縦延縄漁具の漁獲過程について〔英文〕

概要

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The capture process in vertical longline fishing was studied on the basis of field experiments along a barrier reef off Port Moresby, Papua New Guinea. Fishing results were analyzed with respect to a variable soaking period and hook position. The numbers of bait retention and fish/hook contacts were compared to the numbers of recorded hooks. The numbers of bait loss, line break and catch were compared to the number of contacts. The contact ratio increased with soaking periods and decreased with hook heights. The bait-loss ratio was constant against a soaking period and greater on low hooks. The break ratio increased with soaking periods. The catch ratio was large on intermediate and upper hooks and levelled off in longer soaking. Satura-tion in fishing efficiency when lines were soaked for a long time was interpreted by a 'contact-re-tention' model. The physical injury suffered by fish during escape and line break may induce mortality and has an implication for fishing efficiency and resource utilization.
日本水産學會の論文