Residency, Growth, and Outmigration Size of Juvenile Chinook Salmon (Onchorhynchus Tshawytscha), Across Rearing Locations in the Shasta River, California PDF Download

Author: Christing Mei Ling Roddam
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 178

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Strontium isotope ratios (87Sr/86Sr) in stream water collected in March 2012 and 2013 were measured to be 0.704 (precision of 0.000031) and 0.706 (precision of 0.000019) for the upper basin and the lower basin respectively. Juvenile Chinook salmon that reared in the lower or upper basin are identifiable by the distinct differences in 87Sr/86Sr incorporated into the juvenile region of the otoliths. This creates a unique opportunity to determine the relative contribution of the two rearing areas to juvenile Chinook salmon production and, potentially, adult returns via analysis of juvenile and adult otoliths. Overall, I found consistent difference in the duration of residence, growth, and outmigration size between juvenile Chinook salmon that reared in the upper or lower Shasta River basin, irrespective of the location from which fish were initially sampled. Life history differences reflected differences in habitat conditions between the upper and lower basin. Additionally, this project demonstrated the potential use of otolith isotope analysis to identify the rearing location of juvenile Chinook salmon, which may affect marine survival and adult returns.

Author: Megan Tyler Perry
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 152

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In management of Pacific salmon, it is often assumed that density-dependent factors, mediated by the physical environment during freshwater residency, regulate population size prior to smolting and outmigration. However, in years following low escapement, temperature may be setting the upper limit on growth of juvenile chinook salmon Oncorhynchus tshawytscha during the summer rearing period. Given the importance of juvenile salmon survival for the eventual adult population size, we require a greater understanding of how density-dependent and independent factors affect juvenile demography through time. In this study we tested the hypotheses that (1) juvenile chinook salmon in the Chena River are food limited, and (2) that freshwater growth of juvenile chinook salmon is positively related with marine survival. We tested the first hypotheses using an in-situ supplemental feeding experiment, and the second hypothesis by conducting a retrospective analysis on juvenile growth estimated using a bioenergetics model related to return per spawner estimates from a stock-recruit analysis. We did not find evidence of food limitation, nor evidence that marine survival is correlated with freshwater growth. However, we did find some evidence suggesting that growth during the freshwater rearing period may be limited by food availability following years when adult escapement is high.

Author: Emily Katherine Chen
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 86

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Estuaries are commonly touted as nurseries for out-migrating salmonids, providing higher prey availability than streams, a physiological transition zone, and refugee from marine predators. Yet the diversity of estuaries makes it difficult to generalize the effect they have on salmonid recruitment. In bar-built estuaries, sandbars form at the mouth of rivers during periods of low flow, closing access to the ocean and disrupting outmigration. In this thesis, I evaluated how residency in a bar-built estuary affects the growth, survival, and ultimately recruitment of Chinook salmon (Oncorhynchus tshawytscha) in Redwood Creek, California. I conducted a mark-recapture experiment on out-migrating juveniles during the summer of 2018 to determine estuary abundance, growth, and survival. I used scales and sagittal otoliths collected from spawning adult carcasses to quantify the contribution of different juvenile life histories to the adult population. I then integrated these data and monitoring data collected from spawning ground surveys, rotary screw traps, and estuary seines to create a stage-structured matrix model. Juveniles that remained in the estuary after the mouth closed were larger at ocean entry than ocean rearing juveniles that entered the ocean earlier in the spring. However, estuary-rearing juveniles grew less and ultimately were smaller than ocean rearing juveniles were prior to winter. Despite having a larger ocean entry size, estuary rearing juveniles had lower survival from river outmigration to adult return than ocean rearing juveniles and contributed disproportionately less to the spawning population. Lack of marine influence and low river flow are common attributes of bar-built estuaries that may lower food availability and deteriorate conditions in these estuaries. Levees constructed in lower Redwood Creek prevent flooding and establishment of marsh and floodplain habitat, potentially majorly limiting the productivity of the estuary and salmonid growth. Restoration efforts designed to address limitations to growth in the estuary such as low food availability and high temperatures are needed to increase the ocean survival and ultimately contribution of estuary juveniles to the population.

