Download or read book Population Dynamics and Exploitation of Fishes in Two Eastern Washington Lakes written by Larry C. Phillips (M.S.) and published by . This book was released on 2006 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Non-native sport fishes have been stocked into Washington lakes and rivers for many years. These introductions have resulted in reproducing fish populations in most waters. Today sport fishing for non-native fishes such as largemouth bass (Micropterus salmoides), yellow perch (Percajlavescens), black crappie (Pomoxis nigromaculatus), pumpkinseed sunfish (Lepomis gibbosus), and bullhead (Ameiurus nebulosus), generates millions of dollars to Washington State's economy. A majority of states manage the sport harvest of these species with minimum size restrictions and/or bag limits. Washington State allows anglers to harvest these species without regard to size or number in all but a few select waters. Fish managers with Washington Department of Fish and Wildlife are beginning to question potential impacts to sport fisheries using this management strategy. Harvest restrictions can improve the number and/or size of fish only when populations are limited by harvest. A detailed survey of Downs and Bonnie Lakes in eastern Washington was conducted during 2001 to better understand the relationship between existing fish populations and harvest. The objective of the study was to describe the existing fish populations in terms of species, abundance, age, growth, relative weight, length frequency, catch per unit of effort (CPUE), and also to estimate annual sport fishing exploitation by species and age. During the Downs Lake survey ten fish species were collected, with yellow perch the most abundant by weight (39.9%) and also by number (65.5%). Population estimate (95% confidence intervals) of stock length (when possible) and larger individuals indicate that the yellow perch population consisted of 24,631 (±5,306) fish. Total sport fishing effort was 13,601 (± 3,378) hours. Between April 28th and September 30th 2001, sport anglers harvested 9,519 (± 3,889) fish (all species) from the Lake. Yellow perch was the most abundantly harvested species (4,960) followed by rainbow trout (2,777). The annual exploitation of yellow perch during 2001 at Downs Lake was 20.1 %. Exploitation at age was highest at age 9 (22.2%). During the survey of Bonnie Lake eight fish species were collected, with brown bullhead the most abundant by number (28.8%) and weight (23.2%). The population estimate (including 95% confidence) for black crappie was 43,887 (±24,662). Total sport fishing effort was 6,469 (± 3,196) hours., Between April 28th and September 30th sport anglers harvested 12,842 (±10,808) fish (all species). Black crappie was the most abundantly harvested species (7,493), followed by brown bullhead (2,269). Approximately 17.1% of the black crappie in Bonnie Lake were harvested by sport anglers during 2001. Good growth rates, low exploitation rates, and apparent high natural mortality of stock length fish and/or variable recruitment, indicate that a change to existing sport fishing regulations for yellow perch and black crappie will likely do little to improve size and number of fish harvested at these lakes. It is recommended that no changes be made to current sport fishing regulations at Downs or Bonnie lakes. The brown trout (Salmo trutta) stocking program at Downs Lake does not provide adequate harvest opportunity to justify continuation of the program and should be discontinued"--Document.
Download or read book Prey Selectivity and Population Dynamics of a Lentic Fish Community Twin Lakes Washington written by David R. Christensen and published by . This book was released on 2005 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamics of Good Bluegill Populations in Two Lakes with Dense Vegetation written by James C. Schneider and published by . This book was released on 1993 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sport Fishery Abstracts written by and published by . This book was released on 1980 with total page 814 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Prey Selectivity and Population Dynamics of a Lentic Fish Community Twin Lakes Washington written by David R. Christensen (Fisheries biologist) and published by . This book was released on 2005 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The establishment of non-native species, largemouth bass (Micropterus salmoides L.) and golden shiners (Notemigonus crysoleucus M.) in Twin Lakes, Washington is of concern for potential negative impacts on resident trout populations. Bass were first documented in Twin Lakes in the 1980’s and shiners were confirmed there during the early 1990’s. Since then, golden shiners have become a particular problem, as they compete with trout for food resources and, unlike bass, are not a game fish. Other problems related to eutrophication, such as dense weed beds are also believed to impact Twin Lakes fisheries. A floating-leaved macrophyte, watershield covers about 6% (58 acres) of the summer North Twin surface area and about 2% (19 acres) in South Twin Lake. Because these plants grow in the littoral area, crucial to fish spawning and feeding, the varying coverage between the lakes may affect fish interactions, including bass piscivory. The goal of this study was to develop information on water quality and trophic interactions within the Twin Lakes fish communities to guide fishery management decisions. In particular, data were developed to examine specific management options, including macrophyte reduction and whether bass slot-limits could enhance bass predation on shiners. Increased predation could serve as an indirect control mechanism for shiners, preventing further population growth. Seasonal trophic interactions within the Twin Lakes fish community were examined by monthly sampling from June to September in 2004 and 2005. Length/weight measurements were made and stomach contents were taken by gastric lavage on electrofish- and gillnet- captured individuals. Fish diets were characterized by identification of stomach contents. Population estimates were calculated from mark-recapture data using the Schnabel multiple-census method. Length class histograms were constructed for each species to assess population size distribution. Growth and condition factors were also calculated and compared to regional and national averages. Basic water quality data, including dissolved oxygen and temperature profiles were determined on the same dates. Available trout habitat volume for each lake was calculated from this data. There was significant variation in diets of different age fish as the season progressed. Large bass primarily consumed crawfish, golden shiners, and other fish. Diets of medium bass consisted principally of macroinvertebrates and golden shiners; while small bass diets were feeding on macroinvertebrates and a few golden shiners. The smallest bass consumed only zooplankton and macroinvertebrates. Brook and rainbow trout consumed primarily midges, scuds, and zooplankton. High relative weight (Wr) condition factors and growth rates indicate that current Twin Lake trout populations are generally healthy. However, combined effects of eutrophication and invasive species could have a detrimental impact on Twin Lake salmonids in the near future. Our results indicate that measures to increase bass survival that would shift the population histogram to larger sizes would likely increase predation pressure on shiners. Also, reducing macrophyte densities could also increase predation on shiners by reducing available shelter and by opening lanes for ambush feeding. Implementation to achieve these goals could include fishing slot limits for take of larger bass and varying schemes for mechanical macrophyte harvesting."--Abstract.
