aside such observations based on fishing conditions, and consider the size of the yellowfin, it 

 appears that we can get results which deny the existence of such a migratory route. That is, if 

 we look at the condition factor of the yellowfin taken in these various sea areas at the same 

 season, despite the fact that no conspicuous differences in size composition of the catch can be 

 seen, the condition factor values vary widely, with the highest figures in the Sulu Sea, the lowest 

 values for the Celebes Sea, and with the South China Sea in between. 



Data for this sea areahavebeen reported by the Shonan Maru, Takao Maru, Koho Maru, 

 and the Daijin Maru and Sasshu Maru from Kagoshima Prefecture. These surveys and commer- 

 cial operations have been linnited to the season of the northeasterly winds, so fishing conditions 

 during the southwesterlies are completely unknown. Furthermore, there are no records of the 

 fishing situation by species so no catch rates can be shown except for tunas and spearfishes comi- 

 bined. In the reports of the Koho Maru and the Sasshu Maru the number of hooks is not indicated, 

 only the number of baskets of gear having been recorded. The following table shows the catch 

 rates based on those data for which the number of hooks is known. 



Table 23. --Fishing conditions in the Sulu 

 Sea 



The catch rate is slightly greater than 6.0, better than that for the South China Sea, 

 which will be discussed later, and even surpassing the year-round average for the Celebes Sea. 

 Fishing conditions encountered by the Koho Maru and Sasshu Maru are shown in the following 

 table. 



Table 24. --Fishing conditions in the Sulu 



Sea (according to the Koho Maru 

 and Sasshu Maru) 



If we assume that there were 6 hooks per basket, the catch rate would be slightly less than 5. 3. 



We have no detailed knowledge of seasonal changes in fishing conditions, but it 

 appears that fishing is good from around the end of the season of southwesterlies through the early 

 paj-t of the northeasterlies. Thereafter the fishing gradually falls off as the days pass and it 

 appears that by February and March the catch rates fall to about 4. to 4. 5, values not greatly 

 different from those of the Celebes Sea region. At that time, as has already been remarked, a 

 cold water mass appears in the central part of this sea area and within this cold water mass 

 fishing seems to be very poor, with almost no catches made. 



As already stated, the fishing situation for different species is not known, but 

 yellowfin are the principal catch. It appears that spearfishes adso occupy a rather large 



59 



