耳石微量元素分析によって明らかにされた東京湾産マハゼの稚魚期での河川遡上履歴  [in Japanese] Upstream migratory history in juvenile stage of yellowfin goby <i>Acanthogobius flavimanus</i> in Tokyo Bay as revealed by otolith Sr:Ca ratios  [in Japanese]

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Author(s)

    • 加納 光樹 KANOU KOUKI
    • 茨城大学広域水圏環境科学教育研究センター Center for Water Environment Studies, Ibaraki University
    • 河野 博 KOHNO HIROSHI
    • 東京海洋大学魚類学研究室 Laboratory of Ichthyology, Tokyo University of Marine Science and Technology

Abstract

東京湾とその流入河川の淡水域と汽水域で採集したマハゼ 61 個体(体長 52.4-131.8 mm)の耳石の Sr:Ca 比から河川遡上履歴を調査した。河川淡水域で採集した 21 個体はすべてが稚魚期に汽水・海域から淡水域に移動していた。汽水域で採集した 40 個体中 31 個体は淡水域への遡上履歴をもたないが 8 個体は一時的に淡水域に侵入し,1 個体は淡水域への遡上後に再び降河した履歴をもっていた。したがって,本種は生活史のなかで淡水域や汽水・海域の様々な塩分環境に対応しうる柔軟な回遊パターンをもつことが明らかとなった。<br>

  The migratory history of yellowfin goby <i>Acanthogobius flavimanus</i> collected from brackish and fresh waters in Tokyo Bay and its adjacent rivers, central Japan was examined using otolith Sr:Ca ratios of 61 specimens (52.4-131.8 mm in standard length, SL). All the 21 yellowfin gobies collected from the fresh waters had higher Sr:Ca ratios (3.0-7.5×10<sup>−3</sup>) at the central otolith area, suggesting their origin was estuarine or marine areas, and the ratios decreased rapidly to 2.5×10<sup>−3</sup> and lower toward the otolith edge, indicating their upstream migration to fresh waters in the juvenile stage. Of 40 specimens collected from brackish waters, 31 specimens were determined not to have experience of upstream migration and eight specimens to have temporarily entered or to have been momentarily exposed to fresh waters. The remaining one specimen of 96.5 mm SL had higher Sr:Ca ratios at the otolith center and edge portions and lower ratios at the middle portion, indicating that this specimen had experience of upstream and downstream migrations. The present study suggests that the yellowfin goby has flexible migration patterns, allowing it to utilize the full range of salinity during its life history.<br>

Journal

  • NIPPON SUISAN GAKKAISHI

    NIPPON SUISAN GAKKAISHI 80(6), 928-933, 2014

    The Japanese Society of Fisheries Science

Codes

  • NII Article ID (NAID)
    130004704601
  • NII NACSIS-CAT ID (NCID)
    AN00193422
  • Text Lang
    JPN
  • Article Type
    journal article
  • ISSN
    0021-5392
  • NDL Article ID
    025947853
  • NDL Call No.
    Z18-345
  • Data Source
    NDL  J-STAGE  JASI 
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