漁獲の事故の影響 (マグロ延縄の揚縄速力-1,2-〔英文〕)

概要

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The present report showed the outline of hauling speed and the influence of catch and accident on it observable in the records collected from the hauling work of the 10 strings of tuna longline about at 155°E near the Equator conducted by the Choho-maru (266 gross tons), And the results obtained were summarized as follows: 1. Among 4, 323 sections (a section was 306m long with 5 branch lines), 2, 984 sections were hauled up without catch and accident. The hauling speed of most of them was 75 to 95 seconds, the average being 85.7 seconds, i. e. 80% of the full speed of the line hauler. 2. The retardation of the hauling speed by catch increased with its commercial value: A medium-sized yellowfin needed an additional time of 20 seconds, a small one 10 seconds, a medium-sized bigeye 36 seconds, and a small one 6 seconds on the average. 3. The retardation by a shark or a trash fish averaged 10 seconds, but damaged fish needed no additional time. 4. As much as 7% of the time engaged in the hauling work was expended on the disposal of the entangling and snapping of the mainline.
日本水産學會の論文