1. On Recruitment of Steelhead in Mid Columbia Subbasins
Effects of Hatchery Strays
On Recruitment of Steelhead in
Mid Columbia Subbasins
Steve Cramer & Brent Lister
Funded by Yakima Joint Board
S.P. Cramer & Associates, Inc.
Fisheries Consultants

2. Mid – Columbia Study Area

3. Miles of stream inhabited by O
Miles of stream inhabited by O. mykiss in subbasins of the Mid Columbia Steelhead ESU
Life history type
Basin
Mixed
Rainbow
Steelhead
Totals
Deschutes
121
1,665
396
2,182
John Day 17
3,196
3,213
Klickitat 80
185
264
Umatilla
736
417
1,154
Walla
107
638
745
Yakima
302
500
457
1,260
423
3,105
5,289
8,817

4. Hatchery & Wild Interbreeding
Only Umatilla and Deschutes show >10% hatchery fish among natural spawners
% Hatchery spawners is much lower in key production areas than at passage monitoring stations.

7. % Wild Steelhead on Spawning Grounds

8. Adult summer steelhead collected at the fish trap on Birch Creek (Umatilla River)
Wild
Htchry
% Htchry
Birch Ck
% Htchry 3-Mi Dam
143 6 4%
43%
109 5%
38% 85 1 1%
59% 73 0%
51%
1. mark/recapture study in that approximately 30% of the wild steelhead counted at Three-Mile Dam were accounted for in Birch Creek that year.
2. clear evidence that assumptions employed Chilcote (2001) about mixing of hatchery and wild fish when he estimated the probability of extinction for steelhead in the Umatilla Basin are false. Chilcote (2001) found there was a high probability of extinction in the Umatilla Basin

9. Average Wild Steelhead Recruits per Parent Spawner, 1978-97 broods

10. Average Wild Steelhead Recruits per Parent Spawner, 1985-97 broods

14. Warm Springs River as Control
Major tributary of Deschutes River
USFWS operates a weir where nearly all fish entering the river are trapped
Only unmarked steelhead are released above the weir

16. Correlation Matrix of Naturally Produced Steelhead Abundance Trends

17. *Index includes all of John Day, Yakima and Warm Springs

19. *Index includes all of John Day, Yakima and Warm Springs

21. Conclusions
Population productivity per wild spawner was not measurably affected by hatchery spawners
Trends in abundance of Mid-Columbia steelhead are driven by factors common to all populations
Hatchery strays do not fully mix with wild fish and produce fewer recruits
Hatchery strays should be treated as a separate population when estimating stock recruitment parameters