Øystein Wiig

• Naciri, Marwan; Aars, Jon; Gamelon, Marlene; Andersen, Magnus; Derocher, Andrew E. & Wiig, Øystein [Show all 7 contributors for this article] (2026). Denning Phenology Mediates Sea-Ice Loss Impacts on Early Reproductive Success in Polar Bears. Global Change Biology. ISSN 1354-1013. 32(8). doi: 10.1111/gcb.71042. Full text in Research Archive
• Westbury, Michael V.; Freymueller, Nicholas A.; Cabrera, Andrea A.; Bachmann, Lutz; Ferguson, Steven H. & Heide-Jørgensen, Mads Peter [Show all 12 contributors for this article] (2026). Tracing the Drivers of Range-Wide Bowhead Whale Genomic Structure and Diversity. Molecular Ecology. ISSN 0962-1083. 35(10). doi: 10.1111/mec.70378. Full text in Research Archive Show summary

  In a rapidly warming Arctic, genetic variation might serve to buffer organisms against the effects of environmental change, such as sea ice loss and ocean warming. Yet, this concept remains largely unexplored because comprehensive genome-wide studies across the full ranges of Arctic marine taxa are rare. Bowhead whales (Balaena mysticetus) have a strong association with sea ice and polar water masses, a long history of human exploitation, and a circumpolar distribution, making them a valuable model for evaluating how past environmental and anthropogenic factors have shaped contemporary population variation. We analysed both nuclear and mitochondrial genomes from bowhead whales sampled across the species' range, encompassing all four recognised stocks. Firstly, our results indicate the existence of three genetic groupings instead of four: (1) Okhotsk Sea; (2) East Greenland-Svalbard-Barents Sea; and (3) a population containing two recognised stocks—the Bering-Chukchi-Beaufort and East Canada-West Greenland. We utilised high-resolution ecological niche modelling and bowhead whale movement data to reconstruct inter-stock habitat connectivity over the last 11,700 years, finding that this explains our identified genetic groupings. Bowhead whale populations exhibit little-to-no evidence of recent inbreeding and retain high genetic diversity relative to other mammalian species despite centuries of intensive commercial whaling. The most vulnerable population is that in the Okhotsk Sea, which has the lowest genetic diversity, most inbreeding, and the highest realised genetic load. Collectively, our findings elucidate the recent history and dynamics of bowhead whales, offering valuable baseline data and context on present-day genetic structure and diversity to support effective conservation and management strategies.

• Westbury, Michael V.; Brown, Stuart C.; Cabrera, Andrea A.; Morales, Hernán E.; Parreira, Bárbara & Ma, Jilong [Show all 19 contributors for this article] (2026). Four centuries of commercial whaling eroded 11,000 years of population stability in bowhead whales. Cell. ISSN 0092-8674. 189(7), p. 2040–2053.e19. doi: 10.1016/j.cell.2026.02.022. Full text in Research Archive Show summary

  Bowhead whales were heavily exploited during commercial whaling between the 16th and 20th centuries. Current and near-future climate warming poses a new threat. Assessing bowhead vulnerability to climatic change remains challenging due to insufficient knowledge regarding responses to past climates and pre-whaling population dynamics. We integrate paleogenomics and stable isotopes (δ13C and δ15N) from 206 bowhead fossils from the Atlantic Arctic with paleoclimate and ecological modeling based on 823 radiocarbon-dated fossils, including 140 from this study. We find long-term resilience of bowheads to Holocene environmental perturbations, with no detectable changes in genetic diversity or population structure. Simulated commercial-whaling-driven genetic and fitness changes indicate that population subdivision and loss of genetic diversity are unlikely to be fully realized, despite nearly a century since whaling ceased. Furthermore, even in simulated complete population recovery scenarios, overall fitness did not return to pre-whaling levels, potentially compromising the future resilience of bowhead whales.

• Aars, Jon; Ieno, E. N.; Andersen, Magnus; Derocher, A. E.; Wiig, Øystein & Zuur, A. F. (2026). Body condition among Svalbard Polar bears Ursus maritimus during a period of rapid loss of sea ice. Scientific Reports. 16(1). doi: 10.1038/s41598-025-33227-9. Full text in Research Archive Show summary

  Polar bears are only found in Arctic areas with sufficient access to sea ice and seals on which they prey. Studies have highlighted negative effects on condition and demographics in areas where sea ice cover is declining due to warmer climate, but condition of the Barents Sea polar bear population have not been examined yet. Loss of sea ice rate has been considerably higher here than in other areas with polar bears. We investigated variation in body condition index (BCI) among 770 adult bears, 1188 captures, in March-May 1995–2019, in Svalbard, Norway (western part of the Barents Sea). We assessed how intrinsic (female reproductive state, age) and both males and females, BCI declined until 2000, but increased afterwards, during a period with rapid loss of sea ice. In models including sea ice metrics and climate (Arctic Oscillation), there was no support for the predicted negative effect of warmer weather and habitat loss. This indicates a complex relationship between habitat, ecosystem structure, energy intake, and energy expenditure. Increases in some prey species, including harbour seals, reindeer, and walrus, may partly offset reduced access to seals. Our findings underline the importance not to extrapolate findings across populations.

• Naciri, Marwan; Aars, Jon; Andersen, Magnus; Derocher, Andrew E.; Wiig, Øystein & Cubaynes, Sarah (2025). A capture–recapture framework for combining biologging data with physical captures to decompose and estimate demographic rates: Simulations across life cycles and application to polar bears. Methods in Ecology and Evolution. p. 1–13. doi: 10.1111/2041-210x.70229. Full text in Research Archive Show summary

  1. Estimating demographic rates of wild populations is critical to understanding their dynamics but can be challenging because large amounts of data are required, and parts of the life cycle of individuals may be unobserved. In numerous research programmes, capture–recapture (CR) data and biologging data are collected in parallel. The latter often contain information on individual state (e.g. alive/dead, breeding/non-breeding), but this information is seldom combined with CR data. 2. Here, we present a Bayesian multi-event CR framework to combine biologging containing information on individual state with CR data. Because biologging can inform on unobservable life cycle events like early offspring mortality, it can allow decomposing a demographic rate into two more precise demographic rates. We outline the principle of the model using a generic example then use simulations in a range of life cycles (ungulate, seabird, galliform, bear) to assess model performance. We then apply our model to 38 years of CR and biologging data from the Svalbard polar bear (Ursus maritimus) population. 3. Simulations indicated that across life cycles, our model recovered most parameters well and often outperformed a standard CR model despite increased complexity. Benefits of including biologging data in terms of parameter estimates were apparent even for low biologger deployment probabilities and increased with deployment probability. Benefits were greater at low recapture probability when the amount of information on breeding status contained in biologging data was increased and possibly in long-lived species. Benefits also extended to yearly offspring survival rates in the species with extended parental care. 4. When applied to Svalbard polar bears, our model decomposed the traditionally estimated breeding probability into the denning probability and early litter survival probability. We document sharp age-related changes in survival and reproductive success and find low evidence that denning incurred a future reproduction cost. Finally, we uncover pervasive negative impacts of sea-ice loss on demographic rates. 5. Our model is applicable to any species where CR and biologging data are simultaneously available—provided that biologging data contain information on individual state. It can increase the benefit-to-cost ratio of deploying biologgers and provide new demographic insights.

• Naciri, Marwan; Aars, Jon; Andersen, Magnus; Blanchet, Marie-Anne; Derocher, Andrew E. & Gamelon, Marlene [Show all 8 contributors for this article] (2025). Offspring number, size, and survival: State-dependent optimization of litter size in a long-lived capital breeder. Ecosphere. 16(8). doi: 10.1002/ecs2.70370. Full text in Research Archive Show summary

  Seventy-five years ago, Lack proposed that there should be an optimal clutch size shared by all individuals in a population and favored by natural selection, which maximizes the number of recruited offspring. While some studies support this “common optimum” hypothesis, others have shown that the optimal clutch size depends on maternal state (e.g., age and body condition, “state-dependent optimization”). These contrasting results suggest that the degree of state dependency might itself depend on the ecological context (e.g., capital vs. income breeding). Furthermore, almost all these studies were conducted on fast-living species and have ignored interdependencies among variables such as maternal age and condition. Here, we test whether females share a common optimal litter size or have a state-dependent optimal litter size in a slow-paced capital breeder, the polar bear (Ursus maritimus). To do so, we assess the influences of (1) maternal state on litter size, (2) maternal state and litter size on cub mass, and (3) maternal state, litter size, and cub mass on cub survival, using path analysis to account for interdependencies among variables and capture–recapture modeling to estimate cub survival. We use 34 years (1992–2025) of individual-based data from a polar bear subpopulation in the Svalbard region of Norway. In accordance with the state-dependent optimization hypothesis, litter size varied with maternal age and size. Middle-aged and sized females had the highest probability of having twins. Old and large females more often had triplet litters. Cub mass decreased with increasing litter size, whereas litter mass increased, meaning females with a large litter allocated more resources to reproduction. Cub mass in turn strongly predicted cub survival, indicating that offspring survival was traded against offspring number. In middle-aged and old females, productivity—the number of cubs surviving their first year—increased with litter size, in accordance with the state-dependent optimization hypothesis. Overall, our results are consistent with a state-dependent optimization of litter size in this large, slow-paced mammal producing small litters. State dependence of litter size may be more likely in capital breeders as the amount of energy available for reproduction is known in advance.

• VanCompernolle, Michelle; Morris, Juliet; Calich, Hannah J.; Rodríguez, Jorge P.; Marley, Sarah A. & Pearce, Jessica R. [Show all 310 contributors for this article] (2025). Vulnerability of marine megafauna to global at‐sea anthropogenic threats. Conservation Biology. ISSN 0888-8892. doi: 10.1111/cobi.70147. Full text in Research Archive Show summary

  Marine megafauna species are affected by a wide range of anthropogenic threats. To evaluate the risk of such threats, species’ vulnerability to each threat must first be determined. We build on the existing threats classification scheme and ranking system of the International Union for Conservation of Nature (IUCN) Red List of Threatened Species by assessing the vulnerability of 256 marine megafauna species to 23 at‐sea threats. The threats we considered included individual fishing gear types, climate‐change‐related subthreats not previously assessed, and threats associated with coastal impacts and maritime disturbances. Our ratings resulted in 70 species having high vulnerability ( v  > 0.778 out of 1) to at least 1 threat, primarily drifting longlines, temperature extremes, or fixed gear. These 3 threats were also considered to have the most severe effects (i.e., steepest population declines). Overall, temperature extremes and plastics and other solid waste were rated as affecting the largest proportion of populations. Penguins, pinnipeds, and polar bears had the highest vulnerability to temperature extremes. Bony fishes had the highest vulnerability to drifting longlines and plastics and other solid waste; pelagic cetaceans to 4 maritime disturbance threats; elasmobranchs to 5 fishing threats; and flying birds to drifting longlines and 2 maritime disturbance threats. Sirenians and turtles had the highest vulnerability to at least one threat from all 4 categories. Despite not necessarily having severe effects for most taxonomic groups, temperature extremes were rated among the top threats for all taxa except bony fishes. The vulnerability scores we provide are an important first step in estimating the risk of threats to marine megafauna. Importantly, they help differentiate scope from severity, which is key to identifying threats that should be prioritized for mitigation.

