Northwest Fisheries Science Center

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Document Type: Contract Report
Center: NWFSC
Document ID: 1193
Title: Passage behavior and survival of radio-tagged yearling and subyearling Chinook salmon and juvenile steelhead at Ice Harbor Dam, 2009
Author/Editor: Gordon A. Axel, Eric E. Hockersmith, Brian J. Burke, Kinsey E. Frick, Benjamin P. Sandford, William D. Muir, R. F. Absolon, Nathan D. Dumdei, Jesse J. Lamb, Matthew G. Nesbit
Publication Year: 2010
Publisher: National Marine Fisheries Service
Contracting Agency: U.S. Army Corps of Engineers. Walla Walla, Washington
Contract Number: W68SBV83306729
Pages: 71
Date: May 2010
Abstract:

In 2009, we evaluated passage behavior, distribution, and survival of yearling Chinook salmon, steelhead, and subyearling Chinook salmon at Ice Harbor Dam.  A central objective of these evaluations was to evaluate the effects of a removable spillway weir (RSW) used during two different spill operations.

Study fish were collected and surgically tagged with both a radio transmitter and PIT tag for evaluations at Lower Monumental Dam.  For the Ice Harbor evaluation, treatment groups consisted of fish released either 7 km above Lower Monumental Dam or into the tailrace of Lower Monumental Dam.  These fish were regrouped by day of detection on the Ice Harbor forebay entry line, 600 m upstream from the dam.  A total of 1,887 radio-tagged yearling Chinook salmon, 1,952 juvenile steelhead, and 2,592 subyearling Chinook salmon were evaluated.

Yearling Chinook salmon—Comparisons of estimated survival revealed no significant differences between spill treatments.  Spillway survival was 0.925 during BiOp and 0.939 during 30% spill, and RSW survival was 0.930 during BiOp and 0.939 during 30% spill.  Dam survival was 0.897 during BiOp and 0.922 during 30% spill.  The estimate for bypass survival was 0.854 (SE = 0.054) under BiOp conditions and 0.941 (SE = 0.035) during 30% spill.  Concrete survival, or the survival estimate for all fish that passed the project, was 0.931 during BiOp spill and 0.941 during 30% spill.

Juvenile steelhead—Comparisons of estimated survival between the two spill treatments revealed no significant differences.  Spillway survival was estimated at 0.958 during BiOp spill and 0.940 during 30% spill, and was not significantly different (P = 0.200).  Survival through the RSW was 0.927 during BiOp spill and 0.923 during 30% spill, and was not significantly different between operational treatments.  Dam survival was estimated at 0.911 during BiOp spill and 0.904 during 30% spill.  The estimate for bypass survival was 0.935 (SE = 0.069) under BiOp conditions and 0.944 (SE = 0.021) during 30% spill.  Concrete survival, or the survival estimate for all fish that passed the project, was 0.950 during BiOp spill and 0.943 during 30% spill.

Subyearling Chinook salmon—Comparisons of estimated survival between the two spill treatments showed no significant differences.  Spillway survival was 0.886 during BiOp vs. 0.885 during 30% spill, and RSW survival was 0.877 during BiOp vs. 0.919 during 30% spill.  Dam survival was estimated at 0.843 during BiOp spill and 0.842 during 30% spill.  The estimate for bypass survival was 0.961 under BiOp conditions and 0.958 during 30% spill.  Concrete survival, or the survival estimate for all fish that passed the project, was 0.896 during BiOp spill and 0.913 during 30% spill.

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