Download or read book Seasonal and spatial differences in diet in the western stock of Steller sea lions Eumetopias jubatus written by E.H. SINCLAIR and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Steller Sea Lion and Northern Fur Seal Research written by and published by . This book was released on 2007 with total page 518 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Steller Sea Lion and Northern Fur Seal Research Purpose and need Alternatives Affected environment Environmental consequences National Environmental Policy Act compliance implementation and recommendations List of preparers List of agencies organizations and persons whom the draft EIS was sent References Index written by United States. National Marine Fisheries Service. Office of Protected Resources. Permits Division and published by . This book was released on 2007 with total page 1124 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Steller Sea Lion Protection Measures written by and published by . This book was released on 2001 with total page 716 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Decadal Variation in the Diet of Western Stock Steller Sea Lions Eumetopias Jubatus written by Elizabeth Hacker Sinclair and published by . This book was released on 2013 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: Steller sea lions (Eumetopias jubatus) are listed as an endangered species in western Alaska due to a precipitous decline that occurred in the 1980s and 1990s. In 2000, cascading declines slowed or ceased and clusters of rookeries between the eastern Aleutian Islands and eastern Gulf of Alaska began to show signs of population growth. Reasons for the decline and for a range-wide failure to recover are unresolved, but reduction in the availability of prey due to commercial fishing or environmental perturbation has been hypothesized. Discerning the diet and patterns of prey use by Steller sea lions (SSL) is fundamental to isolating the mechanisms driving population health. Here we evaluate the frequency of occurrence (FO) of prey species in 3,412 scats of adult female and juvenile SSL collected during 1999-2009, across the range of the U. S. Western Stock. Thirteen primary prey are identified based on their occurrence in ≥ 5% of total scats. We reduce the dimension of the diet profile of the 13 primary prey to two categorical groups through principal component analysis (PC). A hierarchical cluster analysis of PC scores on collection site locations describes four geographic regions of SSL diet (with Amak Island as an outlier) nearly identical to those identified in a previously published 1990-1998 (n = 3,762) dataset. Geographic regions of diet continue to correspond with regional population trends of SSL. The species of primary prey consumed by SSL are analogous between 1990-1998 and 1999-2009. However, the rangewide FO of 7 of the 13 primary prey increased significantly (p ≤ 0.05) during the latter decade. Only cephalopods (Gonatidae) and walleye pollock (Theragra chalcogramma) decreased significantly in FO in any season or region between decades. Generalized linear mixed models (GLMM) of seasonal prey FO determined that trends in the FO of primary prey between decades were locally driven by significant changes within one or more of the four diet regions and fishery conservation management areas (RCA). The most significant increases (p = 0.001) in FO during 1999-2009 were for commercial fishes: arrowtooth flounder (Atheresthes sp.), Atka mackerel (Pleurogrammus monopterygius), rock sole (Lepidopsetta sp.), and Pacific cod (Gadus macrocephalus); and one non-commercial fish species (Pacific sand lance, Ammodytes hexapterus) in diet Regions 2 and 3 (RCA zones 6 and 7) between the eastern Aleutian Islands and western Gulf of Alaska. Diversity scores (H') for primary prey were also highest in these regions compared to the previous decade, and are coincident with SSL population increases that began in the same area in 2000. Atka mackerel continues to dominate SSL diet west of Samalga Pass, and walleye pollock continues to dominate SSL diet east of Samalga Pass (despite its decreased presence in diets in Regions 1-3 during 1999-2009). The results of generalized additive mixed models (GAMM) of annual trends (1990-2009) in summer prey FO on each rookery across the study area are consistent with the results of GLMM decadal comparisons. The additional 11 years of data presented here support earlier conclusions that adult female and young juvenile SSL of the Western Stock collectively eat a wide variety of prey species, but demonstrate fidelity to prey types that are predictably available in seasonal concentrations over the continental shelf or other bathymetric structures, within close range of natal rookery sites. Foraging within close proximity to birth and breeding sites keeps adult females close to pups onshore and to young juveniles learning to forage. However, it also increases their vulnerability to potential nearshore environmental and anthropogenic interference which could ultimately influence their reproductive success. It was not the objective of this study to define the relationship between SSL diet and population decline, or to identify the interactive mechanisms that drive diet change. However, coincident patterns emerged that suggest relationships between SSL diet, regional population patterns, climate and fisheries. Some of the patterns are worthy of discussion and future research: 1) the areas of greatest increases in the FO and diversity of prey (Regions 2 and 3) beginning in 1999, overlap with those of the strongest population growth since 1999; 2) the increase in primary prey FO and diversity since 1999 is coincident with increased restrictions on groundfish trawling within SSL Critical Habitat, enacted in 2000; and 3) the area of lowest prey diversity (Region 4) overlaps with those areas of continuing population declines, the most restricted foraging habitat (narrow continental shelf) and the lowest seasonal and temporal variability in sea surface temperature in all years of study.
