Taking a general view of the whole area of 35 to 40 N. 



150° to 180° E. 



it is, as 



has already been stated, aui extraordinarily good albacore ground. The fishing season is from 

 October to January, with the peak in December. The albacore are distributed all over this sea 

 cirea, but there is some difference in fishing conditions from east to west so the distributional 

 pattern is thought to differ. Not only is a difference in the density of distribution detectable, but 

 there appear also to be loczil differences in the size of the fish that are taken, and on the basis 

 of these differences Uda has reported the existence of three groups of fish. Differences from 

 north to south in fishing conditions appear mainly to accompany the seasons, and there seems to 

 be a tendency for the fishing season to be somewhat earlier in the north and later in the south. 



The species next to the albacore in importance is the bigeye tuna. Bigeye catch 

 rates are shown to be higher in the south and to gradually decrease to the northward. No very 

 marked differences in fishing conditions can be detected in an east-west direction, although there 

 appears to be some tendency for catch rates to be higher in the east and lower in the west. The 

 fishing season is from October to December, with the peak of the season in the latter nnonth. 



Spearfishes are generally scarce, most of them being striped marlin and broadbill. 

 Striped marlin catch rates are highest around October, after which they gradually decline to 

 December and then drop off sharply in January. The situation in the summer is unknown be- 

 cause data are completely lacking. Broadbill swordfish gradually increase from October on and 

 attain their highest catch rate around December. Considered geographically, both the striped 

 marlin and the broadbill show a tendency to be nnost abundant in the extreme western part of this 

 sea area and to decrease as one goes eastward. This tendency appecirs particularly conspicuous 

 in the case of the broadbill. In a north-south direction, striped marlin are more abundant in the 

 south and broadbill in the north. Black tuna and yellowfin are almost entirely without signifi- 

 cance in the catch. Shark catch rates tend to be high in the west and low in the east, and if con- 

 sidered in terms of latitude, they appear to be generally high in the south and low in the north, 

 but because many of the data are deficient, there appears to be need for further analysis of the 

 catch rates given in the foregoing tables. 



16. Area of 40° to 43° N. 



150° to 



55° E. 



This sea area is located at the extremity of the tuna longline fishing grounds, so the 

 season is short and the species in the catch are limited. 



There are few data from investigations in this area, and table 110 summarizes them. 



Table 110. --Fishing conditions at 40 to 43 N. , 

 150° to 155° E. 



The overall average catch rate for tuna and spearfishes is only 0. 8. As the table 

 shows, there are no records at all of captures of black tuna or yellowfin. Catches of bigeye tuna 

 and albacore are almost vestigial, and the spearfishes are the main part of the catch. Some 

 sharks are also taken, indeed, shark fishing is, as will be related below, rather active. 



Data exist only for the months of October and November, and the following table 

 gives a comparison of fishing conditions in these two months. 



135 



