o/ 



inches fork length,— 'for example, enter the blue mar- 

 lin graph (fig. 5) from the bottom scale at 175 inches. 

 At the point where the 175-inch line intersects the 

 weight-length curve, read across to the left (weight) 

 scale--here, 1,140 pounds. These graphs are de- 

 rived from hundreds of specimens, but some fish, 

 especially very large ones, may fall at some distance 

 from the curve. 



Figure 5- Length-weight relation tor blue martin 



1,800 



1,600 



1,400 



1,200 



in 

 a 



z 



a. 



5 800 



600 



400 



200 



25 50 75 100 125 150 



FORK LENGTH (INCHES) 



175 



200 



3/ 



— Fork length here is defined as the distance be- 

 tween the tip of the bill and the middle of the notch 

 in the rear edge of the caudal fin. 



10 



