170 EIGHTH PACIFIC SCIENCE CONGRESS 



(1951) found spent fishes in the area 150-200 miles northwest off Ka- 

 pingamarangi Island at the beginning of August. Schaefer (1948) and 

 Schaefer & Marr (1948) found juveniles in Central America from 

 January to May. About N. rarus we have nothing to add to Delsman 

 & Hardenberg (1934) and Serventy (1942). 



About Tetrapterus angustirostris, Nakamura (1937, '38) found 

 ripened ova in the fish caught east of Formosa and thought this would 

 spawn in November and December in this area. About Istiophorus 

 orientalis, Nakamura (1932) reported in December the ripened ovarium 

 in the fish caught from Molucca Strait. And later he (1938, '42, '43) 

 also found ripened ova and juveniles and witnessed the spawning be- 

 haviour near Hainan Island, near Formosa and east of Luzon Island 

 from April to September. Near Japan so many juveniles were found 

 since Uchida (1937). Also, recently Nakamura and his staff obtained 

 so many juveniles from tropical areas such as Micronesia from June to 

 September. However, they have some difficulty identifying these as 

 this species, because the difference from E. nigra is not assured in juve- 

 niles yet, and the latter species matures and grows abundant in the area 

 in this season. About Kajikia mitsukurii, Nakamura found ripened 

 ovarium as usual from April to May near Formosa, and thought that 

 this also spawns in the same season around Bonin Island. Recently 

 Nakamura and his staff found ripened ovaria in the fishes caught from 

 the equatorial area from June to September. About Eumakaira nigra, 

 Nakamura (1938, '42, '49) found ripened ovaria of fish caught east of 

 Luzon Island, and thought this would spawn from April to August near 

 Luzon and Formosa. Recently he and his staff found another spawning 

 ground near Bonin Island in the same season, and in the equatorial 

 area of the Pacific they also found grown-up fishes from June to October. 

 About the above-mentioned four species Nakamura (1944) found the 

 seasonal change of both size composition and sex ratio, which changes 

 remarkably after the spawning season. The juveniles of Xiphias gladius 

 in the Atlantic Ocean have been reported already. About that in the 

 Pacific, Yabe (1951), Nakamura and others (1951) reported 11-35 mm.- 

 long young, and there were plenty of larger young found in the stomach 

 contents of tunas and marlins. 



(4) Age and Growth 



The age determination of these groups of fishes has been made by 

 counting the number of rings in the centrum of the vertebrae. Aikawa 

 (1937) reported the growth of K. pelamis by this method and size 

 composition of the catch. Afterwards Aikawa and Kato (1938) worked 

 on the growth of G. germo, N. macropterus and T. orientalis by the 



