Population Composition, Migration Timing, and Harvest of Columbia River Chinook Salmon in Late Summer and Fall

Jepson, Michael A.; Keefer, Matthew L.; Naughton, George P.; Peery, Christopher A.; Burke, Brian J.

doi:10.1577/m08-078.1

Cited by 10 publications

(15 citation statements)

References 47 publications

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“…It is logistically difficult to proportionately sample salmon at Bonneville Dam (and at most sampling sites), because the timing and daily abundance of passing fish are highly variable within season and among years. As described above, the potential for timing-related bias was highest early in the migrations, when the run disproportionately includes salmon from the upper Columbia River (Jepson et al, 2010), and when there were temperaturerelated tagging restrictions. Under these conditions, the stratified method should provide better escapement estimates in terms of precision because it takes account of the variability or heterogeneousness within season.…”

Section: Comparisons Among Escapement Estimation Methodsmentioning

confidence: 97%

“…A likely explanation is that some Chinook salmon that pass Priest Rapids Dam in the fall-run period defined by managers (14 August to 15 November) are counted as closely related summer-run populations that should probably be considered part of a continuum of oceantype, upriver bright populations (Myers et al, 1998;Brannon et al, 2004). Therefore, date-based escapement estimates can easily be biased by migration timing or relative population size of the respective summer and fall components as currently defined (Dauble and Mueller, 2000;Jepson et al, 2010). These date effects apply both to the timing of tagging at Bonneville Dam (for mark-recapture studies) and to escapement estimates based on salmon counts at upstream dams.…”

Section: Comparisons Among Escapement Estimation Methodsmentioning

confidence: 99%

“…Radio-tagged salmon were monitored using more than 300 underwater and aerial antennas (Jepson et al, 2010). Sites included eight Columbia and Snake River hydroelectric dams operated by the U.S. Army Corps of engineers (USACE), Priest Rapids Dam operated by the Grant County (Washington) Public Utility District, midreservoir sites, and confluence areas of almost all tributaries to the lower Columbia and Snake rivers used by fall Chinook salmon.…”

Section: Salmon Monitoring and Tag Recoverymentioning

confidence: 99%

“…Detections of radio-tagged fish at tributary sites were used to help determine which salmon entered and remained in tributaries during spawning seasons. Records from dam, reservoir, main stem (i.e., Hanford Reach), and mobile-tracking surveys, plus transmitter returns from fisheries (reward-based), hatcheries, traps and spawning ground surveys were also used to establish fish distribution and fate (see Keefer et al, 2005 andJepson et al, 2010). Detection efficiencies were near 100% at dams and were >90% at almost all tributary antennas.…”

Section: Salmon Monitoring and Tag Recoverymentioning

confidence: 99%

“…Our approach was to estimate escapement using mark-recapture data from recent radiotelemetry and PIT-tag studies, and then to compare those estimates with independent estimates from management agencies and from adult Chinook salmon counts at dams. We applied analytical estimators of the escapement and its uncertainty to mark-recapture data, where data were both pooled (i.e., seasonal) and stratified by week to assess effects of seasonal fall Chinook salmon run composition changes (e.g., Jepson et al, 2010). A second objective was to evaluate tradeoffs associated with radiotelemetry versus PITtag monitoring systems, including differences in inferential power, spatial resolution, and ability to discriminate among populations.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Population-specific escapement of Columbia River fall Chinook salmon: Tradeoffs among estimation techniques

et al. 2012

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Section: Comparisons Among Escapement Estimation Methodsmentioning

confidence: 97%

Section: Comparisons Among Escapement Estimation Methodsmentioning

confidence: 99%

Section: Salmon Monitoring and Tag Recoverymentioning

confidence: 99%

Section: Salmon Monitoring and Tag Recoverymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Population-specific escapement of Columbia River fall Chinook salmon: Tradeoffs among estimation techniques

et al. 2012

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Tough places and safe spaces: Can refuges save salmon from a warming climate?

