Table 7 

 Fishing Results of Different Branch Lines (iiakuyo" Maru) 



Notess (l) Short branches 5 ken /To f t_o7" 4 lines 



(2) Long branches 16o5 ken ^9 ft„7 2 lines 



(3) Float lines 15 ken /gO ft^ 



(4) As the number of short branches is twice as great as 

 the number of long branches, it must be halved when 

 calculating the catch per 100 hooks o 



It appears from table 7 that the long branch lines were much 

 more efficient than the short oneso In all of the various sea areas 

 fished the results were approximately the same, with the catch rate 

 of the long branches being about 6 times that of the short brancheSo 

 From these results it is judged that the efficiency of the short 

 branches is markedly inferior to that of the long oneSo This 

 evidences the fact that the suitability or unsuitability of the 

 construction of the gear has a very great effect on the catch rateo 



It may be inferred that the depth at which the catch rate is 

 highest, or in other words, the level where the tunas are most 

 densely distributed or where the light and temperature conditions 

 of the environment make it easiest to catch them, differs according 

 to the sea area and the seasono The necessity of clarifying this 

 situation is incontrovertibly shown in table 8„ For the purpose 

 of ascertaining the level at which the fish are swimming, the gear 

 in general use (including that used by the Hakuy^ Maru) can hardly 

 be said to be suitable <, As the following figure shows ^Tigure 24 

 Plan of tuna longline^, it is hard to tell accurately where the 



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