Organochlorines In Steller Sea Lions (Eumetopias Jubatus)

Thesis (Ph.D.) University of Alaska Fairbanks, 2009Existing populations of Steller sea lions (Eumetopias jubatus ) have declined precipitously over the last half-century. Investigations into the cause of this downward trend have focused on many different possible factors. Toxicity caused by the accumulation of organochlorines (OCs), such as polychlorinated biphenyls (PCBs) and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane or dichlorodiphenyltrichloroethane (DDT), has been demonstrated in marine mammals and was considered here as one possible factor that may have contributed to the decline of Steller sea lions or their failure to recover. The focus of this project was to investigate the relationship of contaminant loads to hormone levels, specifically thyroid hormones and cortisol in Steller sea lions. Two approaches were taken to this study. Firstly, baseline hormone concentrations were identified for the thyroid hormones, thyroxine (T 4) and triiodothyronine (T3), and cortisol. This involves comparison and extrapolation. Secondly, possible risk effects were examined by comparing levels of OCs in captive and free-ranging Steller sea lions to known effects in related species with known physiological thresholds. Serum concentrations of total T4 were highest in Steller sea lions followed by total T3 concentrations. Concentrations of free T4 and free T3 were three to four orders of magnitude lower. Concentrations for all four thyroid hormone measurements tended to a lower level as animals matured beyond the neonatal stage. When thyroid hormones from captive sea lions were evaluated across seasons, all thyroid hormones were highest in the July to September period. Cortisol concentrations were similar in male and female pups. Cortisol varied with age but when considered in regards to time of year when sampled, followed a seasonal pattern. Cortisol was elevated in fall months in captive sea lions (non-pups), which is similar to what is seen in other marine mammals and is likely associated with the annual molt. Male pups from Alaska had lower levels of SigmaPCBs and SigmaDDT when compared to male pups from Russia. Female pups from Alaska were significantly lower in SigmaPCBs than Russian female pups as were female pups for SigmaDDT levels between areas. Anywhere from 12 to 64% (depending on rookery) of Steller sea lion pups investigated for contaminants had concentrations of SigmaPCBs that are high enough to cause physiological problems. Concentrations in blood taken monthly for 2 years in three captive Steller sea lions were similar at any given sampling time and followed a seasonal pattern with levels significantly higher in the summer months of July to September and lower in the three month winter period January to March. Concentrations of OCs in blubber samples collected quarterly for the captive females followed an analogous pattern to blood samples but the captive male sea lion was considerably lower and declined over the study period. A significant relationship between blubber contaminants and lipids was noted in the three captive Steller sea lions. Even though OC contamination has not been hypothesized to be the primary factor that precipitated the population decline, there is a potential for these chemicals to have a negative effect on the health of free-ranging Steller sea lions. These data suggest that concentrations of OCs in Steller sea lions may be high enough to cause endocrine or reproductive dysfunction and could potentially impact fertility or fecundity. Therefore, OC contaminants can not be dismissed as a contributing source to either the decline or the failure to recover of the Steller sea lion population

Effects of organohalogen contaminants on Steller sea lion survival and female reproduction in the Russian Far East

Thesis (M.S.) University of Alaska Fairbanks, 2013The presence of persistent organohalogen contaminants (OCs) in the habitats of Steller sea lions, Eumetopias jubatus, may influence reproductive rates and possibly survival. The lack of recovery and the reduction in natality for the western stock has no apparent cause and OCs may be potential contributing factors. Among the most common synthetic OCs measured in marine mammal tissues are polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethane (DDT), polybrominated diphenyl ethers (PBDEs), and hexachlorobenzene (HCB). This project's focus was on the relationship between OCs and the western stock's lack of recovery. A suite of OCs were quantified from 239 hot-branded pups from 2001-2007 at nine Russian Far East rookeries. The use of brand-resighting data provided the opportunity to contrast pup survival, movement, reproductive success, and age at first reproduction between rookeries and among individuals with varying post-natal loads of OCs. Survival and movement were not affected by OC concentrations, but the estimated probability of survival within the first year was lower than expected at some rookeries. The effects of OCs on reproduction were less clear and no consistent pattern of negative effects emerged. Rookery specific differences indicated that location may be an important variable when considering survival, movement, and reproduction

