[A-OS14] [EE] Marine ecosystems and biogeochemical cycles: theory, observation and modeling

[AOS14-P01] Transport of age-0 jack mackerel (Trachurus japonicus) from the East China Sea to coastal areas along the Kuroshio.

★招待講演

*石川 和雄¹、伊藤 幸彦¹、渡邊 千夏子²、清水 学³、渡慶次 力⁴、西口 政治⁴、橋田 大輔⁵、大河 俊之⁶、原田 慈雄⁷、岡田 誠⁸、鈴木 勇己⁹、高村 正造¹⁰、福元 亨介¹¹ (1.東京大学大気海洋研究所、2.国立研究開発法人 水産研究・教育機構 中央水産研究所、3.国立研究開発法人 水産研究・教育機構、4.宮崎県水産試験場、5.愛媛県水産研究センター、6.高知県水産試験場、7.和歌山県水産試験所、8.三重県水産試験場、9.静岡県水産技術研究所 伊豆分場、10.神奈川県水産技術センター 相模湾試験場、11.鹿児島県水産技術開発センター)

キーワード：Jack mackerel, Kuroshio, larval transport, recruitment process

Jack mackerel (Truchurus japonicus) inhabiting coastal areas in temperate western North Pacific is an important fisheries resource in East Asian countries. Ichthyoplankton sampling surveys indicate that large spawning grounds are formed in the south of East China Sea from February to March, which is thought to be the main source of the resources in the Pacific coastal waters of Japan. However, transport and recruitment processes from the East China Sea to the coastal waters of Japan have yet to be quantified. In the present study, transport of age-0 jack mackerel by the Kuroshio and the recruitment to the southern coastal areas of Japan were investigated by analyzing fisheries landing records and temperature data from real time monitoring buoy systems. Mean seasonal fluctuation of the landing of age-0 jack mackerel compiled from 10-years records showed multiple peaks in the western part (Miyazaki and Kochi prefectures), first in mid spring and second in mid fall, and single peak in the eastern part (Mie, Shizuoka and Kanagawa prefectures). Time lags of the first peaks are not linearly related to the distance between the fishing grounds, and the eastward propagation of the landing is clearly observed only from Ehime to Kochi. The timing of the peaks in the eastern part in Mie (first peak), Shizuoka (single), Kanagawa (single) prefectures were detected in mid fall, later than the timing expected for those from the East China Sea. These results suggest that larvae and juveniles from the East China Sea are not predominant source and local population reproduced in each area is also important. In the presentation, temperature fluctuations around the landing pulses and their physical characteristics are also discussed.