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During summer, native anadromous Arctic char (Salvelinus alpinus) and the alien species pink salmon (Oncorhynchus gorbuscha) now coexist in marine environments in Svalbard, following the introduction of the latter in the Barents Region. To investigate potential dietary competition between these two salmonid species, stomach contents from Arctic char (n = 301) and pink salmon (n = 28) were sampled from different areas within the archipelago. The most important prey in terms of biomass for both salmonid species were amphipods; Themisto libellula (B = 26.0%) for Arctic char and Onisimus litoralis (B = 35.0%) for pink salmon. Pianka's niche overlap revealed that dietary overlap between the two species was moderately high (Oobs = 0.59); both species had strong associations with intertidal invertebrates in areas where direct comparisons were possible (Kongsfjorden/Krossfjorden). However, both salmonid species did also eat some fish, with Arctic char consuming more offshore pelagic fish, while the small number of fish eaten by pink salmon were primarily coastal demersal fish species. Arctic char was a more generalist feeder, while pink salmon was more of a dietary specialist. Furthermore, the diet composition of the Arctic char consisted of 32.9% Atlantic prey while the pink salmon, surprisingly, ate only Arctic species, likely due to their tightly coastal feeding habits. Even though the sample size for pink salmon was low, this study contributes new insights into salmonid diets in Svalbard and the potential for introduced species to compete with native Arctic endemics, particularly in the expected warmer Arctic of the future. [ABSTRACT FROM AUTHOR]

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 phylogenetic groups (nine pinnipeds, three cetaceans, all species) and areas with high species 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 richness generally overlapped high‐density hotspots. Large regional and seasonal differences 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 telemetry 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 complete sex and age coverage, hotspots identified herein can inform management efforts to mitigate the impacts of human activities and ecological changes, including creation of protected areas. [ABSTRACT FROM AUTHOR]

The article focuses on Walruses that have a patchy circumpolar Arctic range. Topics include examines in the North Atlantic, they are distributed in shallow, coastal areas throughout much of the Canadian Eastern Archipelago, the west and northeast coasts of Greenland, the Svalbard and Franz Josef Land Archipelagos and in the southern Barents Region, particularly in the Pechora and Kara Seas.

Background: Health assessment of seals in captivity include haematology and serum biochemistry measurements. Because such parameters differ between species, it is crucial to have species-specific reference values for the interpretation of clinical samples. Furthermore, differences in nutrition and environment, life cycles as well as seasonal/annual cycles and varying physiological conditions can potentially affect serum chemistry and haematology parameters. Blood samples from four captive adult bearded seals (initially caught as pups in Svalbard, Norway, now held at Polaria, an Arctic experience centre in Tromsø, Norway) collected over a 16-month period were analysed for haematology (n = 22) and serum chemistry (n = 25) parameters. Serum chemistry analyses were also conducted on blood samples from 74 wild bearded seals (1995–2007) collected from Svalbard, Norway. Results: We found higher activity of creatine kinase (CK) and higher concentrations of cortisol in the wild animals when compared to the captive seals, probably reflecting the physical restraint and concomitant stress induced during sampling. For the captive bearded seals, we did not find marked differences in haematology or serum chemistry parameters throughout the different seasons of sampling. Conclusions: This study presents haematology and serum chemistry reference values for captive and wild bearded seals. Comparing physiological parameters for captive seals with wild seals indicated that having wild-caught bearded seals under the conditions offered at Polaria for several years did not markedly affect physiological parameters of the animals, and that training may have helped to alleviate stress associated with blood sampling and veterinary inspection. [ABSTRACT FROM AUTHOR]

Background: Health assessment of seals in captivity include haematology and serum biochemistry measurements. Because such parameters differ between species, it is crucial to have species-specific reference values for the interpretation of clinical samples. Furthermore, differences in nutrition and environment, life cycles as well as seasonal/annual cycles and varying physiological conditions can potentially affect serum chemistry and haematology parameters. Blood samples from four captive adult bearded seals (initially caught as pups in Svalbard, Norway, now held at Polaria, an Arctic experience centre in Tromsø, Norway) collected over a 16-month period were analysed for haematology (n = 22) and serum chemistry (n = 25) parameters. Serum chemistry analyses were also conducted on blood samples from 74 wild bearded seals (1995–2007) collected from Svalbard, Norway. Results: We found higher activity of creatine kinase (CK) and higher concentrations of cortisol in the wild animals when compared to the captive seals, probably reflecting the physical restraint and concomitant stress induced during sampling. For the captive bearded seals, we did not find marked differences in haematology or serum chemistry parameters throughout the different seasons of sampling. Conclusions: This study presents haematology and serum chemistry reference values for captive and wild bearded seals. Comparing physiological parameters for captive seals with wild seals indicated that having wild-caught bearded seals under the conditions offered at Polaria for several years did not markedly affect physiological parameters of the animals, and that training may have helped to alleviate stress associated with blood sampling and veterinary inspection. [ABSTRACT FROM AUTHOR]

Abstract: Penguins are a monophyletic group in which many species are found breeding sympatrically, raising questions regarding how these species coexist successfully. Here, the isotopic niche of three sympatric pygoscelid penguin species was investigated at Powell Island, South Orkney Islands, during two breeding seasons (austral summers 2013–2014 and 2015–2016). Measurements of carbon (δ13C) and nitrogen (δ15N) stable isotope ratios were obtained from blood (adults) or feather (chicks) samples collected from Adélie Pygoscelis adeliae, chinstrap P. antarctica, and gentoo P. papua penguins. Isotopic niche regions (a proxy for the realized trophic niches) were computed to provide estimates of the trophic niche width of the studied species during the breeding season. The isotopic niche regions of adults of all three species were similar, but gentoo chicks had noticeably wider isotopic niches than the chicks of the other two species. Moderate to strong overlap in isotopic niche among species was found during each breeding season and for both age groups, suggesting that the potential for competition for shared food sources was similar during the two study years, although the actual level of competition could not be determined owing to the lack of data on resource abundance. Clear interannual shifts in isotopic niche were seen in all three species, though of lower amplitude for adult chinstrap penguins. These shifts were due to variation in carbon, but not nitrogen, isotopic ratios, which could indicate either a change in isotopic signature of their prey or a switch to an alternative food web. The main conclusions of this study are that (1) there is a partial overlap in the isotopic niches of these three congeneric species and that (2) they responded similarly to changes that likely occurred at the base of their food chain between the 2 years of the study. [ABSTRACT FROM AUTHOR]

