274 
BULLETIN OF THE BUREAU OF FISHERIES 
SEASONAL CHANGES IN AVAILABILITY 
Am on g the causes for fluctuations in the yield of the fishery is a seasonal variation 
in the availability of the supply of fish. Figure 6 shows the average catch per boat 
per 10-day period, computed for data from 1923 to 1930, inclusive. The first and 
highest mode of 938 barrels occurs during July, after which there is a steady decline 
until about the 20th of September, when a second rise becomes apparent, reaching a 
Figure 6. — Average catch per boat per 10-day period from 1923 to 1930, inclusive. Solid line indicates 
the average smoothed twice by threes 
mode of 787 barrels during the period September 23 to October 2. Following this sec- 
ond peak the catch declines sharply, fluctuating at a low level until the end of the season. 
Table 8. — Catch per boat in Prince William Sound from 1923 to 1930, inclusive, by 10-day periods 
Period 
No. 
Date 
1923 
1924 
1925 
1926 
1927 
1928 
1929 
1930 
Aver- 
Per 
cent 
of 
total 
Cumu- 
lative 
per- 
cent- 
age 
Average 
smoothed 
twice by 
3’s 
1 
May 2 6- June 4 
(i) 
190 
0) 
(1) 
(1) 
0) 
(1) 
0) 
190 
2.0 
2.0 
2 
June 5-June 14 
438 
941 
(!) 
(!) 
(!) 
0) 
0) 
(1) 
690 
7. 2 
9. 2 
3 
June 1 5-June 24 
1,413 
1,741 
(1) 
0) 
323 
382 
(l) 
(1) 
965 
10. 1 
19.3 
808 
4 
June 25-July 4 
1,469 
1, 221 
611 
274 
308 
2 1, 230 
2 1, 199 
935 
9. 7 
29.0 
915 
5 
July 5-July 14 
1,350 
1,205 
1 , 295 
352 
308 
344 
902 
1, 738 
937 
9.8 
38.8 
934 
6 
July 15- July 24 
1,513 
392 
1, 102 
336 
99 
862 
965 
2, 232 
938 
48.6 
894 
7 
July 25 Aug. 3 
1,031 
767 
468 
195 
139 
702 
1, 212 
2, 559 
884 
a 3 
57.9 
816 
8 
Aug. 4- Aug. 13 
1,025 
17 
57 
86 
513 
633 
1,090 
1, 837 
657 
64. 7 
676 
Aug. 14-Aug. 23 __ 
1,413 
50 
79 
90 
46 
782 
483 
1, 554 
5.9 
70.6 
522 
10 
Aug. 24-Sept. 2 
0 
348 
0 
174 
427 
950 
280 
2.9 
73.5 
390 
11 
Sept. 3-Sept. 12. 
0 
0 
417 
708 
0 
255 
511 
167 
257 
2. 7 
76. 2 
381 
12 
Sept. 13-Sept. 22 
130 
0 
83 
44 
93 
772 
216 
1, 655 
374 
3. 9 
80. 1 
436 
13 __ 
Sept. 23-Oct. 2 
333 
550 
16 
601 
o 
3, 428 
787 
8. 2 
88.3 
494 
14 
Oct. 3-Oct. 12 
69 
0 
75 
87 
492 
679 
213 
1,844 
432 
4 6 
92. 9 
416 
15 
Oct. 13-0 ct. 22 
122 
30 
0 
312 
159 
504 
28 
564 
215 
2.2 
95. 1 
284 
lfi 
Oct. 23-Nov. 1 
0 
0 
0 
0 
280 
234 
0 
(l) 
73 
95. 9 
153 
17 
Nov. 2-Nov. 11 
21 
0 
0 
0 
3 300 
o 
500 
(l) 
117 
l! 2 
97! 1 
117 
18 
Nov. 12-Nov. 21 
0 
( 4 ) 
(4) 
0) 
(4) 
250 
(l) 
6 64 
. 7 
97.8 
19 
Nov. 22-Dec. 1 
336 
83 
0) 
0) 
( l 2 ) 
0) 
225 
0) 
215 
2.2 
100.0 
1 No fishing. 
2 Four days fishing weighted to equal 10 days. 
a Three days fishing weighted to equal 10 days. 
< Four days fishing. 
‘ When computed, the three 4-day open periods of 1925, 1926, and 1929 (totaling 12 days) during which time no fish were taken, 
were considered as one period. 
