Estimation of growth and food consumption in juvenile Japanese flounder Paralichthys olivaceus using carbon stable isotope ratio δ13C under laboratory conditions

To estimate the accumulated food consumption and growth of juvenile Japanese flounder Paralichthys olivaceus, we investigated the relationships between individual food consumption and growth, and the change in the stable carbon isotope ratio (delta C-13). Japanese flounder juveniles were individually reared and their diet was switched from one formulated feed EP1 (delta C-13 = -19.47%) to another EP3 (delta C-13 = -17.2 1 %) and fed at different feeding regimes. After the switch, the delta C-13 content of the dorsal muscle was exponentially shifted to a different level in proportion to the feeding and growth rates. Therefore, measuring the carbon stable isotope ratio is a useful tool for estimating the food consumption and growth rate of juveniles. In addition, since the velocity of change and the asymptotic value of the carbon stable isotope ratio varied in muscle, caudal fin and liver tissue, different tissues can be used for different time scale estimations. (c) 2005 Elsevier B.V. All rights reserved.