Download or read book Analysis of Factors Influencing the Population Dynamics of Chinook Salmon Oncorhynchus Tshawytscha in Central California written by Robert Glenn Kope and published by . This book was released on 1987 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Model of Chinook Salmon Population Dynamics written by Steven Richard Rein and published by . This book was released on 1993 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Factors Affecting the Abundance of Fall Chinook Salmon in the Columbia River written by Jack M. Van Hyning and published by . This book was released on 1968 with total page 848 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study of the population ecology of Columbia River fall chinook salmon, Oncorhynchus tshawytscha (Walbaum), was made in an attempt to determine the cause of a serious decline in this run which occurred in the early 1950's. Fluctuations in abundance of major salmon runs the North Pacific were examined to detect any coastwide pattern. Only chinook salmon in Cook Inlet, Alaska, and chum salmon from Oregon to southwestern Alaska showed a similar trend. The following life history stages broken down into pre- and post-decline years were examined: (1) marine life including distribution and migration, growth and maturity, survival rate, oceanography, and commercial and sport fisheries; (2) upstream migration including river fisheries, gear selectivity, size and age composition of the run, escapement, and influence of dams, diseases, and water quality; (3) reproduction and incubation including spawning areas and spawning and incubation conditions; and (4) downstream migration which included predation, dams and reservoirs, diseases, flow, turbidity and temperature, and estuary life. Salient points of the analysis were: (1) a change in the maturity and survival pattern based on tagged and fin-clipped fish recovered before and after 1950; (2) a significant negative correlation between sea-water temperature during a year class' first year at sea and subsequent survival; (3) a large increase in the ocean fisheries coincident with the decline in the run; (4) catch-effort statistics of the ocean fishery show a near classic example of the effect of overexploitation; (5) estimates of the contribution of Columbia River chinook to the ocean fisheries based on tag recoveries could be underestimates rather than overestimates; (6) a significant inverse correlation between estimated ocean catch of Columbia River fall chinook and numbers entering the river; (7) size and age composition of the ocean and river catches decreased coincident with the decline in the run; (8) the gill-net fishery shows little size selectivity by age, size, or sex in the dominant group; (9) fluctuations in abundance of hatchery stocks are related to differences in survival between fingerling and adult; (10) hatchery, lower river, and upriver populations fluctuate in abundance in much the same pattern; (11) optimum escapement is between 90,000 and 100,000 adults, a value that was exceeded during most years; (12) a highly significant negative correlation between numbers of spawners and return per spawner; (13) most of the early dams had no direct effect on fall chinook and the decline in productivity occurred when river conditions were relatively stable; (14) temperatures at time of migration and spawning for fall chinook have not increased enough to be a serious mortality factor; (15) little relationship between flow, turbidity, and temperature at time of downstream migration and subsequent return was evident except that high temperatures and high flows (and turbidities) tended to produce poorer runs during certain time periods; and (16) predation and delay of smolts in reservoirs are largely unknown factors, but circumstantial evidence suggests that they were not important in regulating fall chinook numbers during the period of the study. Finally, variables that appeared to bear some relationship to fluctuations in abundance of fall chinook were submitted to multiple regression analysis. For the predecline period (1938-46 brood years), sea-water temperature and ocean troll fishing effort were significant variables (R2 = 0.74). For post decline years (1947-59 broods), troll had the most influence on total return with ocean temperature and escapement having lesser effects. For the combined years, troll intensity and ocean temperature were the significant variables (R2 = 0.572). Entering interaction of river flow at downstream migration with the other variables brought R2 to 0.754 which means that 75% of the variability in the returning run could be accounted for by these three factors. Return per spawner was so heavily influenced by numbers of spawners that the other factors assumed negligible importance. Equations were derived that predicted the returning run in close agreement with the actual run size. Substituting a low and constant troll fishing effort in the equation resulted in the predicted run maintaining the average predecline level. The increase in ocean fishing was the main contributor to the decline of the Columbia River fall chinook run as shown by correlation, by analogy, and by the process of elimination. To demonstrate why other chinook runs have not shown similar declines, it was shown that due to several unique features in Columbia River fall chinook life history they are exposed to much more ocean fishing than other populations. It was emphasized that these conclusions should not be extrapolated to the future or to other species or runs of salmon.
