Development of the Size Selectivity Theory of Angling Gear

研究了鱼体尺寸的影响以及垂直器主要部件特性对垂直度的影响。发现了这些因素与尺寸选择性之间的关系，从而发展了倾角齿轮的尺寸选择性理论1)钩子进入口腔模型的过程是由流体阻力引起的。模型中大鱼钩或大诱饵的最大进入距离大于小鱼钩。但大钩的入口率低于小钩。考虑入口比，大钩的最大进入距离的总平均值小于小钩。2)对于长钩，最大进入距离随杆接触模型入口上部而发生变化。对于圆型钩，当柄接触入口处时，最大进入距离似乎没有变化。3)根据垂钓实验估算的硬入饵系数，对于给定的鱼大小，存在一个合适的诱饵大小。诱饵大小与硬入系数有关。由于没有简单的直线关系，所以很难建立数学模型。4)由于在吊钩机构的随机模型中引入了进入距离的限制，该模型可以适用于更多的垂度现象。进入距离的极限与口腔、鱼钩和诱饵的大小或形状之间的关系将在未来进行调查。

In this study, the influence of fish size and the influence of the characteristics of the main components of angling gear were investigated. A relation between those factors and size selectivity was found, so the size selectivity theory of angling gear was developed.1) The entering process of a hook into the model of a mouth cavity occurred by fluid resistance. The maximum entering distance of a big hook or a big bait in the model was longer than a small one. But the ratio of entrance of a big hook was lower than for a small one. Considering the ratio of entrance, the total average of the maximum entering distance of the big hook was shorter than for the small one.2) For the long type hook, the maximum entering distance changed when the shank touched the upper part of the entrance of the model. For the round type hook, it did not appear that the maximum entering distance changed when the shank touched the entrance. And this hook had an advantage for hooking because the hook point easily touched the upper inside of the model.3) It was shown that a suitable bait size existed for a given fish size, according to the hard entering coefficient estimated by angling experiments. Bait size was related to the hard entering coefficient. Because there was not a simple relation, such as liner, it was difficoult to construct a mathematical model.4) As the limit of entering distance was introduced in the stochastic model of the hooking mechanism, this model could be fit on many more cases of angling phenomenon. The relation between the limit of the entering distance and size or shape of a mouth cavity, a hook, and a bait will have to be investigated in the future.