can impose. There is a continuing need for precise measures of metabolism, including quantitative estimates of excretory products, both intrinsically and as a basis for assessing the effect of environmental change. The metabolic cost of locomotion at all levels of performance requires exact definition. Efficiency of performance for fish cannot be determined without a suitable means of relating energy expended to work performed. It is suggested that comparisons be made on the basis of energy required for a propulsion rate of 1 body length per second.