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17 records – page 1 of 2.

Arctic marine mammal population status, sea ice habitat loss, and conservation recommendations for the 21st century.

https://arctichealth.org/en/permalink/ahliterature270034
Source
Conserv Biol. 2015 Jun;29(3):724-37
Publication Type
Article
Date
Jun-2015
Author
Kristin L Laidre
Harry Stern
Kit M Kovacs
Lloyd Lowry
Sue E Moore
Eric V Regehr
Steven H Ferguson
Øystein Wiig
Peter Boveng
Robyn P Angliss
Erik W Born
Dennis Litovka
Lori Quakenbush
Christian Lydersen
Dag Vongraven
Fernando Ugarte
Source
Conserv Biol. 2015 Jun;29(3):724-37
Date
Jun-2015
Language
English
Publication Type
Article
Keywords
Animals
Arctic Regions
Cetacea - physiology
Climate change
Conservation of Natural Resources
Ecosystem
Ice Cover
Pinnipedia - physiology
Population Density
Abstract
Arctic marine mammals (AMMs) are icons of climate change, largely because of their close association with sea ice. However, neither a circumpolar assessment of AMM status nor a standardized metric of sea ice habitat change is available. We summarized available data on abundance and trend for each AMM species and recognized subpopulation. We also examined species diversity, the extent of human use, and temporal trends in sea ice habitat for 12 regions of the Arctic by calculating the dates of spring sea ice retreat and fall sea ice advance from satellite data (1979-2013). Estimates of AMM abundance varied greatly in quality, and few studies were long enough for trend analysis. Of the AMM subpopulations, 78% (61 of 78) are legally harvested for subsistence purposes. Changes in sea ice phenology have been profound. In all regions except the Bering Sea, the duration of the summer (i.e., reduced ice) period increased by 5-10 weeks and by >20 weeks in the Barents Sea between 1979 and 2013. In light of generally poor data, the importance of human use, and forecasted environmental changes in the 21st century, we recommend the following for effective AMM conservation: maintain and improve comanagement by local, federal, and international partners; recognize spatial and temporal variability in AMM subpopulation response to climate change; implement monitoring programs with clear goals; mitigate cumulative impacts of increased human activity; and recognize the limits of current protected species legislation.
PubMed ID
25783745 View in PubMed
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Chlorinated hydrocarbon contaminants and metabolites in polar bears (Ursus maritimus) from Alaska, Canada, East Greenland, and Svalbard: 1996-2002.

https://arctichealth.org/en/permalink/ahliterature5969
Source
Sci Total Environ. 2005 Dec 1;351-352:369-90
Publication Type
Article
Date
Dec-1-2005
  1 website  
Author
Jonathan Verreault
Derek C G Muir
Ross J Norstrom
Ian Stirling
Aaron T Fisk
Geir W Gabrielsen
Andrew E Derocher
Thomas J Evans
Rune Dietz
Christian Sonne
Gregory M Sandala
Wouter Gebbink
Frank F Riget
Erik W Born
Mitch K Taylor
John Nagy
Robert J Letcher
Author Affiliation
University of Windsor, Great Lakes Institute for Environmental Research, Windsor, Canada, ON N9B 3P4.
Source
Sci Total Environ. 2005 Dec 1;351-352:369-90
Date
Dec-1-2005
Language
English
Publication Type
Article
Abstract
A suite of chlorinated hydrocarbon contaminants (CHCs) including organochlorine pesticides (OCPs) and by-products, polychlorinated biphenyls (PCBs), and methyl sulfone (MeSO2) PCB and p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) metabolites were determined in adipose tissue of 107 adult and sub-adult polar bears, almost exclusively females, sampled between 1996 and 2002 from populations spanning Arctic and Subarctic regions of Alaska, Canada, East Greenland, and Svalbard. The East Greenland and Svalbard populations of polar bears were distinguished by higher proportions of dichlorodiphenyldichloroethane (DDT)-related compounds, nonachlors, oxychlordane, and higher-chlorinated and persistent PCB congeners (hepta- to nona-chlorinated). Conversely, Alaska, the westernmost population of the North American Arctic, was characterized by higher proportions of relatively volatile compounds such as hexachlorocyclohexanes (HCHs) and pentachlorobenzene (PnCBz), lower-chlorinated PCB congeners (tri- to penta-chlorinated), and lower proportions of oxychlordane. Geometric mean (GM) with 95% confidence limits (CL) SigmaHCH concentrations were highest in Alaska male polar bear fat samples (GM 593; CL 363-909 ng g-1 lipid weight), SigmaDDT concentration were highest in East Greenland female samples (GM 309; CL 249-490 ng g-1 l.w.), and Sigma42PCB (GM 5972; CL 4637-9129 ng g-1 l.w.) and SigmaMeSO2-PCB (GM 198; CL 162-279 ng g-1 l.w.) concentrations were highest in female samples collected from Svalbard. The distribution of Sigma-chlordane-related compounds (SigmaCHL), SigmaCBz, mirex, and dieldrin was relatively uniform among the populations of polar bears investigated. The present 1996-2002 data of female polar bear fat samples was compared to spatial assessments of female polar bear fat samples collected between 1989 and 1993 from comparable populations. The two-point temporal comparisons showed a general decrease for age-adjusted mean concentrations of SigmaCHL, p,p'-DDE, Sigma42PCB, SigmaMeSO2-PCB and 3-MeSO2-p,p'-DDE over a period of approximately 10 years. However, concentrations of dieldrin were comparatively unchanged. Comparisons of present 2001-2002 concentrations in fat of female polar bears from Western Hudson Bay showed great consistency with temporal trends (1991-1999) previously reported for the same region, i.e. the apparent non-decreasing trend of SigmaCHL, beta-HCH, SigmaHCH and dieldrin, and the apparent declining trend for SigmaPCB. However, present concentrations of alpha-HCH and SigmaCBz were elevated, and SigmaDDT was notably lower in Western Hudson Bay samples compared to the last measurements in fat samples collected in 1999, which was not in accord with reported temporal trends for this region. As a result of their relatively high degree of contamination, East Greenland and Svalbard polar bears are at higher health risk of contaminant exposure among Arctic and Subarctic populations. In addition to continued biomonitoring, further research on health and population status is needed to evaluate the impact from chronic exposure of polar bear populations to CHCs and their metabolites.
PubMed ID
16115663 View in PubMed
Online Resources
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Circumpolar study of perfluoroalkyl contaminants in polar bears (Ursus maritimus).

