102 
Fishery Bulletin 11 7(1-2) 
Table 4 
The number of juvenile steelhead (Oncorhynchus mykiss) caught each year from each genetic stock group, the number that 
were marked with a tag or fin clip, and the overall catch per unit of effort (CPUE) for each year in the period 2006-2012 and 
summarized over all sampling stations in a study area from Puget Sound, Washington, to the Central Valley of California. 
Year 
Total 
number 
Puget 
Sound/ 
Strait of 
Juan de 
Fuca 
Washing¬ 
ton 
coast 
Lower 
Columbia 
River 
summer 
run 
Lower 
Columbia 
River 
winter 
run 
Mid and 
Upper 
Columbia 
River 
Lower 
Snake 
River 
Mid and 
Upper 
Snake 
River 
Oregon 
coast 
Central 
Valley, 
California 
Marked 
Overall 
CPUE 
2006 
234 
2 
16 
33 
44 
82 
54 
3 
0 
193 
2.095 
2007 
45 
5 
11 
2 
19 
5 
0 
2 
1 
17 
0.273 
2008 
72 
4 
23 
4 
9 
12 
16 
4 
0 
40 
0.446 
2009 
41 
4 
8 
3 
8 
8 
10 
0 
0 
29 
0.274 
2010 
46 
1 
10 
6 
18 
7 
3 
1 
0 
27 
0.397 
2011 
38 
2 
9 
3 
11 
8 
4 
1 
0 
23 
0.173 
2012 
14 
0 
0 
1 
1 
5 
7 
0 
0 
8 
0.151 
0 80 
Genetic stock group 
Puget Sound/Strait of Juan de Fuca 
□ Washington coast 
■ Lower Columbia River summer run 
Q Lower Columbia River winter run 
■ Middle and Upper Columbia River/Lower Snake River 
B Middle and Upper Snake River 
□ Oregon coast 
■ Central Valley, California 
JIJIh. jfl 
2006 
2007 
2008 
2009 
Year 
2010 
2011 
2012 
Figure 2 
Catch per unit of effort (CPUR) of steelhead (Oncorhynchus mykiss) from 
trawl hauls conducted in 2006-2012 off the coasts of Washington and Or¬ 
egon, by genetic stock group and year. Values of CPUE were calculated as 
the number of fish caught divided by the number of kilometers trawled. 
southernmost genetic stock groups (in the Central Val¬ 
ley of California). That individual was not included in 
subsequent analyses. 
Stock distributions and catch 
There was considerable variation in CPUE among years 
(Fig. 2). The CPUE values in 2006 were considerably 
greater than those in any other year, especially for 
the genetic stock groups that included 
populations in the Snake River. The 
genetic stock group with the greatest 
CPUE value varied over the study pe¬ 
riod, but it was usually a group of the 
Columbia River, except in 2008, when 
the group from the Washington coast 
had the greatest CPUE value (Table 4). 
There was also considerable varia¬ 
tion in CPUE among transects of the 
trawl hauls each year (Fig. 3). In 
2006, the distribution of the steel- 
head caught was different than in all 
the other years because most of the 
steelhead were caught in the 3 south¬ 
ernmost transects, especially in those 
off Cape Meares, Oregon. Steelhead 
were caught on that transect in only 
one other year: 2012. The transect in 
Willapa Bay, Washington, was where 
most of the steelhead were caught 
in 2010, especially Lower Columbia 
River winter-run fish, whereas the 
greatest concentration of fish occurred 
on the northernmost transect, Father 
and Son, in 2011. The catch in other 
years was spread more evenly among 
transects. 
On average, steelhead from each genetic stock group 
were found north of the mouth of the Columbia River 
(Fig. 4). Lower Columbia River steelhead were found 
farther north than other stock groups of the Columbia 
River. In particular, the Lower Columbia River winter- 
run steelhead were found farther north than all other 
stock groups, although there was considerable over¬ 
lap in the standard deviations of latitudes among all 
groups. The greatest difference in latitude (90 km) was 
