抄録
The tuna long line fishing in business is one of the most important fishing in Japan. But the catch of fishing decreases recently, so clippers are obliged to go out deep sea and to stay at sea for long time. The clippers have to become larger and larger and have large power engine for sake of compensating the loss of economy. There should be an opposite properties between fishing abilities and navigational requiements. We can not ease to take off this custom on the charactaristics of fishing. Author collected the data of tuna long line fishing boats more than 120 in number and compared the boats which were built after 1963 with the ones were built before 1962, and tried to solve in this problem on view point of both economical and fishing ability.
