@article{oai:ir.kagoshima-u.ac.jp:00009277,
 author = {松岡, 達郎 and 小野, 剛 and 川村, 軍蔵 and 石田, 博文},
 journal = {鹿児島大学水産学部紀要=Memoirs of Faculty of Fisheries Kagoshima University},
 month = {2016-10-28},
 note = {In order to reduce incidental catches of sub-legal flounder (smaller than 25cm in TL) in the cuttlefish trammel-net fishery in Southern Kyushu, Japan, a species-selective trammel-net was developed. On the basis of preliminary studies ; (1) observation of behaviour of cuttlefish in a tank and (2) survey of vertical positions of captured cuttlefish and flounder in commercial fishing, semi-demersal trammel-nets which have a space around the bottom were designed. The control net which was similar to commercial nets used in the region and two types of test nets were constructed. In order to make a space, the main net webbing and the footrope were rigged with brown-coloured PA span twine #36. The rigging was vertically zigzag with the width same as that of the outer net, while, two variations were given to the height, i.e. one or half an outer mesh height. These are referred to as test-1 and test-2 nets. A total of 20 operations were conducted in 9 to 23m-deep and sandy/muddy bottomed grounds by two fishing vessels using a set of two each of control, test-1 and test-2 nets respectively. The submersion period of time was the same as that in commercial operations, i.e. 3 to 5 days. There was no significant difference in the numbers of cuttlefish caught by the three types of nets (56 by control, 54 by test-1 and 40 by test-2 nets). The catches of small individuals of flatfishes by the three nets (27, 17 and 3) were significantly different. There was no significant difference in large individuals of flatfishes caught by the three nets (16, 15 and 14). There was also no significant difference in other finfishes from the three nets (171, 171 and 126). The catches including crablet, starfish and shellfishes from the three nets (95, 43 and 58) were significantly different. The experiment was evaluated as having achieved the objectives. The vertical distributions of the caught cuttlefish were not significantly different among the three nets, although there was a common tendency that the lower positions of net caught a larger number of cuttlefish. Flatfishes were also caught in the lowest positions of net. The vertical distributions of small individuals of flatfishes caught by the two test nets were similar to such a distribution excluding the number from the lowest position of the control net. No decline of cuttlefish caught by the test nets was considered to be attributable to the brown-coloured PA span twine used for rigging at the space which might enhance cuttlefish staying around the nets. A hypothesis was proposed that no loss of large individuals of flatfishes occurred for the test nets, while, reduction of small ones was attributable to the swimming layers being different between large and small flatfish and spaces might largely affect the small ones which are conjectured to swim in lower layers.},
 pages = {19--25},
 title = {ヒラメ小型個体の混獲防除を目的とした種選択的コウイカ亜底層三重網の開発},
 volume = {53},
 year = {}
}