to = llh 

 N]_ - y nA'^., and if we take N2 as the number captured during the 



to - 2h 



to s 20h 

 afternoon, N2 r y n At, however, the ratio N2/NI, between the 



to s 12h 

 two is 0.52 for 1936, O.A^ for 1937, 0« 52 for 1938, and 0„5/i for 1939, 

 establishing approximately the relationship (l) for all four years^^). 



Ni z 2N2 (1) 



That is, in every year the catch during the forenoon was about twice the 

 afternoon catch or 2/3 of the day's catch. 



t^r 9h 

 Now if we try calculating the total catch N]_' = ^ ^ n^t in the 



to = 5h 

 first peak from 5:00 to 9:00 a.m., Ni/(Ni / N2) is 0.53 for 1936, 0.46 for 

 1937, 0.48 for 1933, and 0.51 for 1939, establishing the approximate 



relationship 2Ni' . Ni / N2 or Ni' = N (2) 



for all four years. That is, aboiit half of the catch of an entire day 

 (2 - 20h) is sighted and captured between 5:00 and 9s 00 a„mo Noxv if we 

 calculate Ni'/N1 ^to get 0.8 for 1936, 0,7 for 1937, 0,7 for 1938, and O08 

 for 1939 which means that during the five hours from 5sOO to 9:00 a.m, 

 there' is captured 70 or 80 percent of the fish taken in the forenoon (the 

 ten hours from 2:00 to 11:00), 

 From (1) and (2) we get the relationship (3) . 



-i^' = ^ = 0.75.... .0...0 ....(3) 



Ni U 



(2) Relationship of tg and log n„ If, in order to clarify the character 

 of the catch curve described above, we plot the correlation between the log 

 of the catch and tg, a glance at Figure 2 will clearly show that at to 

 later than the 6; 00 to 8:00 a.m, maximum of n the decrease is in almost a 

 straight line except for the deviation caused by modes Nos. 2 and 3. 



Accordingly for to !!> 6 - 8h n = nniax©"Xt ,..,, (4) 



Let us try considering for a bit why it is that we get this sort of a curve. 

 One can think of four factors in this connection, (i) the factor ( X]_) of 

 the disruption of the schooling of the fish due to diurnal changes in the 

 mobility of the schools in relation to their food, (ii) the factor ( A 2) °^ 

 the decrease in the schools due to the number of fish taken from them, 

 (iii) the factor (X3) of the disruption and scattering of the schools due 

 to fish, and (iv) the factor (A 4) of the lowering of the operating efficiency 

 of the fishermen with the passage of time due to fatigue (with regard both 

 to their ability to sight fish and their ability to catch them),, Therefore 



(1) to is the time when fishing begins, however, as will be seen in the 

 following section, T may be considered to be on the order of 10 - 4.0 

 minutes. Therefore in this paper I have not taken this variation into 

 account, but have considered for the purposes of the discussion that it 

 is the median time. Thus where to is given as llh, the fishing time may 

 generally be considered to have been between llh and 12h, 



13 



