Sea-ice cover across the Arctic has declined rapidly over the past several decades owing to amplified climate warming. The Pacific walrus (Odobenus rosmarus divergens) relies on sea-ice floes in the St. Lawrence Island (SLI) and Wainwright regions of the Bering and Chukchi seas surrounding Alaska as a platform for rest, feeding and reproduction. Lower concentrations of thick ice floes are generally associated with earlier seasonal fragmentation and shorter annual persistence of sea-ice cover, potentially affecting the life history of the Pacific walrus. In this study, 24 Landsat satellite images were classified into thick ice, thin ice or open water to assess sea-ice fragmentation over the spring-summer breakup period. Geospatial fragmentation analyses traditionally used in terrestrial landscapes were newly implemented in this study to characterize the icescape environment. Fragmentation of sea ice was assessed based on the Percent of Landscape, Number of Patches, Mean Area, Shape Index, Euclidean Nearest Neighbor and Edge Density. Results show that lower sea-ice concentrations in both the SLI and Wainwright regions were associated with smaller sea-ice floes. In the Bering Sea, lower sea-ice concentrations were also associated with increases in the number of ice floes, floe isolation and edge density. By contrast, lower sea-ice concentrations in the Chukchi Sea were associated with ice floes that were more circular in shape. The continuation of sea-ice decline with shifting icescape characteristics may result in walruses having to swim longer distances in the northern Bering Sea and adapt to use less-preferred, rounder ice floes in the Chukchi Sea.

Beluga whales (Delphinapterus leucas) from Cook Inlet (CI), Alaska, are listed as “endangered” because of dramatic declines in abundance, with no indications of population recovery. Serum samples from this population are exceedingly rare. Longitudinal samples from aquarium (AQ) belugas can potentially provide health assessment reference ranges for free-ranging beluga, including reproductive and metabolic hormones. We analysed serum hormone concentrations from CI (n = 6, three females and three males) and Bristol Bay (Alaska; BB; n = 5, four males and one female), alongside AQ (n = 3, two females and one male) belugas, to conduct physiological comparisons of reproductive hormones (progesterone, testosterone and total oestrogens) and metabolic hormones (total thyroxine, triiodothyronine and cortisol) in beluga serum. Oestrogen and progesterone profiles from January through May from two AQ female beluga were typical of non-pregnant, cycling females. CI and BB sex steroid concentrations were within AQ hormone ranges, with the exception of elevated progesterone concentrations in four potentially pregnant females. Both CI and BB belugas had elevated metabolic hormones, which may indicate greater metabolic effort required in the wild environment or capture response. Because sample collection from CI belugas is rare, analysis of even the few samples that we analysed may contribute to the conservation of the small and declining population of genetically distinct CI beluga whales. It is important that each sample collected from free-range CI belugas provides the maximum biological information possible. Continued comparison of hormones in AQ and free-ranging beluga will enhance the interpretation of health data in both groups.

For more than 20 years Antarctic Treaty Parties have been discussing how to appropriately manage cumulative impacts in the continent. Preventing cumulative impacts requires the fluent exchange of information to enable proper and timely assessment of, and response to, the impacts that result from multiple activities, undertaken by multiple stakeholders and supervised by different Parties. This is a particular challenge for the effective management of Antarctic Specially Protected Areas (ASPAs), as a lack of coordination may potentially put at risk the fulfillment of their conservation objectives. Here we suggest that incorporating lessons learnt from protected areas management elsewhere might improve the effectiveness of ASPAs and provide valuable experiences and insights on how to better manage cumulative impacts in the rest of the continent. Key concepts to incorporate in Antarctica’s environmental management toolbox include (1) the notion of adaptive management, which is a cornerstone of protected areas management effectiveness elsewhere, and (2) the need of empowering protected area managers, which are a key (but often missing) element to ensure local compliance with management plans, co-ordinate on site activities, facilitate exchange of information, promote cooperation and manage conflicts.