Identifying environmental characteristics that define the ecological niche of a species is essential to understanding how changes in physical conditions might affect its distribution and other aspects of its ecology. The present study used satellite relay data loggers (SRDLs) to study habitat use by Northeast Atlantic hooded seals (N = 20; 9 adult females, 3 adult males, and 8 juveniles). Three different methods were used in combination to achieve maximum insight regarding key foraging areas for hooded seals in this region, which have decline by 85% in recent decades: 1) first passage time (FPT); 2) vertical transit rate and; 3) change in dive drift rate. Generalized additive mixed models (GAMM) were applied to each method to determine whether specific habitat characteristics were associated with foraging. Separate models were run for the post-molting and the post-breeding seasons; sex and age classes were included in the GAMMs. All three methods highlighted a few common geographic areas as being important foraging zones; however, there were also some different areas identified by the different methods, which highlights the importance of using multiple indexes when analyzing tracking and diving data to study foraging behavior. Foraging occurred most commonly in relatively shallow areas with high Sea Surface Temperatures (SST), corresponding to continental shelf areas with Atlantic Water masses. All age and sex classes overlapped spatially to some extent, but the different age and sex groups showed differences in the bathymetry of their foraging areas as well as in their vertical use of the water column. When foraging, pups dove in the upper part of the water column in relatively deep areas. Adult females foraged relatively shallowly in deep water areas too, though in shallower areas than pups. Adult males foraged close to the bottom in shallower areas. [ABSTRACT FROM AUTHOR]

Herein, we review and synthesize results from a series of research projects that were conducted to evaluate the role of Greenland sharks ( Somniosus microcephalus) in the marine ecosystem in Kongsfjorden, Svalbard, Norway. A total of 76 sharks were caught on baited lines during the summers of 2008 and 2009 for these investigations. All of these animals, including the largest shark, a female weighing 700 kg, were sexually immature. Approximately half of the gastrointestinal tracts (GITs, N = 33) examined contained seal tissue (42.3 %), and some also contained minke whale ( Balaenoptera acutorostrata) tissue (18.2 %). Atlantic cod ( Gadus morhua), Atlantic wolffish ( Anarhichas lupus) and haddock ( Melanogrammus aeglefinus) were the dominant fish species consumed by the sharks. These fish species were found in 39.4, 18.2 and 18.2 % of the GITs, respectively. Many of the fishes were swallowed whole, including an Atlantic wolffish weighing 8.6 kg. Satellite pop-up tags deployed on 20 of the sharks showed that they travelled in the water column from the surface to depths greater than 1500 m, encountering temperatures from −1.5° to 7.4°. Accelerometers deployed on six of the sharks showed that they swim extremely slowly, with average speeds of 0.34 m/s and burst speeds of only twice this value. Various types of circumstantial evidence, including the condition of the seals and fishes found in the sharks' stomachs, indicate that they are not only scavengers, but also active predators of both fish and mammalian prey. Given the swim speed of these sharks, we suggest that the only way they could successfully capture a healthy seal is via cryptically approaching seals that are asleep in the water. Greenland sharks clearly play a significant role as large predators in the Kongsfjorden marine ecosystem, a fact that has been largely overlooked until recently. [ABSTRACT FROM AUTHOR]

The harbour seal (Phoca vitulina) population in Svalbard marks the northernmost limit of the species’ range. This small population experiences environmental extremes in sea and air temperatures, sea ice cover and also in light regime for this normally temperate species. This study deployed Conductivity Temperature Depth Satellite Relay Data Loggers (CTD-SRDLs) on 30 adult and juvenile harbour seals in 2009 and 2010 to study their foraging behaviour across multiple seasons. A total of 189,104 dives and 16,640 CTD casts (mean depth 72 m ± 59) were recorded. Individuals dove to a mean depth of 41 m ± 24 with a maximum dive depth range of 24 – 403 m. Dives lasted on average 204 sec ± 120 with maximum durations ranging between 240 – 2,220 sec. Average daily depth and duration of dives, number of dives, time spent diving and dive time/surface time were influenced by date, while sex, age, sea-ice concentration and their interactions were not particularly influential. Dives were deeper (~150 m), longer (~480 sec), less numerous (~250 dives/day) and more pelagic during the winter/early spring compared to the fall and animals spent proportionally less time at the bottom of their dives during the winter. Influxes of warm saline water, corresponding to Atlantic Water characteristics, were observed intermittently at depths ~100 m during both winters in this study. The seasonal changes in diving behaviour were linked to average weekly wind stresses from the north or north-east, which induced upwelling events onto the shelf through offshore Ekman transport. During these events the shelf became flooded with AW from the West Spitsbergen Current, which presumably brought Atlantic fish species close to shore and within the seals’ foraging depth-range. Predicted increased in the influx of AW in this region are likely going to favour the growth and geographic expansion of this harbour seal population in the future. [ABSTRACT FROM AUTHOR]

