• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.5
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• pp.598-601
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• 2024

The baleen plates of mysticetes provide valuable insights into their recent foraging activities through stable isotope analyses, with variations in carbon and nitrogen isotopic compositions allowing for the reconstruction of seasonal migration patterns. In March 2023, a sei whale Balaenoptera borealis carcass was stranded off the coast of Buan, Jeonbuk, in the Yellow Sea, Korea. The whale was a young male, measuring 9.39 m in length. The total length of its baleen plate was approximately 34 cm, with δ¹³C values ranging from -20.9 to -18.8‰, and δ¹⁵N values ranging from 8.5 to 12.0‰. The variations in carbon and nitrogen isotopes were as much as 1.26‰ and 1.94‰, respectively. No significant periodicity was observed in the stable isotope fluctuations, which may be attributable to the age of the whale. However, when compared with previous studies on stable isotope analyses of sei whale baleen plates, this study showed similar patterns, as the δ¹³C values gradually increased and δ¹⁵N values decreased. The period during which these two isotope values crossed probably reflects the weaning phase of the whale.