AGE AND GROWTH OF THE CISCO 
301 
different mesh size both in the average size of the fish and in the relative abundance 
of the different age groups. 38 Selectivity according to length appears to be greater in 
the Muskellunge Lake cisco, where the 1%-inch mesh net caught fish 14 millimeters 
longer than the l^-inch mesh sample, than in the Trout Lake cisco (table 71) where 
the fish from the 1%-inch mesh net were only 5 millimeters longer than those from the 
1%-incli mesh net. It will be noticed further that nets of the same size mesh caught 
larger fish in Muskellunge Lake than in Trout Lake (fig. 11). 
Table 72 . — Effect of size of mesh of gill nets on the determination of the average lengths of the age groups 
of the Muskellunge Lake cisco, 1932 collection 
(Sexes combined. Number of specimens in parentheses] 
Size of mesh 
Age group 
Average 
length 
I 
II 
III 
IV 
V 
137 (12) 
150 (3) 
152 (7) 
158 (12) 
159 (11) 
162 (59) 
166 (5) 
168 (3) 
168 (59) 
177 (12) 
150 (33) 
164 (150) 
174 (18) 
XVi inches . 
172 (1) 
139 (15) 
156 (24) 
162 (75) 
170 (74) 
172 (1) 
The question of the reliability of the 1930 and 1931 collections is largely a question 
of the reliability of samples from ljLinch mesh nets, for the collections of these 2 
years were taken in nets of this size mesh. The 1928 samples may be considered as 
reliable as the 1932 samples. The data of table 72 show that in spite of the selection 
that does occur the 1%-inch mesh net samples, with the exception of the I group, 
give averages for the lengths of the different age groups that differ insignificantly 
from the corresponding averages based on the catch of nets of three different sizes of 
mesh. It is, therefore, a safe conclusion that with the elimination of the I groups the 
length data obtained from 1^-inch nets in the preceding seasons are accurate within 
the range of a very few millimeters. 
Table 73 . — Length frequencies of Muskellunge Lake ciscoes taken in 1932 in nets of different mesh size 
[Sexes combined. The frequencies represent 18 lifts for the l!4-inch mesh net, 38 for the lH-ineh mesh net, and 37 for the Hi-inch 
mesh net] 
Length 
Hi-inch 
net 
1 H-inch 
net 
Hi-inch 
net 
Total 
Length 
1)4 -inch 
net 
lH-inch 
net 
Hi-inch 
net 
Total 
185 to 189 
2 
1 
3 
145 to 149 
18 
48 
66 
180 to 184__ 
6 
3 
9 
140 to 144 
24 
20 
44 
175 to 179 
27 
4 
31 
135 to 139... 
40 
4 
44 
170 to 174 
2 
102 
6 
110 
130 to 134 . 
7 
7 
1fi.fi In IfiQ 
5 
2 
160 to 164 
13 
186 
1 
200 
154 
813 
18 
985 
150 to 154 
21 
91 
112 
Average length.. 
146 
160 
174 
The above conclusion is supported by the examination of the length frequencies 
of the total catch of Muskellunge Lake ciscoes in each mesh size in the entire 1932 
season (table 73). In the length frequencies of the 1%-inch net samples there occurs 
at the 145 to 149 millimeter interval a depression that marks the separation of the I 
38 It was pointed out previously (p. 219), that because of slow growth in the later years and the common occurrence of accessory 
annuli the separation of the later age groups above the II group in the 1932 Muskellunge Lake samples was difficult. As a conse- 
quence, the average lengths listed for the Ill-group and the IV-group samples may be slightly in error. Any error that exists should 
not, however, impair greatly the general usefulness of the data for the purpose of studying the effect of net selection on the deter- 
mination of the average lengths of age groups. 
