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Physical Sciences and Mathematics Commons™
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Articles 1 - 3 of 3
Full-Text Articles in Physical Sciences and Mathematics
Social Network Correlates Of Food Availability In An Endangered Population Of Killer Whales, Orcinus Orca, Emma A. Foster, Daniel W. Franks, Lesley J. Morrell, Ken C. Balcomb, Kim M. Parsons, Astrid Van Ginneken, Darren P. Croft
Social Network Correlates Of Food Availability In An Endangered Population Of Killer Whales, Orcinus Orca, Emma A. Foster, Daniel W. Franks, Lesley J. Morrell, Ken C. Balcomb, Kim M. Parsons, Astrid Van Ginneken, Darren P. Croft
United States Department of Commerce: Staff Publications
For the majority of social species, group composition is dynamic, and individuals are interconnected in a heterogeneous social network. Social network structure has far-reaching implications for the ecology of individuals and populations. However, we have little understanding of how ecological variables shape this structure. We used a long-term data set (1984e2007) to examine the relationship between food availability and social network structure in the endangered southern resident killer whales. During the summer months individuals in this population feed primarily on chinook salmon, Oncorhynchus tshawytscha, which show annual variation in abundance. We tested the hypothesis that temporal variation in chinook …
Winter And Summer Upwelling Modes And Their Biological Importance In The California Current Ecosystem, Bryan A. Black, Isaac D. Schroeder, William J. Sydeman, Steven J. Bograd, Brian K. Wells, Franklin B. Schwing
Winter And Summer Upwelling Modes And Their Biological Importance In The California Current Ecosystem, Bryan A. Black, Isaac D. Schroeder, William J. Sydeman, Steven J. Bograd, Brian K. Wells, Franklin B. Schwing
United States Department of Commerce: Staff Publications
Analysis of monthly coastal upwelling intensities revealed two seasonal and biologically relevant upwelling ‘modes’ in the California Current Ecosystem (CCE). The first mode reflected upwelling during the summer months and was characterized by low-frequency (multidecadal) processes, including significant (Po0.01) linear trends at some latitudes. In contrast, the second mode reflected wintertime upwelling and was defined by higher-frequency variability associated with the North Pacific High and El Niño Southern Oscillation events. These modes were compared with multidecadal time series of splitnose rockfish (Sebastes diploproa) otolith growth, yelloweye rockfish (S. ruberrimus) otolith growth, Chinook salmon (Oncorhynchus tshawytscha …
Relating Results Of Chronic Toxicity Responses To Population-Level Effects: Modeling Effects On Wild Chinook Salmon Populations, Julann A. Spromberg, James P. Meador
Relating Results Of Chronic Toxicity Responses To Population-Level Effects: Modeling Effects On Wild Chinook Salmon Populations, Julann A. Spromberg, James P. Meador
United States Department of Commerce: Staff Publications
Standard toxicity tests assess the physiological responses of individual organisms to exposure to toxic substances under controlled conditions. Time and space restrictions often prohibit the assessment of population-level responses to a toxic substance. Compounds affecting various toxicity endpoints, such as growth, fecundity, behavior, or immune function, alter different demographic traits and produce different impacts on the population. Chronic effects of immune suppression, reproductive impairment, and growth reduction were examined using life history models for Chinook salmon (Oncorhynchus tshawytscha). Modeled immune suppression acted through reductions in age-specific survival, with first- and secondyear survival producing the greatest changes in the …