Sea-ice distribution and duration are declining across the circumpolar range of the polar bear (Ursus maritimus), resulting in a reduced access to ice-obligate seals, its primary prey. Consequently, polar bears may have increased reliance on alternative food sources in the future. Foraging on land is well documented but foraging in open water is less understood. We report the successful depredation of a thick-billed murre (Uria lomvia) in open water near Prince Leopold Island, Nunavut, and discuss implications for understanding the behavioural plasticity of polar bears and their opportunistic foraging patterns.

Species with similar ecological requirements that overlap in range tend to segregate their niches to minimize competition for resources. However, the niche segregation possibilities for centrally foraging predators that breed on isolated Subantarctic islands may be reduced by spatial constraints and limitations in the availability of alternative prey. In this study we examined spatial and trophic aspects of the foraging niches of two sympatrically breeding penguin species, macaroni (Eudyptes chrysolophus; MAC) and chinstrap (Pygoscelis antarcticus; CHIN) penguins, at Bouvetøya over two breeding seasons. To measure at-sea movements and diving behaviour, 90 MACs and 49 CHINs were equipped with GPS loggers and dive recorders during two austral summer breeding seasons (2014/15 and 2017/18). In addition, blood samples from tracked birds were analysed for stable isotopes to obtain dietary information. CHINs displayed marked interannual variation in foraging behaviour, diving deeper, utilizing a larger foraging area and displaying enriched values of δ15N in 2014/15 compared to the 2017/18 breeding season. In contrast, MACs dove to similar depths and showed similar δ15N values, while consistently utilizing larger foraging areas compared to CHINs. We suggest that low krill abundances in the waters around Bouvetøya during the 2014/15 season resulted in CHINs shifting toward a diet that increased their niche overlap with MACs. Our findings may partly explain the decreasing number of breeding CHINs at the world’s most remote island, Bouvetøya, while also highlighting the importance of characterizing niche overlap of species using multi-season data sets.

Aquaria that care for and maintain belugas (Delphinapterus leucas) under professional care have the opportunity to contribute to the conservation of wild belugas through research, expertise in animal care and husbandry, and engaging and educating the public about threats to the species’ health and population sustainability. In an aquarium setting, belugas can be studied under controlled conditions, with known variables that are often difficult to discern when studying wild belugas. Information on nutrition, health status and environmental parameters can be easily obtained in a controlled setting. Biological samples are collected from professionally trained whales that voluntarily participate in informative experimental paradigms. Research studies in aquaria seek to contribute to the recovery and management of endangered beluga populations, such as those in Cook Inlet. Mystic Aquarium’s efforts are presented as a case study. Key research priorities address action items in the Cook Inlet Beluga Recovery Plan and include: (1) understanding the beluga immune system, microbial communities, pathogens and disease; (2) development of non-invasive methods for assessing reproductive status, body condition and health in wild whales; (3) investigation of diving physiology and the impact of altered dive patterns on health; (4) understanding reproduction, a key to recovery and sustainability of wild populations; (5) development and testing of new technologies for tracking and monitoring whales and habitat use; and (6) understanding how noise affects beluga hearing, behaviour and physiology. Expertise in animal handling, behaviour and nutrition contribute to rescue, rehabilitation and capture release efforts. Moreover, ‘students’ of all ages have the opportunity to be engaged, educated and contribute to beluga conservation.