• Feuerborn, T. R.; Appelt, M.; Bougiouri, K.; Bachmann, Lutz; Nielsen, I. Broman & Buckley, R. M. [Show all 28 contributors for this article] (2025). Origins and diversity of Greenland’s Qimmit revealed with genomes of ancient and modern sled dogs. Science. ISSN 0036-8075. 389(6756), p. 163–168. doi: 10.1126/science.adu1990. Full text in Research Archive Show summary

  The Qimmeq (Greenland sled dog) has worked continuously with the Inuit in Greenland for more than 800 years. However, they now face drastic population declines caused by climate change, urbanization, and competition from snowmobiles. This study sequenced 92 modern and ancient genomes to investigate how centuries of isolation shaped the regional Qimmeq populations and the impact of European contact. We found distinct regional populations and evidence for two migrations of dogs into Greenland with the Inuit from Canada. Furthermore, we found that there is minimal European ancestry in present day Qimmit and limited recent inbreeding despite low heterozygosity. These insights are critical for conservation efforts aimed at preserving the Qimmit amid environmental changes and cultural transitions.

• AlShukri, Yahya; Visser, Ingrid N.; Wiig, Øystein & Loch, Carolina (2025). Macromorphology, Microstructure, Mechanical Properties, and Elemental Composition of Enamel and Dentine in the Eurasian Otter Lutra lutra. International Journal of Zoology. ISSN 1687-8477. 2025. doi: 10.1155/ijz/2548475. Full text in Research Archive Show summary

  Eurasian otters (Lutra lutra) are mammals found in waterways and coastal areas of Europe, parts of Asia, and northern Africa, where they inhabit aquatic environments with adequate food resources, primarily fish. This descriptive study aimed to investigate and describe the macromorphology, microstructure, mechanical properties, and elemental composition of teeth in two subadult Eurasian otters. A total of six teeth, comprised of two upper incisors, two canines, one premolar, and one molar tooth of two subadult Eurasian otters were analyzed. Teeth were measured, photographed, embedded in epoxy resin, sectioned, polished, and etched for scanning electron microscope (SEM) imaging, nanoindentation, and elemental composition analyses. The enamel of the Eurasian otter specimens analyzed was prismatic, ranging in thickness from 115 to 250 μm in incisors, 150–265 μm in canines, and 120–930 μm in postcanine teeth. The overall enamel microstructure was characterized by distinct transversely oriented undulating Hunter–Schreger bands, running from the enamel–dentine junction (EDJ) to the outer enamel surface, with bands of 5–8 prisms thick. The prisms were semicylindrical in shape with 4–6 μm diameter. Enamel tufts and lamellae were observed near the EDJ, which was straight with minimal scalloping. CaO and P2O5 were the main components in both enamel and dentine; other minor components such as Na2O, MgO, Cl, and SrO were also observed. The dental characteristics of Eurasian otters are similar to other carnivores and reflect their diet and phylogeny. Such comparative dental studies can contribute to our understanding of the biology, functional morphology of and evolution of otters and other closely related species.

• Stern, Jennifer H.; Laidre, Kristin L.; Born, Erik W.; Wiig, Øystein & McKinney, Melissa A. (2024). Space-use strategies drive diet composition of Baffin Bay polar bears. Ecosphere. 15(4), p. 1–13. doi: 10.1002/ecs2.4826. Full text in Research Archive Show summary

  Polar bears (Ursus maritimus) depend on sea ice to hunt their ice-associated prey. However, climate-induced sea ice loss is leading to changes in space-use strategies of polar bears, with bears in some subpopulations spending more time on land or selecting alternative habitats. One such documented alternative habitat is glacier ice, which provides year-round access to prey, although the feeding habits of polar bears using glacier ice relative to those following the retreating ice and/or seasonally moving onshore are not known. Here, we use adipose tissue from polar bears (n = 104) from the Baffin Bay subpopulation live-captured in Northwest Greenland during the springs of 2009–2013 to investigate dietary patterns between space-use strategies inferred from satellite telemetry data, while considering demographic and interannual variation. Using quantitative fatty acid signature analysis (QFASA) to generate diet estimates, ringed seals (Pusa hispida) and bearded seals (Erignathus barbatus) were estimated as the primary and secondary prey of Baffin Bay polar bears for all sex/age classes and sampling years, apart from a single anomalous year (2009) with a relatively high proportion of beluga (Delphinapterus leucas) and narwhal (Monodon monoceros). While demographic and short-term temporal variation was minimal, fatty acid signatures and QFASA-generated diet estimates clearly differed between polar bears using coastal and offshore space-use strategies. “Offshore” adult females (n = 31), which make long-distance movements across the Baffin Bay pack ice, had high proportions of C22-chain length monosaturated fatty acids and diet estimates that included beluga, narwhal, harp (Pagophilus groenlandicus), and hooded seal (Cystophora cristata). “Coastal” adult females (n = 6), which remain resident at glacier fronts in Northwest Greenland year-round including during the sea ice-free season, consumed proportionally more ringed seals (+13%) and similar proportions of bearded seal, but essentially no beluga and narwhal or harp and hooded seal. Thus, space-use strategy is a driver of intrapopulation diet variability. As space-use strategies change with ongoing loss of sea ice habitat, our results suggest important ramifications for polar bear feeding patterns.

• Rivkin, L. Ruth; Richardson, Evan S.; Miller, Joshua M.; Atwood, Todd C.; Baryluk, Steven & Born, Erik W. [Show all 19 contributors for this article] (2024). Assessing the risk of climate maladaptation for Canadian polar bears. Ecology Letters. ISSN 1461-023X. 27(8). doi: 10.1111/ele.14486. Full text in Research Archive Show summary

  The Arctic is warming four times faster than the rest of the world, threatening the persistence of many Arctic species. It is uncertain if Arctic wildlife will have sufficient time to adapt to such rapidly warming environments. We used genetic forecasting to measure the risk of maladaptation to warming temperatures and sea ice loss in polar bears (Ursus maritimus) sampled across the Canadian Arctic. We found evidence for local adaptation to sea ice conditions and temperature. Forecasting of genome-environment mismatches for predicted climate scenarios suggested that polar bears in the Canadian high Arctic had the greatest risk of becoming maladapted to climate warming. While Canadian high Arctic bears may be the most likely to become maladapted, all polar bears face potentially negative outcomes to climate change. Given the importance of the sea ice habitat to polar bears, we expect that maladaptation to future warming is already widespread across Canada.

• Miller, Joshua M.; Malenfant, René M.; Rivkin, L. Ruth; Atwood, Todd C.; Baryluk, Steven & Born, Erik W. [Show all 12 contributors for this article] (2024). Development of an 8K SNP chip to assess adaptive diversity and hybridization in polar bears. Conservation Genetics Resources. ISSN 1877-7252. doi: 10.1007/s12686-024-01359-1. Full text in Research Archive Show summary

  The polar bear (Ursus maritimus) is a species particularly vulnerable to the effects of climate change. As the climate warms, polar bears will be forced to move to more suitable habitats which are likely to shrink, adapt to the new conditions, or decline in population size. However, the genomic diversity within and among all 19 subpopulations of polar bears, and therefore their adaptive potential, is currently unknown. In addition, warmer climates are likely to result in more frequent contact between polar bears and grizzly bears (U. arctos), with which they can hybridize. Here we describe the development, quality control, and application of the Ursus maritimus V2 SNP chip. This 8 K SNP chip contains loci explicitly selected to assess both RAD-derived and transcriptome-derived loci, as well as SNPs to detect hybridization between species. A total of 7,239 loci (90.3% of those printed) were successfully genotyped, with over 99% genotype concordance for individuals typed in duplicate on this chip, and between individuals typed here and on the Ursus maritimus V1 SNP chip. Using simulations, we demonstrate that the markers have high accuracy and efficiency to detect hybridization and backcrosses between polar bears and grizzly bears. However, empirical analysis of 371 polar bears, 440 grizzly bears, and 8 known hybrids found no novel instances of recent hybridization. The Ursus maritimus V2 SNP chip provides a powerful tool for monitoring the adaptive potential of this species along with assessing population structure, quantitative genomics, and hybridization in polar bears.

• Carvalho, André das Neves; Wiig, Øystein; Oliveira, Geovana Linhares de; Celeste, Halicia; Sena, Leonardo & Morato, Ronaldo Gonçalves [Show all 8 contributors for this article] (2024). How large felids of South America are influenced by environmental and anthropogenic variables in the most degraded portion of the Amazon. Austral ecology (Print). ISSN 1442-9985. 49(10). doi: 10.1111/aec.70002. Full text in Research Archive
• Suárez-Menéndez, Marcos; Bérubé, Martine; Bachmann, Lutz; Best, Peter; Davison, Nick & Heide-Jørgensen, Mads Peter [Show all 19 contributors for this article] (2024). Baleen whale microsatellite panel for individual identification and parentage assignment in Mysticeti. Global Ecology and Conservation. 51. doi: 10.1016/j.gecco.2024.e02947. Full text in Research Archive Show summary

  Highly polymorphic single tandem repeat loci (STR, also known as microsatellite loci) remain a familiar, cost efficient class of genetic markers in genetic studies in ecology, behavior and conservation. Here we characterize a new, universal set of ten STR loci in seven species of baleen whales, optimized for PCR amplification in two multiplex reactions along with a Y chromosome marker for sex determination. The optimized, universal set of STR loci provides a convenient starting point for new genetic studies in baleen whales aimed at identifying individuals and populations. Data from the new STR loci were combined with genotypes from previously published STR loci to assess the power to assign parentage using paternity exclusion in four species: fin whale (Balaenoptera physalus), humpback whale (Megaptera novaeangliae), blue whale (B. musculus) and bowhead whale (Balaena mysticetus). Our results suggest that parentage studies should always be accompanied by a power analysis in order to ascertain that each individual specific study is based upon data with sufficient power to assign parentage with statistical rigor.

• Wiig, Øystein; Teixeira, Karollyna Da Silva; Sena, Leonardo; Oliveira, Halícia Celeste Santos De & Mendes-Oliveira, Ana Cristina (2023). Identifying individual jaguars from camera-trap images using the HotSpotter program. Mammalia (Paris). ISSN 0025-1461. 87(6). doi: 10.1515/mammalia-2023-0071. Full text in Research Archive
• Montserrat, Torres-Oliva; Anmarkrud, Jarl Andreas; Arnesen, Paal; Arnesen, Øyvind Kongstun; Arnold, Philipp & Blaj, Iulia [Show all 27 contributors for this article] (2023). Whole-genome sequencing of reindeer (Rangifer tarandus) populations reveals independent origins of dwarf ecotypes and potential molecular mechanisms underpinning cold adaptation. Research Square. ISSN 2693-5015. doi: 10.21203/rs.3.rs-3619721/v1. Full text in Research Archive
• Suárez-Menéndez, M.; Berube, Martine; Bachmann, Lutz; Best, Peter B.; Heide-Jørgensen, Mads Peter & Lesage, V. [Show all 17 contributors for this article] (2023). Universal baleen whale microsatellite panel for individual identification and power to detect parentage. BioRxiv. ISSN 0362-4331. doi: 10.1101/2023.04.12.536337. Full text in Research Archive
• Oliveira, Geovana Linhares de; Viana-Junior, Arleu Barbosa; Trindade, Paulo Henrique Santos; Santos, Iara Ramos dos Santos1,3; Almeida-Maués, Paula Cristina R. de & Carvalho, Fernando Geraldo [Show all 10 contributors for this article] (2023). Wild canids and the ecological traps facing the climate change and deforestation in the Amazon Forest. Ecology and Evolution. 13(6). doi: 10.1002/ece3.10150. Full text in Research Archive
• Yu, Fangzhou; Bignon-Lau, Olivier; Pedersen, Åshild Ønvik; Strand, Olav; Veiberg, Vebjørn & Wiig, Øystein [Show all 7 contributors for this article] (2023). Morphometrics highlights subspecies differentiation of continental (Rangifer t. tarandus) and insular (Rangifer t. platyrhynchus) Norwegian reindeer. Mammalia (Paris). ISSN 0025-1461. doi: 10.1515/mammalia-2023-0004. Full text in Research Archive
• Laidre, Kristin L.; Durner, George M.; Lunn, Nicholas J.; Regehr, Eric V.; Atwood, Todd C. & Rode, Karyn D. [Show all 14 contributors for this article] (2022). The role of satellite telemetry data in 21st century conservation of polar bears (Ursus maritimus). Frontiers in Marine Science. 9. doi: 10.3389/fmars.2022.816666. Full text in Research Archive Show summary

