6. Variations in fishing conditions with longitude coincide completely in their 

 trends, although there are Sonne differences in the actual catch rate values. 



7. The changes from month to month in fishing conditions for each species are 

 also sinnilar, but it looks as if the peak season for spearfishes is about 1 month 

 later in this sea area. 



The facts listed above show that this sea area is more closely related to the area 

 adjacent to the south than to that on the west. In addition to the tunas and spearfishes there is a 

 considerable catch of sharks, and therefore it can probably be said that, aside from the slack 

 seasons of spring and autumn, this sea area affords rather good fishing grounds for small and 

 medium boats. In the summer, besides the longline fishery, a harpoon fishery for spearfishes 

 and pole-and-line fishing for small tuna and albacore are carried on. The weather, as is gener- 

 ally known, is extremely calm in the summer except when typhoons are originating. During the 

 winter strong westerly winds blow continuously and the sea becomes quite rough with consequent 

 difficulty in operating. 



13. Northeastern sea area (35° N. , 140° to 1 50° E. ) 



The area north of 35 N. latitude and between 140 and 150 E. longitude will be 

 described as the northeastern sea area. Its northern boundary is in the vicinity of 42 N. 



At the height of summer a part of the Kuroshio flows northward or north-northeast- 

 ward from the vicinity of Inubo MisaJci and passes through this sea area. The Oyashio flows 

 southwestward from the Kurile Islands area in a direction roughly opposite to that of the 

 Kuroshio. This current generally becomes submerged, but here and there it flows in wedge- 

 shaped tongues into the Kuroshio. Also at times parts of the warm or cold currents get cut off 

 from the currents of origin and beconne isolated water nnasses within different currents. Very 

 close to the coast in the Sanriku area of northeastern Japan a tail end of the Tsushima Current, 

 which has come through the Tsugaru Strait, flows southward. In the winter the strength of the 

 Oyashio increases and it forces the Kuroshio southward so that the influence of the Kuroshio does 

 not extend to the northward, but is deflected eastward into the central Pacific. The tail end of 

 the Tsushima Current which has come .through the Tsugaru Strait flows weakly south along the 

 coast. 



The foregoing is an outline of the distribution of ocean currents in this sea area, but 

 because of this clash of sea currents of completely different character and because of the annual 

 or seasonal differences in their strength, there aire rather conspicuous fluctuations in oceano- 

 graphic conditions fronn year to year, and in many cases there are violent short-ternn fluctua- 

 tions so that the situation is a great deal more complicated than in the tropical and subtropical 

 regions. 



The following tables present oceanographic data for this sea area abstracted from the 

 Report of Oceainographic Works for 1937. 



As the table shows, the distribution of water temperatures in Jzmuary is 

 approximately uniform up to about 100 miles off the coast with temperatures of about 10. 5 C, 

 and with almost no change from the surface to the 100-meter levels In the vicinity of 150 miles 

 off shore the water temperatures fall rather conspicuously to 8. 6 C. at the surface and 8. 1 C. 

 ^t the 100-meter level. 



o 



In February the water temperatures are everywhere conspicuously lower, falling 2 



to 4 C. At a point 50 miles off the coast the water temperatures at all levels from 10 meters 

 on down are conspicuously lower than those at other points. At the station 150 miles off the 

 coast just as in January the vjilues are low at cill levels. 



107 



