O / o 



rates of better than 3.0. In the waters between 150 E. and 160 E. , 



in October fishing was generally a good deal poorer thain in areas to 

 the east and west; in November this area of low catch rates is con- 

 spicuously narrower than in October, but in Decennber there still 

 remains an area of poor fishing running obliquely north and south and 

 dividing the fishing in the North Pacific into two parts. 



Annual variation 



There appears to be considerable variation from year to year in 

 the positions at which fishing grounds are formed and in the quality of 

 the fishing on the North Pacific grounds. The reasons for such fluctua- 

 tions are thought to be two: (a) differences from year to year in the 

 amount of fish present; (b) differences from year to year in the move- 

 ments of the fishing grounds. It is difficult to exannine this situation on 

 the basis of data for December alone, so an attennpt will be made to out- 

 line our knowledge of it using data extending throughout the fishing season. 



In figure 1 this area is first divided into four segments of 10 of 

 longitude, these are further divided into segments of 2° of latitude, and 

 the catch rates are shown for each of these sections. 



'\ 



->'i- 



'" x.^— 



•<" 



— \^ 



:j ii 20 :r i'^'u 



33 3T 35 33 3i 



Figure 1. --Catch rates by month and area. 



29 



