Population viability of the Snake River chinook salmon (Oncorhynchus tshawytscha)

1995 ◽  
Vol 52 (7) ◽  
pp. 1442-1448 ◽  
Author(s):  
John M. Emlen
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Population Viability ◽  
Snake River ◽  
Management Actions ◽  
Population Dynamics Model ◽  
The Status ◽  
Salmon Population ◽  
Mortality Improvement ◽  
Best Fit

In the presence of historical data, population viability models of intermediate complexity can be parameterized and utilized to project the consequences of various management actions for endangered species. A general stochastic population dynamics model with density feedback, age structure, and autocorrelated environmental fluctuations was constructed and parameterized for best fit over 36 years of spring chinook salmon (Oncorhynchus tshawytscha) redd count data in five Idaho index streams. Simulations indicate that persistence of the Snake River spring chinook salmon population depends primarily on density-independent mortality. Improvement of rearing habitat, predator control, reduced fishing pressure, and improved dam passage all would alleviate density-independent mortality. The current value of the Ricker α should provide for a continuation of the status quo. A recovery of the population to 1957–1961 levels within 100 years would require an approximately 75% increase in survival and (or) fecundity. Manipulations of the Ricker β are likely to have little or no effect on persistence versus extinction, but considerable influence on population size.

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.

Forecasting climate-induced changes in the survival of Snake River spring/summer Chinook salmon (Oncorhynchus tshawytscha)

2005 ◽  
Vol 14 (6) ◽  
pp. 448-457 ◽  
Author(s):  
MARK D. SCHEUERELL ◽  
JOHN G. WILLIAMS
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Snake River ◽  
Induced Changes

Experimental management for Snake River spring–summer chinook (Oncorhynchus tshawytscha): trade-offs between conservation and learning for a threatened species

2002 ◽  
Vol 59 (4) ◽  
pp. 717-725 ◽  
Author(s):  
Charles M Paulsen ◽  
Richard A Hinrichsen
Keyword(s):  
Oncorhynchus Tshawytscha ◽  
Management Strategies ◽  
Snake River ◽  
Evolutionarily Significant Unit ◽  
Management Actions ◽  
Trade Offs ◽  
Increase Productivity ◽  
Population Viability Analyses ◽  
Experimental Management ◽  
Power Analyses

Using Snake River spring–summer chinook (Oncorhynchus tshawytscha) as an example, we explore trade-offs between conservation (restoring population abundance to self-sustaining levels) and learning (reliably estimating how management strategies affect productivity). The population has been studied extensively, especially since 1992, when the evolutionarily significant unit (ESU) was listed under the U.S. Endangered Species Act. Understanding both the conservation and learning dimensions is crucial in evaluating management actions. Using a Bayesian simulation model calibrated with 40+ years of spawner–recruit estimates, we performed population viability analyses to examine the biological risks of an array of management strategies. We also performed power analyses to estimate the precision of estimates of the actions' effects. The results suggest that if one can take actions that increase productivity and manage those actions as experiments, one can simultaneously increase fish numbers and reduce the uncertainty about the effects of those actions. However, because more powerful experiments will utilize controls where no action is taken, an experimental approach may increase risks to the ESU when compared to a strategy that tries to maximize productivity as soon as possible.

A multiple-reach model describing the migratory behavior of Snake River yearling chinook salmon (Oncorhynchus tshawytscha)

1998 ◽  
Vol 55 (3) ◽  
pp. 658-667 ◽  
Author(s):  
Richard W Zabel ◽  
James J Anderson ◽  
Pamela A Shaw
Keyword(s):  
Chinook Salmon ◽  
Migration Rate ◽  
River Flow ◽  
Oncorhynchus Tshawytscha ◽  
Nonlinear Models ◽  
Columbia River ◽  
River System ◽  
Snake River ◽  
Migration Route ◽  
Time Step

A multiple-reach model was developed to describe the downstream migration of juvenile salmonids in the Columbia River system. Migration rate for cohorts of fish was allowed to vary by reach and time step. A nested sequence of linear and nonlinear models related the variation in migration rates to river flow, date in season, and experience in the river. By comparing predicted with observed travel times at multiple observation sites along the migration route, the relative performance of the migration rate models was assessed. The analysis was applied to cohorts of yearling chinook salmon (Oncorhynchus tshawytscha) captured at the Snake River Trap near Lewiston, Idaho, and fitted with passive integrated transponder (PIT) tags over the 8-year period 1989-1996. The fish were observed at Lower Granite and Little Goose dams on the Snake River and McNary Dam on the Columbia River covering a migration distance of 277 km. The data supported a model containing two behavioral components: a flow term related to season where fish spend more time in regions of higher river velocity later in the season and a flow-independent experience effect where the fish migrate faster the longer they have been in the river.

Fall Chinook Salmon (Oncorhynchus tshawytscha), Sand Roller (Percopsis transmontana), and Smallmouth Bass (Micropterus dolomieu) Interactions in a Snake River Reservoir: A Tale of Three Species

2019 ◽  
Vol 100 (1) ◽  
pp. 26 ◽  
Author(s):  
Rulon J Hemingway ◽  
Kenneth F Tiffan ◽  
John M Erhardt ◽  
Tobyn N Rhodes ◽  
Brad K Bickford
Keyword(s):  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Smallmouth Bass ◽  
Snake River ◽  
Micropterus Dolomieu ◽  
River Reservoir

Translating restoration scenarios into habitat conditions: an initial step in evaluating recovery strategies for Chinook salmon (Oncorhynchus tshawytscha)

2006 ◽  
Vol 63 (7) ◽  
pp. 1578-1595 ◽  
Author(s):  
Krista K Bartz ◽  
Kerry M Lagueux ◽  
Mark D Scheuerell ◽  
Tim Beechie ◽  
Andrew D Haas ◽  
...  
Keyword(s):  
Land Use ◽  
Chinook Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Initial Step ◽  
Decision Makers ◽  
Habitat Conditions ◽  
Recovery Strategies ◽  
Salmon Population ◽  
Alternative Scenarios ◽  
Imperiled Species

One of the challenges associated with recovering imperiled species, such as Chinook salmon (Oncorhynchus tshawytscha), is identifying a set of actions that will ensure species' persistence. Here we evaluate the effects of alternative land use scenarios on habitat conditions potentially important to Chinook salmon. We first summarize the alternative scenarios as target levels for certain land use characteristics. We then use the target levels to estimate changes in current habitat conditions. The scenarios we explore indicate considerable potential to improve both the quality and quantity of salmon habitat through protection and restoration. Results from this analysis constitute the habitat inputs to a population model linking changes in habitat to salmon population status. By transparently documenting the approach we use to translate land use actions into changes in salmon habitat conditions, we provide decision makers with a clear basis for choosing strategies to recover salmon.

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