https://arctichealth.org/en/permalink/ahliterature5521
Source
Environ Sci Technol. 2005 Aug 1;39(15):5517-23
Publication Type
Article
Date
Aug-1-2005
Author
Marla Smithwick
Scott A Mabury
Keith R Solomon
Christian Sonne
Jonathan W Martin
Erik W Born
Rune Dietz
Andrew E Derocher
Robert J Letcher
Thomas J Evans
Geir W Gabrielsen
John Nagy
Ian Stirling
Mitch K Taylor
Derek C G Muir
Author Affiliation
Department of Environmental Biology, University of Guelph, Bovey Building, Guelph, Ontario N1G 2W1, Canada.
Source
Environ Sci Technol. 2005 Aug 1;39(15):5517-23
Date
Aug-1-2005
Language
English
Publication Type
Article
Keywords
Adipose Tissue - chemistry
Animals
Arctic Regions
Chromatography, Liquid
Environmental monitoring
Environmental Pollutants - analysis
Fluorocarbons - analysis
Liver - chemistry
Polychlorinated biphenyls - analysis
Research Support, Non-U.S. Gov't
Spectrum Analysis, Mass
Ursidae
Abstract
Perfluoroalkyl substances were determined in liver tissues and blood of polar bears (Ursus maritimus) from five locations in the North American Arctic and two locations in the European Arctic. Concentrations of perfluorooctane sulfonate (PFOS), perfluorohexane sulfonate, heptadecafluorooctane sulfonamide, and perfluoroalkyl carboxylates with C(8)-C(15) perfluorinated carbon chains were determined using liquid chromatography tandem mass spectrometry. PFOS concentrations were significantly correlated with age at four of seven sampling locations, while gender was not correlated to concentration for any compound measured. Populations in South Hudson Bay (2000-2730 ng/g wet wt), East Greenland (911-2140 ng/g wet wt), and Svalbard (756-1290 ng/g wet wt) had significantly (P
PubMed ID
16124282 View in PubMed
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Do organohalogen contaminants contribute to histopathology in liver from East Greenland polar bears (Ursus maritimus)?

