Table 5. --Frequency of coefficients of variation of catch rates in 

 unit areas east of 150 E. longitude 



Table 6. --Average weight (in kan = 8. 27 lbs. ) 

 of albacore landed from the North Pacific 

 ground in March. Figures in ( ) are ratio 

 to February 



2, Kinan Ground 



Figure 5 presents the results of sectional observations made to 

 the south-southeast of Cape Ashizuri in 1936. There is a good deal of 

 difference in the water temperatures at intermediate levels as between 

 the main stream of the Kuroshio and the gyre area; in 1936 there was a 

 conspicuous boundary in the vicinity of 31°N. , and south of it, in the gyre 

 area, the difference between tennperatures of the upper and lower levels 

 was slight. A similar small difference in the temperatures at upper and 

 lower levels within the gyre area was found as a result of sectional obser- 

 vations south of Cape Shionomisaki in January. The distribution of the 

 surface isotherms is shown in figure 6, where it is indicated that the water 

 temperature at the surface was about 1 lower than in Jcinuary. 



The cases with the highest catch rates are in the gyre region, 

 where there is little difference between the water temperatures at the 

 upper and lower levels, eind in the sea areas adjacent to it on the south 



87 



