Relative reproductive success of hatchery and wild steelhead in the Hood River Dept. Zoology Oregon State University

left in wild taken into hatchery Demographic boost two generations later Wild fish H H H H Supplementation of wild populations

left in wild taken into hatchery Wild fish H H H H ? Supplementation assumes fitness of H fish similar to W Big question: fitness of H fish after one generation through hatchery?

Steelhead (Oncorhynchus mykiss) in the Hood River, Oregon

Powerdale dam Winter-run Egg-laying site Summer-run Egg-laying site

dang

Hood River Steelhead Stock History Winter run Old Big Creek stock (H old ) phased out in 1991 Supplementation hatchery (H new ) program began, first releases in 1992 Summer run Old Skamania stock phased out in 1997 (H old ) Supplementation hatchery program (H new ) first releases in 1998 Note: all hatchery fish are marked with a stock-specific fin clip before release

% 4% 5% 61% 2% 64% 31% First generation of H new conservation hatchery fish created. H new parental generation released in 92. Returned to spawn in the wild mostly in 95 and 96. F1 offspring of the 185 H new and 276 W parents that Potentially spawned in the 95 run year H Example: winter run

Run year Wild (unmarked fish passed) H old fish passed H new fish passed Adult offspring from that run year Winter run New hatchery program begun in 92. Old stock phased out.

Run year Wild (unmarked fish passed) H old fish passed H new fish passed Adult offspring from that run year Summer run New hatchery program begun in 97. Old stock phased out.

Comparisons: Winter Run 1991 H old vs. wild 1995 H new vs. wild 1996 H new vs. wild 1997 H new vs. wild Summer Run 1995 H old vs. wild 1996 H old vs. wild

Whos your daddy?

Typed 97.2% of all fish passed 8 microsatellite loci Highly polymorphic (N a = 40.6, H e = 0.92) Pure exclusion with no mismatches allowed Relative reprod. success (RRS)* = mean #offspr. assigned per H adult mean #offspr. assigned per W adult *correction for bias: see Araki and Blouin (2005) Molecular Ecology

Frequency distribution of number of offspring Traditional hatchery v.s. Wild (Winter91) New hatchery v.s. Wild (Winter96) Male Female Freq. N[offspring] MaleFemale Freq. N[offspring] Hatchery-born Wild-born Hatchery-born Wild-born Hatchery-born Wild-born Hatchery-born Wild-born

Run-YearRRS [H/W] -Male RRS [H/W] -Female Summer950.31**0.33** Summer960.30**0.28** Average0.30**0.30** Winter910.06**0.11** Traditional hatchery v.s. Wild New hatchery v.s. Wild Run-YearRRS [H/W] -Male RRS [H/W] -Female Winter950.67*0.77 Winter Winter Average

Summary H old summers ~ 30% fitness of wild fish H old winters 6-11% fitness of wild fish H new winters % (avg %) fitness of wild fish

Summary H old summers ~ 30% fitness of wild fish H old winters 6-11% fitness of wild fish H new winters % (avg %) fitness of wild fish Angling correction H old summers ~ 40% fitness of wild fish H old winters 6-11% fitness of wild fish H new winters % (avg %) fitness of wild fish

Taken into hatchery Success of Hood River supplementation program? 5-10X 0.85X H H H H H H H H

Supplementation a good idea? Ecological issues Effective size When do you stop?

steelhead (this study) steelhead Atlantic salmon (farmed) steelhead Brown trout From: Travis et al., Salmon Recovery Science Review Panel Report for NMFS Decline in fitness with generations through hatchery

% 77% 20% 29% 4% 6% 61% Returning H new adults mixed with wild broodstock in Hatchery beginning in % 77% 20% Future work Effects of incorporating H new into broodstock (i.e. effects of more than one generation through hatchery)?

Acknowledgements Hitoshi Araki Bill Ardren Becky Cooper Charles Criscione Rod French Kathryn Kostow ODFW Staff at Powerdale Dam Erik Olsen Ruben Van Dam Funding BPA ODFW