AGE AND GROWTH OF THE CISCO 
305 
Table 78.- — Length frequencies of Clear Lake ciscoes taken in nets of different mesh size 
[The 1931 and 1932 collections and the sexes are combined] 
Length 
inches 
\Yi inches 
1% inches 
2 inches 
2% inches 
2>£ inches 
3 inches 
Total 
160 to 159 
1 
1 
160 to 169 
4 
6 
10 
170 to 179 - 
10 
17 
3 
30 
180 to 189 
3 
12 
3 
18 
190 to 199 
2 
2 
200 to 209 
1 
i 
1 
3 
210 to 219 
1 
1 
220 to 229 
1 
1 
230 to 239 
2 
3 
6 
240 to 249 
2 
1 
8 
11 
250 to 259 
i 
4 
7 
12 
8 
32 
260 to 269 
2 
5 
11 
8 
26 
270 to 279 
3 
1 
9 
4 
17 
280 to 289 
1 
2 
2 
4 
7 
16 
290 to 299 
4 
8 
10 
22 
300 to 309 
2 
8 
6 
6 
22 
310 to 319 
1 
3 
4 
12 
13 
33 
320 to 329 
2 
7 
6 
11 
26 
330 to 339 
1 
2 
2 
6 
7 
12 
30 
340 to 349 
1 
1 
1 
4 
10 
12 
29 
350 to 359 
2 
2 
2 
3 
6 
10 
25 
360 to 369 
1 
1 
5 
1 
6 
13 
370 to 379 
1 
2 
2 
1 
6 
380 to 389 
1 
i 
2 
Total 
3 
24 
44 
35 
64 
103 
108 
382 
Average length 
259 
217 
201 
271 
306 
299 
315 
The Clear Lake samples with the exception of the I groups do not show as close 
dependence between the determination of the average length of individual age 
groups and the size of mesh by which the sample was taken (tables 76 and 77) as 
was observed in the other three populations. The proof of the reliability of the 
Clear Lake growth data must be based, therefore, on a demonstration that the 
population was adequately sampled throughout its length range rather than on a 
comparison of the average lengths of age groups|as determined from samples from 
nets of different mesh size. It was pointed out in the preceding paragraph that the 
sampling of the larger fish was probably adequate. The scarcity of fish in the 
1%-inch net can be taken to show that the younger age groups were also adequately 
sampled. Accordingly, no age groups were eliminated from the Clear Lake samples. 
RELATIVE ABUNDANCE OF AGE GROUPS IN GILL NET SAMPLES 
The examination of tables 71, 72, 74, 75, 76, and 77 shows that on the whole the 
selectivity of nets is much more sharp in its effect on the number of fish in a given age 
group than in its effect on the determination of the average length of that age group. 
The following examples will illustrate this point. In Muskellunge Lake (table 72) 
the average lengths of the Ill-group fish in the 1 /- and 1 ^-inch-mesh nets were 159 
millimeters and 162 millimeters, respectively; however, the 1%-inch net took only 11 
fish of this age group while the 1%-inch net took 59. In Silver Lake (table 75, data on 
lift of new nets) the Ill-group sample of the l)4-inch mesh had an average length only 
2 millimeters less than the Ill-group sample from the 1 / 4 -inch net, but was nevertheless 
represented by only 4 fish as compared with the 22 fish from the 1 %-inch-mesli net. 
In the same day’s collection the V-group samples from the same two sizes of mesh had 
practically identical average lengths, but were more than three times as numerous in 
the 1%-inch-mesh net as in the lK-inch net. In Clear Lake (tables 76 and 77) the fish 
of the older age groups were more abundant in the samples of the 2)4- and 3-inch-mesh 
nets, but the average lengths of these older age groups as determined from 2)4- and 
