412 BULLETIN OF THE BUREAU OF FISHERIES 



10. In lake herring the various areas of a single scale may increase in length at 

 different relative rates. 



11. Lake herring scales taken from the same area on the body grow more nearly 

 at the same rate than those taken from various parts of the body. 



12. The body -scale length ratios (K/V) of lake herring of age groups III and 

 older decrease slowly but consistently v.'ith eacli older age group, irrespective of v/hether 

 selected corresponding scales (X scales) or unselected scales (non-X scales or those 

 actually used for the life-history work) are employed. That is, the percentage of 

 increase in length with age is greater in tlie scale t^ian in the body of the herring. 



1.3. The decrease in the body-scale length ratios with age is not due to the age 

 variations in head length, for the length of the head in proportion to that of the 

 body remains virtually constant with age in herring 3 years of age and older. 



14. The body-scale length ratios (K/V) of juvenile coregonids decrease very 

 rapidly with age and growth in the first year of life. 



15. The scales of lake herring increase in length comparatively faster than the 

 body until a body length of approximately 200 millmieters (age groiip VI) is reached, 

 when the scales increase proportionately more slowly. In early life the scales increase 

 in length much faster relatively, than the body; in later hfe (third year and there- 

 after throughout the sixth year) only a little faster. 



16. In both lake herring (LeucicMhys artedi) and whitefish (Coregonus clupeafor- 

 7ms) scale formation begins when the fisli has attained a length of approximately .35 

 to 40 millimeters. 



17. The diameter of a herring scale increases in length more nearly proportional 

 to the increase in the length of the body than does the anterior radius. 



18. The diameter dimension of the scales of an individual herring varies less 

 than the anterior radius dimension. 



19. In lake herring the computed lengths based on the diameter dimension of 

 scales are always higher for corresponding years of life tJian those based on the ante- 

 rior radius. The difference between the two increases consistently with each earlier 

 year of life for which calculations are made, so that the maximum average difference 

 is found in year I. 



20. In lake herring the computed lengths based on the diameter measurements 

 of scales are in general lower than the corresponding lengths obtained from direct 

 ineasurements of fish of the same year class. The differences between the actual 

 and computed lengths are in general greatest for the early years of life. 



21. The length value computed for a particular year of life generally decreases 

 as the age of the herring v»'hose scales are employed increases. (Lee's "phenomenon 

 of apparent change in growth rate".) 



22. The decrease with age in the computed length values of corresponding years 

 of life (Lee's "phenomenon") occurs when the calculated length values of herring of 

 different age groups and of different year classes are compared. 



23. The decrease with age in the computed length values of corresponding years 

 of hfe (Lee's "phenomenon") also occurs when the calculated length values of herring 

 of different age groups but of the same year class are compared. 



24. A phenomenon similar to that of Lee occurs when the "annular" scale-diasn- 

 ^ter measurements of herring of different age groups but of the same year class are 