https://arctichealth.org/en/permalink/ahliterature70514
Source
Environ Health Perspect. 2005 Nov;113(11):1569-74
Publication Type
Article
Date
Nov-2005
Author
Christian Sonne
Rune Dietz
Pall S Leifsson
Erik W Born
Robert J Letcher
Maja Kirkegaard
Derek C G Muir
Frank F Riget
Lars Hyldstrup
Author Affiliation
Department of Arctic Environment, National Environmental Research Institute, Roskilde, Denmark. csh@dmu.dk
Source
Environ Health Perspect. 2005 Nov;113(11):1569-74
Date
Nov-2005
Language
English
Publication Type
Article
Keywords
Adipose Tissue - chemistry
Aging - physiology
Animals
Biological Markers
Environmental monitoring
Female
Greenland
Hydrocarbons, Halogenated - analysis - toxicity
Lipids - analysis
Liver - drug effects - pathology
Male
Research Support, Non-U.S. Gov't
Ursidae
Water Pollutants, Chemical - analysis - toxicity
Abstract
In East Greenland polar bears (Ursus maritimus), anthropogenic organohalogen compounds (OHCs) (e.g., polychlorinated biphenyls, dichlorodiphenyltrichloroethane, and polybrominated diphenyl ethers) contributed to renal lesions and are believed to reduce bone mineral density. Because OHCs are also hepatotoxic, we investigated liver histology of 32 subadult, 24 adult female, and 23 adult male East Greenland polar bears sampled during 1999-2002. Light microscopic changes consisted of nuclear displacement from the normal central cytoplasmic location in parenchymal cells, mononuclear cell infiltrations (mainly portally and as lipid granulomas), mild bile duct proliferation accompanied by fibrosis, and fat accumulation in hepatocytes and pluripotent Ito cells. Lipid accumulation in Ito cells and bile duct hyperplasia accompanied by portal fibrosis were correlated to age, whereas no changes were associated with either sex or season (summer vs. winter). For adult females, hepatocytic intracellular fat increased significantly with concentrations of the sum of hexachlorocyclohexanes, as was the case for lipid granulomas and hexachlorobenzene in adult males. Based on these relationships and the nature of the chronic inflammation, we suggest that these findings were caused by aging and long-term exposure to OHCs. Therefore, these changes may be used as biomarkers for OHC exposure in wildlife and humans. To our knowledge, this is the first time liver histology has been evaluated in relation to OHC concentrations in a mammalian wildlife species, and the information is important to future polar bear conservation strategies and health assessments of humans relying on OHC-contaminated food resources.
PubMed ID
16263513 View in PubMed
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Flame retardants and legacy contaminants in polar bears from Alaska, Canada, East Greenland and Svalbard, 2005-2008.

https://arctichealth.org/en/permalink/ahliterature99935
Source
Environ Int. 2010 Dec 3;
Publication Type
Article
Date
Dec-3-2010
Author
Melissa A McKinney
Robert J Letcher
Jon Aars
Erik W Born
Marsha Branigan
Rune Dietz
Thomas J Evans
Geir W Gabrielsen
Elizabeth Peacock
Christian Sonne
Author Affiliation
Ecotoxicology and Wildlife Health Division, Science and Technology Branch, Environment Canada, Ottawa, Ontario K1A 0H3, Canada; Department of Chemistry, Carleton University, Ottawa, Ontario K1S 5B6, Canada.
Source
Environ Int. 2010 Dec 3;
Date
Dec-3-2010
Language
English
Publication Type
Article
Abstract
Flame retardants and legacy contaminants were analyzed in adipose tissue from 11 circumpolar polar bear (Ursus maritimus) subpopulations in 2005-2008 spanning Alaska east to Svalbard. Although 37 polybrominated diphenyl ethers (PBDEs), total-(a)-hexabromocyclododecane (HBCD), 2 polybrominated biphenyls (PBBs), pentabromotoluene, pentabromoethylbenzene, hexabromobenzene, 1,2-bis(2,4,6-tribromophenoxy(ethane) and decabromodiphenyl ethane were screened, only 4 PBDEs, total-(a-)HBCD and BB153 were consistently found. Geometric mean ?PBDE (4.6-78.4ng/g lipid weight (lw)) and BB153 (2.5-81.1ng/g lw) levels were highest in East Greenland (43.2 and 39.2ng/g lipid weight (lw), respectively), Svalbard (44.4 and 20.9ng/g lw) and western (38.6 and 30.1ng/g lw) and southern Hudson Bay (78.4 and 81.1ng/g lw). Total-(a)-HBCD levels (
PubMed ID
21131049 View in PubMed
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Immunologic, reproductive, and carcinogenic risk assessment from POP exposure in East Greenland polar bears (Ursus maritimus) during 1983-2013.

