Concentrations of mercury and polychlorinated biphenyls in blood of Southern Beaufort Sea polar bears (Ursus maritimus) during spring: variations with lipids and stable isotope (δ15N, δ13C) values

2011 ◽  
Vol 89 (11) ◽  
pp. 999-1012 ◽  
Author(s):  
Katrina K. Knott ◽  
Daryle Boyd ◽  
Gina M. Ylitalo ◽  
Todd M. O’Hara
Keyword(s):  
Polychlorinated Biphenyls ◽  
Body Condition ◽  
Neutral Lipids ◽  
Trophic Position ◽  
Beaufort Sea ◽  
Ursus Maritimus ◽  
Polar Bears ◽  
Adult Males ◽  
Blood Concentrations ◽  
Condition Indices

Polar bears ( Ursus maritimus Phipps, 1774) are exposed to heavy metal and lipophilic contaminants that are known to bioaccumulate and biomagnify. Few studies concurrently report both chemical classes in the same individuals and are thus unable to assess drivers of observed tissue concentrations, and the potential adverse biological responses to combined exposures. We examined blood concentrations of mercury (Hg) and the sum of seven polychlorinated biphenyls (Σ7PCB) from free-ranging Southern Beaufort Sea polar bears to assess which factors contributed to variations among cohorts (adult males, adult females, young) during spring. Concentrations of Hg ranged from 10.3 to 228.0 ng/g wet mass, but mean concentrations were similar between males and females independent of age. Concentrations of Σ7PCB (range 2.0–132.8 ng/g wet mass) were greater among females and young than among males. Toxicant concentrations were related to packed cell δ15N, an estimate of trophic position, after the inclusion of packed cell δ13C. Concentrations of Σ7PCB were also positively correlated with concentrations of neutral lipids (triglycerides and free fatty acids) and inversely correlated to body condition indices. Elevated concentrations of toxicants and lower body condition indices in females and young compared with males may be a sentinel to a changing arctic environment. Further assessment of the potential adverse health impacts of contaminants and nutritional stress in these cohorts is warranted.

Climate-associated drivers of plasma cytokines and contaminant concentrations in Beaufort Sea polar bears (Ursus maritimus)

2020 ◽  
Vol 745 ◽  
pp. 140978
Author(s):  
Jennifer Bourque ◽  
Jean-Pierre Desforges ◽  
Milton Levin ◽  
Todd C. Atwood ◽  
Christian Sonne ◽  
...  
Keyword(s):  
Beaufort Sea ◽  
Ursus Maritimus ◽  
Polar Bears ◽  
Plasma Cytokines

Summer refugia of polar bears (Ursus maritimus) in the southern Beaufort Sea

Polar Biology ◽  
2016 ◽  
Vol 40 (4) ◽  
pp. 753-763 ◽  
Author(s):  
Jodie D. Pongracz ◽  
Andrew E. Derocher
Keyword(s):  
Beaufort Sea ◽  
Ursus Maritimus ◽  
Polar Bears

Survival rates of radio-collared female polar bears and their dependent young

1995 ◽  
Vol 73 (7) ◽  
pp. 1312-1322 ◽  
Author(s):  
S. C. Amstrup ◽  
G. M. Durner
Keyword(s):  
Adult Female ◽  
Survival Rates ◽  
Beaufort Sea ◽  
First Year ◽  
Human Populations ◽  
Polar Bears ◽  
Adult Males ◽  
Kaplan Meier ◽  
Second Year ◽  
Sea Survival

Polar bears (Ursus maritimus) are hunted throughout most of their range. In addition to hunting, polar bears of the Beaufort Sea region are exposed to mineral and hydrocarbon extraction and related human activities such as shipping, road building, and seismic testing. As human populations increase and demands for polar bears and other arctic resources escalate, reliable estimates of survivorship of polar bears are needed to predict and manage the impacts of those activities. We used the Kaplan–Meier model to estimate annual survival (with 95% confidence intervals) for radio-collared female polar bears and their dependent young that were followed during a 12-year study in the Alaskan Beaufort Sea. Survival of adult female polar bears was higher than had been previously thought: Ŝ = 0.969 (range 0.952–0.983). If human-caused mortalities were deleted, the computed survival rate was 0.996 (0.990–1.002). Survival of young from den exit to weaning was 0.676 (0.634–0.701). Survival during the second year of life, 0.860 (0.751–0.903), was substantially higher than during the first year, 0.651 (0.610–0.675). Shooting by local hunters accounted for 85% of the documented deaths of adult female polar bears. Conversely, 90% of documented losses of young accompanying radio-collared females were not directly caused by humans. Deaths of dependent young were independent of litter size (P = 0.36), indicating that parental investment in single cubs was not different from investment in litters of two or more. Precise estimates of the survival of independent juveniles and adult males still need to be developed.