Long-term meteorological data for the Arctic are sparse. One of the longest quasi-continuous temperature time series in the High Arctic is the extended Svalbard Airport series, providing daily temperature data from 1898 until the present. Here, I derive an adjustment to historic temperature observations on the island of Nordaustlandet, north-east Svalbard, in order to link these to the extended Svalbard Airport series. This includes the Haudegen observations at Rijpfjorden during 1944/45 and a previously unrecognized data set obtained by the Norwegian hunters and trappers Gunnar Knoph and Henry Rudi during their wintering at Rijpfjorden in 1934/35. The adjustment is based on data from an automatic weather station at Rijpfjorden during 2014–16 and verified with other independent historic temperature observations on Nordaustlandet. An analysis of the Haudegen radiosonde data indicates that the surface temperature observations at Rijpfjorden are generally well correlated with the free tropospheric temperatures at 850 hPa, but occasionally show the occurrence of boundary-layer inversions during winter, where local temperatures fall substantially below what is expected from the regression. The adjusted historic observations from Nordaustlandet can, therefore, be used to fill remaining gaps in the extended Svalbard Airport series.

This study reports the disappearance of a small Arctic wolf population in north-east Greenland founded in 1979 and provides the first long-term information on the wolf packs of this region. Data sources comprised specialized wolf surveys in two of three distributional core areas during three summers, 2012–14, and incidental sightings of wolves by military ground patrols during winter and by others year-round. The resulting time series spans 40 years (1979–2018). After gradually increasing for 14 years, the sighting rate peaked in 1996 and then declined to zero after May 2002, suggesting that the population went extinct. The crash occurred despite year-round legal protection in a national park and resulted in a 51.2% reduction in the extent of the occupied wolf range in Greenland and a 41.8% reduction in Greenland’s wolf population size. It was outside the scope of this study to conduct a complete analysis of all potential factors in the disappearance. In north Greenland, a small population of up to 32 wolves during optimal years continues to exist, and dispersers reach north-east Greenland occasionally. A number of measures are proposed that, if implemented by the Greenland Home Rule Government, would help secure the future of the few remaining wolves on the island.

Food security is a complex topic defined not just by having enough nutritious food to eat but also by cost, safety and cultural considerations. In Arctic Inuit communities, food security is intimately connected to culture through traditional methods of harvesting country food. In Chesterfield Inlet, Nunavut, community-based research was conducted in collaboration with Chesterfield Inlet community members using interviews and community engagement. Community members were consulted about the design of the interview guide, recruitment of participants, analysis and validation of results. This study aims to develop a theoretical framework of how food security, cultural continuity and community health and well-being are interconnected to allow for a richer understanding of how increased shipping, climate change and social changes are impacting community members. In Chesterfield Inlet, harvesting and consuming country food (e.g., seal) is perceived as the mechanism that connects food, culture and community health. Sharing of freshly harvested country food supports the food security of community members without hunters in their families, aligns with hunters’ cultural beliefs and promotes community health and well-being. Changes that reduce a hunter’s success in harvesting country food limit her or his ability to share country food, which negatively impacts community health and well-being. The results of this study support existing community efforts to adapt to changes that impact harvesting success.

Zooplankton predator–prey relations in northern Norwegian fjords are highly variable in time and space, and the mechanisms driving this variability are still poorly understood. Replicate Juday net sampling in October and February from 1983 to 2005, which included five repeated tows from bottom to surface, was conducted in Saltfjord and Mistfjord, northern Norway. The time-series provided evidence of in situ variability in species abundance, as well as seasonal and interannual changes in standing stock abundance. The shallow sill of one fjord caused accumulation of coastal water in the fjord’s basin, while the other fjord’s deeper sill selected denser water of Atlantic origin from the same open shelf habitat. The selective advection caused differences in the immigration of species recruiting to the fjords’ specific overwintering communities of zooplankton. Statistical analyses of the cumulated replicate data indicated significant in situ variability in the spatial density of species. Cases with an abundance of carnivores relating positively to other species probably resulted from the carnivores’ attraction to patches with concentrations of prey. Interspecific negative density relations likely indicated either predator avoidance or substantial trophic activity during the sampling. During years of high abundance, some wintering stocks of carnivores evidently reduced the local stocks of overwintering prey. We conclude that predator–prey interactions and stock variability in Subarctic fjords result from complex bio-geophysical interactions that occur on the scales of local habitats and basin-scale population systems.