scholarly journals Assessing Hydrosystem Influence on Delayed Mortality of Snake River Stream-Type Chinook Salmon

2007 ◽  
Vol 27 (3) ◽  
pp. 810-824 ◽  
Author(s):  
Howard A. Schaller ◽  
Charles E. Petrosky
Keyword(s):  
Chinook Salmon ◽  
Snake River ◽  
Delayed Mortality ◽  
Stream Type

Post-Hydropower System Delayed Mortality of Transported Snake River Stream-Type Chinook Salmon: Unraveling the Mystery

2006 ◽  
Vol 135 (6) ◽  
pp. 1523-1534 ◽  
Author(s):  
William D. Muir ◽  
Douglas M. Marsh ◽  
Benjamin P. Sandford ◽  
Steven G. Smith ◽  
John G. Williams
Keyword(s):  
Chinook Salmon ◽  
Snake River ◽  
Hydropower System ◽  
Delayed Mortality ◽  
Stream Type

Evaluating river management during seaward migration to recover Columbia River stream-type Chinook salmon considering the variation in marine conditions

2014 ◽  
Vol 71 (2) ◽  
pp. 259-271 ◽  
Author(s):  
Howard A. Schaller ◽  
Charles E. Petrosky ◽  
Eric S. Tinus
Keyword(s):  
Marine Environment ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Columbia River ◽  
Temporal Analysis ◽  
Adult Survival ◽  
Snake River ◽  
Data Sets ◽  
Delayed Mortality ◽  
Stream Type

Evidence suggests Snake River stream-type Chinook salmon (Oncorhynchus tshawytscha) experience substantial delayed mortality in the marine environment as a result of their outmigration experience through the Federal Columbia River Power System (FCRPS). We analyzed mortality patterns using methods that incorporated downriver reference populations passing fewer dams, and temporal approaches that were independent of reference populations. Our results from the alternative spatial and temporal methods consistently corroborated with spawner–recruit residuals and smolt-to-adult survival rate data sets, indicating that Snake River salmon survived about one quarter as well as the reference populations. Temporal analysis indicated that a high percentage (76%) of Snake River juvenile salmon that survived the FCRPS subsequently died in the marine environment as a result of their outmigration experience. Through this and previous studies, it is evident that delayed hydrosystem mortality increases with the number of powerhouse passages and decreases with the speed of outmigration. Therefore, a promising conservation approach would be to explore management experiments that evaluate these relationships by increasing managed spill levels at the dams during the spring migration period.

The importance of influence diagnostics: examples from Snake River chinook salmon spawner-recruit models

2001 ◽  
Vol 58 (3) ◽  
pp. 551-559
Author(s):  
Richard A Hinrichsen
Keyword(s):  
Chinook Salmon ◽  
Main Stem ◽  
Columbia River Basin ◽  
Snake River ◽  
Rapid Decline ◽  
Single Observation ◽  
Influence Diagnostics ◽  
Direct Measurements ◽  
Transportation Program ◽  
Stream Type

The rapid decline of some salmonid populations in the Columbia River Basin led investigators to analyze spawner-recruit (SR) data in order to understand the potential gains of improving main-stem passage conditions and quantify the effectiveness of the juvenile transportation program. Direct measurements of passage survival and transportation were not always available, so instead, the researchers attempted to tease out the passage or transportation effects by using trends in production estimated from SR models. Small subsets of data, or even single observations, highly influenced the estimates of passage survival and transportation effectiveness derived from these models. For stream-type chinook salmon, deleting 1 of 13 stocks changed the estimate of main-stem passage survival from 11 to 34%. For ocean-type chinook salmon, the conclusion that transportation should be immediately halted hinged on a single observation. The Snake River salmon SR models starkly illustrate the importance of using influence diagnostics to temper inferences.

Productivity and survival rate trends in the freshwater spawning and rearing stage of Snake River chinook salmon (Oncorhynchus tshawytscha)

2001 ◽  
Vol 58 (6) ◽  
pp. 1196-1207 ◽  
Author(s):  
C E Petrosky ◽  
H A Schaller ◽  
P Budy
Keyword(s):  
Survival Rate ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Adult Stage ◽  
Life Stage ◽  
Snake River ◽  
Climate Conditions ◽  
Management Actions ◽  
Significant Survival ◽  
Stream Type

Stream-type chinook salmon (Oncorhynchus tshawytscha) populations in the Snake River (northwest United States) have declined dramatically since completion of the federal hydrosystem. Identifying the life stage that is limiting the survival of these stocks is crucial for evaluating the potential of management actions to recover these stocks. We tested the hypothesis that a decrease in productivity and survival rate in the freshwater spawning and rearing (FSR) life stage since completion of the hydropower system could explain the decline observed over the life cycle. The decline of chinook populations following completion of the hydrosystem was not accompanied by major survival changes in the FSR life stage. FSR productivity showed no significant decline, and the FSR survival rate decline was small relative to the overall decline. However, significant survival declines did occur in the smolt-to-adult stage coincident primarily with hydrosystem completion, combined with poorer climate conditions and possibly hatchery effects. Potential improvements in survival that occur only at the FSR life stage are unlikely to offset these impacts and increase survival to a level that ensures the recovery of Snake River stream-type chinook.

Experimental measurement of hydrosystem-induced delayed mortality in juvenile Snake River spring Chinook salmon (Oncorhynchus tshawytscha) using a large-scale acoustic array

2009 ◽  
Vol 66 (7) ◽  
pp. 1019-1024 ◽  
Author(s):  
Erin L. Rechisky ◽  
David W. Welch ◽  
Aswea D. Porter ◽  
Melinda C. Jacobs ◽  
Adrian Ladouceur
Keyword(s):  
Pacific Ocean ◽  
Chinook Salmon ◽  
Large Scale ◽  
Oncorhynchus Tshawytscha ◽  
Fork Length ◽  
Snake River ◽  
Return Rates ◽  
The Pacific ◽  
The Pacific Ocean ◽  
Delayed Mortality

Out-migrating Snake River salmon smolts must pass eight major hydro dams before reaching the Pacific Ocean. Direct mortality at the dams is generally low; however, the cumulative stress caused by dam passage is hypothesized to result in delayed mortality, which occurs beyond the impounded section of the river. We tested the delayed mortality hypothesis by comparing in-river and early ocean survival of hatchery-origin spring Chinook salmon ( Oncorhynchus tshawytscha ) from the Snake River to a mid-Columbia River population that passes through only four dams and has higher smolt to adult return rates. Smolts >140 mm fork length were implanted with acoustic transmitters and tracked with the Pacific Ocean Shelf Tracking (POST) array to as far as Alaska. There was no detectable difference in survivorship to the first ocean detection line, 274 km beyond the final dam (SSnake = 29% ± 4%, SYakima = 28% ± 5%), indicating that the survival disparity observed in adult return rates may develop later in the marine life history phase. Our study is the first to estimate survival in the coastal ocean and demonstrates the utility of a large-scale array in testing previously intractable hypotheses.

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