HERRING IN PRINCE WILLIAM SOUND, ALASKA 
279 
Table 11. — Percentage length frequencies for June and July from the vicinity of Latouche smoothed 
twice by threes — Continued 
By plotting the deviations of the curves for each year from the average curve for 
the seven years, the relative lack of certain size groups becomes apparent, not only 
as compared to the other sizes for the same year, but also as compared to the average 
of the same sizes over the entire period of seven years. (Fig. 9.) The top curve 
shows the average for the seven years, computed by summing the weighted (percent- 
age) frequencies of each of the seven annual curves, and dividing by seven to obtain 
the mean at each ordinate. From this standard curve the deviations of each of the 
seven years were plotted, those above the line (solid black) indicating a frequency 
greater than the average, those below the line (diagonally barred) indicating a fre- 
quency less than average. Here we find the same condition of certain abundant 
size-groups progressing through the catch from year to year as is shown by Figure 8. 
Figure 9 also shows, however, that certain size-classes are present in less than normal 
proportions. ( C and E, fig. 8.) Those size-classes which are not present in normal 
proportions, likewise progress through the catch from year to year. 
Evidence that the progression of size-modes is due to growth from year to year, is 
furnished by the age analysis. Figure 10 shows the age frequency distributions on a 
percentage basis. Although there may be some error in the age readings, they are of 
great value in interpreting the significance of the size-modes, and the consistency of 
the results obtained by the two methods is further proof of their validity. 
Table 12. — Percentage age distributions from the vicinity of Latouche, Prince William Sound 1 
1925 
1926 
1927 
1928 
1929 
1930 
Age 
Actual 
Per- 
centage 
Actual 
Per- 
centage 
Actual 
Per- 
centage 
Actual 
Per- 
centage 
Actual 
Per- 
centage 
Actual 
Per- 
centage 
26 
4.0 
13 
7.9 
35 
9.0 
38 
6.1 
330 
78.2 
36 
3.1 
7 
0.9 
42 
25.4 
137 
35.4 
343 
55.2 
39 
9.2 
1, 067 
93.3 
82 
10.8 
59 
35.8 
82 
21.1 
69 
11.1 
37 
8.8 
24 
2.1 
662 
87.5 
11 
6.7 
120 
31.0 
43 
6.9 
15 
3.6 
13 
1.1 
5 
.7 
11 
6.7 
3 
.8 
82 
13.2 
.2 
4 
.4 
.1 
K 
6 
3.6 
3 
2 
.3 
4 
2.4 
!3 
9 
1.4 
]() 
9 
5.4 
1 
.3 
5 
.8 
11 
10 
6.1 
3 
4 
.6 
12 
2 
.5 
1 
.2 
Number 
165 
387 
621 
422 
1, 144 
757 
* Inclusive of Evans Island, southern Knight Island, and Montague Island during the months of June and July. 
