Temperature dependence of δ18O in otolith of juvenile Japanese sardine: Laboratory rearing experiment with micro-scale analysis

Tatsuya Sakamoto, Kosei Komatsu, Michio Yoneda, Toyoho Ishimura, Tomihiko Higuchi, Kotaro Shirai, Yasuhiro Kamimura, Chikako Watanabe, Atsushi Kawabata

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


We evaluated the use of the stable oxygen isotope (δ18O) in the otolith as a proxy for the temperature history of Japanese sardine Sardinops melanostictus individuals. Japanese sardine juveniles were reared in three different water temperatures over the course of a month. Otolith δ18O (δotolith) was analyzed by extracting the portions formed during the rearing period using a micromill. δ18O of the rearing water (δwater) was also analyzed. A linear relationship between otolith δ18O and ambient water temperature was identified as follows: δotolith − δwater = −0.18 * T + 2.69 (r2 = 0.91, p < 0.01). This equation is different from that proposed for inorganic aragonite or other Sardinops spp., with resulting application to wild Japanese sardine captured in the Pacific Ocean showing that it estimates a more realistic in situ temperature. Our findings suggest that the Japanese sardine-specific isotopic fractionation equation should be used when interpreting otolith δ18O of the Japanese sardine, and the methods presented here could also be useful to understand the temperature history of other fish species.

Original languageEnglish
Pages (from-to)55-59
Number of pages5
JournalFisheries Research
Publication statusPublished - Oct 2017
Externally publishedYes


  • Fractionation equation
  • Japanese sardine otolith
  • Micro-scale analysis
  • Stable oxygen isotope
  • Temperature proxy

ASJC Scopus subject areas

  • Aquatic Science


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