https://arctichealth.org/en/permalink/ahliterature292152
Source
Environ Int. 2018 Jun 05; 118:169-178
Publication Type
Journal Article
Date
Jun-05-2018
Author
Rune Dietz
Jean-Pierre Desforges
Kim Gustavson
Frank F Rigét
Erik W Born
Robert J Letcher
Christian Sonne
Author Affiliation
Department of Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark. Electronic address: rdi@bios.au.dk.
Source
Environ Int. 2018 Jun 05; 118:169-178
Date
Jun-05-2018
Language
English
Publication Type
Journal Article
Abstract
Polar bears (Ursus maritimus) are among the world's highest trophic level marine predators and as such have some of the highest tissue concentrations of organohalogen contaminants (OHCs) among Arctic biota. In this paper we present the results of a three decade (1983-2013) risk assessment of OHC exposure and effects on reproduction, immunity, and cancer (genotoxicity) in polar bears from Central East Greenland. Risk of adverse effects are evaluated using a risk quotient (RQ) approach with derivation from measured OHC concentrations in polar bear tissue and critical body residues (CBR) extrapolated for polar bears using physiologically-based pharmacokinetic modelling (PBPK). The additive RQs for all OHCs in polar bears were above the threshold for all effect categories (RQ?>?1) in every year, suggesting this population has been at significant and continuous risk of contaminant-mediated effects for over three decades. RQs peaked in 1983 (RQ?>?58) and again in 2013 (RQ?>?50) after a period of decline. These trends follow SPCB levels during that time, and contributed almost all of the risk to immune, reproductive, and carcinogenic effects (71-99% of total RQ). The recent spike in RQs suggests a major shift in polar bear contaminant exposure from climate related changes in food composition and hereby the increased risk of adverse health effects. In the context of lifetime exposure SPCB and PFOS levels showed the interactive importance of year of birth, age, and emission history. In conclusion, the results indicate that East Greenland polar bears have been exposed to OHC levels over the period of 1983-2013 that potentially and continuously affected individual and theoretically also population health, with a peaking risk in the more recent years.
PubMed ID
29883763 View in PubMed
Less detail

Immunologic, reproductive, and carcinogenic risk assessment from POP exposure in East Greenland polar bears (Ursus maritimus) during 1983-2013.

https://arctichealth.org/en/permalink/ahliterature298466
Source
Environ Int. 2018 09; 118:169-178
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
09-2018
Author
Rune Dietz
Jean-Pierre Desforges
Kim Gustavson
Frank F Rigét
Erik W Born
Robert J Letcher
Christian Sonne
Author Affiliation
Department of Bioscience, Arctic Research Centre, Aarhus University, Frederiksborgvej 399, PO Box 358, DK-4000 Roskilde, Denmark. Electronic address: rdi@bios.au.dk.
Source
Environ Int. 2018 09; 118:169-178
Date
09-2018
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Keywords
Animals
Environmental Exposure - analysis - statistics & numerical data
Environmental Pollutants - analysis
Risk assessment
Ursidae
Abstract
Polar bears (Ursus maritimus) are among the world's highest trophic level marine predators and as such have some of the highest tissue concentrations of organohalogen contaminants (OHCs) among Arctic biota. In this paper we present the results of a three decade (1983-2013) risk assessment of OHC exposure and effects on reproduction, immunity, and cancer (genotoxicity) in polar bears from Central East Greenland. Risk of adverse effects are evaluated using a risk quotient (RQ) approach with derivation from measured OHC concentrations in polar bear tissue and critical body residues (CBR) extrapolated for polar bears using physiologically-based pharmacokinetic modelling (PBPK). The additive RQs for all OHCs in polar bears were above the threshold for all effect categories (RQ?>?1) in every year, suggesting this population has been at significant and continuous risk of contaminant-mediated effects for over three decades. RQs peaked in 1983 (RQ?>?58) and again in 2013 (RQ?>?50) after a period of decline. These trends follow SPCB levels during that time, and contributed almost all of the risk to immune, reproductive, and carcinogenic effects (71-99% of total RQ). The recent spike in RQs suggests a major shift in polar bear contaminant exposure from climate related changes in food composition and hereby the increased risk of adverse health effects. In the context of lifetime exposure SPCB and PFOS levels showed the interactive importance of year of birth, age, and emission history. In conclusion, the results indicate that East Greenland polar bears have been exposed to OHC levels over the period of 1983-2013 that potentially and continuously affected individual and theoretically also population health, with a peaking risk in the more recent years.
PubMed ID
29883763 View in PubMed
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Implications of the circumpolar genetic structure of polar bears for their conservation in a rapidly warming arctic.

