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 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 2003-04-04 with total page 216 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 Steller Sea Lion Decline written by Douglas P. DeMaster and published by . This book was released on 2002 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: The most likely cause of the moderate decline of western Alaska Steller sea lions, in the 1990s, is poor recruitment (reproduction and survival of young). Also implicated are nutritional stress, predation, and disease. In contrast, nutritional stress alone was the leading hypothesis for a steep decline in sea lions the 1980s. This book has 13 extended abstracts presented at a May 2001 workshop. Attendees included the nation's leading authorities on Alaska's Steller sea lions.

Download or read book Recovery Plan for the Steller Sea Lion Eumetopias Jubatus written by and published by . This book was released on 1992 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Steller Sea Lion Eumetopias Jubatus Decline and the Gulf of Alaska Bering Sea Commercial Fishery written by Daniel Reneau Hennen and published by . This book was released on 2004 with total page 414 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Steller sea lion (SSL) population in Alaska was listed as threatened under the Endangered Species Act in 1991. Several procedural restrictions were placed on the commercial fisheries of the region at that time in an effort to reduce the potential for human induced mortality on sea lions. Several years have elapsed since these restrictions were put into place and questions about their efficacy abound. In an effort to determine whether or not fisheries interventions have helped the SSL population to recover, estimates of the fishing activity of the Bering Sea/Gulf of Alaska commercial fisheries in the vicinity of individual Steller sea lion rookeries and SSL population trends at those rookeries were made using data from the National Marine Fisheries Service (NMFS) Fisheries Observer Program and Steller Sea Lion Adult Count Database. Fisheries data from 1976-2000 were analyzed in relation to SSL population counts from 1956-2001, at 32 rookeries from the endangered western stock. Linear regression on the principal components of the fisheries data show that a positive correlation exists between several metrics of historical fishing activity and SSL population decline. The relationship is less consistent after 1991, supporting a hypothesis that fishing closures around some of the rookeries have been effective in moderating the localized effects of fishing activity on SSL.

Download or read book Steller Sea Lions Eumetopias Jubatus written by Andrew W. Trites and published by . This book was released on 1998 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents the changes in the Steller sea lion's diet over time (from a diverse diet including fatty fishes to one dominated by pollock), which has resulted in negative reproductive and survival consequences

Download or read book Correlates of the Decline of the Steller Sea Lion in the North Pacific written by Hans Nesse and published by . This book was released on 2009 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Review of Proposed Fishery Management Actions and the Decline of Steller Sea Lions Eumetopias Jubatus in Alaska written by Morgen Crow and published by . This book was released on 2001 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ethology and Behavioral Ecology of Otariids and the Odobenid written by Claudio Campagna and published by Springer. This book was released on 2022-06-05 with total page 672 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is focused on the marine mammalian groups the Otariidae and the Odobenidae, otherwise known as fur seals, sea lions and the walrus. In 30 chapters, more than 60 authors from 30 institutions and 13 nationalities, discuss a broad suite of topics from maternal care and mating behavior, through play, cognition and personality, to adaptation to life in the Anthropocene. The authors explore the behaviors that have allowed these semi-aquatic mammals to thrive in the marine realm. Many populations have recovered following historical decimation, with interesting evolutionary consequences which are explored. Detailed, selected, individual species descriptions are also provided, showcasing the behavioral diversity of this engaging, adaptive and highly successful group of marine mammals.

Download or read book Steller Sea Lion Research written by I. L. Boyd and published by . This book was released on 1995 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The decline of the Steller sea lion in the northeast Pacific written by M.A. PASCUAL and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Marine Mammals of the World A Comprehensive Guide to Their Identification written by Thomas Allen Jefferson and published by Elsevier. This book was released on 2011-08-29 with total page 589 pages. Available in PDF, EPUB and Kindle. Book excerpt: With coverage on all the marine mammals of the world, authors Jefferson, Webber, and Pitman have created a user-friendly guide to identify marine mammals alive in nature (at sea or on the beach), dead specimens “in hand , and also to identify marine mammals based on features of the skull. This handy guide provides marine biologists and interested lay people with detailed descriptions of diagnostic features, illustrations of external appearance, beautiful photographs, dichotomous keys, and more. Full color illustrations and vivid photographs of every living marine mammal species are incorporated, as well as comprehendible maps showing a range of information. For readers who desire further consultation, authors have included a list of literature references at the end of each species account. For an enhanced understanding of habitation, this guide also includes recognizable geographic forms described separately with colorful paintings and photographs. All of these essential tools provided make Marine Mammals of the World the most detailed and authoritative guide available! * Contains superb photographs of every species of marine mammal for accurate identification * Authors’ collective experience adds up to 80 years, and have seen nearly all of the species and distinctive geographic forms described in the guide * Provides the most detailed and anatomically accurate illustrations currently available * Special emphasis is placed on the identification of species in “problem groups, such as the beaked whales, long-beaked oceanic dolphin, and southern fur seals * Includes a detailed list of sources for more information at the back of the book.

