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

On-board survey of the fishing gear loss rate in the crab trap fishing ground in the Sea of Japan，在3个国家和under-water observation of theconsequent changesin entry and death of crabs in deliberatery -set derelict traps were conducted. Theghost-fishing mortality in a trap was represented with an experimental and theoretical equation as；​f_g(t) = a(1-c^t) / (1-b) Annual gear loss rates were 0.2 in Japanese crab-trap fisheryat the Seaof 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 againstghost fishing to have an additional function to increase large individuals in catch。

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.