@article{oai:ir.kagoshima-u.ac.jp:00004836,
 author = {盛田, 友弌},
 journal = {鹿児島大学水産学部紀要=Memoirs of Faculty of Fisheries Kagoshima University},
 month = {2016-10-28},
 note = {On the fish-catching-fluctuation of the respective hook, based on the variation in the construction of the yellowfin tuna drifting long-line gear and its deformation in the water some experimental researches were carried out, with the measurement of the tension coming on to the main-line and the clarification of the physical basic conditions of the main-line. The results obtained may be summarized as in the following : 1) The main-line of the tuna long-line in the water shows catenary form or its variation. 2) Feeding-ratio of the fish to the respective hook is highest at the hook attached to the dropper hanged from the main-line drifting deepest, and is lowest at the hook attached to the dropper hanged from either end of the main-line drifting shallowest. The shorter is the distance between the buoys at the both ends of the main-line, the bigger becomes the differences in the feeding-ratioes of the hooks. On the other hand, by experiments, it was ascertained that in case of the long-line gear in which the depth at which the droppers are hanged is equal, the difference in the feeding-ratio is negligible. Accordingly, the ratio of the feeding frequency of the tuna at the hook of the dropper hanged deepest, to the feeding-difference between the hook of the dropper hanged from the main-line drifting deepest and the hook hanged from another location of the main-line (x) ; and the ratio of the main-line length between the above mentioned two hooks, to the depth-difference between them (y) were sought out, and the relationship of (x) and (y) was expressed in the following experimental formulas (1~8). 3) Within the range of the identical fishing gear, the effectiveness in the catching faculty of the long line at the respective hook is in the right proportion to the increase of the depth of the hook ; while between the gears with different constructions there is no constant relationship between the depth of the fishing hook and the effectiveness in the catching faculty. Hence it was assumed that the difference in the catching effectiveness between the hooks within one gear is not related with the difference in the vertical density of the fish school, but rather is due to the fluctuations in the arrangement of the hooks, based on the changing deformation of the catenary form of the main-line. 4) The relationship of the enrolling velocity (V) and the main-line tension (T) was measured experimentally, and an experimental formulars were made up. 5) Concerning the three fishing vessels of the three different sizes ; large, middle and small, the main-line tensions under the fishing hours were measured : and the additional tensions of the main-line which is to be brought forth by the hook-dragging fed by tuna and others were also measured and examined.},
 pages = {145--215},
 title = {マグロ延縄漁具に関する研究},
 volume = {18},
 year = {}
}