Fasting status of Steller sea lion pups

Thesis (M.S.) University of Alaska Fairbanks, 2021Following population declines in species of concern, wildlife managers often seek to identify underlying causes to understand and predict population dynamics for better future management. Often, physiological and/or behavioral metrics are measurable markers of decline, and these are often detectable well before declines are measurable through population surveys. During the 1970's, 80's, and 90's Steller sea lion (SSL; Eumetopias jubatus) populations in the western portion of their breeding range declined by ~85%. Though declines in most regions have since stabilized or exhibited modest recovery, some subpopulations breeding in the Aleutian Islands continue to decline. In contrast, SSL subpopulations in eastern regions of their range have steadily grown since the 1970s. Prior studies on the maternal attendance behaviors of SSL have noted differences in the timing of parturition, the duration of the perinatal period, foraging trip duration of nursing females, and the duration of periods dams spend ashore tending their pups. Variability in these metrics has been associated with year, location, the dam's age and parity, environmental oscillations (i.e. El Niño Southern Oscillation), and pup age over the lactation period. This study utilized prior findings of predictable changes in metabolite concentrations while pups fasted during their mother's foraging trips as a new approach for assessing maternal attendance patterns. The distributions of fasting phase categories, assigned based on the relative concentrations of plasma betahydroxybutyrate and blood urea nitrogen, were compared across 12 subpopulations extending from eastern Russia along the coastal northern Pacific into southeastern Alaska from blood samples of 1528 SSL pups. Fasting phase categories were merged into Short and Long fasting durations to compare pups sparing critical proteins (relying on lipid reserves) to those with plasma profiles indicative of metabolic protein reliance (muscle & organ breakdown), respectively. Notably the subpopulations with the maximal (western Aleutian Islands) and minimal (eastern Aleutian Islands) observed proportions of Long fasting pups were in the same broad Aleutian Island region. Three metapopulations had significantly greater proportions of Long fasting pups: the western and central Aleutian Islands and the southern portion of southeastern Alaska. Due to contrasting population trends among these metapopulations, we suggest that both density-dependent and density-independent factors contributed to extended fasting durations in SSL pups.Chapter 1: General introduction -- 1.1. Maternal attendance metrics -- 1.1a. Parturition timing -- 1.1b. Perinatal period -- 1.1c. Foraging trip duration -- 1.1d. Shore visit duration -- 1.2. Pup fasting -- 1.3. Summary -- 1.4. References. Chapter 2: Fasting status of free-ranging Steller sea lion pups -- Abstract -- 2.1. Introduction -- 2.1a. Background -- 2.1b. Biomarkers of metabolic status -- 2.1c. Distinctions among fasting phases -- 2.1d. Study importance -- 2.2. Methods -- 2.2a. Study area -- 2.2b. Sample collection -- 2.2c. Metabolite assays -- 2.2d. Fasting phase categorization -- 2.2e. Data selection -- 2.2f. Body condition indices -- 2.2g. Data analysis -- 2.3. Results -- 2.3a. Within-phase comparisons -- 2.3b. Binomial model of fasting duration -- 2.4. Discussion -- 2.4a. Potential drivers for extended foraging trip durations -- 2.4b. Alternate interpretation of increased dam foraging effort -- 2.4c. Future directions -- 2.5. Conclusions -- 2.6. Ethics statement -- 2.7. Funding -- 2.8. References. Chapter 3: General conclusions -- 3.1. Study significance -- 3.2. Study contributions -- 3.3. Future research directions -- 3.4. Summary -- 3.5. References -- Appendix assessment of a point-of-care ketometer for sea-lion blood and plasma

