Growth, Survival and Production of Juvenile Chinook Salmon in Two Alaskan Lakes PDF Download
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Author: Jeffrey John Hard
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 29
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Author: Jeffrey John Hard
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 29
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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:
Publisher:
ISBN:
Category : Fish culture
Languages : en
Pages : 148
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Author: Peter Andre Bisson
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 160
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Temperature was elevated approximately 4° C in a model stream relative to an unheated, but otherwise similar control stream. The streams were located outdoors, received identical amounts of exchange water from a nearby creek, and followed natural diurnal and seasonal temperature cycles Juvenile spring chinook salmon (Oncorhynchus tshawytscha) were introduced into each stream and allowed to remain about 1 year until the following winter. Their production was measured tri-weekly and related to changes in temperature, food availability, and other environmental factors. Ancillary experiments utilizing water from the model streams measured changes in pre-feeding survival and weight and differences in growth efficiencies at various rations. Two year-classes of juvenile salmon were studied. Chinook production in the unheated control stream exceeded that in the heated stream. In 1972 total production was twofold greater and in 1973 it was about 30 percent higher. Elevated temperature lowered productivity of the heated stream by causing increased mortality of eggs and fry and reduced growth efficiencies of juveniles as food became less abundant. It also resulted in lower biomasses of food organisms, either because the experimental elevation directly affected survival and growth of benthic invertebrates or because increased siltation associated with heavier growths of filamentous algae made riffle substrate less suitable for immature stages of certain insects. Beneficial effects of increased temperature included protection from infection by a trematode parasite (Nanophyetus salmincola) and, possibly, increased tendencies of some invertebrates to enter the drift.
Author:
Publisher:
ISBN:
Category : Fish-culture
Languages : en
Pages : 590
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Author:
Publisher:
ISBN:
Category : Fishes
Languages : en
Pages : 392
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"Due to increasing pressures from recreational and commercial development in the Kenai River, this three-year study was undertaken to gather baseline data on salmon spawning and rearing for land-use planners."--Abstract.
Author: Pascale A. L. Goertler
Publisher:
ISBN:
Category :
Languages : en
Pages : 91
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For many fish and wildlife species, a mosaic of available habitats is required to complete their life cycle, and is considered necessary to ensure population stability and persistence. Particularly for young animals, nursery habitats provide opportunities for rapid growth and high survival during this vulnerable life stage. My thesis focuses on juvenile Chinook salmon (Oncorhynchus tshawytscha) and their use of estuarine wetlands as nursery habitat. Estuaries are highly productive systems representing a mosaic of habitats connecting rivers to the sea, and freshwater tidal estuaries provide abundant prey communities, shade, refuge from predation and transitional habitat for the osmoregulatory changes experienced by anadromous fishes. I will be discussing the freshwater tidal wetland habitat use of juvenile Chinook salmon in the Columbia River estuary, which are listed under the Endangered Species Act. I used otolith microstructural growth estimates and prey consumption to measure rearing habitat quality. This sampling effort was designed to target as much genetic diversity as possible, and individual assignment to regional stocks of origin was used to describe the diversity of juvenile Chinook salmon groups inhabiting the estuary. Diversity is important for resilience, and in salmon biocomplexity within fish stocks has been shown to ensure collective productivity despite environmental change. However much of the research which links diversity to resilience in salmon has focused on the adult portion of the life cycle and many resource management policies oversimplify juvenile life history diversity. When this oversimplification of juvenile life history diversity is applied to salmon conservation it may be ignoring critical indicators for stability. Therefore in addition to genetic diversity I also explore methods for better defining juvenile life history diversity and its application in salmon management, such as permitting requirements, habitat restoration, hydropower practices and hatchery management. This study addresses how juvenile salmon growth changes among a range of wetland habitats in the freshwater tidal portion of the Columbia River estuary and how growth variation describes and contributes to life history diversity. To do this, I incorporated otolith microstructure, individual assignment to regional stock of