3. Speaurfishes are somewhat more abundant in this ajea, yellowfin are nnore 

 abundant in the Nankai sea area, and there is almost no perceptible difference 

 in bigeye tuna. 



4. As for changes in fishing conditions from month to month, in the case of the 

 most important species, the spearfishes and albacore, it appears that the 

 fluctuations in fishing conditions show almost identical trends in the two sea 

 areas. However, it appears that the peak of the albacore season is somewhat 

 later in the Nankai sea area than in this area. 



5. The highest catch rate for bigeye tuna in the Nankai sea area occurs in October, 

 auid it is difficult to make a comparison with this sea area because of the paucity 

 of data. 



6. The east and west sides of the Izu Islands show almost the same catch rates for 

 spearfishes, but the species are not necessarily the same, as will be explained 

 later. 



It is observed that the fishing grounds to the east and west of the Izu Islands are not 

 quite the same in character but have sonnewhat different characteristics. 



Table 74. --Distribution of the data by months and areas 

 (sea area east of Izu Islands) 



Nate: The catch rate is combined for tunas and spearfishes. 



If this sea area is further compared with the northern part of the waters adjacent to 

 the Ogasawara archipelago on the south, 



1. There is no great difference in the black tuna catch rates. 



2. Yellowfin are somewhat less numerous in this sea area. 



3. Bigeye tuna are somewhat more abundant in this sea area. 



4. Albacore catch rates show values of about 1.0 per hundred higher in this sea area. 



5. Spearfishes are somewhat less abundant in this sea area. 



106 