Understanding how an animal utilises its surroundings requires its movements through space to be described accurately. Satellite telemetry is the only means of acquiring movement data for many species however data are prone to varying amounts of spatial error; the recent application of state-space models (SSMs) to the location estimation problem have provided a means to incorporate spatial errors when characterising animal movements. The predominant platform for collecting satellite telemetry data on free-ranging animals, Service Argos, recently provided an alternative Doppler location estimation algorithm that is purported to be more accurate and generate a greater number of locations that its predecessor. We provide a comprehensive assessment of this new estimation process performance on data from free-ranging animals relative to concurrently collected Fastloc GPS data. Additionally, we test the efficacy of three readily-available SSM in predicting the movement of two focal animals. Raw Argos location estimates generated by the new algorithm were greatly improved compared to the old system. Approximately twice as many Argos locations were derived compared to GPS on the devices used. Root Mean Square Errors (RMSE) for each optimal SSM were less than 4.25km with some producing RMSE of less than 2.50km. Differences in the biological plausibility of the tracks between the two focal animals used to investigate the utility of SSM highlights the importance of considering animal behaviour in movement studies. The ability to reprocess Argos data collected since 2008 with the new algorithm should permit questions of animal movement to be revisited at a finer resolution. [ABSTRACT FROM AUTHOR]

The harbour seal population in Svalbard occurs at the northernmost limit of the species' range. It experiences environmental extremes far beyond the norm for this species, including an extended period of polar night and extensive sea ice cover. In 2009 and 2010, 60 harbour seals (30 pups + 30 immature/mature seals) from this population were equipped with Satellite-Relay Data Loggers (SRDLs) to study their haul-out behaviour, with a special focus on the winter period. Using a combination of Generalized Additive Mixed Models and Cox Proportional Hazard models, the influences of sex, maturity, temporal, spatial and environmental factors on haul-out behaviour were explored. All of the seals continued to haul out even through the coldest periods during the polar night, though clear seasonality in the time spent hauled out daily was displayed by both immature and mature seals. Time spent hauled out daily decreased from ∼5.2 hrs in September to ∼1.2 hrs in February in these age groups, while pups displayed less seasonality (∼2.4 hrs/day throughout most of the year). The average at-sea period also exhibited seasonality, increasing to a maximum of ∼1.6 days in February (monthly maxima for individual animals ranged from 7 to 19 days). The seals showed a strong preference to haul out at low tide when hauling out on land but not when using sea ice as a haul-out platform. A diel rhythm in haul-out behaviour was present during the months with day–night cycling and midnight sun but not during the polar night. Haul-out behaviour was impacted to a greater extent by air pressure, through its effect on wind speed, than by absolute temperature values. The extreme environment in Svalbard likely causes some physiological challenges that might impact survival rates negatively, particularly among pups. Climate warming is likely to have positive effects on Svalbard's harbour seal population. [ABSTRACT FROM AUTHOR]

Abstract: Approximately 60% of Svalbard's land areas are glaciated at the present time. The Archipelago has more than 1100 glaciers (>1km2) and 163 of these are “tidewater glaciers” — that is glaciers that terminate (with their calving front) at the sea. It has been known for a long time that these glacier front areas are important feeding areas for seabirds and marine mammals. Herein, we review current knowledge regarding the importance of these areas for these animals and reflect upon the processes that create these apparent “hotspots”. Kittiwakes Rissa tridactyla, routinely dominate avian assemblages in front of glaciers in Svalbard, but fulmars Fulmarus glacialis, ivory gulls Pagophila eburnea and glaucous gulls Larus hyperboreus also contribute to aggregations, which can sometimes comprise many thousands of individuals. The birds are often found in the so-called “brown zone”, which is an area in front of tidewater glaciers that is ice-free due to currents and muddy due to suspended sediments. Animals at these sites typically have their stomachs full of large zooplankton or fish. These brown zones are also foraging hotspots for Svalbard's ringed seals (Pusa hispida) and white whales (Delphinapterus leucas). Prime breeding habitat for ringed seals in Svalbard occurs deep in the fjords where ice pieces calved from the glacier fronts become frozen into land-fast sea-ice, promoting the accumulation of snow to a depth suitable for ringed seal females to dig out birth lairs above breathing holes in the ice. These pupping areas are important hunting areas for polar bears (Ursus maritimus) in spring, especially female bears with cubs of the year during the period following emergence from the winter/birthing den. Glacier-ice pieces floating in coastal areas are also important for all seal species in the region as dry platforms during moulting and also as general resting platforms for both birds and seals. During the last decade there have been several years with a complete lack of spring sea ice in many of the fjords along the west coast of Spitsbergen. During the spring periods in these years, bearded seals (Erignathus barbatus) have replaced their regular sea-ice platform with glacier ice, using it as a solid substrate for both birthing and nursing as well as general resting. The mechanisms that create foraging hotspots at the fronts of tidewater glaciers are related to the massive subsurface plumes of freshwater discharged from the glacier fronts. As these plumes rise towards the surface they entrain large volumes of ambient water, tens to hundreds of times the original discharge volume. This water is drawn from all depth levels as the plume ascends. This entrainment ensures a continuous resupply of intermediate depth waters from the outer parts of the fjords towards the glacier front and greatly amplifies the general estuarine circulation. The intermediate water masses carry plankton from a broad area, including the outer fjord, into the glacier front area, where they get entrained in the plume rising towards the surface, and often become stunned or die from freshwater osmotic shock. These small animals fall as an easy prey to the surface feeding predators. Large, strong swimming marine zooplankton species can sometimes escape by swimming below the inflow of marine water. But, they then become concentrated in a water layer near the bottom, making them of interest and susceptible to predators. The intermediate water masses also bring nutrients towards the glacier fronts where they are transported up to the surface layer where they can subsequently be utilized for post-bloom primary production. However, this tends to have greatest influence some distance away from the glacier front, when much of the outflow sediment has settled out. Currently, the mass balance for Svalbard glaciers is negative and climate change predictions for the future suggest continued warming, and hence continued glacial retreat. This will result in a reduction in both the number of glaciers calving into the ocean in Svalbard and the total length of calving fronts around the Archipelago. Similar to the retraction of the northern sea-ice edge (which is another diminishing foraging hotspot for these same arctic vertebrates), the climate-warming-induced changes in glaciers will likely lead to substantial distributional shifts and abundance reductions for many arctic species. [Copyright &y& Elsevier]