  Satellite telemetry (ST) has played a critical role in the management and conservation of polar bears (Ursus maritimus) over the last 50 years. ST data provide biological information relevant to subpopulation delineation, movements, habitat use, maternal denning, health, human-bear interactions, and accurate estimates of vital rates and abundance. Given that polar bears are distributed at low densities over vast and remote habitats, much of the information provided by ST data cannot be collected by other means. Obtaining ST data for polar bears requires chemical immobilization and application of a tracking device. Although immobilization has not been found to have negative effects beyond a several-day reduction in activity, over the last few decades opposition to immobilization and deployment of satellite-linked radio collars has resulted in a lack of current ST data in many of the 19 recognized polar bear subpopulations. Here, we review the uses of ST data for polar bears and evaluate its role in addressing 21st century conservation and management challenges, which include estimation of sustainable harvest rates, understanding the impacts of climate warming, delineating critical habitat, and assessing potential anthropogenic impacts from tourism, resource development and extraction. We found that in subpopulations where ST data have been consistently collected, information was available to estimate vital rates and subpopulation density, document the effects of sea-ice loss, and inform management related to subsistence harvest and regulatory requirements. In contrast, a lack of ST data in some subpopulations resulted in increased bias and uncertainty in ecological and demographic parameters, which has a range of negative consequences. As sea-ice loss due to climate warming continues, there is a greater need to monitor polar bear distribution, habitat use, abundance, and subpopulation connectivity. We conclude that continued collection of ST data will be critically important for polar bear management and conservation in the 21st century and that the benefits of immobilizing small numbers of individual polar bears in order to deploy ST devices significantly outweigh the risks.

• Lan, Tianying; Leppälä, Kalle; Tomlin, Crystal; Talbot, Sandra L; Sage, George K. & Farley, Sean [Show all 15 contributors for this article] (2022). Insights into bear evolution from a Pleistocene polar bear genome. Proceedings of the National Academy of Sciences of the United States of America (PNAS). ISSN 0027-8424. 119. doi: 10.1073/pnas.2200016119. Full text in Research Archive Show summary

  The polar bear (Ursus maritimus) has become a symbol of the threat to biodiversity from climate change. Understanding polar bear evolutionary history may provide insights into apex carnivore responses and prospects during periods of extreme environmental perturbations. In recent years, genomic studies have examined bear speciation and population history, including evidence for ancient admixture between polar bears and brown bears (Ursus arctos). Here, we extend our earlier studies of a 130,000- to 115,000-y-old polar bear from the Svalbard Archipelago using a 10× coverage genome sequence and 10 new genomes of polar and brown bears from contemporary zones of overlap in northern Alaska. We demonstrate a dramatic decline in effective population size for this ancient polar bear’s lineage, followed by a modest increase just before its demise. A slightly higher genetic diversity in the ancient polar bear suggests a severe genetic erosion over a prolonged bottleneck in modern polar bears. Statistical fitting of data to alternative admixture graph scenarios favors at least one ancient introgression event from brown bears into the ancestor of polar bears, possibly dating back over 150,000 y. Gene flow was likely bidirectional, but allelic transfer from brown into polar bear is the strongest detected signal, which contrasts with other published work. These findings may have implications for our understanding of climate change impacts: Polar bears, a specialist Arctic lineage, may not only have undergone severe genetic bottlenecks but also been the recipient of generalist, boreal genetic variants from brown bears during critical phases of Northern Hemisphere glacial oscillations.

• Dietz, Rune; Letcher, Robert J.; Aars, Jon; Andersen, Magnus; Boltunov, Andrei & Born, Erik W. [Show all 42 contributors for this article] (2022). A risk assessment review of mercury exposure in Arctic marine and terrestrial mammals. Science of the Total Environment. ISSN 0048-9697. 829. doi: 10.1016/j.scitotenv.2022.154445. Full text in Research Archive Show summary

  There has been a considerable number of reports on Hg concentrations in Arctic mammals since the last Arctic Monitoring and Assessment Programme (AMAP) effort to review biological effects of the exposure to mercury (Hg) in Arctic biota in 2010 and 2018. Here, we provide an update on the state of the knowledge of health risk associated with Hg concentrations in Arctic marine and terrestrial mammal species. Using available population-specific data post-2000, our ultimate goal is to provide an updated evidence-based estimate of the risk for adverse health effects from Hg exposure in Arctic mammal species at the individual and population level. Tissue residues of Hg in 13 species across the Arctic were classified into five risk categories (from No risk to Severe risk) based on critical tissue concentrations derived from experimental studies on harp seals and mink. Exposure to Hg lead to low or no risk for health effects in most populations of marine and terrestrial mammals, however, subpopulations of polar bears, pilot whales, narwhals, beluga and hooded seals are highly exposed in geographic hotspots raising concern for Hg-induced toxicological effects. About 6% of a total of 3500 individuals, across different marine mammal species, age groups and regions, are at high or severe risk of health effects from Hg exposure. The corresponding figure for the 12 terrestrial species, regions and age groups was as low as 0.3% of a total of 731 individuals analyzed for their Hg loads. Temporal analyses indicated that the proportion of polar bears at low or moderate risk has increased in East/West Greenland and Western Hudson Bay, respectively. However, there remain numerous knowledge gaps to improve risk assessments of Hg exposure in Arctic mammalian species, including the establishment of improved concentration thresholds and upscaling to the assessment of population-level effects.

• Cabrera, Andrea A.; Schall, Elena; Bérubé, Martine; Anderwald, Pia; Bachmann, Lutz & Berrow, Simon [Show all 37 contributors for this article] (2022). Strong and lasting impacts of past global warming on baleen whales and their prey. Global Change Biology. ISSN 1354-1013. 28(8), p. 2657–2677. doi: 10.1111/gcb.16085. Full text in Research Archive Show summary

  Global warming is affecting the population dynamics and trophic interactions across a wide range of ecosystems and habitats. Translating these real-time effects into their long-term consequences remains a challenge. The rapid and extreme warming period that occurred after the Last Glacial Maximum (LGM) during the Pleistocene–Holocene transition (7–12 thousand years ago) provides an opportunity to gain insights into the long-term responses of natural populations to periods with global warming. The effects of this post-LGM warming period have been assessed in many terrestrial taxa, whereas insights into the impacts of rapid global warming on marine taxa remain limited, especially for megafauna. In order to understand how large-scale climate fluctuations during the post-LGM affected baleen whales and their prey, we conducted an extensive, large-scale analysis of the long-term effects of the post-LGM warming on abundance and inter-ocean connectivity in eight baleen whale and seven prey (fish and invertebrates) species across the Southern and the North Atlantic Ocean; two ocean basins that differ in key oceanographic features. The analysis was based upon 7032 mitochondrial DNA sequences as well as genome-wide DNA sequence variation in 100 individuals. The estimated temporal changes in genetic diversity during the last 30,000 years indicated that most baleen whale populations underwent post-LGM expansions in both ocean basins. The increase in baleen whale abundance during the Holocene was associated with simultaneous changes in their prey and climate. Highly correlated, synchronized and exponential increases in abundance in both baleen whales and their prey in the Southern Ocean were indicative of a dramatic increase in ocean productivity. In contrast, the demographic fluctuations observed in baleen whales and their prey in the North Atlantic Ocean were subtle, varying across taxa and time. Perhaps most important was the observation that the ocean-wide expansions and decreases in abundance that were initiated by the post-LGM global warming, continued for millennia after global temperatures stabilized, reflecting persistent, long-lasting impacts of global warming on marine fauna.

• Cerca, José; Westbury, Michael V; Heide-Jørgensen, Mads-Peter; Kovacs, Kit M.; Lorenzen, Eline D. & Lydersen, Christian [Show all 9 contributors for this article] (2022). High genomic diversity in the endangered East Greenland Svalbard Barents Sea stock of bowhead whales (Balaena mysticetus). Scientific Reports. 12. doi: 10.1038/s41598-022-09868-5. Full text in Research Archive Show summary

  The East Greenland-Svalbard-Barents Sea (EGSB) bowhead whale stock (Balaena mysticetus) was hunted to near extinction and remains Endangered on the International Union of Conservation of Nature Red List. The intense, temporally extensive hunting pressure may have left the population vulnerable to other perturbations, such as environmental change. However, the lack of genomic baseline data renders it difficult to evaluate the impacts of various potential stressors on this stock. Twelve EGSB bowhead whales sampled in 2017/2018 were re-sequenced and mapped to a previously published draft genome. All individuals were unrelated and void of significant signs of inbreeding, with similar observed and expected homo- and heterozygosity levels. Despite the small population size, mean autosome-wide heterozygosity was 0.00102, which is higher than that of most mammals for which comparable estimates are calculated using the same parameters, and three times higher than a conspecific individual from the Eastern-Canada-West-Greenland bowhead whale stock. Demographic history analyses indicated a continual decrease of Ne from ca. 1.5 million to ca. 250,000 years ago, followed by a slight increase until ca. 100,000 years ago, followed by a rapid decrease in Ne between 50,000 and 10,000 years ago. These estimates are lower than previously suggested based on mitochondrial DNA, but suggested demographic patterns over time are similar.

• Hamilton, Charmain D.; Lydersen, Christian; Aars, Jon; Acquarone, Mario; Atwood, Todd & Baylis, Alastair [Show all 56 contributors for this article] (2022). Marine mammal hotspots across the circumpolar Arctic. Diversity and Distributions: A Journal of Conservation Biogeography. ISSN 1366-9516. 28(12), p. 2729–2753. doi: 10.1111/ddi.13543. Full text in Research Archive Show summary

  Aim: Identify hotspots and areas of high species richness for Arctic marine mammals. Location: Circumpolar Arctic. Methods: A total of 2115 biologging devices were deployed on marine mammals from 13 species in the Arctic from 2005 to 2019. Getis-Ord Gi* hotspots were calculated based on the number of individuals in grid cells for each species and for phyloge-netic groups (nine pinnipeds, three cetaceans, all species) and areas with high spe-cies richness were identified for summer (Jun-Nov), winter (Dec-May) and the entire year. Seasonal habitat differences among species’ hotspots were investigated using Principal Component Analysis. Results: Hotspots and areas with high species richness occurred within the Arctic continental-shelf seas and within the marginal ice zone, particularly in the “Arctic gateways” of the north Atlantic and Pacific oceans. Summer hotspots were generally found further north than winter hotspots, but there were exceptions to this pattern, including bowhead whales in the Greenland-Barents Seas and species with coastal distributions in Svalbard, Norway and East Greenland. Areas with high species rich-ness generally overlapped high-density hotspots. Large regional and seasonal dif-ferences in habitat features of hotspots were found among species but also within species from different regions. Gap analysis (discrepancy between hotspots and IUCN ranges) identified species and regions where more research is required. Main conclusions: This study identified important areas (and habitat types) for Arctic marine mammals using available biotelemetry data. The results herein serve as a benchmark to measure future distributional shifts. Expanded monitoring and teleme-try studies are needed on Arctic species to understand the impacts of climate change and concomitant ecosystem changes (synergistic effects of multiple stressors). While efforts should be made to fill knowledge gaps, including regional gaps and more com-plete sex and age coverage, hotspots identified herein can inform management ef-forts to mitigate the impacts of human activities and ecological changes, including creation of protected areas.

