Marine mammal detections on the Chukchi Plateau 2009-2020.

The Arctic Ice Monitoring (AIM) observatory has been maintained on the Chukchi Plateau at 75.1° N 168.0° W nearly continuously since 2003. The AIM site consists of a submerged mooring that, since October 2008, has been instrumented with a passive acoustic recorder to sample ambient sound, with a focus on marine mammal detections in the High Arctic. Year-long data sets for 2009, 2012, and 2014-2020 were analyzed for the presence of signals from Arctic species including bowhead and beluga whales, bearded seals, and walrus. Calls from subarctic ribbon seals were commonly detected in autumn months, suggesting they have expanded their distribution much further northward. Killer whale calls were detected in recent years providing evidence that they have moved further north into the Pacific Arctic. No other subarctic cetaceans were heard. Year-round passive acoustic sampling of sounds produced by marine mammals over a decadal timescale has enhanced our understanding of how climate-driven changes in biodiversity are affecting even the very High Arctic.

Changes in gray whale phenology and distribution related to prey variability and ocean biophysics in the northern Bering and eastern Chukchi seas.

Changes in gray whale (Eschrichtius robustus) phenology and distribution are related to observed and hypothesized prey availability, bottom water temperature, salinity, sea ice persistence, integrated water column and sediment chlorophyll a, and patterns of wind-driven biophysical forcing in the northern Bering and eastern Chukchi seas. This portion of the Pacific Arctic includes four Distributed Biological Observatory (DBO) sampling regions. In the Bering Strait area, passive acoustic data showed marked declines in gray whale calling activity coincident with unprecedented wintertime sea ice loss there in 2017-2019, although some whales were seen there during DBO cruises in those years. In the northern Bering Sea, sightings during DBO cruises show changes in gray whale distribution coincident with a shrinking field of infaunal amphipods, with a significant decrease in prey abundance (r = -0.314, p<0.05) observed in the DBO 2 region over the 2010-2019 period. In the eastern Chukchi Sea, sightings during broad scale aerial surveys show that gray whale distribution is associated with localized areas of high infaunal crustacean abundance. Although infaunal crustacean prey abundance was unchanged in DBO regions 3, 4 and 5, a mid-decade shift in gray whale distribution corresponded to both: (i) a localized increase in infaunal prey abundance in DBO regions 4 and 5, and (ii) a correlation of whale relative abundance with wind patterns that can influence epi-benthic and pelagic prey availability. Specifically, in the northeastern Chukchi Sea, increased sighting rates (whales/km) associated with an ~110 km (60 nm) offshore shift in distribution was positively correlated with large scale and local wind patterns conducive to increased availability of krill. In the southern Chukchi Sea, gray whale distribution clustered in all years near an amphipod-krill 'hotspot' associated with a 50-60m deep trough. We discuss potential impacts of observed and inferred prey shifts on gray whale nutrition in the context of an ongoing unusual gray whale mortality event. To conclude, we use the conceptual Arctic Marine Pulses (AMP) model to frame hypotheses that may guide future research on whales in the Pacific Arctic marine ecosystem.

Interaction between socioeconomic deprivation and ethnicity for likelihood of receiving living-donor kidney transplantation.

BACKGROUND: The interplay between ethnicity and socioeconomic deprivation for living-donor kidney transplantation (LDKT) opportunities is unclear. METHODS: Data for 2040 consecutive kidney-alone transplant recipients receiving an allograft between 1st January 2007 and 30th June 2020 at a single center were retrospectively analyzed. The associations between the proportions of transplants that were LDKT (versus deceased donation) and both ethnicity and socioeconomic deprivation were assessed, with the latter quantified by the Index of Multiple Deprivation (IMD) quintile. RESULTS: The cohort comprised recipients of White (64.7%), South Asian (21.7%), Black (7.0%) and other (6.6%) ethnic groups. Recipients tended to be from socioeconomically deprived areas, with the most deprived quintile being the most frequently observed (quintile 1: 38.6% of patients); non-White recipients were significantly more likely to live in socioeconomically deprived areas (p < 0.001). Overall, 36.5% of transplants were LDKT, with this proportion declining progressively with socioeconomic deprivation, from 50.4 to 27.6% in the least versus most deprived IMD quintile (p < 0.001). A significant difference across recipient ethnicities was also observed, with the proportion of LDKTs ranging from 43.2% in White recipients to 17.8% in Black recipients (p < 0.001). Both socioeconomic deprivation (p < 0.001) and ethnicity (p = 0.005) remained significant predictors of LDKT on multivariable analysis, with a significant interaction between these factors also being observed (p < 0.001). Further assessment of this interaction effect found that, whilst there was a marked difference in the proportions of transplants that were LDKT between White versus non-White recipients in the most socioeconomically deprived groups (39.5% versus 19.3%), no such difference was seen in the least deprived recipients (48.5% versus 51.9%). CONCLUSIONS: Whilst both socioeconomic deprivation and non-White ethnicity are independent predictors for lower proportions of LDKTs, the significant interaction between the two factors should be appreciated.