et al. 2022

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The importance of thermal refuges in a rapidly warming world is particularly evident for migratory species, where individuals encounter a wide range of conditions throughout their lives. In this study, we used a spatially explicit, individual‐based simulation model to evaluate the buffering potential of cold‐water thermal refuges for anadromous salmon and trout (Oncorhynchus spp.) migrating upstream through a warm river corridor that can expose individuals to physiologically stressful temperatures. We considered upstream migration in relation to migratory phenotypes that were defined in terms of migration timing, spawn timing, swim speed, and use of cold‐water thermal refuges. Individuals with different migratory phenotypes migrated upstream through riverine corridors with variable availability of cold‐water thermal refuges and mainstem temperatures. Use of cold‐water refuges (CWRs) decreased accumulated sublethal exposures to physiologically stressful temperatures when measured in degree‐days above 20, 21, and 22°C. The availability of CWRs was an order of magnitude more effective in lowering accumulated sublethal exposures under current and future mainstem temperatures for summer steelhead than fall Chinook Salmon. We considered two emergent model outcomes, survival and percent of available energy used, in relation to thermal heterogeneity and migratory phenotype. Mean percent energy loss attributed to future warmer mainstem temperatures was at least two times larger than the difference in energy used in simulations without CWRs for steelhead and salmon. We also found that loss of CWRs reduced the diversity of energy‐conserving migratory phenotypes when we examined the variability in entry timing and travel time outside of CWRs in relation to energy loss. Energy‐conserving phenotypic space contracted by 7%–23% when CWRs were unavailable under the current thermal regime. Our simulations suggest that, while CWRs do not entirely mitigate for stressful thermal exposures in mainstem rivers, these features are important for maintaining a diversity of migration phenotypes. Our study suggests that the maintenance of diverse portfolios of migratory phenotypes and cool‐ and cold‐water refuges might be added to the suite of policies and management actions presently being deployed to improve the likelihood of Pacific salmonid persistence into a future characterized by climate change.

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Individual based modeling of fish migration in a 2-D river system: model description and case study

et al. 2019

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Context-Diadromous fish populations in the Pacific Northwest face challenges along their migratory routes from declining habitat quality, harvest, and barriers to longitudinal connectivity. These stressors complicate the prioritization of proposed management actions intended to improve conditions for migratory fishes including anadromous salmon and trout.Objectives-We describe a multi-scale hybrid mechanistic-probabilistic simulation model linking migration corridor conditions to fish fitness outcomes. We demonstrate the model's utility using a case study of salmon and steelhead adults in the Columbia River migration corridor exposed to spatially-and temporally-varying stressors.Methods-The migration corridor simulation model is based on a behavioral decision tree that governs individual interactions with the environment, and an energetic submodel that estimates the hourly costs of migration. Emergent properties of the migration corridor simulation model include passage time, energy use, and survival.Results-We observed that the simulated fishes' initial energy density, the migration corridor temperatures they experienced, and their history of behavioral thermoregulation were the primary determinants of their fitness outcomes. Insights gained from use of the model might be exploited to identify management interventions that increase successful migration outcomes.Conclusions-This paper describes new methods that extend the suite of tools available to aquatic biologists and conservation practitioners. We have developed a 2-dimensional spatiallyexplicit behavioral and physiological model and illustrated how it can be used to simulate fish *

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Population Composition, Migration Timing, and Harvest of Columbia River Chinook Salmon in Late Summer and Fall

Cited by 10 publications

References 47 publications

Population-specific escapement of Columbia River fall Chinook salmon: Tradeoffs among estimation techniques

Population-specific escapement of Columbia River fall Chinook salmon: Tradeoffs among estimation techniques

Tough places and safe spaces: Can refuges save salmon from a warming climate?

Individual based modeling of fish migration in a 2-D river system: model description and case study

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