ova contained in the ovaries of one fish amount to over one million 

 (Figure 5) . 



On the coasts of Japan proper fish with conspicuously developed 

 gonads are seen from June to July, and in August spawning is already 

 finished. This being so, the tuna which migrate to the Japanese coasts 

 and those which appear in Formosan waters may be considered to be clearly 

 of different populations. With regard to the black tuna of Japan proper, 

 Dr. Kishinouye recorded that he had never seen any completely ripe eg£S, 

 but that spawning probably took place off the Pacific coasts of Kyushu and 

 Honshu. 



The smallest specimen collected up to the present time is one of 22 cm 

 total length obtained by Dr. Kishinouye. Fish 25 cm long and weighing 

 about 20 g are taken on hook and line in the sumrer on the coast of 

 Miyazaki Prefecture, where they are known as imoshibi. Even smaller ones 

 are taken in Kanagawa and Mie prefectures, where they are called kakinotane, 

 abuko . or bintsu . By winter these fish attain a length of UO cm, and in 

 the sumrrer of the following year they -veigh 2 to 3 kg. It is thought that 

 after three years have passed the fish become mature and begin to spawn. 

 It appears that among the fish commonly caught those 5 to 7 years old 

 predominate. 



The smallest specimen collected in Formosan waters was about UO cm 

 long and it was collected in February, Tfe have not yet been able to get 

 any smaller examples. 



Almost nothing is knovm of the spavming season and spawning ground 

 of the albacore. They probably spa^vn in the open sea. The same is true 

 of the big-eyed tuna. 



The yellowfin is presumed to spa\"/n around February in the southern 

 part of the South China Sea. The reason is that among the fish which are 

 landed around February at Takao specimens are occasionally seen with 

 extraordinarily well-developed gonads. The spawning grounds are not 

 limited to the South China Sea, however, and spawning probably takes place 

 everywhere in the seas of Greater East Asia. Among these the Banda and 

 Flores seas area is receiving particular attention, but there are as yet 

 no data. 



There used to be a cannery called the Sea-Food Cooperation / sic_7 

 at Zamboanga, and a man who worked there has reported that in the Sulu 

 Sea area fish with ripe gonads were often taken. 



Fish of around AO cm body length generally inhabit the open sea 

 where they either forn solitary schools or school together with skipjack. 

 They are occasionally taken in large set-nets in the waters east of Formosa. 



Among the spearfishes the short-nosed marlin appears to spawn around 

 December in an area centered about 150 miles east of Formosa, and some ripe 

 ova of this species have been obtained. (Figure 5) 



38 