• Laidre, Kristin L.; Supple, Megan A.; Born, Erik W.; Regehr, Eric V.; Wiig, Øystein & Ugarte, Fernando [Show all 19 contributors for this article] (2022). Glacial ice supports a distinct and undocumented polar bear subpopulation persisting in late 21st-century sea-ice conditions. Science. ISSN 0036-8075. 376(6599), p. 1333–1338. doi: 10.1126/science.abk2793. Full text in Research Archive Show summary

  Polar bears are susceptible to climate warming because of their dependence on sea ice, which is declining rapidly. We present the first evidence for a genetically distinct and functionally isolated group of polar bears in Southeast Greenland. These bears occupy sea-ice conditions resembling those projected for the High Arctic in the late 21st century, with an annual ice-free period that is >100 days longer than the estimated fasting threshold for the species. Whereas polar bears in most of the Arctic depend on annual sea ice to catch seals, Southeast Greenland bears have a year-round hunting platform in the form of freshwater glacial mélange. This suggests that marine-terminating glaciers, although of limited availability, may serve as previously unrecognized climate refugia. Conservation of Southeast Greenland polar bears, which meet criteria for recognition as the world’s 20th polar bear subpopulation, is necessary to preserve the genetic diversity and evolutionary potential of the species.

• Stern, Jennifer H.; Laidre, Kristin L.; Born, Erik W.; Wiig, Øystein; Sonne, Christian & Dietz, Rune [Show all 8 contributors for this article] (2021). Feeding habits of Baffin Bay polar bears Ursus maritimus: insight from stable isotopes and total mercury in hair. Marine Ecology Progress Series. ISSN 0171-8630. 677, p. 233–244. doi: 10.3354/MEPS13864. Full text in Research Archive
• Hamilton, Charmain Danielle; Lydersen, Christian; Aars, Jon; Biuw, Martin; Boltunov, Andrei & Born, Erik W. [Show all 23 contributors for this article] (2021). Marine mammal hotspots in the Greenland and Barents Seas. Marine Ecology Progress Series. ISSN 0171-8630. 659, p. 3–28. doi: 10.3354/meps13584. Full text in Research Archive Show summary

  Environmental change and increasing levels of human activity are threats to marine mam- mals in the Arctic. Identifying marine mammal hot - spots and areas of high species richness are essential to help guide management and conservation efforts. Herein, space use based on biotelemetric tracking devices deployed on 13 species (ringed seal <i>Pusa hispida</i>, bearded seal <i>Erignathus barbatus</i> , harbour seal <i>Phoca vitulina</i>, walrus <i>Odobenus rosmarus</i>, harp seal <i>Pagophilus groenlandicus</i>, hooded seal <i>Cysto - phora cristata</i>, polar bear <i>Ursus maritimus</i> , bowhead whale <i>Balaena mysticetus</i>, narwhal <i>Monodon mono- ceros</i>, white whale <i>Delphinapterus leucas</i> , blue whale <i>Balaenoptera musculus</i> , fin whale <i>Balaeno - ptera</i> phy salus and humpback whale <i>Megaptera novaeangliae</i>; total = 585 individuals) in the Green- land and northern Barents Seas between 2005 and 2018 is reported. Getis−Ord Gi* hotspots were calcu- lated for each species as well as all species combined, and areas of high species richness were identified for summer/autumn (Jun−Dec), winter/spring (Jan− May) and the entire year. The marginal ice zone (MIZ) of the Greenland Sea and northern Barents Sea, the waters surrounding the Svalbard Archipel- ago and a few Northeast Greenland coastal sites were identified as key marine mammal hotspots and areas of high species richness in this region. Individ- ual hotspots identified areas important for most of the tagged animals, such as common resting, nursing, moulting and foraging areas. Location hotspots iden- tified areas heavily used by segments of the tagged populations, including denning areas for polar bears and foraging areas. The hotspots identified herein are also important habitats for seabirds and fishes, and thus conservation and management measures targeting these regions would benefit multiple groups of Arctic animals.

• Atkinson, Stephen; Laidre, Kristin L.; Arnold, Todd W.; Stapleton, Seth; Regehr, Eric V. & Born, Erik W. [Show all 11 contributors for this article] (2021). A novel mark-recapture-recovery survey using genetic sampling for polar bears Ursus maritimus in Baffin Bay. Endangered Species Research. ISSN 1863-5407. 46, p. 105–120. doi: 10.3354/ESR01148. Full text in Research Archive Show summary

  Changes in sea-ice dynamics are affecting polar bears Ursus maritimus across their circumpolar range, which highlights the importance of periodic demographic assessments to inform management and conservation. We used genetic mark-recapture-recovery to derive estimates of abundance and survival for the Baffin Bay (BB) polar bear subpopulation—the first time this method has been used successfully for this species. Genetic data from tissue samples we collected via biopsy darting were combined with historical physical capture and harvest recovery data. The combined data set consisted of 1410 genetic samples (2011-2013), 914 physical captures (1993-1995, 1997), and 234 harvest returns of marked bears (1993-2013). The estimate of mean subpopulation abundance was 2826 (95% CI = 2284-3367) in 2012-2013. Estimates of annual survival (mean ± SE) were 0.90 ± 0.05 and 0.78 ± 0.06 for females and males age ≥2 yr, respectively. The proportion of total mortality of adult females and males that was attributed to legal harvest was 0.16 ± 0.05 and 0.26 ± 0.06, respectively. Remote sensing sea-ice data, telemetry data, and spatial distribution of onshore sampling indicated that polar bears were more likely to use offshore sea-ice habitat during the 1990s sampling period compared to the 2010s. Furthermore, in the 1990s, sampling of deep fjords and inland areas was limited, and no offshore sampling occurred in either time period, which precluded comparisons of abundance between the 1993-1997 and 2011-2013 study periods. Our findings demonstrate that genetic sampling can be a practical method for demographic assessment of polar bears over large spatial and temporal scales.

• Wiig, Øystein; Atkinson, Stephen N.; Born, Erik W; Stapleton, Seth; Arnold, Todd & Dyck, Markus [Show all 9 contributors for this article] (2021). An on-ice aerial survey of the Kane Basin polar bear (Ursus maritimus) subpopulation. Polar Biology. ISSN 0722-4060. doi: 10.1007/s00300-021-02974-6. Full text in Research Archive Show summary

  Abstract There is an imminent need to collect information on distribution and abundance of polar bears ( Ursus maritimus ) to understand how they are affected by the ongoing decrease in Arctic sea ice. The Kane Basin (KB) subpopulation is a group of high-latitude polar bears that ranges between High Arctic Canada and NW Greenland around and north of the North Water polynya (NOW). We conducted a line transect distance sampling aerial survey of KB polar bears during 28 April–12 May 2014. A total of 4160 linear kilometers were flown in a helicopter over fast ice in the fjords and over offshore pack ice between 76° 50′ and 80° N′. Using a mark-recapture distance sampling protocol, the estimated abundance was 190 bears (95% lognormal CI: 87–411; CV 39%). This estimate is likely negatively biased to an unknown degree because the offshore sectors of the NOW with much open water were not surveyed because of logistical and safety reasons. Our study demonstrated that aerial surveys may be a feasible method for obtaining abundance estimates for small subpopulations of polar bears.

• Maduna, Simo; Aars, Jon; Fløystad, Ida; Klutsch, Cornelya; Fiskebeck, Eve Marie Louise Zeyl & Wiig, Øystein [Show all 13 contributors for this article] (2021). Sea ice reduction drives genetic differentiation among Barents Sea polar bears. Proceedings of the Royal Society of London. Biological Sciences. ISSN 0962-8452. 288(1958), p. 1–10. doi: 10.1098/rspb.2021.1741. Full text in Research Archive Show summary

  Loss of Arctic sea ice owing to climate change is predicted to reduce both genetic diversity and gene flow in ice-dependent species, with potentially negative consequences for their long-term viability. Here, we tested for the population-genetic impacts of reduced sea ice cover on the polar bear (Ursus maritimus) sampled across two decades (1995–2016) from the Svalbard Archipelago, Norway, an area that is affected by rapid sea ice loss in the Arctic Barents Sea. We analysed genetic variation at 22 microsatellite loci for 626 polar bears from four sampling areas within the archipelago. Our results revealed a 3–10% loss of genetic diversity across the study period, accompanied by a near 200% increase in genetic differentiation across regions. These effects may best be explained by a decrease in gene flow caused by habitat fragmentation owing to the loss of sea ice coverage, resulting in increased inbreeding of local polar bears within the focal sampling areas in the Svalbard Archipelago. This study illustrates the importance of genetic monitoring for developing adaptive management strategies for polar bears and other ice-dependent species.

• Loch, Carolina; Hemm, Louisa; Taylor, Bertie; Visser, Ingrid N. & Wiig, Øystein (2021). Microstructure, elemental composition and mechanical properties of enamel and dentine in the polar bear Ursus maritimus. Archives of Oral Biology. ISSN 0003-9969. 134. doi: 10.1016/j.archoralbio.2021.105318. Full text in Research Archive
• Cubaynes, Sarah; Aars, Jon; Yoccoz, Nigel; Pradel, Roger; Wiig, Øystein & Ims, Rolf Anker [Show all 7 contributors for this article] (2021). Modeling the demography of species providing extended parental care: A capture–recapture multievent model with a case study on polar bears (Ursus maritimus). Ecology and Evolution. 11(7), p. 3380–3392. doi: 10.1002/ece3.7296. Full text in Research Archive Show summary

  1. In species providing extended parental care, one or both parents care for altricial young over a period including more than one breeding season. We expect large parental investment and long-term dependency within family units to cause high variability in life trajectories among individuals with complex consequences at the population level. So far, models for estimating demographic parameters in free-ranging animal populations mostly ignore extended parental care, thereby limiting our understanding of its consequences on parents and offspring life histories. 2. We designed a capture–recapture multievent model for studying the demography of species providing extended parental care. It handles statistical multiple-year dependency among individual demographic parameters grouped within family units, variable litter size, and uncertainty on the timing at offspring independence. It allows for the evaluation of trade-offs among demographic parameters, the influence of past reproductive history on the caring parent's survival status, breeding probability, and litter size probability, while accounting for imperfect detection of family units. We assess the model performance using simulated data and illustrate its use with a long-term dataset collected on the Svalbard polar bears (Ursus maritimus). 3. Our model performed well in terms of bias and mean square error and in estimating demographic parameters in all simulated scenarios, both when offspring departure probability from the family unit occurred at a constant rate or varied during the field season depending on the date of capture. For the polar bear case study, we provide estimates of adult and dependent offspring survival rates, breeding probability, and litter size probability. Results showed that the outcome of the previous reproduction influenced breeding probability. 4. Overall, our results show the importance of accounting for i) the multiple-year statistical dependency within family units, ii) uncertainty on the timing at offspring independence, and iii) past reproductive history of the caring parent. If ignored, estimates obtained for breeding probability, litter size, and survival can be biased. This is of interest in terms of conservation because species providing extended parental care are often long-living mammals vulnerable or threatened with extinction.