This study presents the first abundance estimate for the world’s northernmost harbour seal (Phoca vitulina) population, which resides in Svalbard, Norway, based on three digital stereoscopic photographic surveys conducted in 2009 and 2010. The counts from these high resolution 3D images were combined with a novel method for estimating correction factors for animals that were in the water at the time of the surveys, in which extensive behavioural data from radio-tagged harbour seals were used together with age distribution data to estimate the proportion of seals of various age and sex classes hauled out at the times of the surveys. To detect possible seasonal shifts in age distribution between surveys, lengths of hauled out seals were measured from the stereoscopic images. No body-length differences were detected between the surveys; but, this may be due to a high degree of sexual dimorphism exhibited in this population. Applying the modelled correction factors, a total of 1888 (95% CI: 1660–3023), 1742 (1381–3549) and 1812 (1656–4418) harbour seals were estimated for the surveys flown on 01 August 2009, 01 August 2010 and 19 August 2010, respectively. The similarity between the three survey estimates (despite significant differences in the number of animals actually counted on the photos from each survey effort) suggests that the variation in numbers of hauled out seals is reasonably accurately adjusted for by the haul-out probability model. The low population size, the limited spatial distribution of the population and its reduced genetic diversity make this population vulnerable to chance events, such as disease epidemics. [ABSTRACT FROM AUTHOR]

Basic knowledge of the population biology of Atlantic walruses throughout the eastern parts of their range, including the Pechora Sea, is scarce or nonexistent. Herein, we present the first estimate of walrus numbers from the Pechora Sea based on an aerial survey of 2,563 km of coastline, using a combination of infrared techniques and digital imagery. Hauled out walruses were found at three sites (Vaygach Island and two sites on Matveyev Island). A total of 968 animals were counted on aerial photographs; all of the animals appeared to be males. Crude measurements of dorsal curvilinear lengths of a subset of the photographed animals ( N = 504) showed that many were adults, but 14.5 % belonged to younger age classes (shorter than 225 cm). Using an adjustment factor developed for male walruses in Svalbard, to account for animals at sea during the survey, the number of walruses occupying this area was estimated to be 3,943 (95 % CI, 3,605-4,325). No females with calves were seen in this survey, implying that the population that uses the Pechora Sea during summer has a distributional area that is larger than the survey area. Extensive oil exploration, development and production are currently taking place in the Pechora Sea. Risks posed to walruses and their prey by these industrial activities should be assessed immediately, and the genetic delineations of this population should be clarified. [ABSTRACT FROM AUTHOR]

Abstract: Locomotory muscle function of ectothermic fishes is generally depressed in cold waters, making them vulnerable to avian and mammalian predators whose body temperature remains high. Paradoxically, Greenland sharks Somniosus microcephalus exhibit the reverse of this usual predator–prey thermal pattern by apparently hunting seals in Arctic waters. To examine whether this species possesses cold-adaptations that enhance its swimming performance, we used data-logging tags to measure swim speed and tail-beat frequency (which reflects muscle-shortening speed) of six free-swimming sharks (204–343kg). For comparison, we compiled these parameters for wild fishes from the literature over a wide body mass range (0.2–3900kg) and examined the scaling relationships using phylogenetically informed statistics. The sharks cruised at 0.34m·s−1 with a tail-beat frequency of 0.15Hz, both of which were the lowest values for their size across fish species. The mean and maximum speed (0.74m·s−1) and acceleration during burst swimming (0.008m·s−2) were much lower than those of seals. Our results indicate that the swimming performance of Greenland sharks is limited by cold waters (~2°C) and insufficient to catch swimming seals. However, Arctic seals sleep in water to avoid predation by polar bears Ursus maritimus, which may leave them vulnerable to this cryptic slow-swimming predator. [Copyright &y& Elsevier]

Harbour seals in Svalbard have short longevity, despite being protected from human hunting and having limited terrestrial predation at their haulout sites, low contaminant burdens and no fishery by-catch issues. This led us to explore the diet of Greenland sharks ( Somniosus microcephalus) in this region as a potential seal predator. We examined gastrointestinal tracts (GITs) from 45 Greenland sharks in this study. These sharks ranged from 229 to 381 cm in fork length and 136-700 kg in body mass; all were sexually immature. Seal and whale tissues were found in 36.4 and 18.2%, respectively, of the GITs that had contents ( n = 33). Based on genetic analyses, the dominant seal prey species was the ringed seal ( Pusa hispida); bearded seal ( Erignathus barbatus) and hooded seal ( Cystophora cristata) tissues were each found in a single shark. The sharks had eaten ringed seal pups and adults based on the presence of lanugo-covered prey (pups) and age determinations based on growth rings on claws (≤1 year and adults). All of the whale tissue was from minke whale ( Balenoptera acutorostrata) offal, from animals that had been harvested in the whale fishery near Svalbard. Fish dominated the sharks' diet, with Atlantic cod ( Gadus morhua), Atlantic wolffish ( Anarhichas lupus) and haddock ( Melanogrammus aeglefinus) being the most important fish species. Circumstantial evidence suggests that these sharks actively prey on seals and fishes, in addition to eating carrion such as the whale tissue. Our study suggests that Greenland sharks may play a significant predatory role in Arctic food webs. [ABSTRACT FROM AUTHOR]

