Effects of temperature, body size and feeding on rates of metabolism in young-of-the-year haddock

The mean rate of oxygen consumption (routine respiration rate, R-R, mg O-2 fish(-1) h(-1)), measured for individual or small groups of haddock Melanogrammus aeglefinus (3-12cm standard length, L-S) maintained for 5 days within flow-through respiratory chambers at four different temperatures, increased with increasing dry mass (MD). The relationship between RR and MD was allometric (R-R=alpha M-b) with b values of 0.631, 0.606, 0.655 and 0.650 at 5.0, 8.0, 12.0 and 15.0 degrees C, respectively. The effect of temperature (T) and M-D on mean R-R was described by R-R = 0.387(.)M(D)(0.630 .)e(T.0.082) (n = 82, r(2) = 0.896) indicating a Q(10) of 2.27 between 5 and 15 degrees C. Juvenile haddock routine metabolic scope, calculated as the ratio of the mean of highest and lowest deciles of R-R measured in each chamber, significantly decreased with temperature such that the routine scope at 15 degrees C was half that at 5 degrees C. The cost of feeding (RSDA) was c. 3% of consumed food energy, a value half that found for larger gadoid juveniles and adults. (c) 2005 The Fisheries Society of the British Isles.