• Born, Erik W; Wiig, Øystein & Olsen, M Tange (2021). The future of Atlantic walrus in a warming Arctic. In Weber, Xenia; Olsen, Morten Tange; Jordan, Peter & Desjardins, Sean P.A. (Ed.), The Atlantic Walrus: Biological, Historical, and Indigenous Insights into the Species-Human Interactions. Academic Press. ISSN 9780128174302. p. 309–332. doi: 10.1016/B978-0-12-817430-2.00012-1. Full text in Research Archive
• Born, Erik W; Wiig, Øystein & Olsen, M. Tange (2021). Anthropogenic impacts on Atlantic walrus. In Weber, Xenia; Olsen, Morten Tange; Jordan, Peter & Desjardins, Sean P.A. (Ed.), The Atlantic Walrus: Biological, Historical, and Indigenous Insights into the Species-Human Interactions. Academic Press. ISSN 9780128174302. p. 263–308. doi: 10.1016/B978-0-12-817430-2.00013-3. Full text in Research Archive
• Born, Erik W & Wiig, Øystein (2021). Ecology and behavior of Atlantic walrus. In Weber, Xenia; Olsen, Morten Tange; Jordan, Peter & Desjardins, Sean P.A. (Ed.), The Atlantic Walrus: Biological, Historical, and Indigenous Insights into the Species-Human Interactions. Academic Press. ISSN 9780128174302. p. 39–76. doi: 10.1016/B978-0-12-817430-2.00001-7. Full text in Research Archive
• Laidre, Kristin L.; Atkinson, Stephen; Regehr, Eric V.; Stern, Harry; Born, Erik W. & Wiig, Øystein [Show all 8 contributors for this article] (2020). Interrelated ecological impacts of climate change on an apex predator. Ecological Applications. ISSN 1051-0761. 30(4). doi: 10.1002/eap.2071. Full text in Research Archive
• Bachmann, Lutz; Cabrera, Andrea A.; Heide-Jørgensen, Mads Peter; Shpak, Olga V.; Lydersen, Christian & Wiig, Øystein [Show all 7 contributors for this article] (2020). Mitogenomics and the genetic differentiation of contemporary Balaena mysticetus (Cetacea) from Svalbard. Zoological Journal of the Linnean Society. ISSN 0024-4082. 191(4), p. 1192–1203. doi: 10.1093/zoolinnean/zlaa082. Full text in Research Archive Show summary

  Full mitochondrial genomes were assembled for 12 recently sampled animals from the Svalbard bowhead whale (Balaena mysticetus) stock via high-throughput sequencing data, facilitating analysis of the demographic history of the population for the first time. The Svalbard population has retained noticeable amounts of mitochondrial genome diversity despite extreme historical harvest levels. Haplotype and nucleotide diversities were similar to those estimated earlier for other bowhead whale populations. The reconstructed demographic history was in accordance with a boom–bust scenario, combining a slight Pleistocene population growth 25 000–35 000 years ago and a Holocene decline. Employing a mutation rate of 3.418 × 10^–8 substitutions per site per year, the time to the most recent common ancestor for the mitochondrial genomes of the contemporary Svalbard bowhead whales was estimated to be 68 782 (54 353–83 216) years before the present. Based on 370 bp fragments of the D-loop region, significant genetic differentiation was detected between all extant bowhead whale populations across the circumpolar Arctic. Thus, the Svalbard bowhead whales can be regarded as a population with its own genetic legacy.

• Sinding, Mikkel Holger Strander; Gopalakrishnan, Shyam; Ramos-Madrigal, Jazmín; Manuel, Marc de; Pitulko, Vladimir V. & Kuderna, Lukas [Show all 35 contributors for this article] (2020). Arctic-adapted dogs emerged at the Pleistocene–Holocene transition. Science. ISSN 0036-8075. 368(6498), p. 1495–1499. doi: 10.1126/science.aaz8599. Full text in Research Archive Show summary

  Although sled dogs are one of the most specialized groups of dogs, their origin and evolution has received much less attention than many other dog groups. We applied a genomic approach to investigate their spatiotemporal emergence by sequencing the genomes of 10 modern Greenland sled dogs, an ~9500-year-old Siberian dog associated with archaeological evidence for sled technology, and an ~33,000-year-old Siberian wolf. We found noteworthy genetic similarity between the ancient dog and modern sled dogs. We detected gene flow from Pleistocene Siberian wolves, but not modern American wolves, to present-day sled dogs. The results indicate that the major ancestry of modern sled dogs traces back to Siberia, where sled dog–specific haplotypes of genes that potentially relate to Arctic adaptation were established by 9500 years ago.

• Lippold, Anna; Aars, Jon; Andersen, Magnus; Aubail, Aurore; Derocher, Andrew E. & Dietz, Rune [Show all 11 contributors for this article] (2020). Two decades of mercury concentrations in Barents Sea polar bears (Ursus maritimus) in relation to dietary carbon, sulfur, and nitrogen. Environmental Science and Technology. ISSN 0013-936X. 54(12), p. 7388–7397. doi: 10.1021/acs.est.0c01848. Full text in Research Archive
• Teixeira-Santos, Juliana; Ribeiro, Ana Carolina da Cunha; Wiig, Øystein; Pinto, Nelson Silva; Cantanhêde, Lorrane Gabrielle & Sena, Leonardo [Show all 7 contributors for this article] (2020). Environmental factors influencing the abundance of four species of threatened mammals in degraded habitats in the eastern Brazilian Amazon. PLOS ONE. 15(2), p. 1–16. doi: 10.1371/journal.pone.0229459. Full text in Research Archive
• Ramos-Madrigal, Jazmín; Sinding, Mikkel Holger Strander; Carøe, Christian; Mak, Sarah Siu Tze; Niemann, Jonas & Castruita, José A. Samaniego [Show all 27 contributors for this article] (2020). Genomes of Pleistocene Siberian Wolves Uncover Multiple Extinct Wolf Lineages. Current Biology. ISSN 0960-9822. 31(1), p. 198–206. doi: 10.1016/j.cub.2020.10.002. Full text in Research Archive Show summary

  Extant Canis lupus genetic diversity can be grouped into three phylogenetically distinct clades: Eurasian and American wolves and domestic dogs.1 Genetic studies have suggested these groups trace their origins to a wolf population that expanded during the last glacial maximum (LGM)1, 2, 3 and replaced local wolf populations.4 Moreover, ancient genomes from the Yana basin and the Taimyr peninsula provided evidence of at least one extinct wolf lineage that dwelled in Siberia during the Pleistocene.35 Previous studies have suggested that Pleistocene Siberian canids can be classified into two groups based on cranial morphology. Wolves in the first group are most similar to present-day populations, although those in the second group possess intermediate features between dogs and wolves.67 However, whether this morphological classification represents distinct genetic groups remains unknown. To investigate this question and the relationships between Pleistocene canids, present-day wolves, and dogs, we resequenced the genomes of four Pleistocene canids from Northeast Siberia dated between >50 and 14 ka old, including samples from the two morphological categories. We found these specimens cluster with the two previously sequenced Pleistocene wolves, which are genetically more similar to Eurasian wolves. Our results show that, though the four specimens represent extinct wolf lineages, they do not form a monophyletic group. Instead, each Pleistocene Siberian canid branched off the lineage that gave rise to present-day wolves and dogs. Finally, our results suggest the two previously described morphological groups could represent independent lineages similarly related to present-day wolves and dogs.

• Laidre, Kristin L.; Atkinson, Stephen; Regehr, Eric V.; Stern, Harry; Born, Erik W. & Wiig, Øystein [Show all 10 contributors for this article] (2020). Transient benefits of climate change for a high-Arctic polar bear (Ursus maritimus) subpopulation. Global Change Biology. ISSN 1354-1013. 26(11), p. 6251–6265. doi: 10.1111/gcb.15286. Full text in Research Archive
• Ameen, Carly; Feuerborn, Tatiana R.; Brown, Sarah K.; Linderholm, Anna; Hulme-Beaman, Ardern & Lebrasseur, Ophélie [Show all 59 contributors for this article] (2019). Specialized sledge dogs accompanied Inuit dispersal across the North American Arctic. Proceedings of the Royal Society of London. Biological Sciences. ISSN 0962-8452. 286:20291929(1929), p. 1–10. doi: 10.1098/rspb.2019.1929. Full text in Research Archive Show summary

  Domestic dogs have been central to life in the North American Arctic for millennia. The ancestors of the Inuit were the first to introduce the widespread usage of dog sledge transportation technology to the Americas, but whether the Inuit adopted local Palaeo-Inuit dogs or introduced a new dog population to the region remains unknown. To test these hypotheses, we generated mitochondrial DNA and geometric morphometric data of skull and dental elements from a total of 922 North American Arctic dogs and wolves spanning over 4500 years. Our analyses revealed that dogs from Inuit sites dating from 2000 BP possess morphological and genetic signatures that distinguish them from earlier Palaeo-Inuit dogs, and identified a novel mitochondrial clade in eastern Siberia and Alaska. The genetic legacy of these Inuit dogs survives today in modern Arctic sledge dogs despite phenotypic differences between archaeological and modern Arctic dogs. Together, our data reveal that Inuit dogs derive from a secondary pre-contact migration of dogs distinct from Palaeo-Inuit dogs, and probably aided the Inuit expansion across the North American Arctic beginning around 1000 BP.

• Grond, Joost; Piecha, Magdalena; Hahn, Christoph; Wiig, Øystein & Bachmann, Lutz (2019). Mitochondrial genomes of ancient bowhead whales (Balaena mysticetus) from Svalbard. Mitochondrial DNA Part B: Resources. 4(2), p. 4152–4154. doi: 10.1080/23802359.2019.1693284. Full text in Research Archive Show summary

  The endangered Spitsbergen stock of bowhead whales (Balaena mysticetus) has once been large with up to estimated 100,000 individuals. Genetic diversity of the extant Spitsbergen stock is unknown. We present 10 complete mitochondrial genomes of heterochronous ancient bowhead whale samples from Svalbard (14C age estimate range: 215–8885years) obtained via NGS of total genomic DNA extracts. The ten mitogenomes differed by nucleotide substitutions and/or indels, and there was a total of 160 variable positions. The average nucleotide diversity was p 1⁄4 0.0029. There was no statistically significant correlation between genetic divergence and time.

• González-Moreno, Pablo; Lazzaro, Lorenzo; Vilà, Montserrat; Preda, Cristina; Adriaens, Tim & Bacher, Sven [Show all 88 contributors for this article] (2019). Consistency of impact assessment protocols for non-native species. NeoBiota. ISSN 1619-0033. 44, p. 1–25. doi: 10.3897/neobiota.44.31650. Full text in Research Archive Show summary

  Standardized tools are needed to identify and prioritize the most harmful non-native species (NNS). A plethora of assessment protocols have been developed to evaluate the current and potential impacts of non-native species, but consistency among them has received limited attention. To estimate the consistency across impact assessment protocols, 89 specialists in biological invasions used 11 protocols to screen 57 NNS (2614 assessments). We tested if the consistency in the impact scoring across assessors, quantified as the coefficient of variation (CV), was dependent on the characteristics of the protocol, the taxonomic group and the expertise of the assessor. Mean CV across assessors was 40%, with a maximum of 223%. CV was lower for protocols with a low number of score levels, which demanded high levels of expertise, and when the assessors had greater expertise on the assessed species. The similarity among protocols with respect to the final scores was higher when the protocols considered the same impact types. We conclude that all protocols led to considerable inconsistency among assessors. In order to improve consistency, we highlight the importance of selecting assessors with high expertise, providing clear guidelines and adequate training but also deriving final decisions collaboratively by consensus.

