8 
Fishery Bulletin 1 15(1) 
Table 4 
Sample size {n, number of steelhead), abundance estimate, and individual and joint confi- 
dence interval half-width (%) for age groups (brood years) within stocks of wild steelhead 
trout {Oncorhynchus mykiss) that spawned in 2011. Groups are identified by brood year (BY) 
and the location where the stock spawns. 
Group 
n 
Abundance 
Individual 
Joint 
Grande Ronde BY2004 
6 
116 
19.0 
34.1 
Grande Ronde BY2005 
67 
1501 
8.6 
16.2 
Grande Ronde BY2006 
222 
4912 
7.4 
12.8 
Grande Ronde BY2007 
133 
2875 
7.7 
14.2 
Grande Ronde BY2008 
2 
38 
31.9 
54.5 
Imnaha BY2004 
2 
43 
35.1 
63.3 
Imnaha BY2005 
22 
537 
17.2 
32.0 
Imnaha BY2006 
82 
1781 
12.9 
23.7 
Imnaha BY2007 
43 
957 
13.8 
26.0 
Lower Clearwater BY2004 
1 
32 
46.8 
84.2 
Lower Clearwater BY2005 
24 
522 
14.7 
25.7 
Lower Clearwater BY2006 
78 
1693 
12.7 
23.2 
Lower Clearwater BY2007 
49 
1097 
13.5 
24.2 
Lower Clearwater BY2008 
4 
78 
30.2 
55.3 
Lower Salmon BY2004 
1 
23 
57.5 
106.1 
Lower Salmon BY2005 
18 
409 
19.5 
35.4 
Lower Salmon BY2006 
40 
909 
17.9 
30.6 
Lower Salmon BY2007 
26 
557 
17.9 
31.1 
Lower Salmon BY2008 
2 
44 
48.3 
87.6 
Lower Snake BY2004 
1 
21 
50.8 
91.9 
Lower Snake BY2005 
13 
324 
16.2 
29.5 
Lower Snake BY2006 
99 
2268 
11.4 
20.2 
Lower Snake BY2007 
72 
1614 
11.4 
29.4 
Lower Snake BY2008 
6 
147 
23.1 
40.5 
Middle Fork Salmon BY2004 
10 
222 
16.2 
'31.4 
Middle Fork Salmon BY2005 
99 
2245 
11.7 
21.7 
Middle Fork Salmon BY2006 
72 
1543 
11.8 
23.2 
Middle Fork Salmon BY2007 
6 
303 
22.1 
40.4 
South Fork Clearwater BY2004 
3 
59 
28.2 
50.3 
South Fork Clearwater BY2005 
44 
906 
12.1 
22.5 
South Fork Clearwater BY2006 
144 
3010 
10.5 
19.6 
South Fork Clearwater BY2007 
12 
254 
22.6 
40.9 
South Fork Salmon BY2004 
6 
132 
28 
51.8 
South Fork Salmon BY2005 
75 
1612 
14.3 
25.2 
South Fork Salmon BY2006 
31 
695 
18.3 
33.5 
South Fork Salmon BY2007 
3 
73 
34.2 
62.2 
Upper Clearwater BY2004 
5 
99 
25.1 
47.8 
Upper Clearwater BY2005 
120 
2425 
11.0 
20.1 
Upper Clearwater BY2006 
63 
1283 
12.2 
22.7 
Upper Clearwater BY2007 
3 
54 
29.8 
54.0 
Upper Clearwater BY2008 
1 
24 
53.0 
97.6 
Upper Salmon BY2004 
2 
39 
29.7 
54.2 
Upper Salmon BY2005 
35 
758 
10.6 
21.0 
Upper Salmon BY2006 
156 
3356 
8.8 
16.3 
Upper Salmon BY2007 
107 
2319 
9.1 
17.9 
Upper Salmon BY2008 
10 
227 
15.4 
28.1 
able of interest (Table 3). Widths of the joint CIs for 
females and males were not markedly wider than those 
of the individual CIs. For age, the widths of the joint 
CIs were 1.2-3. 4 times the widths of the individual CIs. 
For stock, the joint CIs were 1.2-2. 5 times wider. For 
some age-by-stock groups, the joint CIs were consider- 
ably wider than those of the individual CIs (Table 4). 
Attainment of precision goals depended on the group 
and whether individual or joint CIs were considered 
(Tables 3 and 4). All sex and age groups met the 10% 
