As a first step for field applications of stable isotope techniques to investigate the migration of Japanese temperate bass (Lateolabrax japonicus) (Perciformes) juveniles, we conducted a diet switch experiment and fitted an exponential model to changes in stable carbon (delta(13)C) and nitrogen (delta(15)N) isotope ratios for muscle, fin, and liver. The trophic enrichment values were ranked liver < muscle < fin for delta(13)C (range -0.80e to +3.66e) and liver < fin < muscle for delta(15)N (+0.59e to +3.12e). The half-life values were similar for muscle and fin for both delta(13)C and delta(15)N (19.3-25.7 days), while those for liver were 5.3 days for delta(13)C and 14.4 days for delta(15)N. Both the delta(13)C and delta(15)N values of muscle reached the asymptotic value after a threefold body weight increase, reflecting the diet after the switch. These results suggest that fin is a useful substitute for muscle in field applications of stable isotope techniques and that liver, with a shorter half-life, has the potential to provide more recent information about migration.