Julie P Avery

University of Alaska Fairbanks · Water and Environmental Research Center (WERC)

Steller sea lion (Eumetopias jubatus) tissue mercury concentration increasingly above thresholds of concern occur in regions of Alaska where lack of population recovery is noted. Selenium‐monomethyl mercury interactions may mitigate toxicosis but may also result in functional selenium deficiency, impacting essential selenium‐dependent processes. Ph...

Mammals with increased requirements for adipose tissue stores, such as marine mammals, have altered nutrient allocation priorities compared to many terrestrial mammals and thus the physiological response to undernutrition (low nutritional status) and realimentation (refeeding) may differ. Key regulators of nutrient allocation and tissue specific gr...

Mercury (Hg) can be neurotoxic to mammals and impact reproduction, whereas selenium (Se) is an important antioxidant known to ameliorate some adverse effects of Hg. Total Hg concentrations ([THg]) were measured in lanugo (pelage grown in utero) of 812 Steller sea lion (Eumetopias jubatus) pups across Alaska and Russia to assess fetal exposure durin...

The nutritive components of breast milk are well studied including the macronutrients, protein, lipid, and carbohydrates, as well as micronutrients such as vitamins and minerals. Recently, greater research attention has turned to other bioactive molecules found in milk that may play a significant non-nutritive role in normal infant development. Lon...

Female Weddell seals (Leptonychotes weddellii) undergo rapid fluctuations in mass and body condition (% lipid) during the summer in association with reproduction and molt, but the physiological regulation of these changes is poorly understood. Recently, we determined that post-partum females rapidly deposit lean mass across summer after they wean t...

Most organisms undergo changes in their environment, both predictably and unpredictably, which require them to alter priorities in nutrient allocation with regards to food availability. Species that more predictably encounter extended periods of limited food resources or intake while mitigating the negative effects of starvation are considered to b...

Steller sea lion (Eumetopias jubatus) young-of-the-year (YOY) are nutritionally dependent upon their dam through the majority of their first year. Several indices of body condition were measured in YOY 1.5-9 mo of age captured in Southeast Alaska (n = 122), the Gulf of Alaska (n = 182), and the Aleutian Islands (n = 38) to test the hypothesis that...

Seasonal changes in light, temperature, and food availability stimulate a physiological response in an animal. Seasonal adaptations are well studied in Arctic, Sub-Arctic, and hibernating mammals; however, limited studies have been conducted in sub-tropical species. The Florida manatee (Trichechus manatus latirostris), a sub-tropical marine mammal,...

Reproductive success can be influenced by maternal physiological condition at the time of embryo implantation and by foraging success during gestation. Polar marine mammals experience drastic fluctuations in body composition (lipid stores) as a result of life history events and large-scale changes in seasonal productivity and environmental conditio...

Fluctuations in availability of prey resources can impede acquisition of sufficient energy for maintenance and growth. By investigating the hormonal mechanisms of the somatotropic axis that link nutrition, fat metabolism, and lean tissue accretion, we can assess the physiological impact of decreased nutrient intake on growth. Further, species that...

The metabolic hormones, growth hormone (GH) and insulin-like growth factor (IGF)-I, together with IGF binding proteins (IGFBP), have been well studied in domestic species and are the primary components of the somatotropic axis. This hormone axis is responsive to nutrient intake, associated with growth rate, and accretion of protein and adipose. How...

Feeding fish to captive piscivores can be challenging owing to cost, availability, variability in nutrient, and caloric composition, as well as handling and storage concerns. This trial evaluated the response of three belugas to being fed Fish Analog, an alternative to frozen fish. Body condition, gut transit time, serum chemistry and metabolic hor...

Physiological responses to changes in energy balance are tightly regulated by the endocrine system through glucocorticoids, IGF-I and thyroid hormones. Changes in these hormones were studied in eight captive female Steller sea lions that experienced changes in food intake, body mass, body composition, and blood metabolites during summer and winter....

Growth hormone (GH) is a homeorhetic hormone that coordinates diverse physiological processes to partition nutrients toward lean tissue accretion and milk production, and to inhibit utilization of nutrients by adipose tissue, especially during periods of energy deficiency. Due to age-related declines in GH, GH is negatively correlated with overall...

The somatotropic axis, including growth hormone (GH), insulin-like growth factor (IGF)-I, and IGF binding proteins (IGFBP), is a bridge between growth physiology, developmental age, and nutritional status in domestic animals. However, the importance of the somatotropic axis in nutrition, growth, and development of harbor seals has not been previous...

The somatotropic axis, including growth hormone, insulin-like growth factor (IGF)-I and IGF binding proteins, is a bridge between growth physiology, sex, developmental age and nutritional status in domestic animals. However, the importance of the somatotropic axis in growth and development of marine mammals has not been previously explored. Further...

Two key factors influence the diving and hence foraging ability of marine mammals: increased oxygen stores prolong aerobic metabolism and decreased metabolism slows rate of fuel consumption. In young animals, foraging ability may be physiologically limited due to low total body oxygen stores and high mass specific metabolic rates. To examine the de...

The hormone erythropoietin (EPO) is responsible for the increased production of red blood cells (RBC) in response to tissue hypoxia. While the role of EPO in hematological development has been established in humans and terrestrial mammals, this relationship has never been examined in marine mammals that rely heavily on stored oxygen to maintain aer...

The hormone erythropoietin (EPO) is responsible for the increased production of red blood cells (RBC) in response to tissue hypoxia. While the role of EPO in hematological development has been established in humans and terrestrial mammals, this relationship has never been examined in marine mammals that rely heavily on stored oxygen to maintain aer...

Lactating marine mammals provision their offspring either by providing large amounts of lipid-rich milk over a short period during which females fast (capital provisioning), or smaller amounts of less energetically dense milk over an extended period during which females forage (income provisioning). While it has long been recognized that these two...