• Wiig, Øystein; Bachmann, Lutz & Hufthammer, Anne Karin (2019). Late Pleistocene and Holocene occurrence of bowhead whales (Balaena mysticetus) along the coasts of Norway. Polar Biology. ISSN 0722-4060. 42(6), p. 645–656. doi: 10.1007/s00300-019-02460-0. Full text in Research Archive
• Folio, Dorinda Marie; Aars, Jon; Gimenez, Olivier; Derocher, Andrew E.; Wiig, Øystein & Cubaynes, Sarah (2019). How many cubs can a mum nurse? Maternal age and size influence litter size in polar bears. Biology Letters. ISSN 1744-9561. 15(5), p. 1–5. doi: 10.1098/rsbl.2019.0070. Full text in Research Archive
• Laidre, Kristin L.; Stern, Harry; Born, Erik W.; Heagerty, Patrick; Atkinson, Stephen & Wiig, Øystein [Show all 10 contributors for this article] (2018). Changes in winter and spring resource selection by polar bears Ursus maritimus in Baffin Bay over two decades of sea-ice loss. Endangered Species Research. ISSN 1863-5407. 36, p. 1–14. doi: 10.3354/esr00886. Full text in Research Archive Show summary

  Loss of Arctic sea ice has implications for the distribution and population structure of ice-dependent species such as polar bears Ursus maritimus. We used remotely sensed sea-ice concentration data for Baffin Bay, Canada, and satellite telemetry for adult female polar bears in the 1990s (n = 43) and 2000s (n = 38) to assess whether sea-ice habitat changes have influenced movements and habitat selection. Both the timing and availability of sea-ice habitat changed significantly between the 1990s and 2000s. Mean sea-ice concentration in June-October declined from 22 to 12%. Spring sea-ice retreat occurred 2 wk earlier and fall sea-ice advance 2 wk later in the 2000s. These changes translated directly to changes in habitat use by polar bears. In the 2000s, bears used significantly lower sea-ice concentrations in winter and spring. Also, bears were significantly closer to land in all months, except at the end of spring breakup when they remained on offshore sea ice as long as possible, likely to maximize foraging time prior to coming on land where they are largely food deprived. The presence of summer offshore sea ice facilitated broad movement of bears in the 1990s; however, this ice disappeared in the 2000s and resulted in significant declines in monthly movement rates. In the 2000s, adult females selected for lower sea-ice concentrations if they facilitated access to the continental shelf (<300 m). Our findings indicate that significant changes in available sea-ice habitat and habitat use in Baffin Bay have occurred since the mid-1990s and this subpopulation will likely experience negative population-level impacts related to a changing climate in the coming decades. In some other parts of the Arctic, such changes have preceded negative nutritional and demographic impacts.

• Sonne, Christian; Andersen-Ranberg, Emilie; Rajala, Elisabeth; Agerholm, Jørgen S.; Bonefeld-Jørgensen, Eva & Desforges, Jean-Pierre [Show all 22 contributors for this article] (2018). Prevalence of antibodies against Brucella spp. in West Greenland polar bears (Ursus maritimus) and East Greenland muskoxen (Ovibos moschatus). Polar Biology. ISSN 0722-4060. 41(9), p. 1671–1680. doi: 10.1007/s00300-018-2307-4. Full text in Research Archive Show summary

  Zoonotic infections transmitted from terrestrial and marine mammals to humans in European Arctic are of unknown significance, despite considerable potential for transmission due to local hunt and a rapidly changing environment. As an example, infection with Brucella bacteria may have significant impact on human health due to consumption of raw meat or otherwise contact with tissues and fluids of infected game species such as muskoxen and polar bears. Here, we present serological results for Baffin Bay polar bears (Ursus maritimus) (n = 96) and North East Greenland muskoxen (Ovibos moschatus) (n = 32) for antibodies against Brucella spp. The analysis was a two-step trial initially using the Rose Bengal Test (RBT), followed by confirmative competitive enzyme-linked immunosorbent assays of RBT-positive samples. No muskoxen had antibodies against Brucella spp., while antibodies were detected in six polar bears (6.25%) rendering a seroprevalence in line with previous findings in other Arctic regions. Seropositivity was not related to sex, age or biometrics i.e. size and body condition. Whether Brucella spp. antibodies found in polar bears were due to either prey spill over or true recurrent Brucella spp. infections is unknown. Our results therefore highlight the importance of further research into the zoonotic aspects of Brucella spp. infections, and the impact on wildlife and human health in the Arctic region.

• Sinding, Mikkel Holger Strander; Gopalakrishnan, Shyam; Vieira, Filipe G.; Samaniego, Jose A; Raundrup, Katrine & Jørgensen, Mads Peter Heide [Show all 18 contributors for this article] (2018). Population genomics of grey wolves and wolf-like canids in North America. PLoS Genetics. ISSN 1553-7390. 14:e1007745(11). doi: 10.1371/journal.pgen.1007745. Full text in Research Archive Show summary

  North America is currently home to a number of grey wolf (Canis lupus) and wolf-like canid populations, including the coyote (Canis latrans) and the taxonomically controversial red, Eastern timber and Great Lakes wolves. We explored their population structure and regional gene flow using a dataset of 40 full genome sequences that represent the extant diversity of North American wolves and wolf-like canid populations. This included 15 new genomes (13 North American grey wolves, 1 red wolf and 1 Eastern timber/Great Lakes wolf), ranging from 0.4 to 15x coverage. In addition to providing full genome support for the previously proposed coyote-wolf admixture origin for the taxonomically controversial red, Eastern timber and Great Lakes wolves, the discriminatory power offered by our dataset suggests all North American grey wolves, including the Mexican form, are monophyletic, and thus share a common ancestor to the exclusion of all other wolves. Furthermore, we identify three distinct populations in the high arctic, one being a previously unidentified “Polar wolf” population endemic to Ellesmere Island and Greenland. Genetic diversity analyses reveal particularly high inbreeding and low heterozygosity in these Polar wolves, consistent with long-term isolation from the other North American wolves.

• Selås, Vidar; Framstad, Erik; Sonerud, Geir Andreas; Wegge, Per & Wiig, Øystein (2018). Voles and climate in Norway: Is the abundance of herbivorous species inversely related to summer temperature? Acta Oecologica. ISSN 1146-609X. 95, p. 93–99. doi: 10.1016/j.actao.2018.12.002. Full text in Research Archive Show summary

  For several mammalian species, both population levels and distribution ranges are predicted to change due to changing habitat conditions caused by climate change. A general decrease in the amplitude of small rodent population cycles in northern Europe since the late 1980s has commonly been attributed to a lack of permanent snow cover during winter, or to unfavourable snow conditions. An alternative explanation is that increasing summer temperatures and an extended growing season are unfavourable for herbivorous rodents, by reducing the forage quality. If so, the negative effect should be stronger for the strictly herbivorous Microtus voles than for the herbivorous-granivorous Myodes voles. In a previous study small rodents were snap trapped in 22 regions in Norway during 1971–1979. We found that the trapping index of Microtus voles, but not Myodes voles, in this study was negatively related to summer temperatures. Both in this study and in a snap trapping study from 1994 to 2015, conducted in 13 study areas in Norway, the proportion of Microtus voles among voles captured was negatively related to summer temperatures. Summer temperature was a better predictor than snow depth, but both variables contributed significantly in multiple regression models. We conclude that summer temperature is likely to be a more important factor than snow cover for the population dynamics of herbivorous voles in northern Europe.

• Wiig, Øystein; Henrichsen, P.; Sjøvold, T.; Born, E.W.; Laidre, K.L. & Dietz, R. [Show all 8 contributors for this article] (2018). Variation in non-metrical skull traits (1830-2013) across East Greenland and adjacent polar bear (Ursus maritimus) subpopulations. Polar Biology. ISSN 0722-4060. doi: 10.1007/s00300-018-2435-x. Full text in Research Archive
• Stafford, K.M.; Lydersen, Christian; Wiig, Øystein & Kovacs, Kit M. (2018). Extreme diversity in the songs of Spitsbergen's bowhead whales. Biology Letters. ISSN 1744-9561. 14(4). doi: 10.1098/rsbl.2018.0056. Full text in Research Archive Show summary

  Almost all mammals communicate using sound, but few species produce complex songs. Two baleen whales sing complex songs that change annually, though only the humpback whale (Megaptera novaeangliae) has received much research attention. This study focuses on the other baleen whale singer, the bowhead whale (Balaena mysticetus). Members of the Spitsbergen bowhead whale population produced 184 different song types over a 3-year period, based on duty-cycled recordings from a site in Fram Strait in the northeast Atlantic. Distinct song types were recorded over short periods, lasting at most some months. This song diversity could be the result of population expansion, or immigration of animals from other populations that are no longer isolated from each other by heavy sea ice. However, this explanation does not account for the within season and annual shifting of song types. Other possible explanations for the extraordinary diversity in songs could be that it results either from weak selection pressure for interspecific identification or for maintenance of song characteristics or, alternatively, from strong pressure for novelty in a small population.

• Gopalakrishnan, Shyam; Sinding, Mikkel Holger Strander; Ramos-Madrigal, Jazmín; Niemann, Jonas; Castruita, Jose A. Samaniego & Vieira, Filipe G. [Show all 27 contributors for this article] (2018). Interspecific gene flow shaped the evolution of the genus Canis. Current Biology. ISSN 0960-9822. 28(21), p. 3441–3449. doi: 10.1016/j.cub.2018.08.041. Full text in Research Archive Show summary

  The evolutionary history of the wolf-like canids of the genus Canis has been heavily debated, especially regarding the number of distinct species and their relationships at the population and species level [1, 2, 3, 4, 5, 6]. We assembled a dataset of 48 resequenced genomes spanning all members of the genus Canis except the black-backed and side-striped jackals, encompassing the global diversity of seven extant canid lineages. This includes eight new genomes, including the first resequenced Ethiopian wolf (Canis simensis), one dhole (Cuon alpinus), two East African hunting dogs (Lycaon pictus), two Eurasian golden jackals (Canis aureus), and two Middle Eastern gray wolves (Canis lupus). The relationships between the Ethiopian wolf, African golden wolf, and golden jackal were resolved. We highlight the role of interspecific hybridization in the evolution of this charismatic group. Specifically, we find gene flow between the ancestors of the dhole and African hunting dog and admixture between the gray wolf, coyote (Canis latrans), golden jackal, and African golden wolf. Additionally, we report gene flow from gray and Ethiopian wolves to the African golden wolf, suggesting that the African golden wolf originated through hybridization between these species. Finally, we hypothesize that coyotes and gray wolves carry genetic material derived from a “ghost” basal canid lineage.

• Laidre, K.L.; Born, Erik W.; Atkinson, Stephen N.; Wiig, Øystein; Andersen, Liselotte W. & Lunn, Nicholas J. [Show all 11 contributors for this article] (2018). Range contraction and increasing isolation of a polar bear subpopulation in an era of sea ice loss. Ecology and Evolution. 8(4), p. 2062–2075. doi: 10.1002/ece3.3809. Full text in Research Archive Show summary

  Climate change is expected to result in range shifts and habitat fragmentation for many species. In the Arctic, loss of sea ice will reduce barriers to dispersal or eliminate movement corridors, resulting in increased connectivity or geographic isolation with sweeping implications for conservation. We used satellite telemetry, data from individually marked animals (research and harvest), and microsatellite genetic data to examine changes in geographic range, emigration, and interpopulation connectivity of the Baffin Bay (BB) polar bear (Ursus maritimus) subpopulation over a 25‐year period of sea‐ice loss. Satellite telemetry collected from n = 43 (1991–1995) and 38 (2009–2015) adult females revealed a significant contraction in subpopulation range size (95% bivariate normal kernel range) in most months and seasons, with the most marked reduction being a 70% decline in summer from 716,000 km2 (SE 58,000) to 211,000 km2 (SE 23,000) (p < .001). Between the 1990s and 2000s, there was a significant shift northward during the on‐ice seasons (2.6° shift in winter median latitude, 1.1° shift in spring median latitude) and a significant range contraction in the ice‐free summers. Bears in the 2000s were less likely to leave BB, with significant reductions in the numbers of bears moving into Davis Strait (DS) in winter and Lancaster Sound (LS) in summer. Harvest recoveries suggested both short and long‐term fidelity to BB remained high over both periods (83–99% of marked bears remained in BB). Genetic analyses using eight polymorphic microsatellites confirmed a previously documented differentiation between BB, DS, and LS; yet weakly differentiated BB from Kane Basin (KB) for the first time. Our results provide the first multiple lines of evidence for an increasingly geographically and functionally isolated subpopulation of polar bears in the context of long‐term sea‐ice loss. This may be indicative of future patterns for other polar bear subpopulations under climate change.

