沖合底曳網におけるアカムツとマアナゴに対するコッドエンド選択性に及ぼす角目網ウインドーの効果  [in Japanese] Effect of square mesh window on codend selectivity for blackthroat seaperch and white-spotted conger in offshore trawl net  [in Japanese]

Access this Article

Search this Article

Author(s)

Abstract

日本海西部海域の沖合底曳網で,現在の菱目網(目合内径 33 mm)コッドエンドと,その前半部の両脇部か天井部あるいは両方に角目網(目合内径 72 あるいは 81 mm)を装着した選別式コッドエンド,菱目網(目合内径 79 mm)コッドエンドを用いて,カバーネット操業実験を行った。標本抽出率を考慮した SELECT 解析によりアカムツとマアナゴに対する選択性曲線を推定した。選択性曲線における曳網間の変動は大きいが,平均的な選択性曲線を比較すると,アカムツは天井部から,またマアナゴは両脇部から抜け出やすい傾向がある。<br>

  Covered-codend fishing experiments were conducted to assess the selectivity of a 33-mm diamond mesh codend with square mesh window in offshore pair trawlers. Six types of square mesh window were tested: two mesh sizes of 72 mm and 81 mm mesh openings; and three window positions of top, both-sides, and top & both-sides attached at the anterior half of the codend. Logistic parameters to express the selection curve of each haul for blackthroat seaperch <i>Doederleinia berycoides</i> and white-spotted conger <i>Conger myriaster</i> were estimated by the maximum likelihood method with the SELECT process considering sampling fraction. There were large variations in selectivity parameters between hauls in each type of codend, but no effect of catch size in the codend on the selectivity. The square mesh window had a larger 50% selection length in mean selection curves than the 33-mm diamond mesh codend. The top & both-sides window was most effective to allow fish to escape. For white-spotted conger, the both-sides window was equivalent to the top & both-sides window in selectivity. For blackthroat seaperch, the 50% selection length was larger in the top window than in the both-sides one. The effectiveness of the square mesh window to reduce the bycatch of young blackthroat seaperch while retaining marketable white-spotted conger was also discussed.<br>

Journal

  • NIPPON SUISAN GAKKAISHI

    NIPPON SUISAN GAKKAISHI 76(5), 824-840, 2010-09-15

    The Japanese Society of Fisheries Science

References:  36

Cited by:  3

Codes

  • NII Article ID (NAID)
    10026641623
  • NII NACSIS-CAT ID (NCID)
    AN00193422
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    00215392
  • NDL Article ID
    10844698
  • NDL Source Classification
    ZR26(科学技術--農林水産--水産)
  • NDL Call No.
    Z18-345
  • Data Source
    CJP  CJPref  NDL  J-STAGE  JASI 
Page Top