o o 



There are very few data for the latitudes between 10 and 20 N. 



so that the 



situation there is not well understood, however, areas with high catch rates 



o o 



appear in these latitudes in the vicinity of 135 E. and again between 145 and 



155° E. 



3. Farther to the north the catch rates are high in a rather broad area centered 



o o 



around 155 E. and in the waters east of 165 E. 



4. In all of these cases, it appears that one cam detect a tendency for the catch 

 rates to increase as one goes eastward. 



The foregoing remarks take no account of the uneven seasonal distribution of the 

 data. Seasonal changes in the density of distribution cannot be thoroughly investigated because of 

 this characteristic of the data, but the general outline of the distribution as between the various 

 sea area^ is as follows. 



The following figures show graphically the changes from month to month in fishing 

 conditions in the South China Sea. There are no data at all for April and May and very little for 

 August. Within the range covered by the available data, there is no catch at all from June to 

 August, while there is a rather conspicuous peak in September with a catch rate of 0.35. In 

 October and November the catch rate gradually declines only to increase again in December. The 

 highest catch rates of the year are reached in February with a figure of 0. 53. 



0.6 



UJ 



04 



< 



X 



O 02 - 



I- 

 < 

 o 



I I r 



TT 



I I I I I ,UJ^ 



MONTH 

 STATIONS 



HOOKS 



Data for such con- 

 tiguous waters of the South China 

 Sea as the waters east of 

 Formosa, the Sulu Sea, and the 

 Celebes Sea are unevenly dis- 

 tributed seasonally and therefore 

 it is not possible to compare the 

 monthly changes in the fishing 

 conditions in these waters with 

 those of the South China Sea. 



Fishing conditions 



by months in the vicinity of the 



o o 



Ecjuator from to 5 N. and 



from 150 to 160 E. are shown 



in figure 20. The nunnber of 



stations fished and the number of 



hooks employed are shown in the 



figure in the same manner as in 



figure 15. 



Figure 19.--Bigeye tuna fishing conditions Data are completely 



by months lacking for June. The cg.tch rate 



reaches its low in March with a 

 figure of only 0.02. Thereafter it shows a tendency to gradually increase and in September it 

 reaches its highest point of the year with a rate of about 1.5. In October it drops off sharply and 

 hits a low again in November, increasing slightly again from December to January and showing 

 little difference between January and February. If this is compared with the curve for the South 

 China Sea, there is agreennent in the peak in September, but the January peak appears in 

 February in the South China Sea. A conspicuous low appears in this area in March, but it seenns 

 to appear in the South China Sea after April. 



146 



