Download or read book Predation on Sockeye Salmon Fry by Piscivorous Fishes in Southern Lake Washington 1996 Western Washington Office Aquatic Resources Division Olympia Washington June 1997 written by and published by . This book was released on 1997* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Predation on Sockeye Salmon Fry by Piscivorous Fishes in Southern Lake Washington 1996 written by Roger Tabor and published by . This book was released on 1997 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Predation on Sockeye Salmon Fry by Piscivorous Fishes in the Lower Cedar River and Southern Lake Washington written by Roger Tabor and published by . This book was released on 1996 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Predation of Sockeye Salmon Fry by Cottids and Other Predatory Fishes in the Cedar River and Southern Lake Washington 1997 written by Roger Tabor and published by . This book was released on 1998 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Predation on Sockeye Salmon Fry by Piscivorous Fishes in Southern Lake Washington written by and published by . This book was released on 1997 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book PREDATION OF SOCKEYE SALMON FRY BY COTTIDS AND OTHER PREDATORY FISHES IN THE CEDAR RIVER AND SOUTHERN LAKE WASHINGTON 1997 U S DEPARTME written by U.S. Fish and Wildlife Service and published by . This book was released on 1999* with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Light Intensity on Predation of Sockeye Salmon Fry by Prickly Sculpin and Torrent Sculpin written by Roger Tabor and published by . This book was released on 1998 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantifying the Impact of Two Native Predators on Juvenile Sockeye Salmon Survival in Lake Washington written by Casey Porter Clark and published by . This book was released on 2017 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the mechanisms regulating population fluctuations, such as births, reproduction, and deaths, remains a persistent question in ecology. Mortality can be incurred at any point during the lifecycle, but mortality rates can be high for juvenile animals in particular. One source of this early life history mortality is via predation. Accurately measuring predation rates requires intensive studies, and is further complicated by variability in habitats and changes in the extent of spatial and temporal overlap between predators and prey. In this study, we examined abundance, spatial distributions and diets of two piscivorous fishes and their predation impact on juvenile salmonids in a well-studied large western lake, Lake Washington. We addressed the following questions: (i) What is the abundance of cutthroat trout and northern pikeminnow in Lake Washington? (ii) At what rates do these predators consume juvenile salmon throughout the year, and how many total juvenile salmon are consumed given the predator population size? Understanding which factors influence predation and the extent of this predatory impact requires temporally and spatially explicit data on the interaction between predators and prey, including both juvenile sockeye salmon and the main alternative prey fish species. To observe these interactions, we used several overlapping sampling types across trophic levels. We used a Chapman-modified population estimation procedure to estimate a cutthroat trout population size of 22,791 ≥300 mm FL and the same procedure to estimate a northern pikeminnow population size of 13,582 ≥300 mm FL. We also used a relative catch method to estimate a northern pikeminnow population size of 112,816 ≥300 mm FL. The magnitude of predation on juvenile salmon and other prey fishes varied considerably among months and between cutthroat trout and northern pikeminnow, between small and large size classes of each predator species, and between years. In 2015, predation mortality of lake entry 2015 (sub-yearling) sockeye salmon was 20% of fry production in that year, and predation losses of lake entry 2014 (yearling) sockeye were 56% of pre-smolt production. In 2016, mortality of lake entry 2016 (sub-yearling) sockeye was 44% of fry production, and predation losses of lake entry 2014 sockeye were 473% of pre-smolt production of that year. Our work shows that the current predation rate is high enough and these predator populations are of sufficient size that predation is a significant source of mortality for juvenile sockeye and Chinook salmon in this system. This work highlights a scenario of combined physical and biological factors that influence mortality in juvenile fish, and can potentially inform the potential for predation mortality in other lake systems.
