Estimation of lifelong metabolic rates in marine fish: A combination of oxygen consumption measurements and <scp>δ¹³C</scp> metabolic proxy derived from vertebral structural carbonates

Abstract Adjustments in the metabolism of marine fish are associated with the complexity of resource availability, prey–predator relationships, and biotic and abiotic interactions in the natural environment. To investigate the relationship between metabolism and body mass, this study used a conventional method to estimate the oxygen consumption rate (reflecting the resting metabolic rate) in black porgy, Acanthopagrus schlegelii , over a year of rearing. In addition, we developed a novel metabolic proxy using the δ 13 C values of vertebral structural carbonates to monitor lifelong metabolic changes. The oxygen consumption measurements followed a decreasing mass‐dependent trend and yielded a mass‐specific allometric exponent scaling (−0.24). By integrating the oxygen consumption with the advanced δ 13 C metabolic proxy, we established a decay model in an increasing form to describe the relationship of the two measurements, and it could be further used in wild fishes and broaden the metabolic studies in marine vertebrates.