The boundaries between currents on this chart and the 

 boundaries of fish distribution which appear in figure 28 

 coincide almost perfect ly. Figure 28 shows that in the range 

 of 5° - 6° north and south of the Equator the majority of the 

 yellowfin have an average w^eight of 30 - 40 kilograms, followed 

 by those of 20 - 30 kilogramSo Fish of 10 - 20 kilograms are 

 few, and there are none over 50 kilograms o North of 5° N„ fish 

 of 30 - 40 kilograms and those of 40 - 50 kilograms are about 

 equal in numbers, and some fish v/eighing more than 50 kilograms 

 also appearc South of 5° So averages of 30 - 40 kilograms 

 hardly appear at all, the majority being within the ranges of 

 40 - 50 and 50 - 60 kilograms o These relationships are 

 presented in tabular form in table 16o 



Kotess (Ij The number of trials is the number of fishing experime nt s 

 in which the average weight fell within the particular 

 weight category o 



(2) % is the percentage which (l) was of all fishing experiments 

 within the areao 



As was stated at the beginning of this section, it is very 

 natural that there should be a close relationship between the 

 ocean currents and the distribution of the tunas, and there 

 hardly seems to be any need for stating it anew„ Nevertheless, 

 it must be said that the sort of facts that appear in table 3, 

 tables 14-16, and figure 28 provide very important indications 

 for the consideration of fishing groundso Furthermore, it is 

 thought that these facts indicate, not only that the density of 

 distribution of the tunas differs in different current systems, 

 but that in different currents, even though they may be 

 adjacent to each other, there occur different kinds of fish and 

 different age groups » 



It cannot be denied that in past surveys of tuna grounds 

 this point of view has been neglected. In the future, investiga- 

 tions in this field must be greatly emphasized, both in order 



102 