Download or read book The Lake Charr Salvelinus namaycush Biology Ecology Distribution and Management written by Andrew M. Muir and published by Springer Nature. This book was released on 2021-03-03 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: The lake charr Salvelinus namaycush is a ubiquitous member of cold-water lake ecosystems in previously glaciated regions of northern continental U.S., Alaska, and Canada that often support important commercial, recreational, and subsistence fisheries. The lake charr differs from other charrs by its large size, longevity, iteroparity, top-predator specialization, reduced sexual dimorphism, prevalence of lacustrine spawning, and use of deepwater habitat. The species is remarkably variable in phenotype, physiology, and life history, some of which is reflected in its ecology and genetics, with as many as four morphs or ecotypes co-occurring in a single lake. The lake charr is often the top predator in these systems, but is highly adaptable trophically, and is frequently planktivorous in small lakes. The lake charr by their name highlights their common habitat, lakes both large and small, but often frequents rivers and occasionally moves into the Arctic Ocean. Movement and behaviour of lake charr are motivated by access to cool, well-oxygenated water, foraging opportunities, predator avoidance, and reproduction. Owing to their broad distribution and trophic level, the lake charr serves as a sentinel of anthropogenic change. This volume will provide an up-to-date summary of what is currently known about lake charr from distribution to genetics to physiology to ecology. The book provides a compilation and synthesis of available information on the lake charr, beginning with an updated distribution and a revised treatment of the paleoecology of the species. Understanding of ecological and genetic diversity and movement and behaviour of the species has advanced remarkably since the last major synthesis on the species over 40 years ago. Mid-sections of the book provide detailed accounts of the biology and life history of the species, and later sections are devoted to threats to conservation and fishery management practices used to ensure sustainability. A new standard lake charr-specific terminology is also presented. The book will be a valuable reference text for biologists around the world, ecologists, and fishery managers, and of interest to the angling public.
Download or read book Population dynamics and exploitation in some freshwater fish written by E D. Le Cren and published by . This book was released on 1964 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1990 with total page 946 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Percid Fishes written by John F. Craig and published by John Wiley & Sons. This book was released on 2008-04-30 with total page 371 pages. Available in PDF, EPUB and Kindle. Book excerpt: The percid fishes (or perch family) comprise many species including the perch, pikeperch, yellow perch, walleye and the darters. These species are of great ecological and economic importance, being important components of the freshwater ecosystem and recreational and commercial fisheries. Percid Fishes covers aspects such as systematics, morphology, biology, ecology, diseases and parasites and the economic importance of percid fisheries. Special emphasis is placed within the book on the complex relationship between this family of fishes and their environment and how they respond to perturbations, especially those induced by humans. The author, John Craig who has a great deal of experience working on these fishes in many of the countries in which they occur, has drawn together an extremely important book which provides a unique, comprehensive and indispensable review of this most significant group of fish.
Download or read book The Development of an Aquatic Habitat Classification System for Lakes written by W.D.N. Busch and published by CRC Press. This book was released on 2018-01-18 with total page 251 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the context of freshwater fisheries changing their strategies from the regulation of harvest and the enhancement of populations, to the creation and protection of habitats and the management of ecosystems, moves toward establishing an aquatic habitat classification system. Eight papers, from the February 1988 Symposium on the Classification and Inventory of Great Lakes Aquatic Habitats (the last in a series of Great Lakes Symposia), propose various classification approaches, most using a limited number of physical, chemical, and/or biological variables to produce some form of index. They also include overviews and summaries of the classification process.
Download or read book Canadian Journal of Fisheries and Aquatic Sciences written by and published by . This book was released on 2001 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fishery Bulletin written by and published by . This book was released on 1997 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Collected Reprints written by and published by . This book was released on 1993 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Size Structured Populations written by Bo Ebenman and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: At last both ecology and evolution are covered in this study on the dynamics of size-structured populations. How does natural selection shape growth patterns and life cycles of individuals, and hence the size-structure of populations? This book will stimulate biologists to look into some important and interesting biological problems from a new angle of approach, concerning: - life history evolution, - intraspecific competition and niche theory, - structure and dynamics of ecological communities.
Download or read book Collected Reprints written by Southwest Fisheries Center (U.S.) and published by . This book was released on 1977 with total page 848 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biodiversity Dynamics and Conservation written by C. Lévêque and published by Cambridge University Press. This book was released on 1997-05-13 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a comprehensive book on the biodiversity of one of the most diverse ecosystems known - tropical freshwater.
Download or read book Grant in aid for Fisheries Program Activities written by United States. National Marine Fisheries Service and published by . This book was released on 1977 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:
