Natural growth regimes for hatcheryreared steelhead to reduce residualism and negative ecological interactions

Transcription

1 Natural growth regimes for hatcheryreared steelhead to reduce residualism and negative ecological interactions B. Berejikian 1, C. Tatara 1, M. Moore 1, P. Swanson 1 D. Larsen 1, W. Gale 2, C. Pasley 3, B. Beckman 1 1/ NOAA Fisheries, Northwest Fisheries Science Center 2/ US Fish and Wildlife Service, Mid-Columbia River Fishery Resource Office 3/ US Fish and Wildlife Service, Winthrop National Fish Hatchery

2 Frequency A Size-at-age and smoltification Age-2 smolt Stock in Environment Age-1 smolt Age-3 smolt Wild in Natural Freq quency B Age-1 smolt Fork length (mm) at age 1 (spring) residuals Domesticated in S1 Hatchery Frequency C residuals Age-1 smolt Fork length (mm) at age 1 (spring) Wild in S1 Hatchery Fork length (mm) at age 1 (spring)

3 Model for integrated hatchery programs Age-2 smolt Frequency Age-1 smolt Fork length (mm) at age 1 (spring) Frequency residual Age-2 smolt Mature residuals? Fork length (mm) at age 2 (spring)

4 Causes of residualism Ecological interactions and residualism Early male maturity (Sharpe et al. 2007) Small body size (Sharpe et al. 2007, Viola and Schuck 1995) Incomplete smoltification (Kennedy et al. 2007, Hill et al. 2006) Broodstock choice (domesticated vs wild) Potential Consequences Size-biased and density-dependent interference competition (McMichael et al. 2000) Disruptive breeding interactions (Atlantic salmon: Fleming et al. 1998) Predation on juvenile salmonids (Kostow 2008; Naman and Sharpe)

5 Methods to reduce residualism Volitional release and retention of non-migrants (Viola and Schuck 1995; Gale et al. 2009) Growth modulation to improve age-1 smoltification (Sharpe et al. 2007) Size sort in the fall prior to smoltification push growth of smaller fish Hypothesis: Growth modulation and age-2 smolt rearing will improve migratory behavior, survival, and reduce residualism

6 Hood Canal Steelhead Hydraulic redd sampling LLTK Hatchery WDFW Hatchery Age-2 smolt rearing

7 Hood Canal steelhead age-2 smolt size Hatchery template Duckabush Dewatto Skokomish Dewatto Body weight (g) Frequency Fork length 7% male May-07 Jul-07 Sep-07 Nov-07 Jan-08 Mar-08 May-08 Jul-08 Sep-08 Nov-08 Jan-09 Mar-09 May Skokomish 20% male Frequency Duckabush 2% male Fork length Fork length Frequency

8 Hood Canal steelhead residuals (mid-summer: TL mm) Wild fish = 1.0 a Hatchery fish = 0.8 Proportion glide pool riffle run glide pool riffle run glide pool riffle run (120) (653) (9) (168) (258) (985) (211) (978) (118) (2073) (291) (1445) Dewatto Duckabush Skokomish No. released 7,375 1,574 23,747 No. wild obs ,927 2,435 No. hatch obs

9 Hood Canal steelhead residuals (mid-summer: TL > 200 mm) Wild fish = 1.0 b Hatchery fish = 0.8 Propor rtion glide pool riffle run glide pool riffle run glide pool riffle run (10) (37) (0) (9) (62) (189) (64) (276) (36) (128) (16) (64) Dewatto Duckabush Skokomish No. released 7,375 1,574 23,747 No. wild obs No. H obs

10 Methow River summer steelhead Methow R Winthrop NFH Hood Canal Wells Dam Columbia River

11 Growth Modulation Source: Charlie Snow, WDFW, unpublished data

12 Size frequency of S1 and S2 smolts 21.7 cm FL 22 cm FL

13 Early male maturity? Frequency S1 S2 Are these males that could mature at age 2 or 3? Log 11KT (ng/ml) S1-0.0% mature males S2-3.8% of males were mature mean KT levels higher in S2 running males FSH 11-KT StAR Steroidogenic enzymes Do plasma levels of 11KT, or mrnas for pituitary FSH or testis StAR predict male maturation? - at age-3 for S2 smolts - at age-2 for S1 smolts

14 Migration monitoring Mark-recapture survival estimates Migratory behavior Residual behavior Source (P. Connelly, USGS)

15 Final thoughts S2 smolt programs require Careful planning, execution, and evaluation Suitable rearing environment (space + temps) Optimal rearing strategy depends on Program goals Broodstock characteristics Water supply Cost-benefit ($ and ecological)

16 Acknowledgements Hood Canal Steelhead Project partners NWFSC REUT and CB Divisions, Washington Department of Fish and Wildlife, Long Live the Kings, Hood Canal Salmon Enhancement Group, US Fish and Wildlife Service, US Forest Service, Skokomish Tribal Nation, Point No Point Treaty Tribes, Private landowners Swanson lab: Jon Dickey, Shelly Nance, Molly Middleton, and Yoji Yamamoto. Winthrop National Fish Hatchery Staff USGS (Pat Connelly) BOR (Michael Newsome) Bonneville Power Administration