Tracking arctic marine mammal resilience in an era of rapid ecosystem alteration.

Global warming is significantly altering arctic marine ecosystems. Specifically, the precipitous loss of sea ice is creating a dichotomy between ice-dependent polar bears and pinnipeds that are losing habitat and some cetaceans that are gaining habitat. While final outcomes are hard to predict for the many and varied marine mammal populations that rely on arctic habitats, we suggest a simplified framework to assess status, based upon ranking a population's size, range, behavior, and health. This basic approach is proposed as a means to prioritize and expedite conservation and management efforts in an era of rapid ecosystem alteration.

The Associations of Endotoxemia With Systemic Inflammation, Endothelial Activation, and Cardiovascular Outcome in Kidney Transplantation.

OBJECTIVE: Cardiovascular disease is the leading cause of death in kidney transplant recipients (KTRs), yet incompletely accountable by traditional risk factors. Inflammation is an unconventional cardiovascular risk factor, with gut-derived endotoxemia potentially driving inflammation and endothelial disease. Comparable data are lacking in kidney transplantation. This study investigated the associations of endotoxemia with inflammation, endothelial activation, and 5-year cardiovascular events in KTRs. Determinants of endotoxemia were also explored. DESIGN AND METHODS: This is a single-center cross-sectional study with prospective follow-up from a prevalent cohort of 128 KTRs. MAIN OUTCOME MEASURES: Demographic, nutritional and clinical predictors of inflammation (high-sensitivity C-reactive protein [hsCRP]), endothelial activation (sE-selectin), and endotoxemia (endotoxin) were assessed. Follow-up data on 5-year cardiovascular event rates were collected. RESULTS: Endotoxemia (P = .03), reduced 25-hydroxyvitamin D (P = .04), high fructose intake (P < .001), decreased fiber intake (P < .001), and abdominal obesity (P = .002) were independently associated with elevated hsCRP. In turn, endotoxemia (P = .007) and increasing hsCRP (P = .02) were both independently associated with raised sE-selectin. Furthermore, endotoxemia predicted increased cardiovascular event rate (P = .02), independent of hsCRP and a global measure of cardiovascular risk estimated by a validated algorithm of 7-year risk for major adverse cardiac events in kidney transplantation. Determinants of endotoxemia included reduced 25-hydroxyvitamin D (P < .001), hypertriglyceridemia (P < .001), increased fructose intake (P = .01), and abdominal obesity (P = .01). CONCLUSIONS: Endotoxemia in KTRs contributes to inflammation, endothelial activation, and increased cardiovascular events. This study highlights the clinical relevance of endotoxemia in KTRs, suggesting future interventional targets.

Habitat selection by two beluga whale populations in the Chukchi and Beaufort seas.

There has been extensive sea ice loss in the Chukchi and Beaufort seas where two beluga whale (Delphinapterus leucas) populations occur between July-November. Our goal was to develop population-specific beluga habitat selection models that quantify relative use of sea ice and bathymetric features related to oceanographic processes, which can provide context to the importance of changing sea ice conditions. We established habitat selection models that incorporated daily sea ice measures (sea ice concentration, proximity to ice edge and dense ice) and bathymetric features (slope, depth, proximity to the continental slope, Barrow Canyon, and shore) to establish quantitative estimates of habitat use for the Eastern Chukchi Sea ('Chukchi') and Eastern Beaufort Sea ('Beaufort') populations. We applied 'used v. available' resource selection functions to locations of 65 whales tagged from 1993-2012, revealing large variations in seasonal habitat selection that were distinct between sex and population groups. Chukchi whales of both sexes were predicted to use areas in close proximity to Barrow Canyon (typically <200 km) as well as the continental slope in summer, although deeper water and denser ice were stronger predictors for males than females. Habitat selection differed more between sexes for Beaufort belugas. Beaufort males selected higher ice concentrations (≥40%) than females (0-40%) in July-August. Proximity to shore (<200 km) strongly predicted summer habitat of Beaufort females, while distance to the ice edge was important for male habitat selection, especially during westward migration in September. Overall, our results indicate that sea ice variables were rarely the primary drivers of beluga summer-fall habitat selection. While diminished sea ice may indirectly affect belugas through changes in the ecosystem, associations with bathymetric features that affect prey availability seemed key to habitat selection during summer and fall. These results provide a benchmark by which to assess future changes in beluga habitat use of the Pacific Arctic.

