LIFE HISTORY OF LAKE HERRING OP LAKE HURON 303 



except for computations for the third year, which are usually about 1 centimeter 

 too low. The author, therefore, added 1 centhnetcr to all these calculations. 



Fraser (1916, 1917) thought that Lee's "phenomenon" was due to the fact that 

 scales do not appear until the fish has attained a certain length and early body growth, 

 therefore is not represented in the scale. In the salmon, scales first appear at a body 

 length of 1.5 or 2 inches. If 1.5 or 2 inches are taken from the total length and the 

 remainder divided in the same ratio as the growth -zones divide the scales, Lee's 

 "phenomenon"', so Fraser found, is eliminated from the computations of the salmon. 



Meek (1916) compares the actual lengths of the scales of younger herring with 

 the corresponding lengths at each annulus of the scales of older fish and concludes 

 that no shrinkage takes place in the scale. Meek plots the growth of the scales in 

 relation to the length of the herring and finds that, due to the late appearance of the 

 scale, it grows relatively faster than the body, the curve of scale growth crossing that 

 of body growth in the fourth year. The author finds that the selective efi'ect of nets 

 on the young age groups would not e.xplain the "phenomenon" in older fish, and that 

 Lea's explanation relative to the segregation of the sexually mature j^oung fish would 

 not explain the "phenomenon" in his (Meek's) material, which consists largely of 

 immature herring. Meek ascribes to the imequal growth rate of body and scale the 

 fact that his calculated length values are always too low in the first two years, nearly 

 accurate in the third year, and always too high in the fourth j'ear of life. 



Mottram (1916) discards Lea's method of computing lengths, for "* * * this 

 method can not be of value uidess the length of the fish, before scales are laid down, 

 be taken into account, or unless the fish begins to form scales at a very small size, 

 or unless the figures so obtained are such that they can not possibly be accounted 

 for by the error in this method. Further, this method will be liable to an additional 

 error if the scale-covered part of the fish does not always bear the same relation to 

 the whole length of the fish [p. 45]." Lea's scale method is subjected to another 

 source of error, owing to the fact that there is a wide variation in the relative sizes 

 of the different parts of the scale among scales taken from the same fish. Mottram 

 found, further, that Lee's "phenomenon" is reversed in Dahl's calculated measure- 

 ments of the trout — that is, the corresponding computed values for any one year of 

 life are larger in the big fish than in the small. In a study of comparative growth 

 rates Mottram, therefore, groups his salmon according to the order of size of the 

 actual scale measurements. 



Taylor (1916) first pointed out that the error due to the more rapid growth of 

 the scales than of the body relatively in early life "is probably compensated for by 

 the late appearance of the scales," for he found that this error was negligible in his 

 calculated lengths of the squeteague (Cynoscion regalis). 



Molander (1918) attempted to ascertain whether the noted irregularities in the 

 relations between herring and scales might not explain the irregularities in calculated 

 growths. He obtained some interesting results: 



1. In herring of different ages but of the same length the older have the larger 

 scales. The scales, therefore, have not been developed to the same degree in a 

 rapidly growing herring as in a slowly growing fish. 



2. "The growth relation between fish and scales is entirely reversed in the course 

 of years. The relatively greater growth of the herring, to begin with, is accompanied 



