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研究延绳钓渔获物的垂直分布结构对于评估延绳钓渔业对目标和兼捕种类的影响具有重要的理论和实际参考价值。根据2007-2010年间2个航次调查采集的热带大西洋公海海域(05°N～15°N,29°W～41°W)金枪鱼延绳钓主要兼捕鱼种的渔获资料,估算了14种渔获物的钓获深度,包括金枪鱼类3种、旗鱼类3种、鲨鱼类3种、其它鱼类3种、海龟2种。当钓钩上浮率假设分别为15%、20%和25%时,最小估算深度分别为122、114和107m,最大估算深度分别为311、293和275m。叉尾长鳍乌鲂的平均钓获深度最深,海龟类的平均钓获深度最浅。四分位距图(IQR)显示,各物种的深度分布范围变化很大,有些种类之间的深度分布中值虽然相近,但深度分布范围却相差很大。除剑鱼外,其余兼捕物种与大眼金枪鱼的深度分布均值均有显著性差异。而除剑鱼和红棱鲂外,其余兼捕物种与大眼金枪鱼的深度分布函数均有显著性差异。聚类分析显示14种渔获物可以分成3种垂直分布结构。
Studying the vertical distribution structure of longline fisheries has important theoretical and practical reference values for assessing the impact of longline fisheries on target and bycatch species. Based on the data of the catch of the major tuna catch of tuna longline in the high seas of the Atlantic Ocean (05 ° N ~ 15 ° N, 29 ° W ~ 41 ° W) collected during the two voyage surveys from 2007 to 2010, 14 species Catch catch depth, including three species of tuna, swordfish three, three sharks, three other fish, two kinds of turtles. The minimum estimated depths are 122, 114 and 107 m, respectively. The maximum estimated depths are 311, 293 and 275 m, respectively, when the hooks float rates are assumed to be 15%, 20% and 25% respectively. The average length of the fins of the black fawn is the deepest, and the average depth of the turtles is the lowest. The interquartile range map (IQR) shows that the depth distribution range of each species varies greatly. Although the median depth distribution of some species is similar, the depth distribution range is quite different. In addition to the swordfish, there was a significant difference in the depth distribution of the other bycatch species and the big-eye tuna. In addition to the swordfish and Rhodospirillum japonicus, the depth distribution function of other bycatch species and the big-eye tuna were significantly different. Cluster analysis showed that the 14 catch species could be divided into three vertical distributions.