PREVALENCE AND SPATIO-TEMPORAL VARIATION OF AN ALOPECIA SYNDROME IN POLAR BEARS (URSUS MARITIMUS) OF THE SOUTHERN BEAUFORT SEA

2015 ◽  
Vol 51 (1) ◽  
pp. 48-59 ◽  
Author(s):  
Todd Atwood ◽  
Elizabeth Peacock ◽  
Kathy Burek-Huntington ◽  
Valerie Shearn-Bochsler ◽  
Barbara Bodenstein ◽  
...  
Keyword(s):  
Temporal Variation ◽  
Beaufort Sea ◽  
Ursus Maritimus ◽  
Polar Bears ◽  
Spatio Temporal

Effects of capturing and collaring on polar bears: findings from long-term research on the southern Beaufort Sea population

2014 ◽  
Vol 41 (4) ◽  
pp. 311 ◽  
Author(s):  
Karyn D. Rode ◽  
Anthony M. Pagano ◽  
Jeffrey F. Bromaghin ◽  
Todd C. Atwood ◽  
George M. Durner ◽  
...  
Keyword(s):  
Research Methods ◽  
Body Mass ◽  
Body Condition ◽  
Polar Bear ◽  
Beaufort Sea ◽  
Polar Bears ◽  
Long Term Effects ◽  
Movement Rates ◽  
Related Mortality

Context The potential for research methods to affect wildlife is an increasing concern among both scientists and the public. This topic has a particular urgency for polar bears because additional research is needed to monitor and understand population responses to rapid loss of sea ice habitat. Aims This study used data collected from polar bears sampled in the Alaska portion of the southern Beaufort Sea to investigate the potential for capture to adversely affect behaviour and vital rates. We evaluated the extent to which capture, collaring and handling may influence activity and movement days to weeks post-capture, and body mass, body condition, reproduction and survival over 6 months or more. Methods We compared post-capture activity and movement rates, and relationships between prior capture history and body mass, body condition and reproductive success. We also summarised data on capture-related mortality. Key results Individual-based estimates of activity and movement rates reached near-normal levels within 2–3 days and fully normal levels within 5 days post-capture. Models of activity and movement rates among all bears had poor fit, but suggested potential for prolonged, lower-level rate reductions. Repeated captures was not related to negative effects on body condition, reproduction or cub growth or survival. Capture-related mortality was substantially reduced after 1986, when immobilisation drugs were changed, with only 3 mortalities in 2517 captures from 1987–2013. Conclusions Polar bears in the southern Beaufort Sea exhibited the greatest reductions in activity and movement rates 3.5 days post-capture. These shorter-term, post-capture effects do not appear to have translated into any long-term effects on body condition, reproduction, or cub survival. Additionally, collaring had no effect on polar bear recovery rates, body condition, reproduction or cub survival. Implications This study provides empirical evidence that current capture-based research methods do not have long-term implications, and are not contributing to observed changes in body condition, reproduction or survival in the southern Beaufort Sea. Continued refinement of capture protocols, such as the use of low-impact dart rifles and reversible drug combinations, might improve polar bear response to capture and abate short-term reductions in activity and movement post-capture.

Sea ice-associated decline in body condition leads to increased concentrations of lipophilic pollutants in polar bears ( Ursus maritimus ) from Svalbard, Norway

2017 ◽  
Vol 576 ◽  
pp. 409-419 ◽  
Author(s):  
Sabrina Tartu ◽  
Sophie Bourgeon ◽  
Jon Aars ◽  
Magnus Andersen ◽  
Anuschka Polder ◽  
...  
Keyword(s):  
Sea Ice ◽  
Body Condition ◽  
Ursus Maritimus ◽  
Polar Bears

Microsatellite DNA and mitochondrial DNA variation in polar bears (Ursus maritimus) from the Beaufort and Chukchi seas, Alaska

2006 ◽  
Vol 84 (5) ◽  
pp. 655-660 ◽  
Author(s):  
M.A. Cronin ◽  
S.C. Amstrup ◽  
K.T. Scribner
Keyword(s):  
Mitochondrial Dna ◽  
Microsatellite Dna ◽  
Chukchi Sea ◽  
Genetic Data ◽  
Beaufort Sea ◽  
Ursus Maritimus ◽  
Polar Bears ◽  
Dna Variation ◽  
Movement Data ◽  
Mtdna Haplotype

Radiotelemetry data have shown that polar bears ( Ursus maritimus Phipps, 1774 ) occur in separate subpopulations in the Chukchi Sea and the southern Beaufort Sea. However, segregation is not absolute, and there is overlap of ranges of animals in each subpopulation. We used genetic variation at eight microsatellite DNA loci and mitochondrial DNA (mtDNA) to further assess the degree of spatial structure of polar bears from the Chukchi and southern Beaufort seas. Microsatellite allele frequencies and mtDNA haplotype frequencies of bears from the southern Beaufort and Chukchi seas did not differ significantly. Lack of differentiation at both maternally inherited mtDNA and bi-parentally inherited microsatellite loci suggests that gene flow between the two areas is mediated by both sexes. The genetic data indicate that polar bears in the southern Beaufort and Chukchi seas compose one interbreeding population. However, there is considerable fidelity to ranges in each area, particularly by adult females. The combined genetic and movement data suggest that polar bears could be managed as Beaufort Sea and Chukchi Sea subpopulations of a combined southern Beaufort Sea and Chukchi Sea population.

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