certain that the ipearfishes are quite abundant. It is also certain, o£ course, that their catch 

 rates show seasonal fluctuations. 



Table 20. --Fishing conditions in the Celebes Sea 



The nnost numerous species in the catch is naturally the yellowfin. The density of 

 distribution of the yellowfin -appears to undergo large seasonal fluctuations as can be inferred 

 from the following table. 



Table 21. --Fishing conditions by season 

 (Celebes Sea) 



Notes: (1) Catch and catch rate figures represent 

 the total of tunas and spearfishes. 



(2) April to September is the season of 

 southerly winds, October to March 

 that of northerly winds. 



As the number of hooks fished during the season of southerly winds is very small, the 

 numerical values for the seasonal changes in fishing conditions shown in the above table cannot 

 perhaps be said to be accurate ones. However, it can be seen at any rate that within the scope of 

 this table the seasonal changes in fishing conditions aire extrennely nnarked. The table indicates 

 that the catch rates during the season of southerly winds are more than twice as much as those 

 during the season of northerly winds, and it goes without saying that the greatest factor in this 

 change in catch rates is an increase in yellowfin. 



In addition to the surveys mentioned above, the Koho Maru of the Kochi Prefecture 

 Fisheries Experiment Station also investigated this sea area. This work was done in November 

 and December of 1931. It is not possible to calculate the catch rate because the construction 

 of the fishing gear employed has not been reported, but during the period mentioned, the Koho 

 Maru fished a total of 721 baskets and took a total of tunas and spearfishes amounting to 341 fish. 

 This is a catch of more than 47 fish per hundred baskets. If we assume that there were six hooks 

 per basket, the catch rate would be about 8.0, a rather high figure. 



kno-v 



There are few records concerning the size of the yellowfin and the details are not 

 Consideration of a certain amount of data makes it appear that large fish are generally 



56 



