Tracking reproductive events: Hoof growth and steroid hormone concentrations in hair and hoof tissues in moose ().

Measurements of reproductive and stress-related hormones in keratinous tissues (e.g. hair, claws, hooves, baleen) can provide a record of stress and reproductive response in wildlife.

Regional, seasonal and age class blubber fatty acid signature analysis of harbour seals in Alaska from 1997 to 2010.

Alaskan harbour seal populations are currently listed as a species of special concern. Although there is evidence of recent stabilization or even partial recovery of harbour seal numbers in areas of historic decline, most populations have not made substantial recoveries. To date, few data exist regarding spatial and seasonal changes in blubber fatty acids (FAs) for Alaskan harbour seal populations.

Whiskers as a novel tissue for tracking reproductive and stress-related hormones in North Pacific otariid pinnipeds.

Keratinized tissues, including whiskers, are ideal for acquiring a record of physiological parameters. Most tissues provide a snapshot of physiological status; however, whiskers may support longitudinal sampling for reproductive and stress-related hormones, if hormones are incorporated as whiskers grow and concentrations change with physiological state. Whiskers from female Steller sea lions () and northern fur seals () were serially sectioned and pulverized and steroid hormones were extracted.

Stress-related and reproductive hormones in hair from three north Pacific otariid species: Steller sea lions, California sea lions and northern fur seals.

Assessing the physiological impact of stressors in pinnipeds is logistically challenging, and many hormones are altered by capture and handling, limiting the utility of metabolically active tissues. Hair is increasingly being used to investigate stress-related and reproductive hormones in wildlife populations due to less-invasive collection methods, being metabolically inert once grown and containing multiple biomarkers of ecological interest. We validated enzyme immunoassays for measuring aldosterone, cortisol, corticosterone, and testosterone in lanugo (natal hair grown ) samples collected from Steller sea lions (), California sea lions (), and northern fur seals ().

Organochlorine contaminant concentrations in blubber of young Steller sea lion (Eumetopias jubatus) are influenced by region, age, sex, and lipid stores.

Contaminant exposure is particularly important for species and populations of conservation concern, such as the Steller sea lion (Eumetopias jubatus). We used blubber samples (n = 120) to determine organochlorine concentrations, including polychlorinated biphenyls (PCBs) and dichloro-diphenyl-trichloroethane (DDTs), and blood samples (n = 107) to estimate total body lipids based on the hydrogen isotope dilution method. We assessed the influence of age, sex, condition, and geographic area on contaminant concentrations in blubber and contaminant body load.

Organochlorine contaminant concentrations in multiple tissues of free-ranging Steller sea lions (Eumetopias jubatus) in Alaska.

The relationships of selected organochlorine (OC) contaminants between blubber, blood, feces, and milk of young, free-ranging Steller sea lions (Eumetopias jubatus) were examined. Both between and within each tissue there was considerable individual variation. In spite of the variation, similar patterns were observed across the tissues for most of the selected PCB congeners.

Endocrine and immunological responses to adrenocorticotrophic hormone (ACTH) administration in juvenile harbor seals (Phoca vitulina) during winter and summer.

There is increasing interest in measuring endocrine and immune parameters in free-ranging seals and sea lions, but there is a lack of understanding in how an acute stress response, often associated with capture and handling, influences these parameters of interest. The main objective of this study was to assess the impact of a simulated stressor on both endocrine and immune parameters. During two seasons, exogenous adrenocorticotrophic hormone (ACTH) was administered to seven female juvenile harbor seals and the response of several hormones (cortisol, aldosterone, total and free thyroxine and total triiodothyronine) and immunological parameters (total and differential leukocyte counts and peripheral blood mononuclear cells (PBMC) proliferation) were assessed.

Body condition and endocrine profiles of Steller sea lion (Eumetopias jubatus) pups during the early postnatal period.

Body condition indices have been useful in assessing the health of domestic and free ranging populations of terrestrial mammals. Given the high energy demand and rapid growth during the postnatal period of Steller sea lion (Eumetopias jubatus) (SSL) pups, body condition was expected to be related to concentrations of a suite of hormones (cortisol, aldosterone, thyroxine, triiodothyronine, leptin) previously associated with changes in body mass and composition in developing pinnipeds. Blood samples were collected from free ranging SSL pups of known ages and sex.

Steller sea lion (Eumetopias jubatus) pups undergo a decrease in circulating white blood cells and the ability of T cells to proliferate during early postnatal development.

Postnatal changes in circulating immune components and peripheral blood mononuclear cell (PBMC) proliferation were assessed in Steller sea lion pups (SSL; Eumetopias jubatus). Blood samples were collected for complete blood cell counts including total and differential white blood cell (WBC) counts from 46 pups ranging in age from 5 to 38 days old. Total WBC and neutrophil counts decreased in association with increased age of the pups.

Neuronal fiber composition of the corpus callosum within some odontocetes.

Odontocetes (toothed whales) evolved from terrestrial mammals approximately 55 million years ago and have since remained on a unique evolutionary trajectory. This study used formalin-fixed tissue and light microscopy to quantify the size and number of fibers along the corpus callosum of the bottlenose dolphin (n = 8). Two other species, the Amazon River dolphin (n = 1) and the killer whale (n = 1), were included for comparison.