Japan Geoscience Union Meeting 2018

Presentation information

[EE] Oral

A (Atmospheric and Hydrospheric Sciences) » A-OS Ocean Sciences & Ocean Environment

[A-OS09] Marine ecosystems and biogeochemical cycles: theory, observation and modeling

Wed. May 23, 2018 1:45 PM - 3:15 PM 105 (1F International Conference Hall, Makuhari Messe)

convener:Shin-ichi Ito(Atmosphere and Ocean Research Institute, The University of Tokyo), Takafumi Hirata(Faculty of Environmental Earth Science, Hokkaido University), Eileen E Hofmann (共同), Enrique N Curchitser (Rutgers University New Brunswick), Chairperson:Ito Shin-Ichi(The University of Tokyo)

2:30 PM - 2:45 PM

[AOS09-15] A scheme to reproduce migration history of the Japanese sardine; combination use of otolith d18O and an individual-based migration model

*Tatsuya Sakamoto1, Kosei Komatsu2,1, Shirai Kotaro1, Tomihiko Higuchi1, Toyoho Ishimura3, Takashi Setou4, Yasuhiro Kamimura4, Chikako Watanabe4, Atsushi Kawabata5 (1.Atomsphere and Ocean Research Institute, The University of Tokyo, 2.Graduate School of Frontier Sciences, The University of Tokyo, 3.National Institute of Technology, Ibaraki College, 4.National Research Institute of Fisheries Science, 5.Fisheries Agency)

Keywords:sardine, otolith, individual-based model, data assimilation model

Tracking the movement of migratory fish are of great importance in fisheries science, although it has been technically difficult for small sized fish to which artificial tags cannot be attached. Oxygen stable isotope ratio (δ18O) in otolith is known to record the linear combination of temperature and salinity variation of ambient water, and thus considered to be a potential alternative for conventional techniques such as tagging and electronic loggers. However, the difficulty of separating the two factors have been limiting its application. In this study, we show that the migration history of small pelagic fish, the Japanese sardine, can be individually reproduced by the combination use isotopic analysis and numerical migration simulations. We found that the detailed and reasonable movements can be estimated by searching the routes that should be passed to reproduce the otolith δ18O history, using a simple individual based migration model in a realistically simulated ocean. The scheme will enable researchers to estimate the environment that an individual fish experienced in the early life history for numerous species, which will improve the understanding of how the survival of fish is affected by environmental variabilities.