1. Waters north of 10 N. and east of the line of islands 



It has already been noted that beginning around March albacore of 

 large size split off from the population on the grounds north of the Conver- 

 gence and move south into this sea area. From May to August over this 

 sea area as a whole the albacore catch rates rise, and cases of catch rates 

 higher than 1.0 are not unusual. In July, particularly, we see catch rates 

 of 3.0 or more. In August the picture is not clear because we lack data 

 between 10 N. and 20 N. , but judging fronn the distribution of albacore in 

 this area from September on it is thought that approximately the sanne con- 

 dition is maintained. From October to January fairly high catch rates occur 

 just north of 10 N. and judging from this point it is thought that the albacore 

 in this area may continue their southward movement from May on continuously 

 to early winter. However, the occurrence of albacore is not very abundant 

 zmd therefore our data are inadequate, so we have no accurate knowledge of 

 the situation. 



Table 1 shows the size composition of the catch, which in this area 

 is composed of extremely large albacore. 



Table 1. --Length composition of albacore landed from waters 

 between 10 N. and 25 N. from May to June (actual numbers) 



The eilbacore occurring in this sea area show a difference in size 

 between the sexes. The males are larger, an overwhelming proportion 

 of those over 105 cm. in length being males. The results of this study 

 axe shown in table 2. 



Table 2. — Length frequency of albacore by sex (in cm. ) 



127 