• Kinoshita, Emi; Kosintsev, P; Raichev, Evgeniy G.; Haukisalmi, Voitto K.; Kryukov, Alexey P. & Wiig, Øystein [Show all 9 contributors for this article] (2017). Molecular phylogeny of Eurasian badgers (Meles) around the distribution boundaries, revealed by analyses of mitochondrial DNA and Y-chromosomal genes. Biochemical Systematics and Ecology. ISSN 0305-1978. 71, p. 121–130. doi: 10.1016/j.bse.2017.01.011. Full text in Research Archive
• Andersen, L.W.; Jacobsen, M.W.; Lydersen, Christian; Semenova, V.; Boltunov, A.N. & Born, E.W. [Show all 8 contributors for this article] (2017). Walruses (Odobenus rosmarus rosmarus) in the Pechora Sea in the context of contemporary population structure of Northeast Atlantic walruses. Biological Journal of the Linnean Society. ISSN 0024-4066. 122(4), p. 897–915. doi: 10.1093/BIOLINNEAN/BLX093. Full text in Research Archive
• Daugaard-Petersen, T.; Langebæk, R.; Riget, F.; Letcher, R.J.; Hyldstryp, L. & Jenssen, J.E.B. [Show all 13 contributors for this article] (2017). Persistent organic pollutants, skull size and bone density of polar bears (Ursus maritimus) from East Greenland 1892-2015 and Svalbard 1964-2004. Environmental Research. ISSN 0013-9351. 162, p. 74–80. doi: 10.1016/j.envres.2017.12.009. Full text in Research Archive Show summary

  We investigated skull size (condylobasal length; CBL) and bone mineral density (BMD) in polar bears (Ursus maritimus) from East Greenland (n = 307) and Svalbard (n = 173) sampled during the period 1892–2015 in East Greenland and 1964–2004 at Svalbard. Adult males from East Greenland showed a continuous decrease in BMD from 1892 to 2015 (linear regression: p < 0.01) indicating that adult male skulls collected in the early pre-pollution period had the highest BMD. A similar decrease in BMD over time was not found for the East Greenland adult females. However, there was a non-significant trend that the skull size of adult East Greenland females was negatively correlated with collection year 1892–2015 (linear regression: p = 0.06). No temporal change was found for BMD or skull size in Svalbard polar bears (ANOVA: all p > 0.05) nor was there any significant difference in BMD between Svalbard and East Greenland subpopulations. Skull size was larger in polar bears from Svalbard than from East Greenland (two-way ANOVA: p = 0.003). T-scores reflecting risk of osteoporosis showed that adult males from both East Greenland and Svalbard are at risk of developing osteopenia. Finally, when correcting for age and sex, BMD in East Greenland polar bears increased with increasing concentrations of persistent organic pollutants (POPs) i.e. ΣPCB (polychlorinated biphenyls), ΣHCH (hexachlorohexane), HCB (hexachlorobenzene) and ΣPBDE (polybrominated diphenyl ethers) while skull size increased with ΣHCH concentrations all in the period 1999–2014 (multiple linear regression: all p < 0.05, n = 175). The results suggest that environmental changes over time, including exposure to POPs, may affect bone density and size of polar bears.

• Wiig, Øystein; Born, Erik W.; Laidre, Kristin L.; Dietz, Rune; Jensen, Mikkel Villum & Durner, George M. [Show all 11 contributors for this article] (2017). Performance and retention of lightweight satellite radio tags applied to the ears of polar bears (Ursus maritimus). Animal Biotelemetry. 5(1), p. 1–11. doi: 10.1186/s40317-017-0124-0. Full text in Research Archive Show summary

  Background Satellite telemetry studies provide information that is critical to the conservation and management of species affected by ecological change. Here we report on the performance and retention of two types (SPOT-227 and SPOT-305A) of ear-mounted Argos-linked satellite transmitters (i.e., platform transmitter terminal, or PTT) deployed on free-ranging polar bears in Eastern Greenland, Baffin Bay, Kane Basin, the southern Beaufort Sea, and the Chukchi Sea during 2007–2013. Results Transmissions from 142 out of 145 PTTs deployed on polar bears were received for an average of 69.3 days. The average functional longevity, defined as the number of days they transmitted while still attached to polar bears, for SPOT-227 was 56.8 days and for SPOT-305A was 48.6 days. Thirty-four of the 142 (24%) PTTs showed signs of being detached before they stopped transmitting, indicating that tag loss was an important aspect of tag failure. Furthermore, 10 of 26 (38%) bears that were re-observed following application of a PTT had a split ear pinna, suggesting that some transmitters were detached by force. All six PTTs that were still on bears upon recapture had lost the antenna, which indicates that antenna breakage was a significant contributor to PTT failure. Finally, only nine of the 142 (6%) PTTs—three of which were still attached to bears—had a final voltage reading close to the value indicating battery exhaustion. This suggests that battery exhaustion was not a major factor in tag performance. Conclusions The average functional longevity of approximately 2 months for ear-mounted PTTs (this study) is poor compared to PTT collars fitted to adult female polar bears, which can last for several years. Early failure of the ear-mounted PTTs appeared to be caused primarily by detachment from the ear or antenna breakage. We suggest that much smaller and lighter ear-mounted transmitters are necessary to reduce the risk of tissue irritation, tissue damage, and tag detachment, and with a more robust antenna design. Our results are applicable to other tag types (e.g., iridium and VHF systems) and to research on other large mammals that cannot wear radio collars.

• Escajeda, Erica; Laidre, Kristin L.; Born, Erik W.; Wiig, Øystein; Atkinson, Stephen & Dyck, Markus [Show all 9 contributors for this article] (2017). Identifying shifts in maternity den phenology and habitat characteristics of polar bears (Ursus maritimus) in Baffin Bay and Kane Basin. Polar Biology. ISSN 0722-4060. 41(1), p. 87–100. doi: 10.1007/s00300-017-2172-6. Full text in Research Archive
• Ahonen, Heidi; Stafford, Kathleen M.; Steur, Laura de; Lydersen, Christian; Wiig, Øystein & Kovacs, Kit M. (2017). The underwater soundscape in western Fram Strait: Breeding ground of Spitsbergen's endangered bowhead whales. Marine Pollution Bulletin. ISSN 0025-326X. 123(1-2), p. 97–112. doi: 10.1016/j.marpolbul.2017.09.019. Full text in Research Archive
• Aars, Jon; Marques, T.A.; Lone, K.; Andersen, Magnus; Wiig, Øystein & Fløystad, I.M.B. [Show all 8 contributors for this article] (2017). The number and distribution of polar bears in the western Barents Sea area. Polar Research. ISSN 0800-0395. 36(1), p. 1–15. doi: 10.1080/17518369.2017.1374125. Full text in Research Archive Show summary

  Polar bears have experienced a rapid loss of sea-ice habitat in the Barents Sea. Monitoring this subpopulation focuses on the effects on polar bear demography. In August 2015, we conducted a survey in the Norwegian Arctic to estimate polar bear numbers and reveal population substructure. DNA profiles from biopsy samples and ear tags identified on photographs revealed that about half of the bears in Svalbard, compared to only 4.5% in the pack ice north of the archipelago, were recognized recaptures. The recaptured bears had originally been marked in Svalbard, mostly in spring. The existence of a local Svalbard stock, and another ecotype of bears using the pack ice in autumn with low likelihood of visiting Svalbard, support separate population size estimation for the two areas. Mainly by aerial survey line transect distance sampling methods, we estimated that 264 (95% CI = 199 – 363) bears were in Svalbard, close to 241 bears estimated for August 2004. The pack ice area had an estimated 709 bears (95% CI = 334 – 1026). The pack ice and the total (Svalbard + pack ice, 973 bears, 95% CI = 665 – 1884) both had higher estimates compared to August 2004 (444 and 685 bears, respectively), but the increase was not significant. There is no evidence that the fast reduction of sea-ice habitat in the area has yet led to a reduction in population size. The carrying capacity is likely reduced significantly, but recovery from earlier depletion up to 1973 may still be ongoing.

• Regehr, E.V.; Laidre, K.L.; Akcakaya, H. Resit; Amstrup, Steven C.; Atwood, T.C. & Lunn, N.J. [Show all 10 contributors for this article] (2016). Conservation status of polar bears (Ursus maritimus)in relation to projected sea-ice declines. Biology Letters. ISSN 1744-9561. 12(12). doi: 10.1098/rsbl.2016.0556. Full text in Research Archive
• Nyhus, Erik Sanderud; Lindqvist, Charlotte; Kovacs, Kit; Lydersen, Christian; Wiig, Øystein & Bachmann, Lutz (2016). Mitogenomes of contemporary Spitsbergen stock bowhead whales (Balaena mysticetus). Mitochondrial DNA Part B: Resources. 1(1), p. 898–900. doi: 10.1080/23802359.2016.1258345. Full text in Research Archive Show summary

  The Spitsbergen stock of bowhead whales (Balaena mysticetus) is considered Critically Endangered by IUCN. Over recent decades, there have been only a few sightings, and very few biological samples are available for molecular analyses. Hence, genetic diversity of the extant Spitsbergen stock is unknown. Here, we present mitochondrial genomes from eight skin biopsy samples that were collected in 2006 and 2010. There were three different haplotypes, two of which have not previously been detected. Six samples shared the same haplotype, indicating that they were obtained from closely related whales, or possibly the same individual. Average nucleotide diversity was π = 0.0037, with a total of 93 variable positions among the haplotypes.

• Lindqvist, Charlotte; Roy, Tilottama; Lydersen, Christian; Kovacs, Kit; Aars, Jon & Wiig, Øystein [Show all 7 contributors for this article] (2016). Genetic diversity of historical Atlantic walruses (Odobenus rosmarus rosmarus) from Bjørnøya and Håøya (Tusenøyane), Svalbard, Norway. BMC Research Notes. 9. doi: 10.1186/s13104-016-1907-8. Full text in Research Archive Show summary

  Background The population size of Atlantic walruses (Odobenus rosmarus rosmarus) is depleted relative to historical abundance levels. In Svalbard, centuries of over-exploitation brought the walrus herds to the verge of extinction, and such bottlenecks may have caused loss of genetic variation. To address this for Svalbard walruses, mitochondrial haplotypes of historical walruses from two major haul-out sites, Bjørnøya and Håøya, within the Archipelago were explored using bone samples from animals killed during the peak period of harvesting. Results Using ancient DNA methodologies, the mitochondrial NADH dehydrogenase 1 (ND1) gene, the cytochrome c oxidase 1 (COI) gene, and the control region (CR) were targeted for 15 specimens from Bjørnøya (of which five were entirely negative) and 9 specimens from Håøya (of which one was entirely negative). While ND1 and COI sequences were obtained for only a few samples, the CR delivered the most comprehensive data set, and the average genetic distance among historic Svalbard samples was 0.0028 (SD = 0.0023). Conclusions The CR sequences from the historical samples appear to be nested among contemporary Atlantic walruses, and no distinct mitochondrial haplogroups were identified in the historical samples that may have been lost during the periods of extensive hunting. However, given the low sample size and poor phylogenetic resolution it cannot be excluded that such haplogroups existed.