Download or read book Decline of the Steller Sea Lion in Alaskan Waters written by National Research Council and published by National Academies Press. This book was released on 2003-05-04 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: For an unknown reason, the Steller sea lion population in Alaska has declined by 80% over the past three decades. In 2001, the National Research Council began a study to assess the many hypotheses proposed to explain the sea lion decline including insufficient food due to fishing or the late 1970s climate/regime shift, a disease epidemic, pollution, illegal shooting, subsistence harvest, and predation by killer whales or sharks. The report's analysis indicates that the population decline cannot be explained only by a decreased availability of food; hence other factors, such as predation and illegal shooting, deserve further study. The report recommends a management strategy that could help determine the impact of fisheries on sea lion survival-establishing open and closed fishing areas around sea lion rookeries. This strategy would allow researchers to study sea lions in relatively controlled, contrasting environments. Experimental area closures will help fill some short-term data gaps, but long-term monitoring will be required to understand why sea lions are at a fraction of their former abundance.
Download or read book Developing a Research and Restoration Plan for Arctic Yukon Kuskokwim Western Alaska Salmon written by National Research Council and published by National Academies Press. This book was released on 2005-07-06 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent declines in the abundance of salmon in the Arctic-Yukon-Kuskokwim (AYK) region of western Alaska have created hardships for the people and communities who depend on this resource. In 2002, the AYK Sustainable Salmon Initiative (SSI) was created to undertake research to understand the reasons for this decline and to help support sustainable management in the region. This report makes recommendations for developing the research that the AYK SSI science plan should be based on, and relates the development of a restoration plan to the results of that research.
Download or read book Long term Ecological Change in the Northern Gulf of Alaska written by R.B. Spies and published by Elsevier. This book was released on 2006-12-12 with total page 609 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive text is a major synthesis on ecological change in the Gulf of Alaska. It encompasses the structural and annual changes, forces of change, long-ecological changes in the atmosphere and ocean, plankton, fish, birds and mammals, and the effects of the 1989 Exxon Valdez Oil Spill. With 5 major sections, Long-term Ecological Change in the Northern Gulf of Alaska first describes the physical features, the atmosphere and physical oceanography, the annual production cycle, the forage base for higher animals and trophic transfer, and the adaptations for survival in this changing environment for 9 portal species. Then, the major forces of change are introduced: climate, geophysics, fisheries and harvesting, species interactions, disease and contaminants. Next, the long-term records of change in physical factors and biological populations are presented, as well as the potential reasons for the biological changes. Following is the history of the Exxon Valdez oil spill and its long-term effects. And, finally, the emergent properties of the ecosystem are discussed and an attempt is made to weigh the importance of the major forcing factors in terms of their temporal and spatial scales of influence. * Examines important data on long-term change in the ecosystem and the forcing factors that are responsible for it * Provides an account of the 1989 Exxon Valdez oil spill with emphasis on the long-term effects * Describes the effects of climate change, geophysical change, species interactions, harvesting, disease, the 1989 oil spill, and marine contaminants on key populations of marine organisms
Download or read book An Introduction to Marine Mammal Biology and Conswervation written by Simmonds, M.P and published by Jones & Bartlett Publishers. This book was released on 2013 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: The charismatic mammals that live in the ocean are a constant source of interest, both for scientists and our society at large. Their biology, behavior, and conservation are of utmost importance, as a vast number of species are currently threatened. Intended for the upper-level undergraduate or graduate student within biology, marine biology, or conservation/environmental science, An Introduction to Marine Mammal Biology and Conservation provides a broad introduction to marine mammal biology using cutting edge information and student-friendly learning tools. The text begins with chapters on the evolution and classification of marine mammals and their general biology. It moves on to discuss the behavior and ecology of different groups of marine mammals, such as polar bears, otters, and cetaceans. Part 3 dives into many different conservation issues facing marine mammals, as well as discussions on how they can be addressed. Closing chapters provide information on how scientists study marine mammals, how society can enjoy observing the animals while making sure they are preserved, and a word to students looking to pursue a career with marine mammals.