Is it 'boom times' for baleen whales in the Pacific Arctic region?

The marine ecosystem in the Pacific Arctic region has experienced dramatic transformation, most obvious by the loss of sea ice volume (75%), late-summer areal extent (50%) and change in phenology (four to six weeks longer open-water period). This alteration has resulted in an opening of habitat for subarctic species of baleen whales, many of which are recovering in number from severe depletions from commercial whaling in the nineteenth and twentieth centuries. Specifically, humpback, fin and minke whales (Megaptera novaeangliae, Balaenoptera physalus and Balaenoptera acutorostrata) are now regularly reported during summer and autumn in the southern Chukchi Sea. These predators of zooplankton and forage fishes join the seasonally resident grey whale (Eschrichtius robustus) and the arctic-endemic bowhead whale (Balaena mysticetus) in the expanding open-ocean habitat of the Pacific Arctic. Questions arising include: (i) what changes in whale-prey production and delivery mechanisms have accompanied the loss of sea ice, and (ii) how are these five baleen whale species partitioning the expanding ice-free habitat? While there has been no programme of research specifically focused on these questions, an examination of seasonal occurrence, foraging plasticity and (for bowhead whales) body condition suggests that the current state of Pacific Arctic marine ecosystem may be 'boom times' for baleen whales. These favourable conditions may be moderated, however, by future shifts in ecosystem structure and/or negative impacts to cetaceans related to increased commercial activities in the region.

Cardiovascular, muscular and perceptual contributions to physical fatigue in prevalent kidney transplant recipients.

Physical fatigue is debilitating and common among kidney transplant recipients (KTRs). This study investigated the mechanistic aetiology of physical fatigue in this setting through examinations of muscle mass, muscular and cardiovascular function, and perceived exertion. The incidence of physical fatigue, its association with quality of life (QoL), and the predictors of perceived exertion, were evaluated. This single-centre observational cross-sectional study enrolled 55 KTRs. Muscle mass was quantified using dual-energy x-ray absorptiometry. Muscular function was assessed by jumping mechanography. Cardiovascular function (maximal oxygen consumption and oxygen pulse) was estimated during submaximal exercise testing, with perceived exertion determined using age-adjusted Borg scale-ratings. Physical fatigue was measured using Multi-Dimensional Fatigue Inventory-20. QoL was assessed using Medical Outcomes Study Short Form-36. Demographic, clinical, nutritional, psychosocial and behavioural predictors of perceived exertion were assessed. Of clinical importance, increased perceived exertion was the only independent predictor of physical fatigue (P = 0.001), with no association found between physical fatigue and muscular or cardiovascular parameters. Physical fatigue occurred in 22% of KTRs, and negatively impacted on QoL (P < 0.001). Predictors of heightened perception included anxiety (P < 0.05) and mental fatigue (P < 0.05). Perception is a key determinant of physical fatigue in KTRs, paving the way for future interventions.

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

Arctic marine mammals (AMMs) are icons of climate change, largely because of their close association with sea ice. However, neither a circumpolar assessment of AMM status nor a standardized metric of sea ice habitat change is available. We summarized available data on abundance and trend for each AMM species and recognized subpopulation. We also examined species diversity, the extent of human use, and temporal trends in sea ice habitat for 12 regions of the Arctic by calculating the dates of spring sea ice retreat and fall sea ice advance from satellite data (1979-2013). Estimates of AMM abundance varied greatly in quality, and few studies were long enough for trend analysis. Of the AMM subpopulations, 78% (61 of 78) are legally harvested for subsistence purposes. Changes in sea ice phenology have been profound. In all regions except the Bering Sea, the duration of the summer (i.e., reduced ice) period increased by 5-10 weeks and by >20 weeks in the Barents Sea between 1979 and 2013. In light of generally poor data, the importance of human use, and forecasted environmental changes in the 21st century, we recommend the following for effective AMM conservation: maintain and improve comanagement by local, federal, and international partners; recognize spatial and temporal variability in AMM subpopulation response to climate change; implement monitoring programs with clear goals; mitigate cumulative impacts of increased human activity; and recognize the limits of current protected species legislation.

