4o Neothunnus macro pterus (Temminck & Schlcgel) 



In Japanese kihada, p;esunaga, itoshibi, shibi ^ and kinhireo 

 Young individuals are generally called kimejio 



First dorsal with 12 - 13 spines, second dorsal with 14 rays 

 and 9 finlets„ Anal with 14-15 rays and 8-9 f inlets. Number of 

 scales in one longitudinal row approximately 270« 



The body length is 3c,5 - 4 times the head length, and about 

 4 times the body deptho The length of the head is about 7 times the 

 diameter of the eye and about 3 times the length of the snouto 



Figure lOo — Neothunnus macropterus. 



The body is fusiform and long, the head is small, and the 

 caudal region is longo The scales are minuteo The pectiral fins are 

 long with their tips extending posterior to a point below the origin 

 of the second dorsalo In old specimens the second dorsal and the anal 

 are greatly developed and somewhat threadlike, and they reach to the 

 caudal peduncle or even farther backo 



The air bladder is well developed, and has the form of a 

 slender sac. The kidneys are elongated posteriorly and the ureters 

 join below the thirteenth vertebra. 



The dorsal surfaces are almost black with more or less of an 

 indigo cast, the sides of the body are pale gray, and the belly is 

 white, although in young specimens there are colorless oblique lines 

 on the bellyo The second dorsal and the anal are touched with yellow, 

 and the finlets are completely yellow. The first dorsal fin is 

 yellowish gray. The pectorals are black, but at times both they and 

 the ventrals have some yellow colore 



The flesh is a clear pink, firm, and delicious when eaten raw„ 



This species is widely distributed, extending generally over 

 the Pacific and Indian oceans. In Japanese waters the northern limit 

 of its distribution is in the neighborhood of 35° N, , but it occasionally 

 reaches 40° No It is extremely rare in the Japan Sea, If the black tuna 

 be taken as representative of the tunas in the waters adjacent to Japan, 

 the yellowfin can be said to be the representative tuna of tropical 

 waters. This species is the most important catch of the longline fishery 

 in tropic seas, and although there is some variation with season and 

 area, in general it comprises 80 = 90 percent of the total catch (exclu- 

 sive of sharks). They are particularly numerous in the Ecuatorial 

 Countercurrent, but they are also plentiful in enclosed sea areas. 

 It appears that they spawn gradually over a wide area of the ocean. 

 They spawn from March to May in the South China Sea area. They are said 



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