ASSESSING THE PHYSIOLOGICAL STATUS OF NORTHERN FUR SEAL POPULATIONS IN NORTH AMERICA WITH FECAL HORMONES
ii The core breeding population of northern fur seals (Callorhinus ursinus) in North America has declined significantly since the 1980s on St. Paul Island (one of the Pribilof Islands) while the smaller nearby population at Bogoslof Island (eastern Bering Sea) has increased exponentially. Further so...
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| Format: | Text |
| Language: | English |
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2012
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.663.51 http://www.marinemammal.org/wp-content/pdfs/ubc_2012_atwood_elizabeth.pdf |
| Summary: | ii The core breeding population of northern fur seals (Callorhinus ursinus) in North America has declined significantly since the 1980s on St. Paul Island (one of the Pribilof Islands) while the smaller nearby population at Bogoslof Island (eastern Bering Sea) has increased exponentially. Further south, the population of northern fur seals on San Miguel Island off the coast of Southern California has fluctuated between exponential growth and catastrophic declines associated with re-occurring El Nino events. The goal of my thesis was to asses the physiological status of these three breeding populations of northern fur seals in North America to determine whether nutritional differences could explain the different population trajectories. I collected fecal samples (scats) in July 2009 from these three islands and measured the fecal metabolites of two hormones — a glucocorticoid associated with the stress response, and triiodothyronine (T3), a thyroid hormone associated with metabolic rate. I also assessed feeding conditions using diet and foraging data. I found that |
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