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

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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QUANTITATIVE THREAT ANALYSIS FOR MANAGEMENT OF AN IMPERILED SPECIES: CHINOOK SALMON (ONCORHYNCHUS TSHAWYTSCHA)

Ecological Applications ◽

10.1890/06-1637.1 ◽

2007 ◽

Vol 17 (7) ◽

pp. 2061-2073 ◽

Cited By ~ 13

Author(s):

Jonathan M. Hoekstra ◽

Krista K. Bartz ◽

Mary H. Ruckelshaus ◽

Jennifer M. Moslemi ◽

Tamara K. Harms

Keyword(s):

Chinook Salmon ◽

Oncorhynchus Tshawytscha ◽

Threat Analysis ◽

Imperiled Species

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f95-139 ◽

1995 ◽

Vol 52 (7) ◽

pp. 1442-1448 ◽

Cited By ~ 20

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.

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Chinook salmon exhibit long-term rearing and early marine growth in the Fraser River, B.C., a large urban estuary

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2020-0247 ◽

2020 ◽

Author(s):

Lia Chalifour ◽

David C Scott ◽

Misty MacDuffee ◽

Steven Stark ◽

John F Dower ◽

...

Keyword(s):

Chinook Salmon ◽

Oncorhynchus Tshawytscha ◽

Pacific Salmon ◽

Genetic Stock ◽

Daily Growth ◽

Estuarine Habitat ◽

Salmon River ◽

Salmon Population ◽

Brackish Marshes ◽

Saline Habitats

Estuaries represent a transition zone for salmon migrating from freshwater to marine waters, yet their contribution to juvenile growth is poorly quantified. Here, we use genetic stock identification and otolith analyses to quantify estuarine habitat use by Chinook salmon (<i>Oncorhynchus tshawytscha</i>) – the Pacific salmon species considered most reliant on this habitat – in Canada’s most productive salmon river, the Fraser. Two years of sampling revealed subyearling migrant (“ocean-type”) Chinook from the Harrison River to be the estuary’s dominant salmon population throughout the emigration period. These Chinook salmon were caught predominantly in the estuary’s brackish marshes but shifted to more saline habitats as they grew. Otolith analyses indicated that these Chinook salmon have wide-ranging entry timing (from February to May), and longer estuarine residency (weeks to months, mean 41.8 days) than estimated by prior studies, but similar daily growth rates (mean 0.57 mm +/- 0.13 SD) across entry dates and residency periods, implying sufficient foraging opportunities throughout the emigration period and habitats. Together, these results suggest that estuarine habitat is more important for early marine growth of subyearling migrant Chinook salmon than previously recognized.

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Weakening portfolio effect strength in a hatchery-supplemented Chinook salmon population complex

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2015-0169 ◽

2015 ◽

Vol 72 (12) ◽

pp. 1860-1875 ◽

Cited By ~ 27

Author(s):

William H. Satterthwaite ◽

Stephanie M. Carlson

Keyword(s):

Chinook Salmon ◽

North Pacific ◽

Oncorhynchus Tshawytscha ◽

Environmental Variability ◽

Central Valley ◽

Simultaneous Increase ◽

Environmental Forcing ◽

Salmon Population ◽

Portfolio Effect ◽

Considerable Degradation

Biocomplexity contributes to asynchronous population dynamics, buffering stock complexes in temporally variable environments, a phenomenon referred to as a “portfolio effect”. We previously revealed a weakened but persistent portfolio effect in California’s Central Valley fall-run Chinook salmon (Oncorhynchus tshawytscha), despite considerable degradation and loss of habitat. Here, we further explore the timing of changes in variability and synchrony and relate these changes to factors hypothesized to influence variability in adult abundance, including hatchery release practices and environmental variables. We found evidence for increasing synchrony among fall-run populations that coincided temporally with increased off-site hatchery releases into the estuary but not with increased North Pacific environmental variability (measured by North Pacific Gyre Oscillation), nor were common trends well explained by a suite of environmental covariates. Moreover, we did not observe a simultaneous increase in synchrony in the nearby Klamath–Trinity system, where nearly all hatchery releases are on-site. Wavelet analysis revealed that variability in production was higher and at a longer time period later in the time series, consistent with increased environmental forcing and a shift away from dynamics driven by natural spawners.

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Tests on the Accuracy of Ageing Chinook Salmon (Oncorhynchus tshawytscha) from their Scales

Journal of the Fisheries Research Board of Canada ◽

10.1139/f68-173 ◽

1968 ◽

Vol 25 (9) ◽

pp. 1971-1982 ◽

Cited By ~ 6

Author(s):

H. Godfrey ◽

D. D. Worlund ◽

H. T. Bilton

Keyword(s):

Chinook Salmon ◽

Oncorhynchus Tshawytscha ◽

Age Composition ◽

Scale Reading ◽

Large Numbers ◽

Two Samples ◽

Salmon Population ◽

Good Scale ◽

Selection Of ◽

Experienced Personnel

The accuracy with which several readers determined the ages of adult chinook salmon from their scales averaged 75% in a test that used scales from fish of known ages. Their consistency in assigning the same age to a scale when presented with the same selection of scales on two occasions averaged 76%. In these tests the readers derived age composition arrays which were similar to the true age compositions of the two samples. When several pairs of readers assigned ages to a large numbers of scales from fish of unknown ages agreement within pairs was good (roughly 75%), and among the pairs the derived age compositions were very similar. The levels of both accuracy and consistency achieved in these tests indicate that experienced personnel, using good scale-reading equipment, are able to produce age composition data that could be used as reliable parameters in chinook salmon population analyses.

