Relationship Between Catch and Fishing Conditions in Domesticated Yellowtail Fishing in Nagasaki Pref., Japan
1977 Volume 43 Issue 3 Pages 271-275
Details
1977 Volume 43 Issue 3 Pages 271-275
1. Fishing ground of domesticated yellowtail distribute in sea areas where the Tsushima Current directly flows. The best fishing season is the period from Septembe to October.
Body size of the yellowtail caught is smaller in Tsushima fishing grounds than in Goto Islands, and larger in the deeper fishing grounds.
2. There are rocks 20-40 m in height on the sea floor 50-75 m deep in the fishing grounds. Sea deposits around the rocks are white sands and the sea conditions of almost all fishing grounds are satisfactory.
Considering sea depth of the fishing grounds, height of the attraction points, sea deposits and other factors in relation to the catch, any especially good condition for catch can not be recognized.
3. It is likely that there are relationships between quantity of ground-bait and catch, because the ground-bait might be controlled in accordance with the amount of the yellowtail catch.
There are two groups of the yellowtail, one which shows small catch in spite of high efficienoy of the ground-bait, and the other shows large catch in spite of low efficiency of the ground-bait. The reason why these two groups are seen is an economical problem that there is a difference between a boss who wants to ger more catch by using less quantity of the gron-bait and a boss who wants to ger more catch by using much ground-bait.