Download or read book EPA 670 2 written by and published by . This book was released on 1973-11 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fish and Fisheries Management in Lakes and Reservoirs written by and published by . This book was released on 1993 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pacific Salmon written by and published by . This book was released on 1995 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Upstream written by National Research Council and published by National Academies Press. This book was released on 1996-07-17 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: The importance of salmon to the Pacific Northwestâ€"economic, recreational, symbolicâ€"is enormous. Generations ago, salmon were abundant from central California through Idaho, Oregon, and Washington to British Columbia and Alaska. Now they have disappeared from about 40 percent of their historical range. The decline in salmon numbers has been lamented for at least 100 years, but the issue has become more widespread and acute recently. The Endangered Species Act has been invoked, federal laws have been passed, and lawsuits have been filed. More than $1 billion has been spent to improve salmon runsâ€"and still the populations decline. In this new volume a committee with diverse expertise explores the complications and conflicts surrounding the salmon problemâ€"starting with available data on the status of salmon populations and an illustrative case study from Washington state's Willapa Bay. The book offers specific recommendations for salmon rehabilitation that take into account the key role played by genetic variability in salmon survival and the urgent need for habitat protection and management of fishing. The committee presents a comprehensive discussion of the salmon problem, with a wealth of informative graphs and charts and the right amount of historical perspective to clarify today's issues, including: Salmon biology and geographyâ€"their life's journey from fresh waters to the sea and back again to spawn, and their interaction with ecosystems along the way. The impacts of human activitiesâ€"grazing, damming, timber, agriculture, and population and economic growth. Included is a case study of Washington state's Elwha River dam removal project. Values, attitudes, and the conflicting desires for short-term economic gain and long-term environmental health. The committee traces the roots of the salmon problem to the extractive philosophy characterizing management of land and water in the West. The impact of hatcheries, which were introduced to build fish stocks but which have actually harmed the genetic variability that wild stocks need to survive. This book offers something for everyone with an interest in the salmon issueâ€"policymakers and regulators in the United States and Canada; environmental scientists; environmental advocates; natural resource managers; commercial, tribal, and recreational fishers; and concerned residents of the Pacific Northwest.
Download or read book Stream Corridor Restoration written by and published by National Technical Info Svc. This book was released on 1998 with total page 648 pages. Available in PDF, EPUB and Kindle. Book excerpt: This document is a cooperative effort among fifteen Federal agencies and partners to produce a common reference on stream corridor restoration. It responds to a growing national and international interest in restoring stream corridors.
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1976 with total page 888 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sturgeons and Paddlefish of North America written by G.T.O LeBreton and published by Springer Science & Business Media. This book was released on 2006-01-20 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern North American sturgeons and paddlefish are the result of 100 million years of evolution. Once an integral part of aboriginal culture, their numbers were decimated by overfishing and habitat destruction during the past two centuries. This book details the extensive science aimed at helping these remarkable species recover from the brink of extinction, and describes the historical, biological, and ecological importance of North American sturgeon and paddlefish. The text is enhanced by photographs and detailed line drawings. This comprehensive volume will be an invaluable resource for researchers, educators, and consultants, in academic and government settings, who work to further scientific understanding of these fishes. No other single compilation has documented current information in such detail.
Download or read book Fisheries Ecology and Management written by Carl J. Walters and published by Princeton University Press. This book was released on 2020-06-30 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantitative modeling methods have become a central tool in the management of harvested fish populations. This book examines how these modeling methods work, why they sometimes fail, and how they might be improved by incorporating larger ecological interactions. Fisheries Ecology and Management provides a broad introduction to the concepts and quantitative models needed to successfully manage fisheries. Walters and Martell develop models that account for key ecological dynamics such as trophic interactions, food webs, multi-species dynamics, risk-avoidance behavior, habitat selection and density-dependence. They treat fisheries policy development as a two-stage process, first identifying strategies for varying harvest in relation to changes in abundance, then finding ways to implement such strategies in terms of monitoring and regulatory procedures. This book provides a general framework for developing assessment models in terms of state-observation dynamics hypotheses, and points out that most fisheries assessment failures have been due to inappropriate observation model hypotheses rather than faulty models for ecological dynamics. Intended as a text in upper division and graduate classes on fisheries assessment and management, this useful guide will also be widely read by ecologists and fisheries scientists.
Download or read book Canadian Special Publication of Fisheries and Aquatic Sciences written by and published by . This book was released on 1990 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:
