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Scientific Evaluation of Biological Opinions on Endangered and Threatened Fishes in the Klamath River Basin Interim Report (2002) / Chapter Skim
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3 Evaluation of the Biological Opinion on Klamath Basin Coho Salmon
Pages 21-25

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From page 21...
... Spawning echo in the Klamath Basin are restricted to use of tributaries that they can reach from the main stem up to iron Gate Dam. Original spawning runs probably were largest in large tributaries but currently are restricted mainly to numerous small tributaries entering the main stem directly (Yurok Tribe 2001, as cited in NMFS 2001~.
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From page 22...
... Summer temperatures appear to be especially critical. In the nearby Matolle River, which contains coho that are part of the SONCC ESU, the juvenile coho reside almost entirely in tributaries but do not persist when summer daily maximum temperatures exceed ~ 8°C for more than a week
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From page 23...
... Further modeling is in progress. The biological opinion issued by the NMFS for the Klamath Basin coho salmon states that the Klamath Project harms coho in the Klamath main stem (NMFS 2001~.
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From page 24...
... ~~:~ ~~ ~ ~~ ~ ~~ _= · Dry Water Years, USBR proposed o Critical Dry Water Years, USBR proposed Mean, ~ Dry Water Years, 1961~1997 ~ ~ Mean, 2 Critical Dry Water Years, 1961-1997 NMFS Biological Opinion FIGURE 6 Three flow regimes for the Klamath River below Iron Gate Dam: USBR proposed minimum flows for dry and critical years (USBR 2001b) , historical mean minimum flows for dry and critical dry years (USBR 2001b)
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From page 25...
... Thus, incremental depletions beyond those reflected in the recent historical record could be accomplished only with increased risk to coho salmon. At the same time, the available information provides little support for benefits presumed to occur through the increase of flows beyond those ofthe past decade.
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Key Terms

  • coho salmon
  • minimum flows
  • iron gate
  • klamath river
  • klamath basin

  • gate dam
  • critical dry
  • dry water
  • basin coho
  • below iron

  • low flows
  • native coho
  • ramping rates
  • biological opinion
  • water temperature

  • life history
  • coho population
  • flows proposed
  • usbr proposed
  • prudent measure

  • spawning coho
  • river coho
  • restricted mainly
  • makes collection
  • stem serves

  • soncc esu
  • historical mean
  • serves adults
  • project harms
  • population significantly


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