Changing patterns of sea-ice distribution and extent have measurable effects on polar marine systems. Beyond the obvious impacts of key-habitat loss, it is unclear how such changes will influence ice-associated marine mammals in part because of the logistical difficulties of studying foraging behaviour or other aspects of the ecology of large, mobile animals at sea during the polar winter. This study investigated the diet of pregnant bearded seals (Erignathus barbatus) during three spring breeding periods (2005, 2006 and 2007) with markedly contrasting ice conditions in Svalbard using stable isotopes (d13C and d15N) measured in whiskers collected from their newborn pups. The d15N values in the whiskers of individual seals ranged from 11.95 to 17.45 %, spanning almost 2 full trophic levels. Some seals were clearly dietary specialists, despite the species being characterised overall as a generalist predator. This may buffer bearded seal populations from the changes in prey distributions lower in the marine food web which seems to accompany continued changes in temperature and ice cover. Comparisons with isotopic signatures of known prey, suggested that benthic gastropods and decapods were the most common prey. Bayesian isotopic mixing models indicated that diet varied considerably among years. In the year with most fast-ice (2005), the seals had the greatest proportion of pelagic fish and lowest benthic invertebrate content, and during the year with the least ice (2006), the seals ate more benthic invertebrates and less pelagic fish. This suggests that the seals fed further offshore in years with greater ice cover, but moved in to the fjords when ice-cover was minimal, giving them access to different types of prey. Long-term trends of sea ice decline, earlier ice melt, and increased water temperatures in the Arctic are likely to have ecosystem-wide effects, including impacts on the forage bases of pagophilic seals. [ABSTRACT FROM AUTHOR]

The Spitsbergen bowhead whale stock is critically endangered. It is believed to number in the tens. Here we report results from the first satellite transmitter ever deployed on an individual from this stock. A female whale was tagged on 3 April 2010 (at 79°54' N, 01°03' E), but no locations were transmitted by the tag until 30 April 2010, after which data were received continuously for 86 days. Additionally, three small clusters of locations were transmitted later in the year; the latest was received 20 December 2010 (262 days after deployment). During the 86 days of continuous tracking, the whale initially remained in the middle of the Fram Strait, between 77°45' N, 5° W and 80°10' N, 5° E. For a two-week period starting around 10 June 2010, the whale traveled southwest down to 73°40' N (at least 950 km). Subsequently it remained at southern latitudes between ~70° and 73° N until the tag stopped continuous transmissions on 24 July. Movement patterns analyzed using first-passage times (FTP), fitted as functions of various environmental variables using Cox Proportional Hazards models, showed that the whale spent most of its time in waters close to the ice edge with modest ice coverage, over areas where the bottom slope was relatively steep. Winter positions (27 November - 20 December 2010) revealed that the whale was back in the North at about 80° N. This information, in combination with recent data from passive acoustic listening devices, suggests that the Spitsbergen bowhead stock overwinters at high-latitude locations. The north-south movements of this whale during summer are consistent with the patterns that early whalers described for bowhead whales in this region in the 16th and 17th centuries. [ABSTRACT FROM AUTHOR]

The diet of ringed seals ( Pusa hispida) from coastal and offshore areas of Northeast Greenland was determined by identifying, to the lowest taxonomic limit possible, all hard-part contents from the gastrointestinal tract of 51 seals sampled (2002-2004) in spring (April to June, N = 35) and autumn (September to October, N = 16). The autumn diet was characterized by high numbers of Parathemisto libellula, and the spring diet was comprised primarily of polar cod ( Boreogadus saida), with few invertebrates consumed. The coastal seal diet samples had a diverse fish prey composition (during both the spring and autumn), whereas the open water seals had eaten mostly crustaceans with P. libellula being most abundant. The sample sizes from the various locations and seasons were not large enough to explore age-class effects on diet in addition. Similar to earlier studies, this study suggests that the ringed seal is a generalist that exploits prey based on availability, with a few key species dominating the diet in an area at least on a seasonal basis. [ABSTRACT FROM AUTHOR]

It is crucial to examine the genetic diversity and structure of small, isolated populations, especially those at the edge of their distribution range, because they are vulnerable to stochastic processes if genetic diversity is low and the isolation level is high, and because such populations provide insight into the consequences of population declines in a broader conservation context. The harbour seal ( Phoca vitulina) population in Svalbard is the world's northernmost P. vitulina population. Nothing is known about the genetic diversity, distinctiveness, or origin of this small, marginalized mammalian population. Thus, the present study investigated its genetic status in the context of nearby P. vitulina in Iceland, south-east Greenland, and northern Norway: this species is depleted/threatened in all of these regions. A total of 174 samples distributed between the four locations were analysed using 15 polymorphic microsatellites and variation in the displacement loop region (D-loop). Each of the four locations was a genetically distinct population. The Svalbard population was highly genetically distinct, had reduced genetic diversity, received limited gene flow, had a rather low effective population size, and showed an indication of having experienced a bottleneck resulting from a recent population decline. The significant heterozygote excess observed in the Svalbard sample might be attributed to the low effective population size, which could initiate future population inbreeding effects. This phenomenon has not been reported earlier from other P. vitulina populations, but if the Svalbard population is experiencing inbreeding, this could reduce its resilience to climate change, disease outbreaks, or other perturbations. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, , 420-439. [ABSTRACT FROM AUTHOR]