Download or read book Age Determination Manual of the Alaska Fisheries Science Center Age and Growth Program written by Mary Elizabeth Matta and published by . This book was released on 2012 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Age and Growth Program at the Alaska Fisheries Science Center is tasked with providing age data in order to improve the basic understanding of the ecology and fisheries dynamics of Alaskan fish species. The primary focus of the Age and Growth Program is to estimate ages from otoliths and other calcified structures for age-structured modeling of commercially exploited stocks; however, the program has recently expanded its interests to include numerous studies on topics ranging from age estimate validation to the growth and life-history of non-target species. Because so many applications rely upon age data and particularly upon assurances as to their accuracy and precision, the Age and Growth Program has developed this practical guide to document the age determination of key groundfish species from Alaskan waters. The main objective of this manual is to describe techniques specific to the age determination of commercially and ecologically important species studied by the Age and Growth Program. The manual also provides general background information on otolith morphology, dissection, and preparation, as well as descriptions of methods used to measure precision and accuracy of age estimates. This manual is intended not only as a reference for age readers at the AFSC and other laboratories, but also to give insight into the quality of age estimates to scientists who routinely use such data.
Download or read book Aquatic Food Webs written by Andrea Belgrano and published by Oxford University Press. This book was released on 2005-04-07 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume provides a current synthesis of theoretical and empirical food web research. Whether they are binary systems or weighted networks, food webs are of particular interest to ecologists in providing a macroscopic view of ecosystems. They describe interactions between species and their environment, and subsequent advances in the understanding of their structure, function, and dynamics are of vital importance to ecosystem management and conservation. Aquatic Food Webs provides a synthesis of the current issues in food web theory and its applications, covering issues of structure, function, scaling, complexity, and stability in the contexts of conservation, fisheries, and climate. Although the focus of this volume is upon aquatic food webs (where many of the recent advances have been made), any ecologist with an interest in food web theory and its applications will find the issues addressed in this book of value and use. This advanced textbook is suitable for graduate level students as well as professional researchers in community, ecosystem, and theoretical ecology, in aquatic ecology, and in conservation biology.
