Relationship between summated tissue respiration and body size in a marine teleost, the porgy Pagrus major

Our hypothesis that the regular decrease in the mass-specific rate of metabolism with increasing body mass can be explained principally by a combination of a decrease in the rate of tissue respiration and an increase in the relative size of tissues of low metabolic activity with increasing body mass was examined with a marine teleost, the porgy Pagrus major. Summated oxygen consumption rate in vitro of an individual (M-in (vitro)) was calculated from an allometric relationship of mass of an organ or part (P) to body mass (M as P = kW(s), and another allometric relationship of rate of tissue respiration in vitro (QO(2)) to body mass (QO(2) = cW(d)), determined with 28 organs and parts. The relationship between M-in (vitro) (mumol O-2/h) at 20degreesC and W (g) was expressed by the formula M-in (vitro) = 5.30 W-0.816 in fish weighing 0.01-1000 g. The mass exponent 0.816 was very close to that (0.821) in another formula (M-in (vivo) = 16.88 W-0.821) determined in our previous study at 20degreesC with intact porgy weighing 0.005-270 g. These results indicate that our hypothesis is quantitatively valid.