Endocrine And Immune Profiles Of Immature Pinnipeds

Thesis (Ph.D.) University of Alaska Fairbanks, 2011There is increasing interest in assessing the health of individuals and populations of pinnipeds found in the North Pacific, primarily due to population declines leading to conservation concerns. This study assessed the "health" of animals by quantifying hormones associated with fat mass (leptin), lipid and water metabolism (cortisol and aldosterone), and growth and metabolism (thyroxine and triiodothyronine) as well as circulating total and differential leukocyte counts and in vitro proliferation of peripheral blood mononuclear cells (PBMC). Body mass and condition are influenced by an individual's disease and nutritional state. Glucocorticoids are known to affect the immune system and may be stimulated by a multitude of factors. I hypothesized that age or body mass would influence leukocyte counts, PBMC proliferation, and hormone concentrations in Steller sea lion (Eumetopias jubatus) pups and that the response of cortisol to an acute stressor would impact immune parameters in juvenile harbor seals (Phoca vitulina ). Further, given the inherent requirements of disturbance and animal handling necessary for sampling pinnipeds, the impact of these activities on endocrine and immune profiles was assessed. Total white blood cell (WBC) counts, neutrophil counts and T cell proliferation decreased with increasing age in Steller sea lion pups. However, no relationship between body condition index and circulating concentration of hormones quantified was detected. Circulating concentrations of cortisol, thyroxine, and triiodothyronine were influenced by the rookery disturbance. However, the variation attributed to the disturbance was low and did not alter total or differential WBC counts or in vitro proliferation of PBMC. In harbor seals, cortisol and aldosterone concentrations increased following an acute stressor which resulted in a stress leukogram. Total WBC decreased driven primarily by the decrease in neutrophil counts with simultaneous increase in lymphocytes leading to an overall decrease in neutrophil to lymphocyte ratio. These findings highlight the endocrine system's influence on the immune system in immature pinnipeds

Toxicodistribution of mercury and selenium in pinnipeds of Alaska

This study is divided into two major parts (chapters) in order to better understand mercury (Hg) and selenium (Se) tissue distribution in pinnipeds. The first part of the study focuses on determining total mercury ([THg]) and selenium ([TSe]) concentrations (mass and molar based) among cardiac and renal tissues of ice seals (focus on bearded seals, Erignathus barbatus) as compared to the more traditionally analyzed tissues (e.g. liver, skeletal muscle). Determining Hg distribution within these tissues is essential in establishing sampling methods for biomonitoring, histopathology and biochemistry of Hg. Age was determined to be an important driver of [THg] and Se:Hg molar ratios in heart and kidney. In bearded seals [THg] varied by heart region and therefore future studies should use consistent sampling methods in order to determine and compare [THg]. Despite the differences in seal kidney structure when compared to many terrestrial mammals, the kidney cortex was the main accumulation site for Hg within the kidney of bearded seals and requires consideration in sampling designs. Se:Hg molar ratios greater than 1 in all tissues can be considered a baseline for normal Se concentrations under relatively low [THg]. The second part of the study focuses on THg and TSe distribution in Steller sea lion (Eumetopias jubatus) pup tissues in addition to THg tissular and body burdens. Hair had the highest [THg] in all 5 Steller sea lion pups as compared to other tissue compartments. Since these pups were 1-2 months of age, the hair (lanugo) sampled was a good indicator of Hg exposure via maternal placental transfer (in utero) and potentially a good indicator of individual THg tissue burdens. The percent of total Hg body burden for many organs in Steller sea lion pups was similar to that found in Pacific harbor seals. The Se:Hg molar ratios were between 1 and 50 in all tissues of 4 of the 5 pups while the pup with the highest [THg] in all tissues, had Se: Hg molar ratios of 0.7 or less in 9 of 14 tissues indicating that this animal may have limited Se-dependent protection related to Hg toxicosis.General introduction -- Mercury in the environment -- Mercury toxicology -- Antioxidants: emphasis on Se -- Mercury and piscivorous marine mammals -- Thesis objectives -- Chapter 1: Mercury and selenium in heart, kidney, skeletal muscle and liver of ice seals from Alaska: focus on bearded seals -- Chapter 2: Assessment of mercury tissular and body burden and selenium concentrations in 5 Steller sea lion pups from the Aleutian Islands -- General conclusion

