University of Alaska Anchorage
Julie Graduated in May 2004 with a MS of Biological Sciences.
Thesis:
Ontogeny of Total Body Oxygen Stores and Aerobic Dive Potential in Steller Sea Lions (Eumetopias jubatus)
Marine mammals rely on elevated total body oxygen stores (TBO2) to significantly enhance the amount of time they can remain submerged to forage. However, since neonatal MM generally lack the physiological adaptations that permit long dives, juveniles must develop physiologically before they can become independent foragers. This study examined the physiological development of juvenile Steller sea lions (2-29mo) by measuring blood and muscle oxygen stores, and calculating aerobic dive limits. While all oxygen stores increased with age, blood developed faster than muscle, perhaps as a result of enhanced EPO production early in year 1. However, TBO2 stores did not reach adult female values until juveniles were 21 months of age, and never achieved adult male values. As a result, juvenile cADLs remained significantly lower than those of adults, suggesting that the physiology of juvenile Steller sea lions is immature and may constrain dive behavior well beyond 2 years.
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