230 
BULLETIN OF THE BUREAU OF FISHERIES 
In the amount of growth the Clear Lake cisco stands far above the other three 
populations. The Trout Lake cisco shows the least amount of growth. The Silver 
Lake fish occupy a position intermediate between the Trout Lake and Muskellunge 
Lake populations. Examination of the curves showing annual increments and annual 
percentage increase throws further light on the nature of the growth of the four popula- 
tions. If the percentage increase is considered to represent the rate of growth, it 
will be seen that beyond the fourth year of life the growth rates of the four populations 
show only small differences and that beyond the fifth year the Trout Lake fish, 
although the smallest in actual size, have consistently the highest rate of growth. The 
annual growth increments of the populations show no great differences beyond the 
fifth year of life. These facts indicate that the differences in the size of the adult 
fish in the four populations depend upon the nature of growth during the early years 
of fife. There is a general convergence of growth rates at the fourth or fifth year of 
fife, but at that time the characteristic nature of the size composition for each popu- 
lation is well established. 
GROWTH IN WEIGHT 
Tables 15 to 18 present the average weight in grams for each age group in each 
year’s collection, together with summaries for the different years’ collections combined, 
of average weight of each age group, the yearly increments based on the average 
weights, and the yearly percentage increase in weight. In the consideration of aver- 
age growth in weight for the different populations the effect of gear selection should 
be kept in mind for the same age groups (marked with asterisks) that were eliminated 
in the calculation of the general growth in length (see footnote p. 226). It was found 
possible to combine the sexes in the Trout Lake and Muskellunge Lake samples, but 
not in the Clear Lake and Silver Lake collections. The females of the Clear Lake 
population grow in weight much more rapidly than do the males, while the males 
from Silver Lake tend toward a slightly better growth than do the females. 
Table 15. — Trout Lake cisco — Average weight in grams of each age group in each year's collection, 
and grand average weight for each age group, 1928, 1930, and 1931 collections combined, together 
with the annual increment and the percentage increase 
[Sexes combined. The average weights for the I-group fish are probably too high as the result of gear selection; selection probably 
affected the II-group weight values only slightly. Number of specimens in parentheses. Groups marked with asterisks un- 
reliable because of selective action of gear] 
Age 
Year of capture 
Grand 
AW 
100 AW 
1928 
1930 
1931 
average 
w 
XII.. 
172 (1) 
119 (2) 
111 (2) 
60 (2) 
45 (23) 
39 (139) 
36 (129) 
*33 (60) 
*27 (2) 
172 (1) 
119 (2) 
111 (2) 
50 (2) 
XI 
VII 
VI 
3 
6.4 
V 
64 (9) 
44 (99) 
37 (347) 
*32 (36) 
47 (32) 
41 (255) 
37 (537) 
31 (102) 
•26 (4) 
6 
14.6 
IV 
42 (17) 
37 (61) 
31 (102) 
*26 (2) 
4 
10. 8 
Ill 
6 
19.4 
II 
I.. 
