Figure 3. --Vertical tem- 

 perature section 300 

 miles southeast of Cape 

 Nojima (1937). 



It can be seen that the strength of the Kuroshio 

 has declined from the previous month. Figure 3 

 shows the results of observations 300 miles 

 southeast from Cape Nojima and indicates that 

 the strength of the Kuroshio is at its lowest 

 level of the year in February and March. 



Connpared with January, the southern 

 edge of the fishing grounds is about 1 farther 

 to the south. The speed of the southward move- 

 ment is rather slow as compared with the period 

 of October to December and is nearly at a stand- 

 still. It appears that one can say that in the 

 early part of the fishing season the rate of 

 southward movement is great and that it 

 decreases as we approach the end of the fish- 

 ing season. 



In February it is nearly at a standstill, 

 and in March it is completely stopped, with 

 its southern edge at exactly the same position 

 that it occupied in February, while in April 

 there is a general trend toward the north. As 

 for the northern edge of the fishing grounds, 

 it is farther south than in January, and north 

 of 34 N. it is discontinuous except for the 

 areas closer to Japan. Consequently, the 

 north-south extent of the fishing grounds is 

 extraordinarily narrow; east of 150 E. it is 

 less than 300 miles. In the sea areas along 

 the Japanese coast there are still fishing 

 grounds developed fairly far north. East of 

 150 E. the isotherms are from 1 to 2 far- 



ther south than they were in January and are distributed in a compressed 

 pattern. West of 150 E. the Kuroshio has penetrated and there is an 

 invasion, in a complex form, of water masses of rather high tempera- 

 tures considerably to the north. This agrees quite well with the shrink- 

 ing and expansion of the fishing grounds. That is, along the Japanese 

 coasts the extent of the fishing grounds from north to south is broad, 

 and they have developed broadly over most of the Kuroshio intrusion. 

 The isotherms in this sea area have not drawn close together, as they 

 have east of 150 E. longitude, and there is quite a broad space between 

 the 17 and 20 isotherms. East of 150 E. the fishing grounds are about 

 1 farther south thaui they were in January, and their breadth from north 

 to south has decreased, a condition which is in good agreement with the 



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