We can see certain local differences in the construction of the fishing gear. On the 

 distant grounds off to the east lines especially designed to take albacore have been much used in 

 the past, and the data which we have handled here are mainly derived fronn this type of line. 

 These longlines usually have a large nunnber of short branch lines. Here and there they have 

 long branch lines called "burakuri", which are said to be intended to catch bigeye tuna. Long- 

 lines of this construction are not used on the fishing grounds of the northeastern area, where 

 spearfishes and tuna other than the albacore are the objective of the fishery. Consequently, 

 room is naturally left for further examination of the appropriateness of discussing the distribu- 

 tion of species and the characteristics of fishing grounds on the basis of the catch rates, as was 

 done in the foregoing. There will doubtless be opportunity for further discussion of this problem 

 in later chapters. 



o o 



Table 104. --Fishing conditions by sections (35 - 40 N. , 



160° - 170° E.) 



In table 104 this sea area has been divided into five parts of 2 of longitude each, and 

 fishing conditions within each of these sections are presented separately. From the table we can 

 see that catch rates for bigeye tuna are low in the extreme western portion and in the center, 

 with fairly high catch rates everywhere else. Albacore catch rates in the central portion are 

 extremely high but tend to decline gradually to the westward. To the eastward they fall off sharp- 

 ly. Differences between localities in the fishing conditions for the spearfishes are not conspicuous. 

 Sharks, on the whole, like the spearfishes are much less abundant than in the area fronn 150 to 

 160 E. As for localized differences, there is clearly a trend for the catch rates to be high in the 

 west and low in the east. 



If we compare this area with the area of 30 - 35 N. , which adjoins it on the south, 

 it is difficult to find any common trends for the principad items in the catch, which are bigeye 

 tuna, albacore, and specurfishes. 



The data are almost confined to the two months of November and December, so 

 seasonal changes in fishing conditions are not clear, however, the data have been assembled in 

 table 105 so as to show changes in fishing conditions from month to month. 



For all species other than albacore the November catch rate values are higher than 

 those for December. Albacore in December have an extraordinarily high catch rate of slightly 

 more than 16.8. The situation in January is not clear because of the paucity of data, but the 

 possibility of rather large catches is indicated. The data for February are also extremely poor, 

 but they too appear to indicate the possibility of fairly high catch rates. 



131 