Variability In Population Trends, Life History Characteristics, Amd Milk Composition Of Northern Fur Seals In Alaska

Thesis (M.S.) University of Alaska Fairbanks, 2012The northern fur seal population on the Pribilof Islands has been declining since the 1960s and is now less than 30% of its former size. Chapter 1 examines factors that might cause a population to decrease to such an extent and concludes that only nutritional limitation caused by climate change or commercial fisheries, predation by killer whales, or a combination of factors that includes conditions in the North Pacific during the winter were possible explanations. Chapter 2 reports the seasonal patterns in proximate composition of fur seal milk between St. Paul Island (one of the Pribilof Islands) and Bogoslof Island (an increasing population) to understand the energy requirements of lactation and the energetics of pup growth and body condition at weaning. Factors that caused variability in milk composition included days postpartum, time ashore, individual phenotype, island and preceding trip duration. Average milk lipid increased from 45.5+/-0.7% to 53.8+/-1.0% at St. Paul and from 45.8+/-0.7% to 57.3+/-0.8% at Bogoslof between July and October, while average milk protein remained relatively stable ranging between 10.0% and 10.5%. The lipid content of northern fur seal milk near peak lactation is the highest reported among otariid seals and among the highest known for all mammals

Assessment of Heavy Metals in Subsistence-Harvested Alaskan Marine Mammal Body Tissues and Vibrissae

The coastal, indigenous communities around Alaska have subsisted on marine animals for generations, often focusing on large apex predators such as seals, sea lions, and whales. Three species of pinnipeds (harbor seal, Steller sea lion, northern fur seal) and the northern sea otter have all undergone significant population declines since the 1970s, some regions more than others. Archived vibrissae (whiskers) and body tissues from these four species were available from the Bering Sea and throughout the Gulf of Alaska from the 1990s and early 2000s. Tissues from these species are exceedingly difficult to obtain; thus, the archived tissues provided a finite and irreplaceable resource of data. Analysis of these archived tissues indicates which species, tissues, and gender bioaccumulate metals more readily. In this study twelve heavy metals (arsenic, cadmium, chromium, cobalt, copper, lead, manganese, mercury, nickel, selenium, vanadium, zinc) were analyzed in vibrissae from the four select species, and in body tissues from harbor seals and Steller sea lions. The samples were collected from three regions (southeastern, southcentral, and southwestern Alaska) during the 1990s through early 2000s. Significant differences of heavy metal concentrations in vibrissae were detected among elements (p2(110) = 454.81, p2(66) = 310.88,

Assessing Mercury Levels, Health Metrics, and Immune Function in Non-stranded Male California and Steller Sea Lions in Oregon

California and Steller sea lions (Zalophus californianus, Eumetopias jubatus, respectively) are considered sentinel species because they have long life spans, are long-term coastal residents, feed at high trophic levels, and have large blubber stores that serve as depots for anthropogenic toxicants. There are few studies on sea lion health and immune function in apparently healthy sea lions, in part due to the Marine Mammal Protection Act, which limits research on non-stranded animals. In this study, we characterized general health, immune function, and biomarkers for mercury exposure in 48 non-stranded male California (n=29) and Steller (n=19) sea lions sampled from Bonneville Dam and Willamette Falls in the Columbia River Basin. Among California sea lions, we also investigated whether urogenital cancer lesions were associated with immune function and mercury exposure. We optimized several new health and immune assays in sea lions and also found that health and immune measurements differed between non-stranded, apparently healthy male California and Steller sea lions. California sea lions had higher packed cell volume, total protein, eosinophils, neutrophils, monocytes, bilirubin, creatine kinase, alkaline phosphatase, T4, and potassium compared to Steller sea lions while Steller sea lions had higher weight, length, albumin, c-glutamyltransferase, alanine aminotransferase, IFN gamma stimulated by Con A, and TNF alpha stimulated by Con A compared to California sea lions (Wilcoxon rank sum test, p< 0.05). Steller sea lions also had higher whisker total mercury, fur total mercury, blood total mercury, blood methylmercury, and estimated blood inorganic mercury compared to California sea lions (Wilcoxon rank sum test, p< 0.001 for all). Of the 29 California sea lions, packed cell volume, cholesterol, blood eosinophils, whisker total mercury, blood total mercury, and estimated blood inorganic mercury were associated with urogenital lesions. This study highlights new lab assays that can be used to better understand pinniped health, including physiological responses to urogenital cancer