Hypervolemia and blood pressure in prevalent kidney transplant recipients.

BACKGROUND: The prevalence and consequences of hypervolemia in kidney transplant recipients (KTRs) have not been investigated. Specifically, its impact on blood pressure (BP) and relationship with N-terminal fragment of prohormone B-type natriuretic peptide (NT-proBNP) are unknown. The objectives of this study were to establish the prevalence of hypervolemia among clinically stable KTRs, investigate the predictors of posttransplant hypervolemia, assess its impact on blood pressure, and determine its relationship with NT-proBNP. METHODS: This single-center cross-sectional study enrolled 123 clinically stable KTRs. Extracellular volume status was determined by multifrequency bioimpedance analysis. Mild and severe hypervolemia were defined as percentage volume expansion of greater than 7% and greater than 15%, respectively. Systolic BP (SBP) and diastolic BP (DBP) were measured, with mean arterial pressure (MAP) calculated. Serum NT-proBNP was quantified using a noncompetitive immunoluminometric assay. Potential demographic, nutritional, and clinical predictors of extracellular volume status, BP, and NT-proBNP levels were assessed. RESULTS: Hypervolemia was present in 30% of KTRs, with 5% classified as severe hypervolemia. Significant predictors of volume expansion were increased sodium intake, advancing age, and reduced fat mass (P<0.01 for all associations). Hypervolemia was the only independent predictor of elevated MAP, SBP, and DBP (P<0.001 for all associations). Raised NT-proBNP levels were independently associated with both hypervolemia (P=0.01) and allograft dysfunction (P=0.03). CONCLUSIONS: Hypervolemia is unexpectedly common among clinically stable KTRs. It is closely associated with elevated BP. The relationship with increased sodium intake signals potential therapeutic focus. Further study is warranted to prospectively investigate objective measures of extracellular volume status among KTRs.

Predictors and consequences of fatigue in prevalent kidney transplant recipients.

BACKGROUND: Fatigue has been underinvestigated in stable kidney transplant recipients (KTRs). The objectives of this study were to investigate the nature, severity, prevalence, and clinical awareness of fatigue in medically stable KTRs, examine the impact of fatigue on quality of life (QoL), and explore the underlying causes of posttransplantation fatigue. METHODS: This single-center cross-sectional study enrolled 106 stable KTRs. Multi-dimensional Fatigue Inventory-20 was used to measure five fatigue dimensions: General Fatigue, Physical Fatigue, Reduced Activity, Reduced Motivation, and Mental Fatigue. Clinical awareness of fatigue was determined by reviewing medical records. QoL was assessed by Medical Outcomes Study Short Form-36 Questionnaire. Demographic, clinical, psychosocial, and behavioral parameters were evaluated as fatigue predictors. RESULTS: Fatigue was found in 59% of KTRs. Only 13% had this symptom documented in medical records. Fatigue in KTRs was in the same range as chronically unwell patients, with Physical Fatigue, Reduced Activity, and Reduced Motivation approached levels observed in chronic fatigue syndrome. All fatigue dimensions significantly and inversely correlated with QoL (P<0.001 for all associations). Demographic predictors were male, older age, and non-Caucasian ethnicity (P≤0.05 for all associations). Clinical predictors included elevated highly sensitive C-reactive protein (inflammation), decreased estimated glomerular filtration rate (graft dysfunction), and reduced lean tissue index (P≤0.05 for all associations). Psychosocial and behavioral predictors were inferior sleep quality, anxiety, and depression (P<0.01 for all associations). CONCLUSIONS: Fatigue is common and pervasive in clinically stable KTRs. It is strongly associated with reduced QoL. This study identified modifiable fatigue predictors and sets the scene for future interventional studies.

A socio-ecological perspective on behavioural interventions to influence food choice in schools: alternative, complementary or synergistic?

