Table 10. --Size composition (numbers of fish) of 

 albacore taken in middle latitude waters 



(3) Grounds of Tropical Seas 



In general the catch rates are lower than they were in January. 

 In the Palau area the catch rate is down below that of the preceding month, 

 but many areas with catch rates above 0.2 are noted where the albacore 

 schools seen from Novennber to January are lingering on. In March the 

 catch rates become extraordinarily low, and it is thought that February 

 is the season at which the Palau population is in the process of disappearing. 

 We have no data on the size of fish in the Palau group, but believe that they 

 are of about the same size as in the preceding month. In the area of 0_ to 

 4°N. , 140 E. to 150 E. , the average weight of the albacore is 6 kan /50 

 lbs. /which is smaller than the fish of the mid-latitude areas. 



MARCH 

 General 



Indications of the decline of the fishing grounds are conspicuous 

 and all grounds look to be in their final stage of the fishing season. There 

 are no longer any noteworthy catches in the South Sea areas. Around Okino- 

 torishima, cases of catch rates of 2.0 or more are still seen, but the catch 

 rates appear to have fallen around the edges of that fish ground. On the 

 fishing grounds north of the Subtropical Convergence (North Pacific ground 

 and Kinan ground) absolutely no southward movement of the southern edges 

 is seen, indicating that the southward nnovement has already stopped. On 

 the other hand, the northernmost portions of the fishing grounds are conspi- 

 cuously fading out, and either there is no operation at all north of 32 N. or 

 the catch rates are extraordinarily low. Between 140 E. and 150 E. in 

 February there was a continuous row of areas of high catch rates extending 

 to the vicinity of 35 N. , but in March this drops off conspicuously. As a 

 result, the fishing grounds have a breadth from north to south of about 200 

 miles and extend from 130 E. to 170 W. The overall average catch rate 

 for the areas east of the Ogasawara and Izu archipelagoes, which was 3.98 

 in February, is 2.42 in March, while in the areas to the west of the islands 

 the 2. 73 catch rate of February is down to 2. 31 in March, indicating that 

 the end of the fishing season is approaching. One noteworthy thing, however, 



96 



