Effect of body size on the standard metabolism of horse mackerel

The routine metabolic rate R(R) and standard metabolic rate R(s) were measured in horse mackerel Trachurus trachurus at 13°C over weight range of 1·4-390 g. A data extraction method rather than the more commonly used method of extrapolating the swimming speed-metabolic rate curves back to zero swimming speed was developed to measure the R(s). The relation between R(R) and R(s) and weight was expressed as a linear regression with the log transformed data. The mean slope of the regression was 0.752 for R(s) and 0.725 for R(s). (C) 2000 The Fisheries Society of the British Isles.