• Wiig, Øystein; Amstrup, S.C.; Atwood, T.; Laidre, K.; Lunn, N. & Obbard, M. [Show all 8 contributors for this article] (2015). Ursus maritimus. The IUCN Red List of Threatened Species. doi: 10.2305/IUCN.UK.2015-4.RLTS.T22823A14871490.en. Full text in Research Archive
• Peacock, Elisabeth; Sonsthagen, Sarah A.; Obbard, Martyn E.; Boltunov, Andrei; Regehr, Eric V. & Ovsyanikov, Nikita [Show all 23 contributors for this article] (2015). Implications of the circumpolar genetic structure of polar bears for their conservation in a rapidly warming Arctic. PLOS ONE. 10:0112021(1). doi: 10.1371/journal.pone.0112021. Full text in Research Archive Show summary

  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.

• Laidre, Kristin L.; Stern, Harry; Kovacs, Kit; Lowry, Lloyd; Moore, Sue E. & Regehr, Eric V. [Show all 16 contributors for this article] (2015). Arctic marine mammal population status, sea ice habitat loss, and conservation recommendations for the 21st century. Conservation Biology. ISSN 0888-8892. 29(3), p. 724–737. doi: 10.1111/cobi.12474. Full text in Research Archive
• Laidre, Kristin L.; Born, Erik W.; Heagerty, Patrick; Wiig, Øystein; Stern, Harry & Dietz, Rune [Show all 8 contributors for this article] (2015). Shifts in female polar bear (Ursus maritimus) habitat use in East Greenland. Polar Biology. ISSN 0722-4060. doi: 10.1007/s00300-015-1648-5. Full text in Research Archive
• Rekdal, Silje Larsen; Hansen, Rikke Guldborg; Borchers, David L.; Bachmann, Lutz; Laidre, Kristin L. & Wiig, Øystein [Show all 10 contributors for this article] (2015). Trends in bowhead whales in West Greenland: aerial surveys versus genetic capture-recapture analyses. Marine mammal science. ISSN 0824-0469. 31, p. 133–154. doi: 10.1111/mms.12150. Full text in Research Archive Show summary

  We contrast two methods for estimating the trends of bowhead whales (Balaena mysticetus) in West Greenland: (1) double platform visual aerial survey, corrected for missed sightings and the time the whales are available at the surface; and (2) a genetic capture-recapture approach based on a 14-yr-long biopsy sampling program in Disko Bay. The aerial survey covered 39,000 km2 and resulted in 58 sightings, yielding an abundance estimate of 744 whales (CV = 0.34, 95% CI: 357–1,461). The genetic method relied on determining sex, mitochondrial haplotypes and genotypes of nine microsatellite markers. Based on samples from a total of 427 individuals, with 11 recaptures from previous years in 2013, this resulted in an estimate of 1,538 whales (CV = 0.24, 95% CI: 827–2,249). While the aerial survey is considered a snapshot of the local spring aggregation in Disko Bay, the genetic approach estimates the abundance of the source of this aggregation. As the whales in Disko Bay primarily are adult females that do not visit the bay annually, the genetic method would presumably yield higher estimates. The studies indicate that an increase in abundance observed between 1998 and 2006 has leveled off.

• Patyk, Kelly A; Duncan, Colleen; Nol, Pauline; Sonne, Christian; Laidre, Kristin L. & Obbard, Martyn [Show all 11 contributors for this article] (2015). Establishing a definition of polar bear (Ursus maritimus) health: A guide to research and management activities. Science of the Total Environment. ISSN 0048-9697. 514, p. 371–378. doi: 10.1016/j.scitotenv.2015.02.007. Full text in Research Archive
• Acquarone, Mario; Born, Erik W.; Griffiths, David; Knutsen, Lars Øyvind; Wiig, Øystein & Gjertz, Ian (2014). Evaluation of etorphine reversed by diprenorphine for the immobilisation of free-ranging Atlantic walrus (Odobenus rosmarus rosmarus L.). NAMMCO scientific publications. ISSN 1560-2206. 9. doi: 10.7557/3.2944. Full text in Research Archive
• Wiig, Øystein & Bachmann, Lutz (2014). Fluctuating asymmetry and inbreeding in Scandinavian gray wolves (Canis lupus). Acta Theriologica. ISSN 0001-7051. 59(3), p. 399–405. doi: 10.1007/s13364-014-0174-0. Full text in Research Archive

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• Aars, Jon; Marques, Tiago A.; Lone, Karen; Andersen, Magnus; Wiig, Øystein & Fløystad, Ida [Show all 8 contributors for this article] (2018). Corrigendum to: The number and distribution of polar bears in the western Barents Sea. Polar Research. ISSN 0800-0395. 37(1). doi: 10.1080/17518369.2018.1457880. Full text in Research Archive
• Wiig, Øystein; Morato, R.; Oliveira, A.C.; Sena, L.; Barbosa, V. & Araujo, G. [Show all 7 contributors for this article] (2017). Pegar onças-pintadas na Paragominas (Tagging jaguars in Paragominas). Full text in Research Archive
• Wiig, Øystein; Oliveira, A.C.; Sena, L.; Santos, J.; Ribeiro, Ana & Carvalho, A. (2017). Pesquisando mamíferos em Paragominas. (Surveying Mammals in Paragominas). Full text in Research Archive
• Oliveira, A.C.; Wiig, Øystein; Sena, L.; Santos, J.; Ribeiro, Ana & Carvalho, A. (2017). Monitoramento de mamíferos terrestres em Paragominas: entendendo como estes animais sobrevivem e se distribuem numa paisagem degradada. (Monitoring terrestrial Mammals in Paragominas). Full text in Research Archive
• Oliveira, A.C.; Wiig, Øystein; Sena, L.; Santos, J.; Ribeiro, Ana & Carvalho, A. (2017). Monitoramento de mamíferos terrestres em Paragominas: entendendo como estes animais sobrevivem e se distribuem numa paisagem degradada (Monitoring terrestrial Mammals in Paragominas). Full text in Research Archive
• Cabrera, A.A.; Aars, Jon; Bachmann, Lutz; Dietz, R.; Heide-Jørgensen, M.P. & Lydersen, Christian [Show all 9 contributors for this article] (2017). Life history traits predict demographic responses to Life history traits predict demographic responses to global warming in Arctic marine mammals. Full text in Research Archive
• Stern, J.H.; Laidre, K.L.; McKinney, M.; Born, E.W.; Wiig, Øystein & Sonne, C. [Show all 8 contributors for this article] (2017). Foraging Strategies of Baffin Bay Polar Bears. Full text in Research Archive
• Born, E.W.; Laidre, K.L. & Wiig, Øystein (2017). Isbjørnene i Baffin Bugt og Kane Bassin. Tidsskriftet Grønland. ISSN 0017-4556. 65, p. 94–107. Full text in Research Archive
• Wiig, Øystein; Gjertz, Ian; Lydersen, Christian; Stewart, Robert EA; Ready, Elspeth & Monchot, Herve (2016). Letter to the Editor/Erratum. Anthropozoologica. ISSN 0761-3032. 51(1), p. 67–69. doi: 10.5252/az2016n1a5. Full text in Research Archive
• Wiig, Øystein; Bjørge, Arne Jostein; Isaksen, Kjell; Kovacs, Kit; Swenson, Jon & Syvertsen, Per Ole (2015). Pattedyr, Mammalia. In Henriksen, Snorre & Hilmo, Olga (Ed.), Norsk rødliste for arter 2015. Versjon 1.2. Artsdatabanken. ISSN 9788292838419. Full text in Research Archive
• Wiig, Øystein (2015). Gaupa kan bli utryddet i Norge. [Journal]. Klassekampen. Full text in Research Archive
• Andersen, Magnus; Lone, K.; Marques, T.A.; Buckland, S.T.; Wiig, Øystein & Aars, Jon (2015). Methodological setup for a large scale polar bear aerial survey in the Barents Sea in 2015. Full text in Research Archive
• Wiig, Øystein (2014). Ga Galapagos-skalle til Darwin Foundation. [Internet]. www.forskning.no. Full text in Research Archive
• Wiig, Øystein (2014). Viltkameraer overvåker Amazonas-regnskogen. [Radio]. NRK P2 Ekko. Full text in Research Archive
• Wiig, Øystein (2014). På jaguarmerking i Amazonas. [Internet]. www.nhm.uio.no. Full text in Research Archive
• Wiig, Øystein (2014). NHM ga Galapagos-skalle til Darwin Foundation. [Internet]. www.nhm.uio.no. Full text in Research Archive
• Wiig, Øystein (2014). Skattekammeret. [Journal]. Apollon. Full text in Research Archive
• Wiig, Øystein (2014). Merking av jaguarer i Brasil. Full text in Research Archive
• Wiig, Øystein (2014). Ekko i Amasonas. Full text in Research Archive
• Wiig, Øystein (2014). Hvorfor isbjørnen er truet av klimaendringer. Full text in Research Archive
• Oliveira, A.C.; Wiig, Øystein & Ribeiro, A.C. (2018). FATORES DETERMINANTES NA OCORRÊNCIA DAS ESPÉCIES DE CARNIVOROS (MAMMALIA: CARNIVORA) EM ÁREAS DEGRADADAS NA AMAZÔNIA ORIENTAL(FACTORS DETERMINING THE OCCURRENCE OF CARNIVORE SPECIES (MAMMALIA: CARNIVORA) IN DEGRADED AREAS IN THE EASTERN AMAZON). UNIVERSIDADE FEDERAL DO PARÁ AND MUSEU PARAENSE EMÍLIO GOELDI. Full text in Research Archive
• Oliveira, A.C.; Wiig, Øystein & Santos, J. (2018). Fatores determinantes para a abundância de espécies de mamíferos ameaçados em área de alta pressão antrópica na Amazônia oriental (Factors determining the abundance of threatened mammal species in an area of high anthropogenic pressure in the eastern Amazon). ZOOLOGIA UNIVERSIDADE FEDERAL DO PARÁ AND MUSEU PARAENSE EMÍLIO GOELDI. Full text in Research Archive
• Wiig, Øystein; Bachmann, Lutz; Hansen, A.J.; Gilbert, M.T.P. & Sinding, Mikkel Holger Strander (2017). Never cry wolf. The origin and genomic history of the indigenous Greenland dogs and wolves. Universitetet i Oslo. Full text in Research Archive
• Bachmann, Lutz; Wiig, Øystein & Nyhus, E.S. (2017). Genomic Analyses of Bowhead Whale (Balaena mysticetus) individuals. Universitetet i Oslo. Full text in Research Archive
• Regehr, E.V.; Atkinson, S.; Born, E.W.; Laidre, K.L.; Lunn, N.J. & Wiig, Øystein (2017). Regehr, E.V., S. Atkinson, E.W. Born, K.L. Laidre, N.J. Harvest Assessment for the Baffin Bay and Kane Basin Polar Bear Subpopulations: Final Report to the Canada-Greenland Joint Commission on Polar Bear. Canada-Greenland Joint Commission on Polar Bear. Full text in Research Archive
• Atkinson, S.; Born, E.W.; Laidre, K.L.; Lunn, N.J.; Wiig, Øystein & Arnold, T. [Show all 10 contributors for this article] (2016). Re-assessment of the Baffin Bay and Kane Basin polar bear subpopulations: final report to the Canada-Greenland Joint Commission on Polar Bear. Environment and Climate Change Canada, Ottawa, ON and Greenland Institute of Natural Resources, Nuuk, Greenland.. Full text in Research Archive

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