Natal origin and age-specific egress of Pacific bluefin tuna from coastal nurseries revealed with geochemical markers
Rooker, J.R.; Wells, R.J.D.; Block, B.A.; Liu, H.; Baumann, H.; Chiang, W.-C.; Sluis, M.Z.; Miller, N.R.; Mohan, J.A.; Ohshimo, S.; Tanaka, Y.; Dance, M.A.; Dewar, H.; Snodgrass, O.E.; Shiao, J.-C. (2021). Natal origin and age-specific egress of Pacific bluefin tuna from coastal nurseries revealed with geochemical markers. NPG Scientific Reports 11(1): 14216. https://dx.doi.org/10.1038/s41598-021-93298-2
In: Scientific Reports (Nature Publishing Group). Nature Publishing Group: London. ISSN 2045-2322; e-ISSN 2045-2322, more
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| Authors | | Top |
- Rooker, J.R.
- Wells, R.J.D.
- Block, B.A.
- Liu, H.
- Baumann, H.
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- Chiang, W.-C.
- Sluis, M.Z.
- Miller, N.R.
- Mohan, J.A.
- Ohshimo, S.
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- Tanaka, Y.
- Dance, M.A.
- Dewar, H.
- Snodgrass, O.E.
- Shiao, J.-C.
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| Abstract |
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. |
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