1. North Pacific Ground 



Figure la euid b shows the general distribution if isotherms on 



this fishing ground based on data supplied by commercial fishing vessels 



(only the data for the period of February 10-15 are used). Figure la 



uses data for 1950, and figure lb data for 1952. All of the isotherms 



are 2 to 3 farther south than they wete in January. The 19 C. isotherm 



o o 



has moved fairther south than the 20 C. isotherm, and the 18 C. isotherm 



has moved south more than the 19 C. isothernn, with the result that these 



isotherms are closer together and the change in temperature from north 



to south is more abrupt. However, in both years in the waters west of 



150 E. the 19 C. isotherm and the 18 C. isotherm are rather far apart, 



and it is the isotherms above 19 C. that are close together. 



1950 



f. 



T 



:: 



Tme" 



^^=i#'=g'^ 



TbFc' 



1952 



Figure 1. --Distribution of surface water 

 temperatures in the North Pacific. 



Consequently, in the 

 general view, the North 

 Pacific Current is flowing 

 to the eastward through sea 

 areas farther south than 

 those in which it flowed in 

 the preceding month. Look- 

 ing at the areas east of 150 E. , 



in 1950 the 19°C. and 20°C. 



o 

 isotherms are south of 30 N. , 



o 

 while the 18 C. isotherm 



runs east and west crossing 

 back and forth over the line 

 of 30°N. In 1952 the south- 

 ward movement was some- 

 what slower than in 1950, 

 and the 18 and 19 C. iso- 



60 120' (80' 



Figure 2. — Vertical tem- 

 perature section due east 

 of C ape Inubo (1936). 

 From Semi-ann. Rpts. 

 Oceanog. Observations. 



therms are approximately 

 on the latitude of 30°N. , while the 2 0°C . 

 isotherm runs somewhat south of 30 N. 



o o 



In the area around 140 E, to 150 E., 



where the Kuroshio turns to the eastward, in 



both years the 18 C, isotherm extends out 



farther to the northward than in the area of 



150 E. and is in about the vicinity of 32 N. 



At times it extends out in a tongue to the 



southwest, re aching to the westward of 140 E, 



Figure 2 shows the results of sectioned, 

 observations due east from Cape Inubo in 1936. 



80 



