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S.P. Cramer & Associates, Inc. Fisheries Consultants spcramer

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 www.spcramer.com. Mid – Columbia Study Area.

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S.P. Cramer & Associates, Inc. Fisheries Consultants spcramer

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

  2. Mid – Columbia Study Area

  3. Miles of stream inhabited by O. mykiss in subbasins of the Mid Columbia Steelhead ESU

  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.

  5. % Wild Steelhead on Spawning Grounds

  6. Adult summer steelhead collected at the fish trap on Birch Creek (Umatilla River)

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

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

  9. 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

  10. Correlation Matrix of Naturally Produced Steelhead Abundance Trends

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

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

  13. 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

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