Population structure in many Arctic marine mammal species reflects a dynamic interplay between physical isolating mechanisms and the extent to which dispersal opportunities are met. We examined variation within mtDNA and eight microsatellite markers to investigate population structure and demographic history in beluga whales in the North Atlantic. Genetic heterogeneity was observed between Svalbard and West Greenland that reveals limited gene flow over ecological time scales. Differentiation was also recorded between Atlantic belugas and two previously studied populations in the North Pacific, the Beaufort Sea and Gulf of Alaska. However, Bayesian cluster analysis of the nDNA data identified two population clusters that did not correspond to the respective ocean basins, as predicted, but to: (1) Arctic (Svalbard–White Sea–Greenland–Beaufort Sea) and (2) Subarctic (Gulf of Alaska) regions. Similarly, the deepest phylogeographic signal was between the Arctic populations and the Gulf of Alaska. Fitting an isolation-with-migration model yielded genetic abundance estimates that match census estimates and revealed that Svalbard and the Beaufort Sea likely diverged 7,600–35,400 years ago but have experienced recurrent periods with gene flow since then, most likely via the Russian Arctic during subsequent warm periods. Considering current projections of continued sea ice losses in the Arctic, this study identified likely routes of future contact among extant beluga populations, and other mobile marine species, which have implications for genetic introgression, health, ecology and behavior. [ABSTRACT FROM AUTHOR]

Blubber biopsies were collected from 18 adult male walruses from Svalbard, Norway. The biopsies were taken vertically through the skin and the entire blubber layer down to, but not including, the muscle layer. Fatty acid (FA) compositions of inner blubber, outer blubber and dermis of the walruses and of potential prey organisms were determined. The three layers differed significantly from one another in FA composition. Generally, the inner blubber contained more long-chained monounsaturated, saturated and polyunsaturated FAs, while the outer blubber and dermis contained more short-chained monounsaturated FAs. This stratification is similar to what has been observed in other marine mammal species. However, differences between layers were less pronounced than in most other species, possibly because the extremely thick overlying dermis of walruses provides an insulating shield, which affects the FA composition of the outer blubber. The FA composition of the potential prey organisms was different from that of the blubber of the walruses, although more similar to the inner blubber than to the outer blubber or dermis. FA composition in the inner blubber was not significantly correlated with age (assessed by tusk volume), while the FA composition of the outer blubber and dermis were significantly correlated with age. [ABSTRACT FROM AUTHOR]

Correction to: Acta Vet Scand (2021) 63:33 https://doi.org/10.1186/s13028-021-00598-8 Following the publication of the original article [[1]], we were notified of erroneously presented units for red and white blood cells in Table 2 and missing unit for Total T4 in Table 3. Reference 1 Tryland M, Lydersen C, Kovacs KM, Rafter E. Serum biochemistry and haematology in wild and captive bearded seals (Erignathus barbatus) from Svalbard, Norway. [Extracted from the article]

In a warmer Arctic, endemic marine mammal species will face extreme levels of habitat change, most notably a dramatic reduction in sea ice. Additionally, the physical environmental changes, including less ice and increased water (and air) temperatures will result in alterations to the forage base of arctic marine mammals, including density and distributional shifts in their prey, as well as potential losses of some of their traditionally favoured fat-rich prey species. In addition they are likely to face increased competition from invasive temperate species, increased predation from species formerly unable to access them in areas of extensive sea ice or simply because the water temperature was restrictive, increased disease risk and perhaps also increased risks from contaminants. Over the coming decades it is also likely that arctic marine mammals will face increased impacts from human traffic and development in previously inaccessible, ice-covered areas. Impacts on ice-associated cetaceans are difficult to predict because the reasons for their affiliation with sea ice are not clearly understood. But, it is certain that ice-breeding seals will have marked, or total, breeding-habitat loss in their traditional breeding areas and will certainly undergo distributional changes and in all probability abundance reductions. If species are fixed in traditional spatial and temporal cycles, and are unable to shift them within decadal time scales, some populations will go extinct. In somewhat longer time frames, species extinctions can also be envisaged. [ABSTRACT FROM AUTHOR]

All known terrestrial haul-out sites for walruses in Svalbard (n = 79) were surveyed during the period 1-3 August 2006, and sites that were in use (n = 17) were documented using digital photography. A total of 657 walruses were counted on land in the resultant images. An extensive behavioural data set from walruses equipped with satellite relay data loggers, covering August 2002 to August 2005, was used to account for walruses that were in the water. The proportion of walruses at sea during the survey was calculated to be 0.750 on the basis of 28 thirty-day periods from 23 male walruses. Time of day and wind chill did not significantly affect haul-out behaviour. However, a logistic regression model revealed both a correlation among haul-out patterns of individuals within years, and a year effect (χ² = 6.42, df = 2, p = 0.04). Because the survey was not flown in a year when satellite tags were deployed, the interannual variance was retained in a model (with no other explanatory variables). The overdispersion parameter from this model was 2.02 (deviance = 28.33, df = 14). Thus, variance in proportions of time individuals spent at sea was multiplied by this parameter to achieve a corrected SE around the estimate. The 95% CI based on this SE corresponded to a proportion of walruses at sea during the survey between 0.717 and 0.781, resulting in an estimated total number of walruses in Svalbard in August 2006 of 2629 (95% CI: 2318- 2998). [ABSTRACT FROM AUTHOR]

Three juvenile narwhals captured during August 1998 in the northeast of Svalbard, Norway, were equipped with satellite-relayed data loggers (SRDLs) that transmitted diving and swim-speed data, in addition to location, for up to 46 days. A total of 1,354 complete dive cycles were recorded. Most of the diving was shallow and of short duration. Maximum recorded dive depth was 546 m, maximum recorded dive duration was 24.8 min, and maximum recorded swim-speed was 4.7 ms−1. Ascent speed, vertical ascent speed, descent speed and vertical descent speed were all significantly higher during deep dives (>200 m) than for shallow dives (<200 m). In addition both ascent and descent angles were much steeper for deep dives than during shallow dives. Most of the shallow diving seemed to be associated with travelling, with the animal shifting between various locations, while the deep diving (often to the bottom) for extended periods in some specific areas might have been associated with foraging. Even though the sample size in this study is small, the data are the first information available for movements and diving behaviour of narwhals near Svalbard. [ABSTRACT FROM AUTHOR]

