1. Otoliths have been widely studied as natural recorders of the entire
life cycle of aquatic teleosts. Trace elements and stable isotope
rations in otoliths are well understood and used as proxies of migration
histories, however few elements have shown the potential to reconstruct
the migration history of oceanodromous fish. 2. This study reports the
first use of radiocarbon in otolith to reconstruct the horizontal
migration history of fish. We analyzed three different stocks of walleye
pollock Gadus chalcogrammus around Hokkaido, Japan. 3. Radiocarbon
concentration from the outermost edge of otoliths showed a general
consistency with seawater radiocarbon concentration of the sampling
region, validating the application of otolith radiocarbon concentration
to fish migration studies. Pollocks of all three stocks generally
inhabited the nearby sampling area throughout their life cycle, though
some pollocks of the Okhotsk and Japan Sea stocks respectively showed a
possibility of migration between different sea regions. 4. This study
confirmed a novel method using radiocarbon concentrations to reconstruct
the migration history of marine teleost. Using the high sensitivity of
otolith radiocarbon concentration observed in this study, it may be
possible to detect fish migration with higher spatial resolution than
previous studies using conventional proxies.