origin, GIS habitat mapping and diet composition, in three habitats (mainstem river, tributary confluence and backwater channel) along ~130 km of the upper estuary. For my first chapter I employed a generalized linear model (GLM) to test three hypotheses: juvenile Chinook growth was best explained by (1) temporal factors, (2) habitat use, or (3) demographic characteristics, such as stock of origin or the timing of seaward migration. I found that variation in growth was best explained by habitat type and an interaction between fork length and month of capture. Juvenile Chinook salmon grew faster in backwater channel habitat and later in the summer. I also found that mid-summer and late summer/fall subyearlings had the highest estuarine growth rates. When compared to other studies in the basin these juvenile Chinook grew on average 0.23, 0.11-0.43 mm/d in the freshwater tidal estuary, similar to estimates in the brackish estuary, but ~4 times slower than those in the plume and upstream reservoirs. However, survival studies from the system elucidated a possible tradeoff between growth and survival in the Columbia River basin. These findings present a unique example of the complexity in understanding the influences of the many processes that generate variation in growth rate for juvenile anadromous fish inhabiting estuaries. In my second chapter, I used otolith microstructure and growth trends produced in a dynamic factor analysis (DFA, a multivariate time series method only recently being used in fisheries) to identify the life history variation in juvenile Chinook salmon caught in the Columbia River estuary over a two-year period (2010-2012). I used genetic assignment to stock of origin and capture location and date with growth trajectories, as a proxy for habitat transitions, to reconstruct life history types. DFA estimated four to five growth trends were present in juvenile Chinook salmon caught in the Columbia River estuary, diversity currently being simplified in many management practices. Regional stocks and habitats did not display divergent growth histories, but the marked hatchery fish did ordinate very similarly in the trend loadings from the DFA analysis, suggesting that hatchery fish may not experience the same breadth of growth variability as wild fish. I was not able to quantify juvenile life history diversity, and juvenile Chinook life history diversity remains difficult to catalog and integrate into species conservation and habitat restoration for resource management. However, by expanding our understanding of how juvenile Chinook salmon experience their freshwater rearing environment we improve our capacity to conserve and manage salmon populations. The findings from my thesis provide the necessary information for a restoration framework to link habitat features with salmon management goals, such as juvenile growth, wild and genetic origin and life history diversity.
Author: Kathrine G. Howard
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 85
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Long-term monitoring of juvenile Chinook salmon Oncorhynchus tshawytscha is needed to identify recruitment and mortality processes, to understand early marine biology and ecology, and develop tools useful for fisheries management. A sampling program for Yukon River salmon was established in the northern Bering Sea in 2003 but annual sampling has been tenuous due to funding limitations. This project was designed to maintain the sampling program for Yukon River stocks, develop a genetic baseline to identify Yukon River stocks, and evaluate a lower cost survey alternative using a smaller vessel and trawl configuration. Results indicated that the genetic baseline can identify four groups of populations from Western Alaska, the two vessel/trawl configurations provided similar estimates of juvenile Chinook salmon abundance (within 20%); however, sea state limitations of the small vessel required an earlier survey timing (August rather than September). The change in survey timing contributed to differences in the spatial distribution and length of salmon caught during the 2 surveys. Surveys identified above average juvenile Chinook salmon abundance during 2014-2016 and above average juvenile abundance per spawner in 2014 and 2015. Both indicate an improvement to the recent poor production of Yukon River Chinook salmon, because juvenile abundance in the northern Bering Sea is known to be a leading indicator of adult returns for this stock. Sampling 2 different time periods provided additional insight into the early marine growth rates of juvenile Yukon River Chinook and other salmon species. Average Chinook salmon growth rate was 1.55 mm per day from marine entry to August, and 1.06 mm per day from August through September. This project represents a critical step to enable the long-term monitoring of juvenile Chinook salmon in Western Alaska and continued pursuit of factors that determine productivity and cohort strength of Yukon River Chinook salmon.
Author:
Publisher:
ISBN:
Category : Fisheries
Languages : en
Pages : 98
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Book Description
Report on activities in the divisions of research and development.
Author: Jeffrey John Hard
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 328
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