Download or read book Bering Sea Chinook Salmon Bycatch Management Regulatory Impact Review initial Regulatory Flexibility Analysis written by and published by . This book was released on 2009 with total page 724 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Marine Conservation written by G. Carleton Ray and published by John Wiley & Sons. This book was released on 2013-10-11 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: Providing a guide for marine conservation practice, Marine Conservation takes a whole-systems approach, covering major advances in marine ecosystem understanding. Its premise is that conservation must be informed by the natural histories of organisms together with the hierarchy of scale-related linkages and ecosystem processes. The authors introduce a broad range of overlapping issues and the conservation mechanisms that have been devised to achieve marine conservation goals. The book provides students and conservation practitioners with a framework for thoughtful, critical thinking in order to incite innovation in the 21st century. "Marine Conservation presents a scholarly but eminently readable case for the necessity of a systems approach to conserving the oceans, combining superb introductions to the science, law and policy frameworks with carefully chosen case studies. This superb volume is a must for anyone interested in marine conservation, from students and practitioners to lay readers and policy-makers." —Simon Levin, George M. Moffett Professor of Biology, Department of Ecology & Evolutionary Biology, Princeton University
Download or read book Culture and Archaeology of the Ancestral Unangax Aleut of the Aleutian Islands Alaska written by Debra Corbett and published by Springer Nature. This book was released on 2024-01-03 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the past 9,000 years, people lived and flourished along the 1,000-mile Aleutian archipelago reaching from the American continent nearly to Asia. The Aleutian chain and surrounding waters supported 40,000 or more people before the Russians arrived. Despite the antiquity of continuous human occupation, the size of the area, and the fascinating and complex social organization, the region has received scant notice from the public. This volume provides a thorough review describing the varied cultures of the ancestral Unangax̂, using archaeological reports, articles, and unpublished data; documented Unangax̂ oral histories, and ethnohistories from early European and American visitors, assessed through the authors’ multi-decade experience working in the Aleutian Archipelago. Unangam Tanangin ilan Unangax̂/Aliguutax̂ Maqax̂singin ama Kadaangim Tanangin Anaĝix̂taqangis (Culture and Archaeology of the Ancestral Unangax̂/Aleut of the Aleutian Islands, Alaska) begins with a description of the physical and biological world (The Physical Environment and The Living Environment) of which the Unangax̂ are part, followed by a description of the archaeological research in the region (The People). The rest of the book addresses ancestral Unangax̂ life including settlement on the land, and the characteristics of sites based on the activities that took place there (People on the Landscape). From this broad perspective, the view narrows to the people making a living through hunting, fishing, and collecting food along the shore-line, making their intricate tools, storing and cooking food, and sewing and weaving (Making a Living); household life including house construction, households, and the work done within the home (Life at Home); and the personal changes an individual goes through from the time they are born through death, including spiritual transitions and ceremonies (Transitions), and the evidence for these events in the material record. This book is written in gratitude to the Unangax̂ and Aleut people for the opportunity to work in Unangam Tanangin or the Aleutian Islands, and to learn about your culture. We hope you find this book useful. The purpose of this book is to introduce the broader public to the cultures of this North Pacific archipelago in a single source, while simultaneously providing researchers a comprehensive synthesis of archaeology in the region.
Download or read book Canadian Journal of Fisheries and Aquatic Sciences written by and published by . This book was released on 2014-05 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Programmatic Supplemental EIS for Alaska Groundfish Fisheries Implemented Under the Authority of the Fishery Management Plans for the Groundfish Fishery of the Gulf of Alaska and the Groundfish of the Bering Sea and Aleutian Islands Area written by and published by . This book was released on 2004 with total page 1124 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Carnivoran Evolution written by Anjali Goswami and published by Cambridge University Press. This book was released on 2010-07-29 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Members of the mammalian clade Carnivora have invaded nearly every continent and ocean, evolving into bamboo-eating pandas, clam-eating walruses and of course, flesh-eating sabre-toothed cats. With this ecological, morphological and taxonomic diversity and a fossil record spanning over sixty million years, Carnivora has proven to be a model clade for addressing questions of broad evolutionary significance. This volume brings together top international scientists with contributions that focus on current advances in our understanding of carnivoran relationships, ecomorphology and macroevolutionary patterns. Topics range from the palaeoecology of the earliest fossil carnivorans to the influences of competition and constraint on diversity and biogeographic distributions. Several studies address ecomorphological convergences among carnivorans and other mammals with morphometric and Finite Element analyses, while others consider how new molecular and palaeontological data have changed our understanding of carnivoran phylogeny. Combined, these studies also illustrate the diverse suite of approaches and questions in evolutionary biology and palaeontology.
