2 resultados para Photographically illustrated books -- Juvenile.

em DigitalCommons@University of Nebraska - Lincoln


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Gray whales are coastal migratory baleen whales that are benthic feeders. Most of their feeding takes place in the northern Pacific Ocean with opportunistic feeding taking place during their migrations and residence on the breeding grounds. The concentrations of organochlorines and trace elements were determined in tissues and stomach contents of juvenile gray whales that were taken on their Arctic feeding grounds in the western Bering Sea during a Russian subsistence harvest. These concentrations were compared to previously published data for contaminants in gray whales that stranded along the west coast of the US during their northbound migration. Feeding in coastal waters during their migrations may present a risk of exposure to toxic chemicals in some regions. The mean concentration (standard error of the mean, SEM) of Σ PCBs [1400 (130) ng/g, lipid weight] in the blubber of juvenile subsistence whales was significantly lower than the mean level [27 000 (11 000) ng/g, lipid weight] reported previously in juvenile gray whales that stranded in waters off the west coast of the US. Aluminum in stomach contents of the subsistence whales was high compared to other marine mammal species, which is consistent with the ingestion of sediment during feeding. Furthermore, the concentrations of potentially toxic chemicals in tissues were relatively low when compared to the concentrations in tissues of other marine mammals feeding at higher trophic levels. These chemical contaminant data for the subsistence gray whales substantially increase the information available for presumably healthy animals.

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Thundering herds of bison have become synonymous with the pre-European colonization of the Great Plains. As such, they have captured the imagination of countless people, including Wes Olson, a 20-year warden for Parks Canada. Throughout Portraits of the Bison, based on both existing literature and the author's extensive experience observing and managing these animals, Olson's bison fascination is not only obvious but infectious. A remarkably talented artist as well, Olson's line drawings appear throughout the book, accompanied by Johane Janelle's photographs.