The Correlation Between the Length and Weight of Yellowfin Tuna 



Based on measurements taken aboard the Shonan Mam during the course of ex- 

 perimental tuna fishing in 193^. January 1935. 



I Intiroduction 



This paper Is an attempt to show the correlation between the lengths and 

 weights of iX yellowfin tuna taken during experimental tuna fishing in 193^1. 



II ISethod of Measuring Length and Weight 



The fish were weighed in the condition in which they were when captured and 

 their lengths were taken as the horizontal distance between the snout and the end 

 of the base of the caudal (see the accompanying sketch). The units of oeasurei»nt 

 employed were kilograms and centimeters. 



Ill Summary 



As is clearly shown by Figure 1, the coordinates of each specimen were found 

 by representing the weights (W) on the X axis and the lengths (L) on the Y axis. 

 The line XY was found by the "method of great majority" CsicH. The line XY satis- 

 fies the equation L s a^. In other words, if a number of points are taken at 

 random on this line, a line connecting the points whose coordinates are represented 

 by Log 10 L Log 10 W of these points taken at random can be considered to be 

 roughly a straight line, as shown in figure 2. If we calculate the constants a and 

 b of the equation L s aW** in Figure 2, they are as follows: 



a » 40.12 

 b s 1/3 



Accordingly we arrive at the equation 



L ' m,TL2K 1/3 



17 Conclusion 



As shown in the preceding paragraph, the correlation between the lengths and 

 weights of yellowfin tuna within ttie range of 5 to 60 kg taken within this area at 

 this season can in general be shown by the formula given in Paragraph III. 



[Tigure 1 is a scatter diagram of the lengths and weights with a curve fitted to it. 

 Figure 2 is a graph with a straight line connecting points whose coordinates are 

 the logs of weights and lengths. There is also a sketch of a tuna showing what 

 measurement was used for L.3 



