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ウナギAnguilla japonicaの資源生態学的研究

Research Project

Project/Area Number 16780135
Research Category

Grant-in-Aid for Young Scientists (B)

Allocation TypeSingle-year Grants
Research Field General fisheries
Research InstitutionThe University of Tokyo

Principal Investigator

青山 潤  東京大学, 海洋研究所, 助手 (30343099)

Project Period (FY) 2004 – 2006
Project Status Completed (Fiscal Year 2006)
Budget Amount *help
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2006: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2005: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2004: ¥1,500,000 (Direct Cost: ¥1,500,000)
Keywords浜名湖 / ウナギ資源 / 河川 / 湖沼 / 成長 / 性比 / 年齢 / 保全 / シラスウナギ / 接岸回遊 / 色素発達段階 / 色素ステージ / STST / 潮汐流 / 月周期 / ウナギ / 資源 / 移動 / 接岸 / 回遊 / 黄ウナギ
Research Abstract

浜名湖の本湖と猪鼻湖、および今川と西神田川においてニホンウナギを計809個(全長範囲:54.2-798mm、体重:0.2-1034.7g)を体採集した。まず、これらの性比を調べたところ、湖では雌雄比がほぼ1:1であるのに対し、河川では6:1と大きく異なることがわかった。採集地点間で全長を比較すると、雌では猪鼻湖の個体が本湖、今川より小型であったが、雄では有意差はみられなかった。
一方、西神田川における黄ウナギ198個体の採集地点をみると、河口からの距離と黄ウナギの全長には有意な正の相関がみられた。このことは、上流に向かうほど大型個体が多いことを示している。さらに河川内における単位面積あたりの個体数密度指数は、上流に向かうほど減少する傾向がみられた。
河川と湖の間で黄ウナギの年齢を雌雄別に比較したところ、河川の雌の年齢(5.2歳)は湖の雌のもの(平均4.5歳)よりも有意に高かく、雄においても同様の傾向が認められた(河川:5.5歳、湖:3.7歳)。年齢ごとに河川と湖の雌雄の成長速度を比較したところ、1〜2歳までの成長は湖の黄ウナギ(131.9mm/年)の方が河川のもの(104.4mm/年)よりも有意に高かった。
本研究の結果、まず河川内のウナギは上流ほど大型個体が低密度で生息していることが明らかになった。また、河川には雌が多く、湖よりも2-4歳の成長の悪い高齢個体が生息していることがわかった。一般的に、高齢・低成長の個体群(河川)は、若齢・高成長の個体群(湖)よりも漁獲の影響を受けやすい。近年明らかになった河川へ遡上しない海ウナギの資源生態学的な側面は未だ明らかでないものの、現時点の資源保全には、少なくとも河川の個体群を重点的に保護する必要があると考えられた。

Report

(3 results)
  • 2006 Annual Research Report
  • 2005 Annual Research Report
  • 2004 Annual Research Report
  • Research Products

    (15 results)

All 2007 2006 2005 2004 Other

All Journal Article (15 results)

  • [Journal Article] Seasonal differences in catches of leptocephali in the East China Sea and Suruga Bay, Japan. Estuarine2007

    • Author(s)
      MINAGAWA G, MJ.MILLER, Y.KIMURA, S.WATANABE, A.SHINODA, J.AOYAMA, K.TSUKAMOTO
    • Journal Title

      Estuarine, Coastal and Shelf Science 71

      Pages: 730-740

    • Related Report
      2006 Annual Research Report
  • [Journal Article] Contrasting patterns of growth and migration of tropical anguillid leptocephali in the western Pacific and Indonesian Seas2006

    • Author(s)
      KUROKI M, J.AOYAMA, M.J.MILLER, S.WOUTHUYZEN, T.ARAI, K.TSUKAMOTO
    • Journal Title

      Marine Ecological Progress Series 309

      Pages: 233-246

    • Related Report
      2006 Annual Research Report
  • [Journal Article] Age and growth of Anguilla interioris Leptocephali collected in Indonesian waters2006

    • Author(s)
      KUROKI M, J.AOYAMA, S.WOUTHUYZEN, K.O.SUMADHIHARGA, MJ.MILLER, G.MINAGAWA, K.TSUKAMOTO
    • Journal Title

      Coastal Marine Science 30

      Pages: 464-468

    • Related Report
      2006 Annual Research Report
  • [Journal Article] Evidence of a local spawning site of marine ells along northeastern Japan, based on the distribution of small leptocephali.2006

