Sr isotopic compositions of ayu otolith and its ambient water

Sr isotopic compositions of ayu otolith and water collected from Japanese rivers were measured to validate the relationship between otolith and ambient water for this species. Micromilling and rostrum-cut methods employed for otolith sampling were compared and yielded almost indistinguishable otolith Sr isotopic composition data. A good correlation observed between data on otolith and those on ambient water (river water and sea water) confirms the usefulness of Sr isotopic composition for elucidating migratory behavior of ayu, as already verified in other species.