20 research outputs found

    Rising land falling fishery: the effects of isostatic rebound and rapid succession on east Alsek River sockeye salmon

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    Thesis (M.S.) University of Alaska Fairbanks, 2008This thesis includes research conducted in the Dry Bay Preserve of Glacier Bay National Park in 2005 and 2006 for the U.S. National Park Service. The research mission was to determine the cause of collapse in the East Alsek commercial sockeye fishery. The focus of the study was to determine if the collapse was due to human caused events or if there was a broader ecological basis for the recent downturn in returning sockeye. The East Alsek had undergone a dramatic decline in returning sockeye in recent years and the changing quality and quantity of habitat was thought to be the culprit for this downturn. However, fishery records and other environmental variables were also examined in order to establish a retrospective association between reduced production, ambient environmental conditions, and commercial fishing. The research for this thesis was funded by the U.S. National Park Service under the request of the City and Borough of Yakutat

    Ecological effects of reservoir operations on Blue Mesa Reservoir

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    Includes bibliographical references.Annual progress report, May 1, 1995-April 30, 1996

    Monitoring of Juvenile Yearling Chinook Salmon and Steelhead Survival and Passage at Bonneville Dam, Spring 2010

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    The purpose of this study was to estimate the survival for yearling Chinook salmon and steelhead smolts during spring 2010 in a portion of the Columbia River that includes Bonneville Dam. The study estimated smolt survival from a virtual release at Bonneville Dam to a survival array 81 km downstream of Bonneville Dam. We also estimated median forebay residence time, median tailrace egress time, and spill passage efficiency (SPE), as required in the Columbia Basin Fish Accords. A single release design was used to estimate survival from Bonneville Dam to a primary array located 81 km downstream of Bonneville. The approach did not include a reference tailrace release. Releases of acoustic-tagged smolts above John Day Dam to Hood River contributed to the formation of virtual releases at a Bonneville Dam forebay entrance array and at the face of the dam. A total of 3,880 yearling Chinook salmon and 3,885 steelhead smolts were tagged and released in the investigation. The Juvenile Salmon Acoustic Telemetry System (JSATS) tag model number ATS-156dB, weighing 0.438 g in air, was used in this investigation

    Survival and Passage of Juvenile Chinook Salmon and Steelhead Passing through Bonneville Dam, 2010

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    Pacific Northwest National Laboratory (PNNL) and subcontractors conducted an acoustic-telemetry study of juvenile salmonid fish passage and survival at Bonneville Dam in 2010. The study was conducted to assess the readiness of the monitoring system for official compliance studies under the 2008 Biological Opinion and Fish Accords and to assess performance measures including route-specific fish passage proportions, travel times, and survival based upon a single-release model. This also was the last year of evaluation of effects of a behavioral guidance device installed in the Powerhouse 2 forebay. The study relied on releases of live Juvenile Salmon Acoustic Telemetry System tagged smolts in the Columbia River and used acoustic telemetry to evaluate the approach, passage, and survival of passing juvenile salmon. This study supports the U.S. Army Corps of Engineers continual effort to improve conditions for juvenile anadromous fish passing through Columbia River dams

    The genetic architecture of the human cerebral cortex

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    The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder
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