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Penney, Z. L., C. M. Moffitt, B. Jones, and B. Marston. 2016. Physiological assessment of steelhead kelts from the Situk River, AK and Clearwater River, ID during early emigration. Environmental Biology of Fishes 99:487-498.


(Oncorhynchus mykiss) from the Situk River,
Alaska, and two tributaries of the Clearwater River,
Idaho, was evaluated to explore potential differences
in post-spawning survival related to energy reserves.
Blood plasma samples were analyzed for metrics related
to nutritional and osmotic status, and samples of white
muscle tissue collected from recent mortalities at weirs
were analyzed for proximate constituents. Female kelts
from the Situk River had significantly higher plasma
cholesterol, triglycerides, glucose and calcium concentrations,
all of which suggested higher lipid and energy
stores. Additional support for energy limitation in kelts
was provided by evaluating the presence of detectable
proteins in the plasma. Most all kelts sampled from the
Situk River populations had detectable plasma proteins,
in contrast to kelts sampled from the Clearwater River
tributary populations where 27 % of kelts from one
tributary, and 68 % of the second tributary were below
the limits of detection.We found proximate constituents
of kelt mortalities were similar between the Situk and
Clearwater River populations, and the lipid fraction of
white muscle averaged 0.1 and 0.2 %. Our findings lend
support to the hypothesis that energetic limitations likely
affect post-spawn survival in the Clearwater River kelts.


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Federal Staff: 3

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5 Year Summary

Students graduated: 25

Scientific Publications: 80

Presentations: 237



April (2nd Quarter/Spring) 2016


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Unit Authors

  • Zachary Penney
  • Bryan Jones
  • Christine Moffitt

Idaho Cooperative Fish and Wildlife Research Unit Cooperators

  1. Idaho Department of Fish and Game
  2. U.S. Fish and Wildlife Service
  3. U.S. Geological Survey
  4. University of Idaho
  5. Wildlife Management Institute