AGE AND GROWTH OF THE CISCO 
251 
Only one year class (1928) occurred in sufficient numbers in more than 1 year’s 
collection of the Muskellunge Lake cisco to make possible a comparison of growth 
up to time of capture with the total season’s growth. The 1930 II group (see table 4) 
had an average calculated growth of 19 millimeters for the 1930 season up to the time 
of capture, August 28 and 29. The 337 specimens of this same year class taken as 
the III group of 1931 showed an average calculated growth of 18 millimeters for the 
entire 1930 season. Although these data can scarcely be taken to demonstrate a 
shri nk age of 1 millimeter in the average size of the 1930 II group between the time of 
capture of the samples and the time of the formation of the third annulus, they do 
indicate that the season’s growth of the Muskellunge Lake cisco is complete at the 
end of August. 
It is, of course, possible that growth in the Muskellunge Lake cisco may be com- 
plete several weeks before the end of August. The 1928 and 1931 collections were 
taken earlier in the summer but, unfortunately, no comparisons are possible between 
the data of any age groups of the samples of these 2 years and data based on collec- 
tions of the same year class in other years. In the 1928 collections (made July 1 to 
July 4) only the II group was well represented and none of the 1926 year class indi- 
viduals was taken in any of the later collections. The 1931 collections (made July 
14 to 28 — over 80 percent of the former date alone) cannot be compared with the 
1932 collections since for reasons discussed previously (p. 219) the 1932 catches were 
not included in the Muskellunge Lake growth data. It is possible, however, to com- 
pare the season’s growth before capture of the 1928 and 1931 II groups with the grand 
average of 18 millimeters calculated growth in the third year of life, based on the 
combination of all age groups above the II group and all years’ collection. These 
comparisons show that the 1928 II group which had grown 13 millimeters at the time 
of capture in early July was still 5 millimeters short of the average growth of fish in 
the t hi rd year of life, while the 1931 Il-group fish which had grown 11 millimeters up 
to the middle of July still lacked 7 millimeters of having attained the average for 
third-year growth. These two comparisons, particularly the latter, indicate that the 
Muskellunge cisco is growing actively throughout July and that in all probability this 
growth extends at least into early August. Consequently the Muskellunge Lake cisco 
may be accredited with a slightly longer growing season than the Trout Lake cisco. 
Since it was felt that the prominence of Lee’s phenomenon in the growth data of 
the Silver Lake cisco made the comparison of age groups separated by more than 1 
year of life inadvisable, none of the 1928 material was used in the study of length of 
the growing season in that lake. Table 36 shows the comparison of the 1930 calcu- 
lated growth of three age groups of the Silver Lake cisco up to the time of capture in 
the middle of August with the total 1930 growth of these age groups calculated from 
1931 collections of the same year classes. It may be seen that at the time of capture 
of the 1930 samples, August 9 to 15, the season’s growth of the Silver Lake cisco was 
approximately two-thirds to three-quarters complete. From this fact it may be 
concluded that the Silver Lake cisco is still growing throughout the month of August 
and that the growing season probably extends on into early September. It may be 
concluded, therefore, that the growing season of the Silver Lake cisco is longer than 
that of either the Trout Lake or the Muskellunge Lake cisco. 
