クロソイはえなわの投・揚縄速度

概要

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The variation of speeds of shooting (270 skates in 18 strings) and hauling (239 skates in 16 strings) of a skate of rockfish bottom longline by 50-ton FRP longliner was examined in the present report. And the results obtained were summarized as follows: 1. The shooting speed of a skate ranged from 24 to 47 seconds, and its frequency distribution was agreeable to normal distribution ( ?? =35.93, σ=3.31). 2. The speed of shooting a skate (y1 in seconds) varied according to string and could be expressed by the following equations: y1=35.82+2.76x2+2.07x3-1.02x4 (Multiple correlation: R=0.668) where x2 and x3... Dummy variables of wave scale (in case of a wave scale i+1, xi=1, other with 0) x4...cos fo the relative direction of wind against foreship y1=37.83-0.34x4+0.44x5 (R=0.625) where x4 and x5... Fore-and-aft and athwartships vectors fo relative wind 3. The hauling speed of a skate was afficed significantly by troubles in main line. The retardation by tangling was about 1.4 to 3.2min, by main line fastened to bottom object being about 4.0min, main line torn-off being about 4.6min, main line torn-off and dropped being about 10.5 to 12.3min and main line tangled with anchor line being 9.5min. 4. The string mean of hauling speed of a skate without trouble ranged from 3.6 to 5.1min, varying according to string, but did not show any significant regression either on hauling conditions or on catch.