Labansen, A. L., Lydersen, C., Haug, T., and Kovacs, K. M. 2007. Spring diet of ringed seals (Phoca hispida) from northwestern Spitsbergen, Norway. – ICES Journal of Marine Science, 64: 1246–1256. Complete gastro-intestinal tracts (GITs) from 267 ringed seals from five different locations in Spitsbergen were collected during spring of the years 2002–2004. Diet was assessed based on hard part remains from prey. Invertebrates constituted <2% of all prey (relative frequency, Ni). Fish otoliths were found in all seals; 1.7, 34.3, and 64.0% of the recovered otoliths were found in the stomach, small and large intestines, respectively, emphasizing the importance of analysing the whole GIT, not only the stomach. Otoliths from stomachs and small intestines with minimal signs of erosion were measured to back-calculate pre-ingested prey size and biomass. Based on measured polar cod (Boreogadus saida) otoliths (n = 7007), the ringed seals fed on fish in the length range 44.4–229.2 mm, primarily consuming the youngest year classes. Adult females ate smaller polar cod more often than adult males or juveniles. Polar cod dominated the diet, with a frequency of occurrence (FO) of 100%, Ni of 71.9%, and a biomass contribution of 77.2%. The taxon Stichaeidae was the second most frequent prey type (FO = 55.6%) followed by Cottidae (FO = 35.6%). The diet of ringed seals from one locality markedly differed from the others, with a greater species diversity, low Ni of polar cod (15%), and a dominance of Stichaeidae (Ni = 67%). Location of sampling, as well as sex and age of the seals, had significant influences on ringed seal diet in spring. [ABSTRACT FROM PUBLISHER]

The harbour seals (Phoca vitulina) in Svalbard are the northernmost population of this species. The population size is thought to be less than 1,000 individuals; these animals reside principally within a national park on Prins Karls Forland on the west coast of Spitsbergen, Svalbard, at about 78°20'N. The material presented in this study was collected from 367 live-captured animals, aged based on growth layers read from stained, decalcified incisor sections (except for pups of the year). Standard length (F1,246=45.70,P<0.0001) and body mass (F1,258=25.28;P<0.0001) were both significantly influenced by sex when age was taken into account. Adult males are both longer [152.9±4.8 (SE) vs 140.1±2.0 cm, standard length] and heavier (104.0±5.0 vs 83.2±2.7 kg, body mass) than adult females in this population. Age at sexual maturity was assessed based on analyses of sex hormones. Testosterone levels in males showed an abrupt increase at 6 years of age, while estradiol levels in females increased from age 4. The reproductive rate of adult females was 0.93. The longevity of Svalbard harbour seals was short compared to harbour-seal populations from other areas. However, these seals are not exposed to terrestrial predation; there is no known mortality due to fisheries or hunting and their pollution burdens are low. Extreme seasonality and perhaps other harsh environmental conditions at the northern edge of this species’ distribution may exert long-term low levels of stress that result in short life span, or there are currently unknown acute sources of mortality in this population. To our knowledge, this is the first study of population parameters on a pinniped species using cross-sectional, non-terminal sampling. [ABSTRACT FROM AUTHOR]

This study used hard-part analyses from scats (n = 117) and stomachs (n = 3) to investigate the diet of high Arctic harbour seals (Phoca vitulina L., 1758) living on Prins Karls Forland, Svalbard, in early autumn. Additionally, it compared the results of fatty-acid analyses of the seals' blubber versus that of potential prey with the findings of the more traditional diet assessment method. Svalbard harbour seals appear to be opportunistic, polyphagous feeders similar to the situation in other parts of their range. Members of the cod-family, and secondarily the sculpin-family, dominated the diet of harbour seals on Svalbard. Small fish comprised most of the diet of the harbour seals; invertebrates appeared to be insignificant. Atlantic cod (Gadus morhua L., 1758) was the most important species in the diet in terms of biomass, whereas polar cod (Boreogadus saida (Lepechin, 1774)) was the most frequently consumed prey. Our comparison between hard-part diet analyses and fatty acids is far from definitive, but it indicates a general influence of the diet on the fatty-acid composition of the inner blubber layer. However, it also suggests systematic selective processes in the incorporation of fatty acids into the blubber. Observed differences between the fatty-acid composition of the different blubber layers and possible differences between sex and age classes warrant further investigation. [ABSTRACT FROM AUTHOR]

We used vocalizations to examine the behaviour of male bearded seals, Erignathus barbatus, in relation to ice cover over 2 consecutive years. Site fidelity varied between males. Territorial males returned to the same display locations in successive years, whereas roaming males returned to the study area but not to specific display locations. Males did not vocalize under the land-fast-ice edge and were therefore limited by access to areas of drift ice and open water for the purpose of displaying. Between-year fluctuations in ice cover restricted the number of displaying males during the early part of the mating season in April. Decreased ice cover during May resulted in more males displaying, but the number of males declined in June irrespective of the continued decline in ice cover. Roaming males were not heard when the ice cover was more than 60%, whereas territorial males were present during all ice conditions. Yearly fluctuations in ice cover may alter the long-term mating success of individuals and predictably available display areas may be preferred to areas that are more likely to be enclosed by fast-ice in some years. [Copyright &y& Elsevier]

