LIFE HISTORY OF LAKE HERRING OF LAKE HURON 



371 



viduals reached a uniform size at maturity. Delsman (1914) noted that in the marine 

 herring of Holland the big yearlings grew more slowly in the second year than the 

 small yearlings. Fraser (1916) observed that the handicapped or slowly growing 

 Pacific spring salmon of the "stream type" gradually catch up (or nearly do so) to 

 the size of the fast-growing individuals of the "sea type." In the herUng sea trout, 

 however, Mottram (1916a) found that the fast-growing young fish continued to 

 grow rapidly throughout life, while the slowly growing fish continued to grow rela- 

 tively slowly throughout life. Dahl (1918) states that this is also true for the trout 

 of Norway, although the disparity between the slow and rapid growers decreases 

 somewhat with increasing age. Molander (1918) divided his marine herring of the 

 ninth age group into three groups, according to the size of the central field (first 

 year's growth) on the scales. He then discovered that scales with large central 

 fields remained the largest throughout the nine years of Hfe, but that the difference in 

 size between the scales with a large central field and those with a small central field 

 is less in the ninth than in the first year of Ufe. Molander referred to this as undu- 

 lating growth, though it is really the same phenomenon designated by Gilbert as 

 compensating growth. According to Hubbs (1921), a "law of growth compensation" 

 is also evident in Labidesihes sicculus and probably in Amphigonopterus aurora (Hubbs 

 1921a). This law was found operative also in the Atlantic salmon by Menzies and 

 Macfarlane (1926, 1926a) and in the sea trout by Nail (1926). Does this law hold 

 for the lake herring? Perhaps the slow growth of years 1915 to 1918 of the herring in 

 Saginaw Bay was compensated by a rapid growth in the later years of life in Lake 

 Huron proper. 



Table 40. — Computed average length increments reached in different years of life by various age groups 

 of Saginaw Bay herring. The data are taken from Table 38 and are rearranged according to age 

 groups 



If we rearrange the increments of length of Table 38 in such a way that those of 

 the same age groups are brought together as shown in Table 40 they may be compared 

 more rapidly. An. examination of this table shows that the 6-year herring hatched 

 in 1916 — that is, during a period of slow growth — grew shghtly faster in the fourth and 



