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Author: National Research Council Publisher: National Academies Press ISBN: 0309168724 Category : Science Languages : en Pages : 216
Book Description
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.
Author: National Research Council Publisher: National Academies Press ISBN: 0309168724 Category : Science Languages : en Pages : 216
Book Description
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.
Author: United States. Congress. House. Committee on Resources. Subcommittee on Fisheries Conservation, Wildlife, and Oceans Publisher: ISBN: Category : Technology & Engineering Languages : en Pages : 132
Author: Fritz Trillmich Publisher: Springer Science & Business Media ISBN: 3642763987 Category : Science Languages : en Pages : 299
Book Description
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.
Author: Fred D. Singer Publisher: Cambridge University Press ISBN: 1316445321 Category : Nature Languages : en Pages : 721
Book Description
Taking a fresh approach to integrating key concepts and research processes, this undergraduate textbook encourages students to develop an understanding of how ecologists raise and answer real-world questions. Four unique chapters describe the development and evolution of different research programs in each of ecology's core areas, showing students that research is undertaken by real people who are profoundly influenced by their social and political environments. Beginning with a case study to capture student interest, each chapter emphasizes the linkage between observations, ideas, questions, hypotheses, predictions, results, and conclusions. Discussion questions, integrated within the text, encourage active participation, and a range of end-of-chapter questions reinforce knowledge and encourage application of analytical and critical thinking skills to real ecological questions. Students are asked to analyze and interpret real data, with support from online tutorials demonstrating the R programming language for statistical analysis.
Author: National Research Council
Author: National Research Council
Author: United States. Congress. House. Committee on Resources. Subcommittee on Fisheries Conservation, Wildlife, and Oceans
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Author: Fritz Trillmich
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Author: Fred D. Singer