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2004 Fiscal Year Final Research Report Summary

Evaluation of separation performance on selective fishing device for fisheries resources management.

Research Project

Project/Area Number 14560145
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field General fisheries
Research InstitutionTokyo University of Marine Science and Technology (2004)
東京水産大学 (2002-2003)

Principal Investigator

TOKAI Tadashi  TUMST, Faculty of Marine Science, Professor, 海洋科学部, 教授 (30237044)

Co-Investigator(Kenkyū-buntansha) HU Fuxiang  TUMST, Faculty of Marine Science, Associate professor, 海洋科学部, 助教授 (80293091)
SHIODE Daisuke  TUMST, Faculty of Marine Science, Assistant professor, 海洋科学部, 助手 (40361810)
Project Period (FY) 2002 – 2004
Keywordsfishing gear selectivity / selection device / separation efficiency / size selection / capture process / contact probability model / dredge
Research Abstract

The size selection curve of fine mesh for Anchovy larvae were estimated by using an extended SELECT model for analyzing size frequency distribution constructed from pockets catches and sampling the cod-end catches, and from covered-net experiments. Higher catch volume were decreasing escape opportunities and selectivity.
Capture process of clam by dredge was modeled. First, Master curve equation of size selectivity of dredge bagnet for a clam, equilateral Venus Gomphina melanaegis was estimated by using cover-net fishing experiments with test bagnets of several mesh sizes. The size selectivity of dredge bagnet was a kind of contact selection of bagnet mesh. Second, The effect of various tooth-spacing on the contact selection and the net-mouth available selection of a dredge for the equilateral Venus clam Gomphina melanaegis was evaluated by applying a contact-probability model based on the SELECT method to the data of paired-gear tests with a control dredge of 12mm tooth spacing and fou … More r test dredges of tooth spacing 16,20,24,and 35mm. A master selection curve was estimated to be s(R)=exp(-11.23R+4.799)/[1+exp(-11.23R+4.799)], where Ris Id, the ratio of the shell length 1 to the tooth spacing d. The shell width of 50% retention was slightly smaller than the tooth spacing, which means that size selectivity of teeth was a type of contact selection which was dependent on the tooth spacing. Contact probability δ of the clams coming into contact with the teeth were 0.625,0.467,0.563,0.670,and 0.976 for tooth spacing 12,16,20,24,and 35mm, respectively. This indicates that some clams entered the dredge bagnet without contacting the teeth as the sand clogging the tooth spacing carried them into the bagnet. Available selection curve of the dredge net-mouth with teeth was obtained as δ s(R)+1-δ and examined in terms of the minimum landing size of the Venus clam.
A method for assessing species-separation performance of size-selective fishing gear is presented. Species composition in catch by selective fishing gear is often discussed to assess the performance of the selective device. However, the catch number (and weight) depends on body size composition in the population when the fishing gear has size selectivity, and thus species composition varies and is not suitable as gear performance index. In fact some selective devices, e.g.mesh panel, grid, and escape-vent have been reported to be size-selective. When a selective device has retention probabilities of body size 1, r_w(l) and r_u(l) for wanted and unwanted species, respectively, separation efficiency p(l_w, 0l_u) between l_w size wanted and l_u-size unwanted species is defined as r_w(l_w)+[1-0r_u(l_u)]-1. The efficiency is 1 when wanted species is completely retained and unwanted is excluded as expected, and is -1 in the exact opposite of the expectation. The equation implied that the separation efficiency is likely to be high as there is larger difference in body size between the two species. Less

  • Research Products

    (15 results)

All 2005 2003 Other

All Journal Article (14 results) Book (1 results)

  • [Journal Article] 多種混獲漁業での魚種別の獲り分けはどの程度可能か?2005

    • Author(s)
      東海 正
    • Journal Title

      月刊海洋 37・3

      Pages: 228-234

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] 船曳網コッドエンドに使用されるモジ網のカタチイワシシラスに対する網目選択性の推定2005

    • Author(s)
      斎浦耕二, 東海 正
    • Journal Title

      日本水産学会誌 71・1

      Pages: 24-32

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] コタマガイに対する桁網袋網の網目選択性2005

    • Author(s)
      金 仁〓, 曹 台鉉, 朴 倉斗, 東海 正
    • Journal Title

      日本水産学会誌 71・1

      Pages: 54-59

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Modelling the contact probability and size-selectivity of toothed dredges2005

    • Author(s)
      Mituhasi, Kitakado, Hu, Tokai
    • Journal Title

      Fisheries Science 71(印刷中)

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Effect of tooth spacing on the contact selection and net-mouth available selection of a dredge for Venus clam2005

    • Author(s)
      Kim, Mituhasi, Jo, Park, Tokai
    • Journal Title

      Fisheries Science 71(印刷中)

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] How is species-selective catch possible in multi-species fisheries?2005

    • Author(s)
      Tadashi Tokai
    • Journal Title

      Kaiyo Monthly 37-3

      Pages: 228-234

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Mesh selectivity of minnow netting used at codend of boat seine fishing Gear for anchovy larvae.2005

    • Author(s)
      Koji Saiura, Tadashi Tokai
    • Journal Title

      Nippon Suisan Gakkaishi 71(1)

      Pages: 24-32

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Mesh selectivity of dredge bagnet for a clam, equilateral Venus Gomphina melanaegis2005

    • Author(s)
      In-Ok Kim, Tae-Hyun Jo, Chang-Doo Park, Tadashi Tokai
    • Journal Title

      Nippon Suisan Gakkaishi 71(1)

      Pages: 54-59

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] ポケット網実験から推定したカタクチイワシシラスに対する船曳網の網目選択性2003

    • Author(s)
      斎浦耕二, 東海 正
    • Journal Title

      日本水産学会誌 69巻・4号

      Pages: 611-619

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Statistical estimation in cover-escape model covered-codend experiments2003

    • Author(s)
      T.Kitakado, T.Mituhashi, T.Tokai
    • Journal Title

      Fisheries Science 69・4

      Pages: 1233-1241

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Mesh selectivity of boat seine fisheries for anchovy larvae on pocket-nets experiment.2003

    • Author(s)
      Koji Saiura, Tadashi Tokai
    • Journal Title

      Nippon Suisan Gakkaishi 69(4)

      Pages: 611-619

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Statistical estimation in cover-escape model covered-codend experiments.2003

    • Author(s)
      Toshihide Kitakado, Takahisa Mituhasi, Tadashi Tokai
    • Journal Title

      Fisheries Science 69(4)

      Pages: 1233-1241

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Modelling the contact probability and size-selectivity of toothed dredges.

    • Author(s)
      Takahisa Mituhashi, Toshihide Kitakado, Fuxiang Hu, Tadashi Tokai
    • Journal Title

      Fisheries Science 71(3)(in press)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Effect of tooth spacing on the contact selection and net-mouth available selection of a dredge for Venus clam.

    • Author(s)
      In-Ok Kim, Takahisa Mituhasi, Tae-Hyun Jo, Chang-Doo Park, Tadashi Tokai
    • Journal Title

      Fisheries Science 71(3)(in press)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Book] 漁獲選択性の解析手法2003

    • Author(s)
      東海 正(編著)
    • Total Pages
      48
    • Publisher
      社団法人 日本水産資源保護協会
    • Description
      「研究成果報告書概要(和文)」より

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Published: 2006-07-11  

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