底曳網の漁獲性能に関する基礎的研究

• Main Author: 肥後 伸夫
• Format: Report
• Language: Japanese
• Published: 鹿児島大学
• Subjects: 664; Bering Sea
• Online Access: http://hdl.handle.net/10232/00000763; https://ir.kagoshima-u.ac.jp/?action=repository_uri&item_id=771; https://ir.kagoshima-u.ac.jp/?action=repository_action_common_download&item_id=771&item_no=1&attribute_id=16&file_no=1

This research was carried out with the use of the three kinds of trawling net using ofby the fishing boats, namely, trawlers, bull trawlers or Danish seiners belonging to thegroups of the fishing boats of the mother ship fishery, fishing on the continental shelf ofthe eastern part of the Bering Sea including near the shelf, during the term from April to October for the three years of 1963, 1965 and 1967.As to the items of the fishing gears used in this research, in table 3, are shown thetonnage of the fishing boat, its number and the scale of the net used in this experiment.Namely, the number of the monther ship is 3 the number of the fishing boats belongingto those mother ships, is as in the following : ― the number of the side trawlers with tonnage of 370, is 2 that of the stern trawlers with the tonnage of 299, is 3 the total ofwhich being 5 that of the bull trawler with the tonnage of 121 and with the tonnage of98, is 4 and 2 the total number of with being 6 the total number of the Danish seiner is, 11 with the tonnage range from 65 to 92.In case of those trawling nets, in accordance with varieties in the sort of the net, aconsiderable difference is to be noted both in the weight of the ground rope and in thebuoyancy of the float, but the whole lengths of the nets are almost equal.As may be seen in the introduction of this thesis, the purpose of this research is as inthe following : ― through the three sorts of the fishing net used as the materials of thisexperimental research, namely, the trawl net, the bull trawl net, and the Danish seine,the following 3 items were aimed : (1) the attempted clarifications of the fishing efficiencyof the fishing net by means of actual measurements and the model experiments (2) theconfirmation of the fundamental characteristics in the designing and making-up the respectivenet (3) accompanied with the analyses of the physical and biological factors in drawing the design of the trawling net in possession of high effectivity. The experimental methods used in ...