OBJECTIVE: An increasing focus on legislation, policy and guidance on the nutritional content of school food has in part been in response to the limited impact of more behavioural or educational approaches. However, there is a risk that a sole focus on policy-level action may lead to neglect of the important contribution that more behavioural approaches can make as components of effective, coordinated, multilevel action to improve the dietary intake of schoolchildren. The current paper aims to highlight the potential importance of viewing alternative approaches as complementary or synergistic, rather than competing. DESIGN: The socio-ecological and RE-AIM frameworks are used to provide a theoretical rationale and demonstrate the importance of explicitly identifying the interdependence of policies, interventions and contextual structures and processes. School food case study evidence is used to exemplify how understanding and exploiting these interdependencies can maximise impact on dietary outcomes. SETTING: Case studies of trials in schools in the UK (South West England and Wales) and Australia (Victoria). SUBJECTS: Schoolchildren. RESULTS: The case studies provide examples to support the hypothesis that the reach, effectiveness, adoption, implementation and maintenance of school food policies and interventions can be maximised by understanding and exploiting the interdependence between levels in the socio-ecological framework. CONCLUSIONS: Rather than being seen as competing alternatives, diverse approaches to improving the diets of schoolchildren should be considered in terms of their potential to be complementary and synergistic, acting at multiple levels to improve acceptability, fidelity, effectiveness and sustainability.

Sounds from airguns and fin whales recorded in the mid-Atlantic Ocean, 1999-2009.

Between 1999 and 2009, autonomous hydrophones were deployed to monitor seismic activity from 16° N to 50° N along the Mid-Atlantic Ridge. These data were examined for airgun sounds produced during offshore surveys for oil and gas deposits, as well as the 20 Hz pulse sounds from fin whales, which may be masked by airgun noise. An automatic detection algorithm was used to identify airgun sound patterns, and fin whale calling levels were summarized via long-term spectral analysis. Both airgun and fin whale sounds were recorded at all sites. Fin whale calling rates were higher at sites north of 32° N, increased during the late summer and fall months at all sites, and peaked during the winter months, a time when airgun noise was often prevalent. Seismic survey vessels were acoustically located off the coasts of three major areas: Newfoundland, northeast Brazil, and Senegal and Mauritania in West Africa. In some cases, airgun sounds were recorded almost 4000 km from the survey vessel in areas that are likely occupied by fin whales, and at some locations airgun sounds were recorded more than 80% days/month for more than 12 consecutive months.

A sound budget for the southeastern Bering Sea: measuring wind, rainfall, shipping, and other sources of underwater sound.

Ambient sound in the ocean contains quantifiable information about the marine environment. A passive aquatic listener (PAL) was deployed at a long-term mooring site in the southeastern Bering Sea from 27 April through 28 September 2004. This was a chain mooring with lots of clanking. However, the sampling strategy of the PAL filtered through this noise and allowed the background sound field to be quantified for natural signals. Distinctive signals include the sound from wind, drizzle and rain. These sources dominate the sound budget and their intensity can be used to quantify wind speed and rainfall rate. The wind speed measurement has an accuracy of +/-0.4 m s(-1) when compared to a buoy-mounted anemometer. The rainfall rate measurement is consistent with a land-based measurement in the Aleutian chain at Cold Bay, AK (170 km south of the mooring location). Other identifiable sounds include ships and short transient tones. The PAL was designed to reject transients in the range important for quantification of wind speed and rainfall, but serendipitously recorded peaks in the sound spectrum between 200 Hz and 3 kHz. Some of these tones are consistent with whale calls, but most are apparently associated with mooring self-noise.

Feeding goals sought by mothers of 3-5-year-old children.

OBJECTIVES: One means through which children learn eating behaviours is the feeding strategies used by parents. Although research has studied the effects of parental feeding strategies on consumption, choice, and liking, little is known about the goals parents themselves seek. The study aimed to explore the feeding goals sought by parents of preschool children. DESIGN: An exploratory qualitative study using in-depth, semi-structured interviews was undertaken. Data were analysed using thematic and interpretative techniques. METHODS: A snowballing sample of 12 mothers of children aged 3-5 years was used. Mothers were asked to recall and talk through their feeding experiences with this child. Probe questions were used to explore the reasoning behind the actions described. Data were transcribed and subjected to concurrent coding and interpretation. RESULTS: Mothers spontaneously classified their child as a 'good' or a 'bad' eater. Consumption emerged as the dominant feeding goal. For 'bad' eaters, a short-term goal of consuming any food, rather than no food, was adopted. For 'good' eaters, a long-term goal of consuming a varied, well-balanced diet was favoured. Liking as a feeding goal was not mentioned. CONCLUSIONS: Although the literature suggests that liking is the most appropriate feeding goal for the establishment of long-term healthy eating behaviours, parents do not knowingly, repeatedly and consistently target food likes as a direct outcome of their feeding strategies. Interventions that focus on 'how' parents feed their children, as well as 'what', are recommended.

