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.

Fluctuations and declines in marine fish populations have caused growing concern among marine scientists, fisheries managers, commercial and recreational fishers, and the public. Sustaining Marine Fisheries explores the nature of marine ecosystems and the complex interacting factors that shape their productivity. The book documents the condition of marine fisheries today, highlighting species and geographic areas that are under particular stress. Challenges to achieving sustainability are discussed, and shortcomings of existing fisheries management and regulation are examined. The volume calls for fisheries management to adopt a broader ecosystem perspective that encompasses all relevant environmental and human influences. Sustaining Marine Fisheries offers new approaches to building workable fisheries management institutions, improving scientific data, and developing management tools. The book recommends ways to change current practices that encourage overexploitation of fish resources. It will be of special interest to marine policymakers and ecologists, fisheries regulators and managers, fisheries scientists and marine ecologists, fishers, and concerned individuals.

Publisher's description and table of contents

This publication examines recent experimental studies of the impact of towed fishing gears, such as trawls and scallop dredges, on benthic habitats and communities (organisms that live at or near the bottom of the sea). The review gives a critical evaluation of the methodological limitations of impact studies, given the complexity and natural variability of benthic communities.

Most of the major impacts of fishing on the ecosystems recorded around the world occur in the Mediterranean. This variety of interactions is due to four main interrelated factors: the wide range of fishing gear and practices; very intensive fishing; a high diversity of exploited habitats, ranging from shallow water to the deep-sea and oceanic domain; and high biological diversity.

The ocean has absorbed a significant portion of all human-made carbon dioxide emissions. This benefits human society by moderating the rate of climate change, but also causes unprecedented changes to ocean chemistry. Carbon dioxide taken up by the ocean decreases the pH of the water and leads to a suite of chemical changes collectively known as ocean acidification. The long term consequences of ocean acidification are not known, but are expected to result in changes to many ecosystems and the services they provide to society. Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean reviews the current state of knowledge, explores gaps in understanding, and identifies several key findings. Like climate change, ocean acidification is a growing global problem that will intensify with continued CO2 emissions and has the potential to change marine ecosystems and affect benefits to society. The federal government has taken positive initial steps by developing a national ocean acidification program, but more information is needed to fully understand and address the threat that ocean acidification may pose to marine ecosystems and the services they provide. In addition, a global observation network of chemical and biological sensors is needed to monitor changes in ocean conditions attributable to acidification.