Factors Affecting Oxidative Stress in Juvenile Chinook Salmon (Oncorhynchus Tshawytscha) of Hatchery Origin PDF Download
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Author: Thomas L. Welker
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 322
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Author: Thomas L. Welker
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 322
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Author: Charles O. Junge
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 40
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Author: Maria Elena Lang Wessel
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 166
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"Hatcheries play an important role in the enhancement of Pacific salmon (genus Oncorhynchus) as a resource, but genetic and phenotypic divergence trom wild populations may occur as a result of founder effects, genetic drift and/or domestication. In this study, agonistic behavior, ability to establish dominance, and morphology were compared among juveniles of chinook salmon (Oncorhynchus tshawytscha) that have experienced five generations of hatchery ranching culture, juveniles derived trom the wild founding stock, and second generation hybrids of the two lines. The parent generation of all lines was cultured in the same hatchery environment as the juveniles tested. Behavioral observations were conducted in replicate artificial stream tanks; hatchery and hybrid fish were significantly more aggressive than wild derived fish. No difference was detected in the ability of fish lines to win dyadic dominance contests. Thin-plate spline analysis was used to characterize morphometric variation; hatchery and wild derived juveniles differed significantly. Canonical discriminant analysis correctly classified 88% of hatchery fish and 90% of wild derived fish. Morphologically, hybrid fish were significantly different trom both hatchery and wild derived fish. These results suggest that the differences observed between lines are genetic in origin although the sources of the divergence were not conclusively identified"--Leaf iii.
Author: Londi M. Tomaro
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 194
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Early ocean residence is assumed to be a critical period for juvenile Pacific salmon Oncorhynchus spp. However, the specific mechanisms influencing growth and survival in the ocean have not been identified for most populations. Therefore, three hypotheses regarding the relationship between early marine residence and subsequent survival of mid-upper Columbia River spring Chinook salmon were evaluated: the 'bigger is better', 'stage duration', and 'match-mistmatch' hypotheses. Six metrics describing juvenile migration history and condition were developed, including 1) size at freshwater exit; 2) size at ocean capture; 3) initial ocean growth rates; 4) timing of ocean entrance; 5) duration of ocean residence; and 6) marine migration rates. Retrospective estimates of size and growth using otolith analyses rely on the assumption that otolith and somatic size are related. Therefore, I verified this assumption for mid-upper Columbia River Chinook salmon and determined that a body-proportional back-calculation method was the best approach for this population. Fish length and otolith width were positively correlated (r > 0.92) and growth rates estimated from back-calculated sizes were positively correlated with observed growth rates (r = 0.96). I also evaluated the utility of using the otolith Sr:Ca pattern as a marker of hatchery-origin and investigated potential mechanisms for the observed Sr:Ca pattern. Visual and quantitative criteria were developed using otoliths of hatchery fish and were used to correctly classify 85% and 78%, respectively, of a sample of known hatchery-origin fish (n = 114) that were collected in coastal waters. Although Sr:Ca in water and hatchery food did not fully account for the observed pattern in otolith Sr:Ca, the pattern can be used to identify mid-upper Columbia River spring Chinook salmon of hatchery-origin with relatively high accuracy (>75%). The six juvenile metrics were used to evaluate mechanisms potentially regulating establishment of year-class abundance. The only metrics found to be significantly related to future adult abundance were size at freshwater exit (r2 = 0.56) and capture (r2 = 0.60). These data support the 'bigger is better' hypothesis and indicate that factors influencing size and growth during freshwater residence should be investigated further. Juveniles resided in the brackish/ocean for one to two months prior to capture in May and June; therefore, ocean conditions after this period may be related to the 40% of variation in adult abundance unexplained by interannual variation in body size.
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: Carol Seals Price
Publisher:
ISBN:
Category : Chinook salmon
Languages : en
Pages : 378
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From 1998-2000, laboratory studies were conducted to examine factors that impact saltwater-entry behavior and saltwater preference (SWP) of juvenile chinook salmon, Oncorhynchus tshawytscha. These factors included bacterial kidney disease, stress and the presence of trout, O. mykiss. An additional study investigated the orientation of the startle response of chinook salmon within a salinity gradient. All experiments were conducted in 757-1 tanks in which a stable, vertical salinity gradient was established. SWP was decreased in fish suffering from bacterial kidney disease (31 ± 20.0%), compared with control fish (85 ± 17.6%). A mild chasing stressor resulted in a 26% decrease in SWP relative to unstressed fish. After a severe handling stressor, only 20% of fish preferred salt water, compared with 100% of unstressed controls. After exposure to an overhead predator model, severely stressed fish descended into the saltwater layer, but this response was transient. The presence of non-aggressive steelhead trout did not affect SWP of chinook salmon. Chinook salmon stocked with rainbow trout displayed decreased SWP. Aggression levels in tanks with rainbow trout were higher than in tanks with only chinook salmon. The orientation of the startle response was affected by the presence of salt water. Fish that preferred salt water within a gradient responded by moving horizontally within the saltwater layer. In contrast, control fish (held only in freshwater) moved vertically within the water colunm when startled. Prior preference for salt water superseded the inclination to move upward in the water column when startled. Smoltification involves physiological, behavioral and morphological changes that prepare healthy chinook salmon for seawater residence. However, disease, stress and aggressive interactions can decrease the SWP of fish at this life history stage. Avoidance of salt water during estuarine outmigration is likely maladaptive, and may have ecological ramifications including increased risk of avian predation during outmigration and decreased fitness in the marine environment.
Author: Jon Joseph Lauer
Publisher:
ISBN:
Category : Salmon
Languages : en
Pages : 148
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Author:
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ISBN:
Category : Dissertation abstracts
Languages : en
Pages : 776
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Author: Charles O. Junge Jr.
Publisher:
ISBN: 9781332919048
Category : Business & Economics
Languages : en
Pages : 40
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Excerpt from Factors Influencing the Return of Fall Chinook Salmon (Oncorhynchus Tshawytscha) To Spring Creek Hatchery Normally the disease makes its first appear ance shortly after the fry have hatched. Johnson also reports an occasional occurrence just prior to hatching but has never noted it earlier in the egg stage. Yolk material has been found in the body cavities long after the fish have started feeding. A cause and a cure for the disease have not been discovered. Delayed mortality after the release of the fish has never been investigated. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
Author: Nathan Gail Smith
Publisher:
ISBN:
Category :
Languages : en
Pages : 154
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