Author: Olivia N. Edwards
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 0

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Chinook Salmon Oncorhynchus tshawytscha have experienced population declines across their range in recent decades, including Alaska where they are a critical subsistence, commercial, and sport fish species. The Alaska Board of Fisheries has listed Yukon River Chinook salmon as a “stock of yield concern” since 2000 prompting the implementation of escapement goals for key spawning tributaries in 2001. Additionally, research efforts across the basin have increased to better understand potential mechanisms behind these declines and provide information to facilitate management decisions. To help fill a critical data gap in the overall understanding of the fishery, this research investigated various freshwater juvenile life history factors including patterns in post-emergence summer body size, movement, and fish size during spring outmigration in the Chena River, Alaska. This research also identified links between these biological factors and freshwater processes that are affected by climate change, including stream temperature and discharge, with the intention of documenting benchmark information as conditions continue to change. Juvenile Chinook Salmon movement among four key rearing areas was observed during summer and fall 2019 and early spring 2020. Despite differences in early summer size patterns, by the end of September mean fork lengths were not statistically different among all rearing areas (ANOVA; all P > 0.05). Additionally, mean September weight varied among six years of empirical data and ranged from 3.19 g in 2018 (0.03 SE) to a maximum of 5.10 g in 2009 (0.05 SE). September weight was simulated across years with variable stream temperatures and discharge (2003 to 2020) using a bioenergetics model, and compared to observed data. Weight simulations were within

Author: Gordon W. Rose
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 111

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Chinook salmon returns to the Columbia River basin have declined due to impacts of a growing human population, despite significant mitigation expenditures. Consequently, fisheries managers have become focused on recovery and long-term viability of at-risk populations. A viable population depends, in part, on the connectivity and quality of diverse habitat types salmon require to complete their anadromous life-cycles. The tidal-fluvial Columbia River estuary is one link in this chain of habitats, but was largely over-looked as important Chinook salmon habitat until recently. Habitat restoration projects are underway in the tidal Columbia River estuary with the goal of increasing survival benefits to juvenile Chinook salmon. However, knowledge gaps remain about stock-specific use of tidal-fluvial habitat and tracking these restoration efforts is largely subjective. This study has sought to quantify the importance of tidal-fluvial habitat for a critical population of Chinook salmon, from the McKenzie River in the upper Willamette River Basin. Using otolith micro-chemistry profile analysis, juvenile net growth in the tidal-fluvial Columbia River was back-calculated for 92 natural-origin McKenzie River Chinook salmon across outmigration years 2005 and 2006. All otoliths were sampled from McKenzie River adult salmon to draw inferences about the juvenile life histories of surviving spawners. Mean ± SD net growth in the tidal fluvial estuary for all years was 5.48 ± 5.81 mm for subyearlings and 7.43 ± 8.32mm for yearlings. Differences in mean net growth by juvenile life-history type were not significant despite a prevailing assumption that subyearlings rear longer in estuary habitat than yearlings. Emigration sizes and net-growth estimates were significantly greater for subyearlings in outmigration year 2005 than 2006; there was only suggestive evidence emigration sizes were greater for yearlings in outmigration year 2005 than 2006, and net-growth estimates were similar between years. Sixteen percent (15 of 92) of McKenzie Chinook salmon grew between 10 and 43 mm over approximately 25-100 days in the tidal-fluvial Columbia River. Extended rearing in tidal-fluvial habitat provided an alternate life-history pathway for some yearling (12), fingerling (one), and fry (two) migrants. Subyearlings with intermediate-rearing or migratory life history pathways had greater net growth in tidal-fluvial habitat during 2005 than 2006, and in 2005 environmental conditions were unfavorable to overall salmon productivity. Fixed effects linear regression models suggest tidal-fluvial habitat supports McKenzie Chinook salmon life-history diversity, growth, and size, and therefore likely contributes to population resilience.