Download or read book The Relationship of the Foraging Ecology of Steller Sea Lions Eumetopias Jubatus to Their Population Decline in Alaska written by Richard Merrick and published by . This book was released on 1995 with total page 438 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 768 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Pinnipeds and El Ni o written by Fritz Trillmich and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: El Niño is a meteorological and oceanographic phenomenon, which occurs at irregular intervals in the eastern tropical Pacific. Its most obvious characteristic is the warming of surface waters, which causes enormous disturbances of the marine environment. A severe Niño may also affect continental systems worldwide. This book gathers in a comprehensive way the information available on the effects of the exceptionally strong 1982-83 Niño on a group of marine mammals, the pinnipeds. It presents an analysis of the effects of environmental stress on the populations of top predators. Data and interpretations are based on a most unusual collection of long-term studies of pinniped population dynamics, behavior and ecology which spanned the El Niño event. The responses of pinniped populations to the El Niño disturbance of the marine ecosystem also has important implications for the management and conservation of marine mammal populations.

Download or read book The Empty Ocean written by Richard Ellis and published by Island Press. This book was released on 2013-03-19 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: In The Empty Ocean, acclaimed author and artist Richard Ellis tells the story of our continued plunder of life in the sea and weighs the chances for its recovery. Through fascinating portraits of a wide array of creatures, he introduces us to the many forms of sea life that humans have fished, hunted, and collected over the centuries, from charismatic whales and dolphins to the lowly menhaden, from sea turtles to cod, tuna, and coral. Rich in history, anecdote, and surprising fact, Richard Ellis’s descriptions bring to life the natural history of the various species, the threats they face, and the losses they have suffered. Killing has occurred on a truly stunning scale, with extinction all too often the result, leaving a once-teeming ocean greatly depleted. But the author also finds instances of hope and resilience, of species that have begun to make remarkable comebacks when given the opportunity. Written with passion and grace, and illustrated with Richard Ellis’s own drawings, The Empty Ocean brings to a wide audience a compelling view of the damage we have caused to life in the sea and what we can do about it. "

Download or read book Population Dynamics of Steller Sea Lions Eumetopias Jubatus in the Eastern Gulf of Alaska written by John Michael Maniscalco and published by . This book was released on 2015 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: Steller sea lions (Eumetopias jubatus) were listed as endangered following a collapse of the western population beginning in the late 1970s. Low juvenile survival and reduced reproductive rates (natality) have been implicated as important factors in the decline. I conducted separate mark-recapture analyses to estimate juvenile survival and natality in an area of the western population where Steller sea lions have begun to show signs of recovery since the early 2000s. I then used these vital-rate estimates in a population matrix to estimate the strength of the recovery and assess which rates pose the greatest threats to recovery. First year survival was estimated at 80% for both males and females, but second-year survival dropped to a low of 40.6% for males and 64.2 % for females that were weaned at age 1. In contrast, survival was greatly improved (88.2%) for males and females that continued to suckle between ages 1 and 2. Cumulative survival to age 4 was double (35.7%) that estimated during the population decline. Natality was also higher in recent years (70%) than during the height of the decline in the 1980s (55%). The mean rate of population growth, based on matrix modeling of vital rates estimated in this study, was 4.1% per year between 2003 and 2013. By projecting these trends into the future, I estimated that the population in the study area may be fully recovered within 14 years, if density independent growth is to be expected in the near future. If density dependent factors come into play, the population will need another 37 years to fully recover. As would be expected from a long-lived, K-selected species, population growth rate was most sensitive to variation in adult survival, less sensitive to juvenile survival, and least sensitivity to natality. The findings of this study have important implications for Steller sea lion population management and suggest research priorities should be shifted from an emphasis on natality to an emphasis on survival rates and causes of mortality.