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Effect of hydroelectric dam operations on the freshwater productivity of a Columbia River fall Chinook salmon population

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2013-0276 ◽

2014 ◽

Vol 71 (4) ◽

pp. 602-615 ◽

Cited By ~ 27

Author(s):

Ryan A. Harnish ◽

Rishi Sharma ◽

Geoffrey A. McMichael ◽

Russell B. Langshaw ◽

Todd N. Pearsons

Keyword(s):

Chinook Salmon ◽

Oncorhynchus Tshawytscha ◽

Columbia River ◽

Life Stages ◽

Hydroelectric Dams ◽

Discharge Fluctuations ◽

Hydroelectric Dam ◽

Salmon Population ◽

Increase In Productivity ◽

Operational Constraints

Altering the timing and magnitude of discharge fluctuations can minimize the adverse effects of operating hydroelectric dams on the productivity of downstream salmon populations. Hydroelectric operations at Priest Rapids Dam during the mid-1970s resulted in dewatering of fall Chinook salmon (Oncorhynchus tshawytscha) redds, causing mortality of intragravel life stages. Since then, a series of operational constraints have been implemented at Priest Rapids Dam to reduce the effects of discharge fluctuations on the population of fall Chinook salmon that spawns and rears downstream from the dam. Initial protections that focused on preventing redd dewatering were subsequently increased to include postemergence life stages. We used stock–recruit analyses to identify changes to the population’s freshwater productivity that occurred over a 30-year period and coincided with changes to dam operations. We observed a 217% increase in productivity that corresponded with constraints enacted to prevent redd dewatering and an additional 130% increase that coincided with enactment of constraints to limit stranding and entrapment of juveniles. The information gained from this study may be used to guide efforts elsewhere to mitigate the effects of hydroelectric dam operations on downstream fish populations.

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Weakened portfolio effect in a collapsed salmon population complex

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f2011-084 ◽

2011 ◽

Vol 68 (9) ◽

pp. 1579-1589 ◽

Cited By ~ 118

Author(s):

Stephanie Marie Carlson ◽

William Hallowell Satterthwaite

Keyword(s):

River Basin ◽

Chinook Salmon ◽

Oncorhynchus Tshawytscha ◽

Central Valley ◽

Salmon Population ◽

Portfolio Effect ◽

Positive Correlations ◽

The Stability ◽

Complexity Hierarchy ◽

San Joaquin Basin

Recent research has highlighted the importance of interpopulation diversity in fostering the stability of population complexes. Here we focus on California’s recently collapsed fall-run Chinook salmon ( Oncorhynchus tshawytscha ) and ask whether portfolio effect induced buffering is observed across the complexity hierarchy from individual populations to populations within a river basin (Sacramento, San Joaquin) to the entire Central Valley. Some buffering was observed when comparing the coefficient of variation in adult returns to a given river basin with its constituent populations but not when comparing returns to the entire Central Valley with its constituent basins because of disproportionately many fish returning to the Sacramento Basin. Moreover, we report that positive correlations in population dynamics between rivers were stronger in the last 25 years of the study compared with the first 25 years. Together, these results suggest evidence of only a weak portfolio effect that has deteriorated in recent years. Nonetheless, we also report that correlations between rivers decreased significantly with distance, suggesting that some biocomplexity remains. Our results suggest that the greatest potential for strengthening the portfolio effect would come through restoration of San Joaquin Basin populations, which at low abundance currently contribute little to the overall buffering capacity despite low cross-basin correlations.

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Thermal histories, stress, and metabolic rates of chinook salmon (Oncorhynchus tshawytscha) in Lake Ontario: evidence from intra-otolith stable isotope analyses

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f04-241 ◽

2005 ◽

Vol 62 (3) ◽

pp. 700-713 ◽

Cited By ~ 42

Author(s):

C M Wurster ◽

W P Patterson ◽

D J Stewart ◽

J N Bowlby ◽

T J Stewart

Keyword(s):

Chinook Salmon ◽

Oncorhynchus Tshawytscha ◽

Cold Water ◽

Lake Ontario ◽

Strong Negative Correlation ◽

Preferred Temperature ◽

Field Activity ◽

Lethal Limit ◽

Salmon Population ◽

Thermal Histories

We describe thermal histories for Lake Ontario chinook salmon (Oncorhynchus tshawytscha) as determined from otolith δ18O thermometry using computer-controlled micromilling techniques to recover otolith aragonite at subseasonal resolution. We find that during the summer months chinook salmon inhabited epilimnetic waters with temperatures of ~1920 °C as far back as the late 1980s. Chinook would approach but rarely exceed their reported upper incipient lethal limit of approximately 22 °C, which suggests that these fish were seeking water with temperatures as high as was tolerable while otolith growth occurred. These results contrast with expected midsummer temperatures for this cold-water salmonine. Bioenergetic simulations indicate significant stress imposed upon chinook salmon. We estimate consumption to be up to 20% more and gross conversion efficiency 18% less annually relative to nominal simulations where chinook salmon are modeled nearer their preferred temperature, reinforcing previous inferences that the chinook salmon population may be near the limits of sustainability. We also find a strong negative correlation between δ18O and δ13C values. Therefore, seasonal and ontogenetic variation in δ13C values of chinook salmon otoliths appear to be related to metabolic rate during pelagic residence and may provide an indirect method for evaluating field activity and other aspects of fish life history.

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