and the inactivity of skipjack at Truk and Ponape implied that the water 

 temperatures at the surface were low. The author then surmised that the 

 reason why the countercurrent area became unsuitable as a fishing ground 

 for yellowfin tuna was the same adverse oceanographic conditions. Condi= 

 tions in the waters adjacent to Palau have since been restored and it 

 appears that, with the exception of the effect produced by bad weather, 

 bonito fishing has become normal since the latter part of Mayo Skipjack 

 fishing at Truk and Ponape also improved about the same period and the 

 tuna fishing grounds centered at 150° also shifted northwards Consequently , 

 it is believed that possibly the conditions in the countercurrent area 

 centered at 150^ are also restored, as in the adjacent waters of Palau. 



From the above, it is believed that the slack in fishing resulting 

 from the adverse conditions in the countercurrent centered at 150° is 

 temporary. When oceanographic conditions are back to normal and fishing 

 improves to its former level, it is proper from the standpoint of fishing 

 management for the fishing ground to shift northward to the north latitudes^, 

 With fuel oil limited as it is today, the equatorial countercurrent^ vrtiich 

 is usually inhabited by a large number of yellowfin tuna, probably will 

 hereafter show increasingly its true worth as the main tuna fishing ground 

 in the Inner South Seas, 



Report of 

 Oceanographic Changes and Fishing Conditions in Palau Waters 



A tuna fishing survey of the seas south of the Palau group was conducted 

 in conjunction with the oceanographic survey of the sea areas within a 600 

 mile radius of Palau from January to March of this year. As a result, our 

 knowledge of oceanographic conditions in Palau waters has been clarifiedo 



According to the results of the survey, the northern limit of the equa- 

 torial countercurrent area south of the Palau group (west of 134.^30' east 

 longitude), as compared to that of normal years, showed a southward shift of 

 0.5° to 1° so that the northern limit was at north latitude 5°30 ' or 6°. The 

 southern limit west of 134.'^30 ' east longitude showed a southward shift of 1° 

 30 that it was at north latitude 3°. The southern limit east of 13^°30" east 

 longitude showed a shift of 1° to 2° so that it was at north latitude 2° or 

 1 . In short, the northern limit of the equatorial countercurrent area, which 

 should be around 7°30' or 8° north latitude in the vicinity of 13B° or 137° 

 east longitude, shifted southward to about 4° north latitude. The western 

 shores of the Palau group, therefore, were all exposed to the main current 

 of the northern equatorial current. The northern equatorial current also 

 flowed westward from the western shores of the Palau group to 130° east 

 longitude without any penetration by the branch currents of the equatorial 

 countercurrent. For this reason, all of the Palau Islands were in the 

 northern equatorial countercurrent area. 



Jt5r 



