SALMON AND SALMON FISHERIES OF SWIFTSURE BANK 
791 
Table 39 . — Indices of abundance of coho salmon from traps 
Year 
Data by areas 
Index figures 
North of Sandy Point 
Rosario Strait • 
Admiralty Inlet 
North of 
Sandy 
Point 
Rosario 
Strait 
Admiral- 
ty Inlet 
Number 
of fish 
Number 
of traps 
Number 
of fish 
Number 
of traps 
Number 
of fish 
Number 
of traps 
1900 
122, 723 
2 
2. 166 
1901 
201, 962 
2 
3. 544 
1902 
113; 063 
2 
2. 071 
1903 
1904 
140, 004 
2 
2. 558 
1905 
26, 353 
2 
195, 469 
4 
4. 409 
1. soe 
1906 
33, 066 
3 
248 189 
4 
3. 923 
2. 03e 
1907 
50, 087 
6 
180, 145 
4 
3. 828 
1. 466 
1908 
47, 856 
5 
165, 054 
3 
5. 431 
1. 644 
1909 
31, 174 
i 
56, 871 
2 
294', 398 
3 
9.888 
8. 288 
3. 195 
1910 . 
99, 579 
10 
64, 779 
2 
163, 185 
4 
4. 009 
9. 238 
1. 548 
1911 _ 
54, 261 
10 
77, 585 
3 
277, 837 
4 
2. 278 
7. 813 
2. 472 
1912 
113, 122 
12 
56, 977 
3 
205, 888 
4 
4. 083 
5. 798 
1. 701 
1913 
36, 503 
5 
47, 753 
3 
159, 062 
3 
2. 598 
4. 787 
1.449 
1914 
58, 640 
10 
32, 398 
2 
68, 166 
3 
2.328 
4. 551 
.718 
1915 
56, 881 
12 
30,114 
3 
131, 229 
4 
1.835 
2. 988 
.992 
1916 
50, 375 
10 
25, 440 
3 
70, 722 
4 
2. 245 
2. 507 
.517 
1917 
53, 562 
12 
23, 418 
3 
94, 769 
4 
1.838 
2. 403 
.754 
1918 
108, 710 
12 
69, 690 
3 
116, 083 
5 
3. 433 
6. 812 
.811 
1919 
73, 488 
. 12 
44, 131 
3 
122, 723 
5 
2. 461 
4. 473 
.862 
1920 
44,597 
10 
21, 485 
3 
69, 010 
4 
1.852 
2. 199 
.731 
1921 
59, 820 
12 
14,844 
2 
78, 967 
3 
2. 143 
2. 330 
1.297 
1922 
86, 589 
7 
46, 791 
2 
61, 253 
2 
6. 332 
6. 740 
1.715 
1923 
70, 529 
12 
32, 619 
2 
166, 608 
6 
2. 672 
4. 950 
1.017 
1924 
92, 276 
10 
25, 802 
2 
166, 520 
6 
3. 978 
3. 748 
1.044 
1925 
57, 501 
12 
21, 950 
3 
165, 477 
5 
1.852 
2. 191 
1.078 
1926 
49, 163 
11 
20, 396 
3 
99, 946 
5 
1.898 
2. 066 
.690 
1927 
56, 853 
12 
26, 584 
2 
186, 117 
6 
1.879 
3. 907 
.996 
1928 
51,430 
10 
23, 784 
2 
104, 412 
6 
2. 009 
3. 510 
.561 
1929 
63, 629 
12 
29, 402 
2 
115, 487 
7 
2.291 
4. 122 
.608 
1930... 
26, 169 
u 
10, 108 
2 
81, 478 
7 
.933 
1.434 
.443 
1931 
28, 659 
n 
13, 470 
3 
58, 381 
4 
1. 182 
1.381 
.722 
1932 
1, 184 
3 
19,919 
3 
33, 155 
2 
. 175 
1. 951 
.710 
1933 
23, 828 
7 
14, 026 
3 
106, 083 
7 
1.342 
1. 350 
.578 
1934 
21, 781 
8 
19, 317 
3 
54,639 
5 
1. 151 
1. 847 
.388 
Total .. 
1, 633, 665 
869, 653 
4, 618, 204 
The third area selected was Admiralty Inlet (see fig. 3). Here, as in Rosario 
Strait, the runs are concentrated while migrating through a restricted passage, and 
the effectiveness of most of the traps is correspondingly great. Catches of from two 
to seven traps were available each year from 1900-1934, with the exception of 1903. 
The number of traps, and their corresponding total catches by years, are tabulated 
in the fifth and sixth columns of table 39. 
The calculation of index figures from these data is complicated by the fact that 
only a few traps in each district have fished continuously throughout this period of 
years. There is a wide variation in the fishing effectiveness of different traps, and 
any determination, such as the average annual catch per trap, must be affected 
considerably by the proportions of efficient and inefficient traps fishing each year. 
In order to minimize this variation it was necessary to weight the catches in such a 
manner that the relative annual change in the average catch of each trap might be 
measured irrespective of the actual sizes of the catches from which the average was 
derived. Such weighting was accomplished for each district by selecting a group of 
traps which had fished in the same years over a long period of time, and from which 
the relative effectiveness of all traps in that district might be measured. From the 
sums of the annual catches of these traps the average annual catches were calculated ; 