https://arctichealth.org/en/permalink/ahliterature259415
Source
PLoS One. 2015;10(1):e112021
Publication Type
Article
Date
2015
Author
Elizabeth Peacock
Sarah A Sonsthagen
Martyn E Obbard
Andrei Boltunov
Eric V Regehr
Nikita Ovsyanikov
Jon Aars
Stephen N Atkinson
George K Sage
Andrew G Hope
Eve Zeyl
Lutz Bachmann
Dorothee Ehrich
Kim T Scribner
Steven C Amstrup
Stanislav Belikov
Erik W Born
Andrew E Derocher
Ian Stirling
Mitchell K Taylor
Øystein Wiig
David Paetkau
Sandra L Talbot
Source
PLoS One. 2015;10(1):e112021
Date
2015
Language
English
Publication Type
Article
Abstract
We provide an expansive analysis of polar bear (Ursus maritimus) circumpolar genetic variation during the last two decades of decline in their sea-ice habitat. We sought to evaluate whether their genetic diversity and structure have changed over this period of habitat decline, how their current genetic patterns compare with past patterns, and how genetic demography changed with ancient fluctuations in climate. Characterizing their circumpolar genetic structure using microsatellite data, we defined four clusters that largely correspond to current ecological and oceanographic factors: Eastern Polar Basin, Western Polar Basin, Canadian Archipelago and Southern Canada. We document evidence for recent (ca. last 1-3 generations) directional gene flow from Southern Canada and the Eastern Polar Basin towards the Canadian Archipelago, an area hypothesized to be a future refugium for polar bears as climate-induced habitat decline continues. Our data provide empirical evidence in support of this hypothesis. The direction of current gene flow differs from earlier patterns of gene flow in the Holocene. From analyses of mitochondrial DNA, the Canadian Archipelago cluster and the Barents Sea subpopulation within the Eastern Polar Basin cluster did not show signals of population expansion, suggesting these areas may have served also as past interglacial refugia. Mismatch analyses of mitochondrial DNA data from polar and the paraphyletic brown bear (U. arctos) uncovered offset signals in timing of population expansion between the two species, that are attributed to differential demographic responses to past climate cycling. Mitogenomic structure of polar bears was shallow and developed recently, in contrast to the multiple clades of brown bears. We found no genetic signatures of recent hybridization between the species in our large, circumpolar sample, suggesting that recently observed hybrids represent localized events. Documenting changes in subpopulation connectivity will allow polar nations to proactively adjust conservation actions to continuing decline in sea-ice habitat.
PubMed ID
25562525 View in PubMed
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Interrelated ecological impacts of climate change on an apex predator.

https://arctichealth.org/en/permalink/ahliterature307352
Source
Ecol Appl. 2020 06; 30(4):e02071
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Date
06-2020
Author
Kristin L Laidre
Stephen Atkinson
Eric V Regehr
Harry L Stern
Erik W Born
Øystein Wiig
Nicholas J Lunn
Markus Dyck
Author Affiliation
Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, Washington, 98105, USA.
Source
Ecol Appl. 2020 06; 30(4):e02071
Date
06-2020
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Keywords
Animals
Arctic Regions
Climate change
Ecosystem
Female
Ice Cover
Pregnancy
Ursidae
Abstract
Climate change has broad ecological implications for species that rely on sensitive habitats. For some top predators, loss of habitat is expected to lead to cascading behavioral, nutritional, and reproductive changes that ultimately accelerate population declines. In the case of the polar bear (Ursus maritimus), declining Arctic sea ice reduces access to prey and lengthens seasonal fasting periods. We used a novel combination of physical capture, biopsy darting, and visual aerial observation data to project reproductive performance for polar bears by linking sea ice loss to changes in habitat use, body condition (i.e., fatness), and cub production. Satellite telemetry data from 43 (1991-1997) and 38 (2009-2015) adult female polar bears in the Baffin Bay subpopulation showed that bears now spend an additional 30 d on land (90 d in total) in the 2000s compared to the 1990s, a change closely correlated with changes in spring sea ice breakup and fall sea ice formation. Body condition declined for all sex, age, and reproductive classes and was positively correlated with sea ice availability in the current and previous year. Furthermore, cub litter size was positively correlated with maternal condition and spring breakup date (i.e., later breakup leading to larger litters), and negatively correlated with the duration of the ice-free period (i.e., longer ice-free periods leading to smaller litters). Based on these relationships, we projected reproductive performance three polar bear generations into the future (approximately 35 yr). Results indicate that two-cub litters, previously the norm, could largely disappear from Baffin Bay as sea ice loss continues. Our findings demonstrate how concurrent analysis of multiple data types collected over long periods from polar bears can provide a mechanistic understanding of the ecological implications of climate change. This information is needed for long-term conservation planning, which includes quantitative harvest risk assessments that incorporate estimated or assumed trends in future environmental carrying capacity.
PubMed ID
31925853 View in PubMed
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17 records – page 1 of 2.