Table 3. --Coefficients of 

 varieince of catch on the 

 North Pacific ground 



From December on there is a gradual 

 narrowing of the north-south extent of the fish- 

 ing grounds, and the form that it takes is a 

 fading-out of the northern edge of the grounds. 

 What this means is that the areas where the 

 fishing is unstable gradually cease to be fished. 

 It is thought that this is because the schools 

 which are being pushed south from the northern 

 areas have declined in numbers and, as a result, 

 all that is left is the accumulation of schools in 

 the fishing grounds along the southern edge. 



Table 4. --Length composition (%) of albacore landed from the North 

 Pacific ground. Mean weights are in kan = 8.27 lbs. 



Note: Underlined figures are the nnost numerous length classes. 



Size of fish 



In general, the tendency for the fish to be larger in the east than 

 in the west and smaller in the north than in the south continues. The fish 

 are smaller thaji in the preceding month, a trend which is particularly 

 outstanding in the fishing grounds of the southern edge. 



Table 5. --Monthly changes 

 in mean weight (in kan ) in 

 the North Pacific at 30°- 

 32°N. 



Table 5 shows a comparison of the 



changes from month to month in the average 



weight of the fish as between the area of 



140 E. to 150 E. , where the fish are small- 



o o 



est, and the area of 170 E. to 180 , where 



they are largest. (Since there is also a 



difference in size from north to south, the 



comparison is based on landings from areas 



along 30°N. to 32°N. ) 



104 



