Table 7 



Number of vessels engaged in the tuna fishery 

 (Compiled by the Oceanic Fisheries Association, 

 based on conditions in the Japanese fishery) 



Year Number of Vessels Tonnage 



Notes? (l) These are index figures with 1931 

 as lOOo 

 (2) The number of vessels in 1938 was 

 about 1,100c 



Comparing tables 6 and 7 it seems that the rate of increase 

 of the number of vessels employed and the rate of increase of the 

 catch roughly parallel each othero If this is really the casej 

 this fact must be said to be of extreme importanceo For it means 

 that although the number of vessels operating has increased^ the 

 boats themselves have increased in size^ and the fishing grounds 

 have in consequence been extended j the annual catch per boat can- 

 not be perceived to have changed very much from what it was before 

 the waro At this stage it cannot yet be thought that the catch is 

 surpassing the natural increase of the tunaso In other words, not 

 only can it be said that there is no indication of overfishing, 

 but the iiif erence can be drawn that this fishery, which has been 

 thought to be lacking in planability, is, in the overall view, sus- 

 ceptible of planning to some degree„ 



Let us add a few considerations anent the third problem, that 

 of the distribution, even or uneven, of fishing grounds and fishing 

 seasonsc 



In the bottom fisheries and the coastal fisheries the fishing 

 grounds are subject to geographical limitations, and these limita- 

 tions are absoluteo In these fisheries, both because of the 

 distribution of the fishes which are their object and because of 

 the fishing techniques employed, the fishing grounds are almost 

 entirely restricted to the so-called continental shelfo Consequently 

 the sea areas suitable as fishing grounds are really only a very 

 small part of the sea as a whole, and they are unevenly distributed. 



In the case of the tuna fisheries the restrictions imposed by 

 the depth of the sea are, in general, exactly the opposite of those 

 imposed in the case of the bottom fisheries o Generally stated,, the 

 sea areas in which tuna are found are centered on the Equator, from 

 which they extend 40"^ - 45° north and southo Accordingly^ all of 



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