266 
BULLETIN OF THE BUREAU OF FISHERIES 
Table 48 . — Age composition of the samples of the Clear Lake cisco 
[The percentages are given in parentheses] 
Age 
Year of capture 
I 
II 
III 
IV 
V 
VI 
VII 
VIII 
IX 
X 
XI 
1931 
38 (15. 3) 
31 (16. 2) 
09 (24. 5) 
33 (17. 3) 
51 (20. 5) 
44 (23. 0) 
14 (5.6) 
25 (13. 1) 
6 (2.4) 
14 (7. 3) 
23 (9. 2) 
3 (1. 6) 
29 (11. 6) 
21 (11.0) 
16 (6. 4) 
15 (7. 9) 
1 (0.4) 
3 (1.6) 
2 (0. 8) 
1 (0. 5) 
1932 
1 (0.5) 
It can be seen at once from the examination of table 48 and figure 5 that in Clear 
Lake the 1926 year class (V group of 1931, VI group of 1932) was very unsuccessful, 
1921 1922 1923 1924 1925 1926 1927 1926 1929 1930 1931 
YEAR CLASS 
Figure 5. — Percentage representation of the different year classes in the Clear Lake cisco collections. 1931, broken line; 1932, 
solid line. 
while the 1929 year class (II group of 1931, III group of 1932) which was dominant 
in the collections of both years may be termed good. It can be considered valid to 
state further that the 1924 and 1925 year classes (VII and VI groups of 1931) and 
probably the 1928 year class (III group of 1931) were more successful than those of 
1926 and 1927 (V and IV groups of 1931), and that the 1929 year class (II group of 
1931) was more successful than either that of 1930 (I group of 1931) or 1931 
(I group of 1932). 24 
In the comparison of the relative abundance of different year classes in Clear 
Lake some consideration should be given the matter of the age of the samples upon 
24 In contrast to the other 3 populations the I-group samples of Clear Lake can be considered representative. (See the 
section on “The selective action of gill nets.”) 