Determining the immune status of Steller sea lions (Eumetopias jubatus): an environmental agents of disease perspective

Dissertation (Ph.D.) University of Alaska Fairbanks, 2019The integrity of the immune system is paramount for preserving overall health for many organisms. Investigating environmental and physiological factors that may be associated with alterations of the immune status in non-traditional sentinel species, like the Steller sea lion (SSL), is a prominent undertaking in eco-immunology research. Changes to immune homeostasis likely impacts the health and survival of SSLs. Recent studies have reported that mercury concentrations in hair in 24 to 36% of newborn SSLs of the Western Aleutian Islands (WAI) exceed thresholds (>30 ppm) for potential adverse effects. Many of these individuals were from WAI rookeries that have historically experienced significant population declines with some slow to recover. Retrospective, and ongoing, analyses of mercury in lanugo coats (natal hair) from young pups of the WAI demonstrate in utero exposure to relatively high levels of mercury during late gestation. Therefore, this dissertation focuses on the notion that dietary acquired mercury could potentially alter immune response in SSLs, especially young pups, and may contribute to the lack of recovery from population declines. In order to gain an understanding of the potential for mercury to adversely affect the immune response of SSLs, selected aspects of immunity were measured (blood cell counts, haptoglobin, immunoglobulins, and cytokines) and investigated within the context of body condition, age, mercury exposure and regional population dynamics. In Chapter Two, the acute phase response protein, haptoglobin, was found to vary significantly with age and region. Individual SSL pups with greater concentrations of mercury had lower predicted concentrations of haptoglobin. In Chapter Three, a colorimetric protein A enzyme-linked immunosorbent assay was modified for enhancing accurate measurement of immunoglobulin concentrations in SSL serum. This improved methodology was then used in Chapter Four for comparing immunoglobulins in young developing SSL pups and dams as a measure of maternal investment of immunity among different rookeries. Lastly, Luminex multiplex technologies were employed for quantifying cell-signaling proteins (cytokines) in SSL serum to compare associations among rookery pups in Chapter Five. Although mercury concentrations in some individuals exceed adverse effects thresholds that are defined for other mammals, no statistically significant associations were found between immunoglobulins and cytokines relative to mercury concentrations in young developing pups. These thesis chapters provide a powerful baseline and improved methods for ongoing and future assessments of haptoglobin, immunoglobulins, and cytokines (combined with traditional hematologic measures) observed in young developing SSL pups in regions experiencing population decline when compared with rookeries with stable or increasing pup production. Some of these findings, especially for haptoglobin, are indicative of alterations in immune status in young SSL pups born to dams from different natal rookeries with higher mercury exposure. Understanding the cause of the differences in the immune status of young SSLs will require additional assessments of the maternal-fetal interface of immunity and other factors like nutrition, metabolic status, and infectious disease that may shape neonatal immunity leading to the regional differences observed.Chapter 1 - Introduction -- Chapter 2 - Regional and age-related variations in haptoglobin concentrations in Steller sea lions (Eumetopias jubatus) from Alaska -- Chapter 3 - Enhanced quantification of serum immunoglobulin G from a non-model wildlife species, the Steller sea lion (Eumetopias jubatus), using a protein A ELISA -- Chapter 4 - Temporal and regional variation in maternal investment of immunity and in utero mercury exposure in Steller sea lions (Eumatopias jubatus) from Alaska -- Chapter 5 - Regional variations in cytokine profiles and in utero mercury exposure in Steller sea lions (Eumetopias jubatus) -- Chapter 6 - Conclusions