From policy to plate: barriers to implementing healthy eating policies in primary schools in Wales.

OBJECTIVES: School meal improvement is a major component of UK government policy to improve children's diets. This study investigated the pragmatic influences on local education authority (LEA) and primary school policies affecting the food available during school mealtimes, together with the professional practices of catering staff that further influence the food served. METHODS: A qualitative case study methodology involving interviews with primary school headteachers, catering managers and staff in a Welsh LEA. RESULTS: Whilst reflecting the primary objective of national policy with respect to the nutritional content of the school meal, LEA and school policies were also influenced by multiple, competing interests including parental views, pupil's food preferences or organisational objectives, such as protecting school meal uptake. Tensions existed between food availability and choice such that menus incorporating choices based on children's preferences were viewed as facilitating service viability and prioritized over promoting healthy eating. CONCLUSIONS: Higher level policy interventions may be limited in their effectiveness if they are undermined by a lack of attention to lower level factors that may compromise their successful implementation. The critical role of school meal providers and school cooks needs to be recognised and strategic partnerships developed to minimise tensions between improved nutritional standards and school meal uptake.

Bowhead whale springtime song off West Greenland.

Three songs were recorded from bowhead whales (Balaena mysticetus) in Disko Bay, West Greenland, during 59 h of recordings via sonobuoys deployed on seven days between 5 and 14 April 2007. Song elements were defined by units following the protocol of previous description of bowhead whale song. The two most prominent songs were loud, complex, and repeated in long bouts on multiple recording days while the third song was much simpler and recorded on only one day. Bowhead whale simple calls and faint song elements were also recorded using digital audio tape recorders and a dipping hydrophone deployed from the sea ice approximately 100-150 km southwest of Disko Bay on three separate days suggesting that song is also produced in the central portion of Baffin Bay in winter. Songs recorded in Disko Bay are from an area where approximately 85% of the whales have been determined to be adult females. Although it is not known which sex was singing, we speculate that, as in humpback whales (Megaptera novaeangliae), male bowhead whales may sing to mediate sexual competition or mate selection behaviors. This is the first detailed description of springtime songs for bowhead whales in the eastern Arctic.

Arctic marine mammals and climate change: impacts and resilience.

Evolutionary selection has refined the life histories of seven species (three cetacean [narwhal, beluga, and bowhead whales], three pinniped [walrus, ringed, and bearded seals], and the polar bear) to spatial and temporal domains influenced by the seasonal extremes and variability of sea ice, temperature, and day length that define the Arctic. Recent changes in Arctic climate may challenge the adaptive capability of these species. Nine other species (five cetacean [fin, humpback, minke, gray, and killer whales] and four pinniped [harp, hooded, ribbon, and spotted seals]) seasonally occupy Arctic and subarctic habitats and may be poised to encroach into more northern latitudes and to remain there longer, thereby competing with extant Arctic species. A synthesis of the impacts of climate change on all these species hinges on sea ice, in its role as: (1) platform, (2) marine ecosystem foundation, and (3) barrier to non-ice-adapted marine mammals and human commercial activities. Therefore, impacts are categorized for: (1) ice-obligate species that rely on sea ice platforms, (2) ice-associated species that are adapted to sea ice-dominated ecosystems, and (3) seasonally migrant species for which sea ice can act as a barrier. An assessment of resilience is far more speculative, as any number of scenarios can be envisioned, most of them involving potential trophic cascades and anticipated human perturbations. Here we provide resilience scenarios for the three ice-related species categories relative to four regions defined by projections of sea ice reductions by 2050 and extant shelf oceanography. These resilience scenarios suggest that: (1) some populations of ice-obligate marine mammals will survive in two regions with sea ice refugia, while other stocks may adapt to ice-free coastal habitats, (2) ice-associated species may find suitable feeding opportunities within the two regions with sea ice refugia and, if capable of shifting among available prey, may benefit from extended foraging periods in formerly ice-covered seas, but (3) they may face increasing competition from seasonally migrant species, which will likely infiltrate Arctic habitats. The means to track and assess Arctic ecosystem change using sentinel marine mammal species are suggested to offer a framework for scientific investigation and responsible resource management.