Natal origin and age-specific egress of Pacific bluefin tuna from coastal nurseries revealed with geochemical markers. Academic Article uri icon


  • Geochemical chronologies were constructed from otoliths of adult Pacific bluefin tuna (PBT) to investigate the timing of age-specific egress of juveniles from coastal nurseries in the East China Sea or Sea of Japan to offshore waters of the Pacific Ocean. Element:Ca chronologies were developed for otolith Li, Mg, Mn, Zn, Sr, and Ba, and our assessment focused on the section of the otolith corresponding to the age-0 to age-1 + interval. Next, we applied a common time-series approach to geochemical profiles to identify divergences presumably linked to inshore-offshore migrations. Conspicuous geochemical shifts were detected during the juvenile interval for Mg:Ca, Mn:Ca, and Sr:Ca that were indicative of coastal-offshore transitions or egress generally occurring for individuals approximately 4-6 mo. old, with later departures (6 mo. or older) linked to overwintering being more limited. Changepoints in otolith Ba:Ca profiles were most common in the early age-1 period (ca. 12-16 mo.) and appear associated with entry into upwelling areas such as the California Current Large Marine Ecosystem following trans-Pacific migrations. Natal origin of PBT was also predicted using the early life portion of geochemical profile in relation to a baseline sample comprised of age-0 PBT from the two primary spawning areas in the East China Sea and Sea of Japan. Mixed-stock analysis indicated that the majority (66%) of adult PBT in our sample originated from the East China Sea, but individuals of Sea of Japan origin were also detected in the Ryukyu Archipelago.

published proceedings

  • Sci Rep

altmetric score

  • 0.5

author list (cited authors)

  • Rooker, J. R., Wells, R., Block, B. A., Liu, H., Baumann, H., Chiang, W., ... Shiao, J.

citation count

  • 0

complete list of authors

  • Rooker, Jay R||Wells, RJ David||Block, Barbara A||Liu, Hui||Baumann, Hannes||Chiang, Wei-Chuan||Sluis, Michelle Zapp||Miller, Nathaniel R||Mohan, John A||Ohshimo, Seiji||Tanaka, Yosuke||Dance, Michael A||Dewar, Heidi||Snodgrass, Owyn E||Shiao, Jen-Chieh

publication date

  • July 2021