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Supplementation using steelhead fry: performance, interactions with natural steelhead, & effect of enriched hatchery

Supplementation using steelhead fry: performance, interactions with natural steelhead, & effect of enriched hatchery environments. Christopher P. Tatara NOAA Fisheries, Northwest Fisheries Science Center Stephen C. Riley USGS, Great Lakes Science Center Julie A. Scheurer

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Supplementation using steelhead fry: performance, interactions with natural steelhead, & effect of enriched hatchery

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  1. Supplementation using steelhead fry: performance, interactions with natural steelhead, & effect of enriched hatchery environments Christopher P. Tatara NOAA Fisheries, Northwest Fisheries Science Center Stephen C. Riley USGS, Great Lakes Science Center Julie A. Scheurer NOAA Fisheries, Sustainable Fisheries Division Barry A. Berejikian NOAA Fisheries, Northwest Fisheries Science Center

  2. Current status of steelhead under ESA Role of hatcheries in steelhead management 2 potential pre-release techniques for steelhead conservation hatcheries Environmental enrichment Stocking fry Field evaluation of these two conservation hatchery techniques Overview

  3. ESA Status of Steelhead

  4. Hatcheries in steelhead management • Historic and current - Stock Enhancement • Provide fish for harvest and recreational angling • More recent – Restocking and Conservation • Restore spawning biomass/population to sustainable/stable level • Controversy over the use of hatchery fish for rebuilding imperiled natural populations • Changes to minimize genetic and environmental influences of hatcheries

  5. Photo: DIPAC Photo:NWPCC 190 mm 90 mm Conservation hatchery techniques Conventional Hatchery Enrichment Stream Smolt release – 1 year Fry release – 4-5 months

  6. Rearing Environments Enriched Photo: USFWS Conventional Natural Photo: Scotty Corp. Photo: USFWS

  7. Evaluating conservation hatchery techniques: Experimental Design Upstream Upstream Stocked: 31 July 2003 Observed: 5 occasions between 6 August and 11 Sept 2003 C + N E + N 12 Creek E + N C + N C + N E + N E + N C + N 11 Creek E + N C + N C + N E + N Final sampling: 16-17 September 2003 Downstream Downstream

  8. Evaluating conservation hatchery techniques: Responses and Hypotheses Upstream Upstream Response Variables: Behavior, Territory size, Habitat use, Spatial distribution, Growth, and Survival C + N E + N 12 Creek E + N C + N H1: How do conventional and enriched hatchery fry compare to natural fry? C = E = N C + N E + N E + N C + N 11 Creek E + N C + N H2: Are natural fry differentially affected by type of hatchery fry stocked? NCON = NENR C + N E + N Downstream Downstream

  9. Hatchery type x Week interaction • (F3,79 = 3.97, p = 0.011) Results: Foraging and aggressive behavior – natural fry • Hatchery type (F1,79 = 5.01, p = 0.028) • Week (F3,79 = 4.34, p = 0.007)

  10. Results: Territory size • H1: C = E = N • (F2,135 = 0.043, p = 0.653) • H2: NCON= NENR • (F1,45 = 0.45, p = 0.504) • Additional analyses • Fork length (F1, 132 = 9.40, p = 0.003) • Spatial use (T-value = 4.37, p < 0.001) • C = E = N (F2,133 = 0.66, p = 0.520) • Local density (p = 0.129)

  11. Results: habitat use Pool Use Index = (# frypool/# fryencl)/(Areapool/Areaencl) Stream x hatchery type stocked interaction F1,36 = 14.40, p = 0.001 Stream x type interaction F2,74 = 11.68, p<0.001

  12. Results: spatial distribution • Standardized Morisita Index • = 0 indicates randomness • > 0 indicates clumping (+) • < 0 indicates uniformity (-) Stream x fish type, F2,76 = 6.42, p = 0.04 Hatchery type, F1,33 = 3.51, p = 0.07

  13. Results: Growth (ANOVA, F1,18 = 7.23, p = 0.02) n=6 for natural n=3 for hatchery Mann-Whitney, n=6

  14. Results: Survival after 6 weeks (ANOVA, F2,18 = 27.57, p < 0.001) n=12 for natural n=6 for hatchery Mann-Whitney, n=6 Paired t-test, n=16

  15. Results: Estimated survival over the course of the experiment Proportion of initial population observed Sheirer-Ray-Hare, F1,95 = 45.2, p < 0.001

  16. Effectiveness of steelhead fry supplementation

  17. Supporting research evaluating effectiveness of fry stocking • Hatchery program established 2002 • Featured fry stocking (after complete yolk absorbance) • Extensive genetic monitoring & adult & outmigrant traps • Used genetic monitoring to compare # age-2 smolts produced by female steelhead • Spawning naturally in the river • Spawned artificially in hatchery with their offspring released as fry Carrofino et al. 2008. Can J Fish Aquat Sci : 65: 309-318

  18. Conclusions • Fry from conventional and enriched hatchery environments develop natural social behaviors shortly after release • Individual hatchery fry establish and use territories like natural fry • Hatchery fry use pools like natural fry, but have a more clumped spatial distribution • Stocking enriched hatchery fry altered the foraging and aggressive behavior of natural fry • No effect on growth or survival of natural fry

  19. Conclusions • Conventional and enriched hatchery fry grow as well as natural fry • Natural fry have higher survival than hatchery fry • most mortality of hatchery fry occurred within 2 weeks of stocking • Growth and survival of natural fry was similar when stocked with conventional or enriched hatchery fry • Supplementation with hatchery fry increased steelhead populations over the short-term (density increase of 2.9X) • no differences using conventional or enriched fry • Fry supplementation increases relative production of age-2 smolts • Longer studies of fry supplementation are needed to fully evaluate effectiveness

  20. Acknowledgements • Rob Endicott • Jeff Atkins • Skip Tezak • Eric Kummerow • Rudy Wynn • Brandon Nickerson • Weyerhaeuser Corporation • WDFW, Bingham Creek Hatchery

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