Effects of Trawling and Dredging on Seafloor Habitat PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Effects of Trawling and Dredging on Seafloor Habitat PDF full book. Access full book title Effects of Trawling and Dredging on Seafloor Habitat by National Research Council. Download full books in PDF and EPUB format.
Author: National Research Council
Publisher: National Academies Press
ISBN: 0309083400
Category : Science
Languages : en
Pages : 137
Get Book Here
Book Description
Concerns over the potential ecological effects of fishing have increased with the expansion of fisheries throughout the marine waters of the United States. Effects of Trawling and Dredging on Seafloor Habitat describes how assessment of fishing impacts depends on gear type, number and location of bottom tows, and the physical and biological characteristics of seafloor habitats. Many experimental studies have documented acute, gear-specific effects of trawling and dredging on various types of habitat. These studies indicate that low mobility, long-lived species are more vulnerable to towed fishing gear than short-lived species in areas where the seabed is often disturbed by natural phenomena. Trawling and dredging may also change the composition and productivity of fish communities dependent on seafloor habitats for food and refuge. The scale of these impacts depends on the level of fishing effort. This volume presents color maps of fishing effort for all regions with significant bottom trawl or dredge fisheries-the first time that such data has been assembled and analyzed for the entire nation.
Author: National Research Council
Publisher: National Academies Press
ISBN: 0309083400
Category : Science
Languages : en
Pages : 137
Get Book Here
Book Description
Concerns over the potential ecological effects of fishing have increased with the expansion of fisheries throughout the marine waters of the United States. Effects of Trawling and Dredging on Seafloor Habitat describes how assessment of fishing impacts depends on gear type, number and location of bottom tows, and the physical and biological characteristics of seafloor habitats. Many experimental studies have documented acute, gear-specific effects of trawling and dredging on various types of habitat. These studies indicate that low mobility, long-lived species are more vulnerable to towed fishing gear than short-lived species in areas where the seabed is often disturbed by natural phenomena. Trawling and dredging may also change the composition and productivity of fish communities dependent on seafloor habitats for food and refuge. The scale of these impacts depends on the level of fishing effort. This volume presents color maps of fishing effort for all regions with significant bottom trawl or dredge fisheries-the first time that such data has been assembled and analyzed for the entire nation.
Author: National Research Council
Publisher: National Academies Press
ISBN: 0309077958
Category : Science
Languages : en
Pages : 352
Get Book Here
Book Description
Author: Charles Prelini
Publisher:
ISBN:
Category : Dredging
Languages : en
Pages : 332
Get Book Here
Book Description
Author: National Research Council
Publisher: National Academies Press
ISBN: 0309134102
Category : Science
Languages : en
Pages : 316
Get Book Here
Book Description
Some of the nation's estuaries, lakes and other water bodies contain contaminated sediments that can adversely affect fish and wildlife and may then find their way into people's diets. Dredging is one of the few options available for attempting to clean up contaminated sediments, but it can uncover and re-suspend buried contaminants, creating additional exposures for wildlife and people. At the request of Congress, EPA asked the National Research Council (NRC) to evaluate dredging as a cleanup technique. The book finds that, based on a review of available evidence, dredging's ability to decrease environmental and health risks is still an open question. Analysis of pre-dredging and post-dredging at about 20 sites found a wide range of outcomes in terms of surface sediment concentrations of contaminants: some sites showed increases, some no change, and some decreases in concentrations. Evaluating the potential long-term benefits of dredging will require that the U.S. Environmental Protection Agency step up monitoring activities before, during and after individual cleanups to determine whether it is working there and what combinations of techniques are most effective.
Author: Richard Nicholas Bray
Publisher:
ISBN:
Category : Dredging
Languages : en
Pages : 434
Get Book Here
Book Description
Author: Thomas M. Turner
Publisher: Cornell Maritime Press/Tidewater Publishers
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 240
Get Book Here
Book Description
Author: Sape A. Miedema
Publisher:
ISBN: 9781614994534
Category : Excavation
Languages : en
Pages : 0
Get Book Here
Book Description
Sand, clay and rock have to be excavated for a variety of purposes, such as dredging, trenching, mining (including deep sea mining), drilling, tunnel boring and many other applications. Many excavations take place on dry land, but they are also frequently required in completely saturated conditions, and the methods necessary to accomplish them consequently vary widely.This book provides an overview of cutting theories. It begins with a generic model, valid for all types of soil (sand, clay and rock), and continues with the specifics of dry sand, water-saturated sand, clay, atmospheric rock and hyperbaric rock. Small blade angles and large blade angles are discussed for each soil type, and for each case considered the equations/model for cutting forces, power and specific energy are given.With models verified by laboratory research, principally from the Delft University of Technology, and data from other recognized sources, this book will prove an invaluable reference for anybody whose work involves major excavations of any kind.
Author: Gilbert M. Gaul
Publisher: Sarah Crichton Books
ISBN: 0374718520
Category : Political Science
Languages : en
Pages : 265
Get Book Here
Book Description
This century has seen the costliest hurricanes in U.S. history—but who bears the brunt of these monster storms? Consider this: Five of the most expensive hurricanes in history have made landfall since 2005: Katrina ($160 billion), Ike ($40 billion), Sandy ($72 billion), Harvey ($125 billion), and Maria ($90 billion). With more property than ever in harm’s way, and the planet and oceans warming dangerously, it won’t be long before we see a $250 billion hurricane. Why? Because Americans have built $3 trillion worth of property in some of the riskiest places on earth: barrier islands and coastal floodplains. And they have been encouraged to do so by what Gilbert M. Gaul reveals in The Geography of Risk to be a confounding array of federal subsidies, tax breaks, low-interest loans, grants, and government flood insurance that shift the risk of life at the beach from private investors to public taxpayers, radically distorting common notions of risk. These federal incentives, Gaul argues, have resulted in one of the worst planning failures in American history, and the costs to taxpayers are reaching unsustainable levels. We have become responsible for a shocking array of coastal amenities: new roads, bridges, buildings, streetlights, tennis courts, marinas, gazebos, and even spoiled food after hurricanes. The Geography of Risk will forever change the way you think about the coasts, from the clash between economic interests and nature, to the heated politics of regulators and developers.
Author: United States. Army. Corps of Engineers
Publisher:
ISBN:
Category : Dredges
Languages : en
Pages : 436
Get Book Here
Book Description
Hopper dredges are designed to vacuum material from the sea floor through drag arms that load the material into the hold of the vessel. The cargo of mud, or sand, can then be transported to either an ocean disposal site, where the material is dropped to the bottom through openings in the bottom of the hull, or at an upland site such as a beach, or reclamation, where the material is pumped ashore by the ship. This method is most suited when excavating loose material from open areas for delivery to a distant disposal location. These vessels are generally certified to sail in coastal or ocean waters and are suited for working in rougher sea conditions beyond those suitable for other dredging plants.
Author: Historical Construction Equipment Association
Publisher: Enthusiast Books
ISBN: 9781583880883
Category : Transportation
Languages : en
Pages : 0
Get Book Here
Book Description
Beginning in 1884 with a prototype steam shovel, Marion went on to produce massive stripping shovels and walking draglines used in surface mining, as well as conventional shovels and dredges.View handpicked photographs from the Archives of the Historical Construction Equipment Association augmented with authoritative captions that highlight Marion's innovations through the years. Includes a concise corporate history of the Marion Power Shovel Company.