    • Author(s)
      KIMURA Y, MJ.MILLER, G.MINAGAWA, S.WATANABE, A.SHINODA, J.AOYAMA, T.INAGAKI, K.TSUKAMOTO
    • Journal Title

      Fisheries Oceanography 15

      Pages: 183-190

    • Related Report
      2005 Annual Research Report
  • [Journal Article] First observations of the burrows of the Japanese ell, Anguilla japonica.2005

    • Author(s)
      AOYAMA J., A.SHINODA, S.SASAI, MJ.MILLER, K.TSUKAMOTO
    • Journal Title

      Journal of Fish Biology 67

      Pages: 1534-1543

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Biodiversity of anguilliform leptocephali in the central Indonesian Seas.2005

    • Author(s)
      WOUTHUYZEN S, MJ.MILLER, J.AOYAMA, G.MINAGAWA, HY.SUGEHA, S.SUHARTI, T.INAGAKI, K.TSUKAMOTO
    • Journal Title

      Bulletin of Marine Science 77

      Pages: 209-223

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Age and growth of Saurenchelys (Nettastomatidae) and Dysomma (Synaphobranchidae) leptocephali in the East China Sea.2005

    • Author(s)
      MA T., MJ.MILLER, A.SHINODA, G.MINAGAWA, J.AOYAMA, K.TSUKAMOTO
    • Journal Title

      Journal of Fish Biology 67

      Pages: 1619-1630

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Correspondence between otolith microstructual changes and early life history events in Anguilla marmorata leptocephalli and glass eels.2005

    • Author(s)
      KUROKI M., J.AOYAMA, MJ.MILLER, T.ARAI, HY.SUGEHA, G.MINAGAWA, S.WOUTHUYZEN, K.TSUKAMOTO
    • Journal Title

      Coastal Marine Science 29

      Pages: 154-161

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Evaluation of the population structure of Anguilla bicolor bicolor using total number of vertebrae and the mtDNA control region.2005

    • Author(s)
      WATANABE S, J.AOYAMA, M.NISHIDA, K.TSUKAMOTO
    • Journal Title

      Coastal Marine Science 29

      Pages: 165-169

    • Related Report
      2005 Annual Research Report
  • [Journal Article] Molecular phylogeny and evolution of the freshwater eels genus Anguilla based on the whole mitochondrial genome sequences2005

    • Author(s)
      Minegishi, Y, Aoyama, J, Inoue, JG, Miya, M, Nishida, M, Tsukamoto, K
    • Journal Title

      MOLECULAR PHYLOGENETICS AND EVOLUTION 34・1

      Pages: 134-146

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Ecological aspects of the downstream migration of introduced European eels in the Uono River, Japan2004

    • Author(s)
      Miyai, T, Aoyama, J, Sasai, S, Inoue, JG, Miller, MJ, Tsukamoto, K
    • Journal Title

      ENVIRONMENTAL BIOLOGY OF FISHES 71

      Pages: 105-114

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Contrasting assemblages of leptocephali in the western Pacific2004

    • Author(s)
      Minagawa, G, Miller, MJ, Aoyama, J, Wouthuyzen, S, Tsukamoto, K
    • Journal Title

      MARINE ECOLOGY-PROGRESS SERIES 271

      Pages: 245-259

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Reexamination of Ege's (1939) use of taxonomic characters of the genus anguilla2004

    • Author(s)
      Watanabe, S, Aoyama, J, Tsukamoto, K
    • Journal Title

      BULLETIN OF MARINE SCIENCE 74・2

      Pages: 337-351

    • Related Report
      2004 Annual Research Report
  • [Journal Article] Age and growth of Anguilla bicolor bicolor leptocephali in the eastern Indian Ocean

    • Author(s)
      KUROKI M, J.AOYAMA, S.WOUTHUYZEN, K.O SUMADHIHARGA, MJ.MILLER, K.TSUKAMOTO
    • Journal Title

      Journal of Fish Biology (In press)

    • Related Report
      2006 Annual Research Report
  • [Journal Article] Distribution of leptocephali of the freshwater eels, genus Anguilla, in the waters off west Sumatra in the Indian Ocean

    • Author(s)
      AOYAMA J, S.WOUTHUYZEN, MJ.MILLER, Y.MINEGISHI, M.KUROKI, SR.SUHARTI, T.KAWAKAMI, KO SUMADHIHARGA, K.TSUKAMOTO
    • Journal Title

      Environmental Biology of Fishes (In press)

    • Related Report
      2006 Annual Research Report

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Published: 2004-04-01   Modified: 2016-04-21  

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