its value as a fishing ground. Furthermore, as regards the catch, the bigeye tuna show a 

 tendency to increase toward the eastward, the spearfishes are most abundant in areas compara- 

 tively close to islands, and the abundance of the albacore seems to be somewhat localized. 

 From these points of view, it cannot be affirmed that all parts of this region have the same 

 characteristics as fishing grounds. 



Table 34 shows in very broad terms the changes in the fishing situation accompanying 

 the change of seasons by dividing the data between the two halves of the year. Needless to say, 

 if the data were more adequate, it would be possible to get a more accurate grasp of the sea- 

 sonal changes in the fishing conditions by a more detailed breakdown of seasons and areas. As 

 there are very few areas for which data adequate to this end have been gathered, a thorough 

 analysis is impossible. In connection with this point, some comments have been made under the 

 heading "The Distribution of the Tunas as Shown by Catch Rates." For one part of this area the 

 fishing situation by months is shown by the following table. 



o o 



Table 35. --Fishing conditions by months (0 - 10 N 



150° - 160° E) 



As records on the measurements of the individual fish in the catch are inadequate, it 

 is not possible to make any comparisons of their areal or seasonal variations. To summarize 

 very roughly, yellowfin of around 35 to 37 kilograms are generally most numerous, those from 

 20 to 30 kilograms and above 40 kilograms appearing to be scarce. A consideration of a certain 

 amiount of data makes it appear that there sire seasonal changes in the size of the fish, but nothing 

 is known for certain. 



As was stated earlier, this region affords rather superior fishing grounds for tuna 

 longline fishing. The most important species in the catch is the yellowfin tuna, followed by the 

 spearfishes. Chjinges in fishing conditions accompanying chcinges in the seasons can be detected, 

 but these changes are comparatively slight, showing that these are generally stabilized fishing 

 grounds throughout the year. 



o o 



Northern part of former South Seas Mandate (10 to 20 N. 



130° to 170° E.) 



This region is in the North Equatorial Current so there are no great changes in the 

 currents throughout the ye£ir, the water always flowing from east to west. In the vicinity of 



71 



