Application of standard method for extensive estimation of ghost-fishing mortality to international fishing ground

• Project/Area Number: 21580231
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: General fisheries
• Research Institution: Kagoshima University
• Principal Investigator: MATSUOKA Tatsuro 鹿児島大学, 水産学部, 教授 (80244268)
• Co-Investigator(Kenkyū-buntansha): ANRAKU Kazuhiko 鹿児島大学, 水産学部, 准教授 (50274840)
• Project Period (FY): 2009 – 2011
• Project Status: Completed (Fiscal Year 2011)
• Budget Amount: ¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000); Fiscal Year 2011: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2010: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2009: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
• Keywords: ゴーストフィッシング / 逸失漁具 / 漁業 / 資源管理

Research Abstract

On-board survey of the fishing gear loss rate in the crab trap fishing ground in the Sea of Japan, interview surveys of fishing gear loss rates in 3 countries and under-water observation of the consequent changesin entry and death of crabs in deliberately-set derelict traps were conducted. The ghost-fishing mortality in a trap was represented with an experimental and theoretical equation as; f_g(t) = a(1-c^t)・(1-b)^t. Annual gear loss rates were 0.2 in Japanese crab-trap fisheryat the Sea of Japan, 0 in coastal fisheries in Thailand and Tanzania, while 0.08 to 0.23 in coastal fisheries in Southern Kyushu. Escape-ring as a countermeasure against ghost fishing was proved to have an additional function to increase large individuals in catch.