In Table 9 the line (v) shows data for the vicinity of Sunda Strait. 

 The catch rate is not greatly different from that obtained north of the 

 Equator, but the size of the yellowfin is markedly different. In (vi) 

 the reason for the large size of the yellowfin taken was probably that the 

 fishing grounds had shifted far to the north of their normal positions. 



The foregoing is an extremely summary presentation, but it seems to 

 show clearly the differences between the schools north and south of the 

 Equator. Seasonal changes are not known because of the lack of data. 



(c) Coastal waters of the Andaman and Nicobar archipelagoes (6 

 90° - 95°E) 



U°N, 



Fishing is fairly brisk though inferior to that found in the coastal 

 waters of Sumatra. The vicinity of 9°N seems to be a boundary on either 

 side of which the fishing situation changes markedly and the size charac- 

 teristics of the fish are different. 



Table 10 Fishing Situation by Areas 

 (Andaman and Nicobar Is., Hakuyo Maru, 1929) 



Area 



north of 9 

 south of 9° 



Number of Hooks 



1,U0 

 1,58A 



Number of Fish Taken 



37 



uo 



Catch Rate 



2o63 

 8„86 



The catch rates are higher south of 9°, as is clear from Table 10, 

 and the yellowfin run around AO kg in weight, but north of 9° the catch 

 rates are lower and the fish are somewhat larger. 



We may summarize the foregoing data on the distribution of tunas 

 and spearfishes in the various sea areas of the Indian Ocean region as 

 follows: 



1. The schools are most densely concentrated in the coastal waters 

 of Sumatra and the Lesser Sunda s„ 



2. Within Sumatran coastal waters fish are most abundant near and 

 north of the Equator. 



3. In the overall view one can detect a tendency for the distri- 

 bution to be most concentrated during the northeast monsoon. Data on the 

 southwest monsoon season are inadequate, but if the fish are more abundant 

 during the northeast monsoon, it will represent a condition exactly opposite 

 to that encountered in the Pacific areas. 



A. Judging from the catch rates, the composition of the catch, and 

 the size chscracteri sties of the yellowfin, the distribution of the schools 

 during the northeast monsoon is as follows: 



31 



