316 



BULLETIN OF THE BUREAtT OF FISHERIES 



abnormally high and the percentages of increase in length with age in body and 

 scale coincide more closely than is indicated in this table. 



However, computations show that the bigger individuals of age group III possess 

 larger scales, on the average, than the smaller fish. The leiigth of the scales of 40 

 herring less than 226 millimeters in length, of age group III, taken at Bay City, 

 Mich., in 1921, averaged 4.88 millimeters, that of the scales of 26 fish of this age 

 group 226 millimeters or more in length averaged 5.24 millimeters. Similar values 

 were obtained for the 3-year herring collected at Bay City on November 1, 1922, 

 and at Oscoda, Mich., on November 2, 1922. The scales of 48 herring less than 226 

 millimeters in length of the former collection averaged 4.80 millimeters long, while 

 those of 88 fish 226 milUmetei-s or more in length averaged 5.15 millimeters; the 

 scales of 71 fish less than 226 millimeters in length of the latter collection averaged 

 4.87 millimeters long, while those of 72 specimens 226 millimeters or more in length 

 averaged 5.11 millimeters. Combining the above averages we find that the scales 

 of the 159 herring less than 226 millimeters long averaged 4.85 millimeters in length, 

 while those of the 186 fish 226 millimeters or more in length averaged 5.15 milli- 

 meters. The KfV ratios of Table 10, therefore, may very well be representative of 

 the younger age groups even though based on the bigger fish, since the lengths of 

 both the body (K) and scale (V) of these bigger fish vary in the same direction. The 

 £^/F ratios of Table 10 show that at least after the second year of life the percentage 

 of increase in length with age is greater in the scale than in the body of the herring. 

 The preceding data also show that the ratios based on unselected (non-X) scales 

 vary no more with the age groups than those based on selected corresponding (X) 

 scales. 



Table 12. — Differences between two series of K/V determinations for several age groups, both made for 

 same individuals but based in part on different scales of these individuals 



AGE VARIATIONS IN BODY-SCALE K/V RATIOS OF JUVENILE COREGONIDS 



The absence of juvenile fish in the Bay City collections is a serious handicap. 

 The trend of the conclusions thus far reached suggests what the relation of the size 

 of the body and scale in the young fish must be. I have at my disposal, however, a 

 miscellaneous collection of juvenile coregonids. Some of these young fish comprise 

 part of the collection made by Prof. T. L. Hankinson during August, 1913, at White- 

 fish Point, Mich., on Lake Superior (Hankinson, 1914); the others were obtained by 

 A. G. Woolman at Kettle Falls, Minn., on July 26, 1895, and turned over to the 

 Bureau of Fisheries. The data of these juveniles are shown in Table 13. The num- 

 ber of circuli indicate roughly the recency of the formation of the scales. A herring 

 34 millimeters in length, not included in the table, had not yet formed its scales. The 



