322 



BULLETIN OF THE BUREAU OF FISHERIES 



the sixth year, when the herring attained an average length of 259 miUimeters, the 

 scale increased in length relatively more slowly than the body. 



In Table 10 the average £'/F ratios of years VII and VIII were based on so few 

 specimens that no safe conclusion regarding the relative increase in length of body and 

 scale during these years could be drawn from them. For years III to VI, inclusive, 

 the data of this table agree with those of Tables 14 and 15. When all the data are 

 considered together we may conclude that the scale of the lake herring increases in 

 length, on the average, proportionately faster than the body until a body length of 

 approximately 260 millimeters (age VI) is reached, whexi the percentage of increase 

 in length is less in the scale than in the body. 



Fig. 14. — Body-scale length relationship of adult lake herring (Leucichthys arUdi) arranged according to their size. 

 The continaous curve based on the average lengths of body and scale shown in Table 15 represents the actual body- 

 scale length relation; the broken line shows what the relation of the length of the body and scale should be if that 

 existing at a body length of 190 millimeters were maintained 



COMPARISON OF COMPUTED LENGTHS BASED ON ANTERIOR RADII AND 

 ON DIAMETERS OF HERRING SCALES 



A preHminary study of length computations based on the diameters and the 

 anterior radii of the scales of an adult herring (p. 311) indicated that the former scale di- 

 mension would in all probabihty furnish higher and perhaps more accurate length values 

 than the latter. This section includes other data that indicate that this preliminary 

 conclusion is correct. Two sets of data are available. Two series of body-scale 

 ratios, the one based on the anterior radii {ac) and the other based on the diameters 

 (F) of identical scales, may be compared with each other, and series of length compu- 

 tations based on both the diameter and radius of identical scales may be compared 

 with each other and with the actual length values. 