Author: Jon Joseph Lauer
Publisher:
ISBN:
Category : Salmon
Languages : en
Pages : 148

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Author: Jeremy Notch
Publisher:
ISBN: 9780355131680
Category :
Languages : en
Pages : 87

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Book Description
Once emerged from the gravel after being spawned in natal streams, Chinook salmon spend many months rearing and growing in freshwater before undergoing smoltification and out-migrating to the ocean. This relatively short period of time is considered to be the most vulnerable and dangerous phase in the life cycle of a Pacific salmon. It is during this phase when smolts navigate around many anthropogenic structures and experience environmental stressors while making their way to the ocean. In California's Central Valley, the few remaining wild populations of Chinook salmon (Oncorhynchus tshawytscha) out-migrate through a highly modified riverine and estuary landscape characterized by leveed banks, altered flow and temperature regimes, transformed food webs, and limited floodplain and rearing habitat. Juvenile salmon smolts migrate through these landscapes within a relatively short period of time, requiring them to quickly adapt to changing water conditions and habitat types. Understanding the survival rates of wild smolts from source tributaries to the Pacific Ocean is essential in protecting and restoring these populations from the low abundances currently observed. When faced with drought conditions out-migrating smolts experience low flows, elevated water temperatures and high densities of predators while out-migrating to sea. In order to assess smolt survival during drought conditions in late spring (April-May), 304 wild smolts were acoustically tagged and tracked from Mill Creek (Tehama County) to the Pacific Ocean between 2013 and 2016. Total outmigration survival to the ocean was 0.3% during these years, with only one fish making it to the Golden Gate and the Pacific Ocean. These survival estimates are some of the lowest ever recorded for salmon out-migrating to the Pacific Ocean, with much of the mortality occurring within Mill Creek and the Sacramento River. Cumulative survival through Mill Creek (rkm 452--441) was 68% (+/-12 S.E.), and cumulative survival through the Sacramento River (rkm 441--203) was 7.6% (+/- 16 S.E.) These low survival rates are likely attributed to low flows in Mill Creek and the Sacramento River resulting from critically dry winters between 2013 and 2015, which were reduced even further by water diversions for agriculture in both Mill Creek and the Sacramento River. During periods of higher flow in 2016 survival rates dramatically increased, suggesting that more water in Mill Creek and the Sacramento River is necessary to improve in-river smolt migration survival during the late spring.

Author: Natalie N McNair
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Outmigration is an important life stage for Chinook salmon (Oncorhynchus tshawytscha) survival in the Sacramento River, and yet our understanding of their behavior and needs during this time is limited. To gain a better understanding of their survival and movement rates during outmigration, late fall run Chinook salmon smolts were tracked using acoustic telemetry techniques. Habitat features were measured and quantified throughout the study area to evaluate how Chinook salmon respond to key levee features including shade, instream woody material, and aquatic vegetation. The overall average movement speed through the entire study area was 0.77 m/s with an overall survival of 86%. Based on multiple linear regressions, vegetation was found to have the largest effect on speed with fish slowing down with increased vegetation cover. Shade, river mile, and velocity also had significant effects on movement speeds, but instream woody material was not significant. The result for woody material was surprising since it was anticipated to have a large impact on movement speeds. A positive correlation was found between faster fish movement speeds and higher survival. No evidence of diel movement patterns was found after releasing the fish. These finding can help managers create sites better designed to help Chinook salmon in the Sacramento River system. Results from this paper indicate that the type of woody material being installed might not be appropriate for this life stage of salmon.

Author: A. Keith Taniguchi
Publisher:
ISBN:
Category : Fishes
Languages : en
Pages : 174

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Author: Colby Hause
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Extirpation of Central Valley spring-run Chinook salmon ESU (Oncorhynchus tshawytscha) from the San Joaquin River is emblematic of salmonid declines across the Pacific Northwest. Previous telemetry studies monitoring reintroduction of threatened spring-run Chinook salmon to the San Joaquin River revealed low out-migration survival of juveniles from rehabilitated upriver habitats to the ocean. To evaluate the link between overall habitat conditions and survivorship, we combined state-of-the-art habitat mapping approaches (Fast Automated Limnological Measurements or "FLAMe") with classic acoustic telemetry technology along the 270 km emigration corridor in Spring of 2019. We used classification algorithms on FLAMe data to develop a zonation scheme for aquatic habitats along the mainstem San Joaquin River, including a portion of the Delta. Despite elevated flow conditions in 2019, outmigration survival of smolts was again comparatively low (5%). However, our habitat-based classification scheme described variation in survival of acoustic-tagged juvenile spring-run Chinook salmon better than other candidate models based on geography or distance. Two regional mortality sinks were evident along the water quality transect, revealing poor survival in areas with higher temperatures and low levels of chlorophyll-[alpha], fDOM, and turbidity. These findings illustrate an overall value in integrating simple classification frameworks to improve our understanding of habitat variation on survival dynamics of imperiled salmonid populations.