obtained by many research vessels in suj-veys in southern waters, 

 there is little difference in the oatoh rates achieved in a given 

 area whether iced, frozen, or salted bait is usedo Purthermorej, 

 on the whole little difference can be detected whether the bait 

 employed was saury^ sardine, herring, or squido 



As has already been stated in the section on food habitSj, 

 there is room for doubt as to whether the tunas and spearfishes 

 select things v;hich they particularly like to feed ono VTnen we 

 actually examine the contents of their stomachs, it appears that 

 they feed on whatever is most plentiful in the area they inhabit^ 

 or whatever is comparatively easy to catch, or whatever strikes 

 their eye most easilyo Of course more thorough studies of the fDod 

 habits of the tunas are necessary, and our conclusions must be 

 verified experimentally, but it is thought that in selecting baits 

 to be used the emphasis should be on their ability to catch the eye 

 of the tuna and their keeping qualities on the hooko Such matters 

 as ease of procurement and cheapness of price go '^Aatnout sayingo 



i'fhether or not the above reflections are correct or not is a 

 question to be settled by future researcheso If they are correct, 

 the fact will have a rather important significance in the operation 

 of this fisheryo Unfortunately, however, there have been few 

 connected, organized studies in this fieldj and the problem of bait 

 is almost entirely left to the futureo 



do Fishing grounds and fishing seasons 



Almost all of the researches and surveys which have been 



carried on hitherto with regard to the tuna fisheries have had as 



their main object the extension of present fishing grounds and the 



discovery of superior new grounds, and not a few of them have pro- 

 duced results worthy of noteo 



After engines began to be installed in fishing vessels in the 

 latter years of the Meiji Eraj, Ime-hauling machines were imported 

 and the efficiency of operation increased epochaliy, while at the 

 same time larger and larger vessels came to be built and the fishing 

 grounds were extended year by yearo Particulai'ly in the period of 

 approximately 10 years from early Showa Era (about 1930) to the 

 beginning of the Pacific 'Var the rapidity with which the fishing 

 grounds were expanded was astonishingo During this period the 

 training vessels of the Fisheries Institute of the Ministry of 

 Agriculture and Forestry and mai^ research vessels surveyed tuna 

 longline grounds from the Maldives in the Indian Ocean on the westj, 

 eastward to the vicinity of 17CP west longitude j, and from 15° south 

 latitude to 45^ north latitude,, As a result of these surveys and 

 the unflagging endeavors of the f ishermen, there were opened up the 

 albacore grounds extending east from Cape Nojima to the Midway area 

 and the fishing grounds, principally for yellowfin, in the former 

 Japanese South Seas mandatej fishing boats from Japan Properj based 



85 