Download or read book Sport Fishery Abstracts written by and published by . This book was released on 1989 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Factors Influencing the Return of Fall Chinook Salmon Oncorhynchus Tshawytscha to Spring Creek Hatchery written by Charles O. Junge and published by . This book was released on 1963 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fisheries Review written by and published by . This book was released on 1995 with total page 590 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ecological Genetics of Fall run Chinook Salmon Oncorhynchus Tshawytscha in California s Central Valley written by Kevin Sean Williamson and published by . This book was released on 2004 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fishery Bulletin written by United States. National Marine Fisheries Service and published by . This book was released on 2000 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Collected Reprints written by Southwest Fisheries Center (U.S.) and published by . This book was released on 1990 with total page 944 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific Framework for Assessing Factors Influencing Endangered Sacramento River Winter run Chinook Salmon Oncorhynchus Tshawytscha Across the Life Cycle written by Sean Windell and published by . This book was released on 2017 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: California's Central Valley Interagency Ecology Program (IEP) formed multi-agency Salmon and Sturgeon Assessment of Indicators by Life Stage (SAIL) synthesis teams to develop a scientific framework for evaluating existing information on endangered Sacramento River winter-run Chinook salmon (SRWRC; Oncorhynchus tshawytscha), green sturgeon (Acipenser medirostris), and white sturgeon (A. transmontanus) and provide recommendations to improve the management value of life stage monitoring. Developing the SAIL framework for SRWRC and sturgeon followed parallel approaches that included three steps. First, existing conceptual models (CMs) were reviewed and modified to characterize specific environmental and management factors that drive SRWRC responses within discrete geographic domains and life stages. Second, the existing monitoring network was compared to fish demographic responses in the CMs to identify deficiencies. The deficiencies were interpreted as gaps in the existing network that prevent annual, quantitative, population-level metrics from being developed that are needed to support water management actions, assess population viability, and prioritize population recovery actions among geographic domains across the freshwater landscape. Lastly, identified absences were used to develop recommendations on ways to improve the scientific and management value of the current monitoring network. This document comprises the first of these steps for the SRWRC portion of the SAIL projects. It consolidates all the CMs developed by the SAIL synthesis team and their associated narratives. [doi:10.7289/V5/TM-SWFSC-586(http://doi.org/10.7289/V5/TM-SWFSC-586)]
Download or read book Collected Reprints written by and published by . This book was released on 1994 with total page 856 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Influence of Environmental Variability on Chinook Salmon and Coho Salmon Population Dynamics written by David Patrick Kilduff and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding how different populations respond to a variable environment is necessary to anticipate and evaluate population persistence as environmental conditions change, possibly through climate change. To understand specifically how atmospheric and oceanographic processes translate to fluctuations in age-structured populations requires knowledge of temporal and spatial variability patterns in both the population and environmental signals, and a mechanistic understanding of how that variability acts in age-structured populations. Recruitment and abundance in many Pacific salmon populations covary with indices of ocean productivity; however, exactly how environmental forcing interacts with population dynamic mechanisms to produce fluctuations remains unclear, which impedes effective management and conservation. This dissertation examines how patterns of ocean survival in Chinook salmon (Oncorhynchus tshawytscha) have changed in recent decades (Chapter 1), identifies a new link between changes observed in low-frequency Pacific oceanographic and climatic conditions that affects both coho salmon (O. kisutch) and Chinook salmon (Chapter 2), and describes how the power spectrum of environmental variability in survival rates influences population persistence in an age-structured population model using spring-run Chinook salmon from Butte Creek, California as an example (Chapter 3). In Chapter 1, I show that the spatial and temporal covariability in Chinook salmon ocean survival rates has increased along the west coast of North America from 1980 to 2006. In Chapter 2, I show that the dominant mode of variability in ocean survival of both Chinook and coho salmon covaries with the North Pacific Gyre Oscillation, an important index of ecosystem productivity in the northeast Pacific Ocean that is linked to changing climatic forcing in the tropical Pacific Ocean. In Chapter 3, I show that the spectrum of environmental variability matters in understanding population variability and extinction risk of age-structured populations in terms of cohort resonance.
Download or read book Climate Change and Northern Fish Populations written by National Research Council Canada and published by NRC Research Press. This book was released on 1995 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt: These documents summarize some of the recent studies of the relationships among climate, the aquatic environment, and the dynamics of fish populations. The studies are mostly from the North Pacific ocean, but there are reports of investigations from the North Atlatic Ocean and from fresh water. Various papers include numerous examples of the relationships between fish abundance trends and the environment.
Download or read book Study of Factors Influencing the Return of Fall Chinook Salmon Oncorhynchus Tshawytscha to Spring Creek Hatchery written by Charles O. Junge and published by . This book was released on 1960 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wildlife 2001 Populations written by D.R. McCullough and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 1156 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1984, a conference called Wildlife 2000: Modeling habitat relationships of terrestrial vertebrates, was held at Stanford Sierra Camp at Fallen Leaf Lake in the Sierra Nevada Mountains of California. The conference was well-received, and the published volume (Verner, J. , M. L. Morrison, and C. J. Ralph, editors. 1986. Wildlife 2000: modeling habitat relationships of terrestrial vertebrates, University of Wisconsin Press, Madison, Wisconsin, USA) proved to be a landmark publication that received a book award by The Wildlife Society. Wildlife 2001: populations was a followup conference with emphasis on the other major biological field of wildlife conservation and management, populations. It was held on July 29-31, 1991, at the Oakland Airport Hilton Hotel in Oakland, California, in accordance with our intent that this conference have a much stronger international representation than did Wildlife 2000. The goal of the conference was to bring together an international group of specialists to address the state of the art in wildlife population dynamics, and set the agenda for future research and management on the threshold of the 21st century. The mix of specialists included workers in theoretical, as well as practical, aspects of wildlife conservation and management. Three general sessions covered methods, modelling, and conservation of threatened species.
Download or read book A Historical Analysis of the Population Dynamics of Columbia River Spring Chinook Salmon written by Jon Aaron Firehammer and published by . This book was released on 1996 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Behavior and Ecology of Pacific Salmon and Trout written by Thomas P. Quinn and published by University of Washington Press. This book was released on 2018-08-06 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Behavior and Ecology of Pacific Salmon and Trout combines in-depth scientific information with outstanding photographs and original artwork to fully describe the fish species critical to the Pacific Rim. This completely revised and updated edition covers all aspects of the life cycle of these remarkable fish in the Pacific: homing migration from the open ocean through coastal waters and up rivers to their breeding grounds; courtship and reproduction; the lives of juvenile salmon and trout in rivers and lakes; migration to the sea; the structure of fish populations; and the importance of fish carcasses to the ecosystem. The book also includes information on salmon and trout transplanted outside their ranges. Fisheries expert Thomas P. Quinn writes with clarity and enthusiasm to interest a wide range of readers, including biologists, anglers, and naturalists. He provides the most current science available as well as perspectives on the past, present, and future of Pacific salmon and trout. In this edition: Over 100 beautiful color photographs of salmon and troutUpdated information on all aspects of the salmon and trout life cycleExpanded coverage of trout
