11, Summary obsorvatlons on fishing boats, gcir, methods, grounds, and 

 seasons 



(a) Fishing Boat 



A vessel like the guide boat of this Station is s-itip factory, but 

 judging by the experience of this year and last yerxT live-bait ;clls arc 

 not necessary and the ideal vessel would be a specialized longline typo 

 with additional fish-holds. The ice and fish capacity should be increased 

 as much as possible, 



(b) Fishing Gear 



The gear used this year was ordinary tuna longlines of the typo employed 

 in the winter season. ITicy differed from those used last year in that 

 sokiyama was used on the small hook branches as well as the large ones 

 and in the length of the float lines, which was eighteen fathoms. In other 

 respects they were about the same as the gear used in the previous year's 

 operations, Also in this year's investigations a part of the gear was made 

 of Now Zealand hemp, which had been in use since the previous autumn, in 

 place of cotton line. No difference was CGtected in the catch ratios 

 obtained with these two sorts of line, but there was some difference in the 

 ease of handling. It was thought, however, that this was duo to the fact 

 that the method of manufacture was somewhat unsatisfactory, and therefore 

 if this is improved or the lino is made by more cxporicnced worker.s it 

 should be possible to eliminate these defects completely. Furthermore it 

 was found that this lino is superior in tc:nsile strength to the cotton line 

 which has been used for the same purposes, a truly important discovery in 

 view of the prevailing conditions of supply. 



As is clearly sho'<7n in Table 7, which gives the catch ratios of the 

 various branch lines and the value of the catch of each hook, the deeper 

 the hooks the better the fish bit. The catch on the small hooks of the 

 central portion of tho line was much bettor than that of the largo hooks. 

 If the big hooks wore taken off and replaced \dth small ones there would be 

 a saving on bait of about ? 2,800 and an increase in the value of tho catch 

 of about ¥ 500. If the length of the float lines wore suitably adjusted, 

 it is thought that the gear would be even more effective. 



If wo consider the catch ratios in relation to tho size of the hooks, 

 on all three cruises the fish taken on th. largo hooks -vore bigsor than 

 those taken on the small ones, but there v/oro 23 per cent fewer of thorn. 

 This gives one tho feeling that the hooks wore too largo for the fish's 

 mouths, but it should be noted as an exception that on thj tliird cruise 

 albacore of around 3 to 9 kg weight wore taken every day on the large hooks 

 while on tho other hand the small hooks caught rather large albacore and 

 sharks. In view of these facts it appears that the size of the hooks is not 

 a great problem, 



(c) Fishing Method 



The exnerienco of this year and the preceding year indicates that long- 

 linos are the only method for catching albacore in polagic waters. It is 



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