小支流におけるイワナ,ヤマメ当歳魚の生息数,移動分散および成長  [in Japanese] Number, Dispersal and Growth of Juvenile Japanese Charr and Masu Salmon in a Small Tributary of a Japanese Mountain Stream  [in Japanese]

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Author(s)

Abstract

1993年6月∿1995年11月にかけて, 利根川水系鬼怒川の小支流において, イワナ, ヤマメの生息数, 当歳魚の移動分散, 成長の季節変化を調査した。3ヶ年の総採捕個体のうち, イワナは81.4%(1073個体中873個体), ヤマメは98.8%(244個体中241個体)が当歳魚であった。ヤマメ当歳魚は2月から採捕され, 8月以降はほとんど採捕されなかった。これに対して, イワナ当歳魚は3月から採捕され, 6月以降は1回の調査あたりの採捕数の変化はなかった。一方, 1995年に鬼怒川本流で採捕調査を行ったところ, 採捕された当歳魚のうちイワナが8.0%, ヤマメが92.0%を占め, ヤマメ当歳魚が優占した。以上の結果から, 小支流は特にイワナ当歳魚にとって重要な成育場所であると考えられた。

We investigated the seasonal changes in number, dispersal and growth of juvenile Japanese charr Salvelinus leucomaenis and masu salmon Oncorhynchus masou masou in the Karatakisawa Stream, a small tributary of the Kinu River in central Japan. 873 (81.4%) of a total 1073 charr caught by monthly sampling from 1993 to 1995 were age-0, and 241 (98.8%) of a total 244 salmon were age-0. Most of the newly emerged age-0 salmon were caught in the spring of 1995. They shifted downstream, and the number of fish decreased markedly by early summer. The number of the age-0 charr caught at any sampling from any month did not decrease until the end of autumn, although the distribution of the age-0 charr shifted downstream. In contrast, of a total 387 age-0 fish captured by samplings in the adjacent Kinu River in 1995, 356 (92.0%) were salmon, whereas only 31 (8.0%) were charr. These results suggest that small tributaries play an important role as nursery habitats, especially for Japanese charr.

Journal

  • NIPPON SUISAN GAKKAISHI

    NIPPON SUISAN GAKKAISHI 67(4), 703-709, 2001-07-15

    The Japanese Society of Fisheries Science

References:  19

Cited by:  5

Codes

  • NII Article ID (NAID)
    110003145326
  • NII NACSIS-CAT ID (NCID)
    AN00193422
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    00215392
  • NDL Article ID
    5848796
  • NDL Source Classification
    ZR26(科学技術--農林水産--水産)
  • NDL Call No.
    Z18-345
  • Data Source
    CJP  CJPref  NDL  NII-ELS  J-STAGE  NDL-Digital  JASI 
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