Free-living ringed seals (N=11) equipped with satellite-relayed data loggers (SRDLs) with incorporated oceanographic-quality temperature sensors were used to collect data from a large sector of the northern Barents Sea during the autumn and early winter. A total of 2346 temperature profiles were collected over a 4-month period from Norwegian and Russian arctic waters in areas that were at times 90–100% ice-covered. Temperature distributions at different depths from northeastern parts of Svalbard, Norway show warm North Atlantic water (NAW) flowing along the continental slope and gradually cooling at all depths as it flows eastwards. The data suggest that most of the cooling takes place west of 30°E. Vertical temperature profiles from the area between Svalbard and Franz Josef Land, Russia show how the surface water cools during freeze-up and demonstrate a warm water flow, which is probably NAW, coming in from the north through a deep trench west of Franz Josef Land. Global oceanographic and climate models require improved oceanographic databases from crucial areas where important hydrological phenomena occur. Such areas in arctic waters are often inaccessible during winter and logistically difficult to reach even in summer. The present study demonstrates how large amounts of oceanographic information can be collected and retrieved in a cost-efficient manner using ice-associated marine mammals as carrier of oceanographic sampling equipment. In addition to the oceanographic value of the data collected by marine mammals in this manner, a vast amount of information regarding the habitat of these animals is concomitantly sampled. [Copyright &y& Elsevier]

The harbor seal population on Svalbard, the northernmost breeding site for this species, appears to have a truncated age distribution with older animals being largely absent. PCBs and pesticides were measured in harbor seal males, females, milk and pups from Svalbard to explore whether contaminant exposure or accumulation is a possible cause of premature death for these animals. The levels and patterns of these contaminants were assessed. In addition, transfer of these compounds from females to their pups during lactation was assessed. Both PCB and pesticide levels were low compared to more southern harbor seal populations. Animals from Svalbard contained 5–10 times lower contaminant levels, compared to seals from the Norwegian mainland, and 30 times lower concentrations than those of harbor seals from the Gulf of St. Lawrence in eastern Canada. Ringed seals from Svalbard have contaminant levels that are comparable to the harbor seals, probably because the diet, as well as the metabolic capacity, of the two species is similar at this location. The findings of this study indicate that the early mortality observed for harbor seals on Svalbard, is not likely to be due to contaminant exposure. Female harbor seals transfer a modified contaminant mixture to their pups compared to that found within their own tissues; compounds with higher log Kow, such as some penta-chlorinated PCBs, were selectively transferred into milk. As a result, the contaminant pattern between males and females differed, with penta-chlorinated PCBs more abundant in males than in females. In addition, pups receive a relatively high amount of the less lipophylic compounds and a low amount of the more lipophylic compounds. The similar contaminant pattern in milk and pups suggested that they are probably unable to metabolize contaminants and consequently, accumulate all ingested chemicals. [Copyright &y& Elsevier]

We combined observations of individual male bearded seal, Erignathus barbabus, behaviour at sea with acoustic localization techniques to investigate their reproductive strategies. Data on trill vocalizations and dive behaviour were collected over consecutive years during the seals'' mating season in Svalbard, Norway. Males showed stereotypical dive and vocal displays, with clear individual variation. Acoustic localization provided at-sea locations for 17 males based on variation in trill parameters. Kernel home range analyses showed that 12 individuals displayed at set locations (95% kernels=0.27–1.93 km2) and five other males displayed within considerably larger geographical areas (95% kernels=5.31–12.5 km2). Males that used the set locations maintained single discrete core areas (50% kernels), while males with large areas moved between multiple core areas. Movement patterns of males suggest that those with small areas patrolled aquatic territories, while those that used larger areas appeared to ‘roam’. Territorial males showed little spatial overlap, while roaming males overlapped substantially with both territorial and other males'' areas. Territorial males had significantly longer trills than roamers. We suggest that trill duration may be a useful indicator of male ‘quality’. Territorial male bearded seals may be ‘successful’ individuals while roaming males may be younger animals or males in poorer condition that are unable to maintain an aquatic territory. Our data on underwater vocalizations and movements of male bearded seals thus provide evidence for the use of alternative mating tactics in this species.Copyright 2003 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved. [Copyright &y& Elsevier]

Recordings were made of the sounds produced by white whales during capture events in Storfjorden, Svalbard, in the late autumn. Only four of eight captured individuals produced sounds. Four subadults, one female and three males, between 330 and 375 cm long, did not produce sounds during handling. The four animals that produced sounds were as follows: a female subadult of 280 cm produced repetitive broadband clicks; a solitary calf produced harmonic sounds, which we suggest may serve as mother-calf "contact calls," and a mother-calf pair were the two animals that produced the most sounds in the study. The mother produced "crooning" broadband clicks and frequently moved her head toward her calf while producing underwater sounds. The calf produced three types of frequency-modulated sounds interspersed within broadband click trains. No sounds were heard from any of the animals once they were free-swimming, or during ad lib recording sessions in the study area, even though groups of white whales were sighted on several occasions away from the capture net. [ABSTRACT FROM AUTHOR]

The present study investigated how concentrations of different organochlorines (OCs) vary with nutritional condition in adult harp seal (Phoca groenlandica) females in a captive fasting experiment and in the wild. During the first part of this study seals in good condition (N=5) were fasted for a period of 28 days and blood and blubber samples were collected at days 1, 14 and 28. Blubber OC concentrations remained unchanged throughout the experimental period, and were consistently significantly higher than concentrations in the blood. In contrast to blubber OC levels, blood OC levels showed a significant time-dependant increase. During the fasting experiment the seals lost an average of 24 kg of body mass, which is less than half the natural annual variation in this species in the wild. The second part of this study compared OC concentrations in blood and blubber from seals collected at prime condition before the breeding season (N=10) with animals collected during molt when condition is poor (N=7). The average mass difference between the two groups was more than 40 kg. Blood levels of most OCs were significantly higher in the thin seals compared with the levels found in the fat seals. These differences in blood OC concentrations were much greater than what was found during the fasting experiment. For example ∑PCB levels in the blood during the fasting experiment increased by ∼83%, while the corresponding increase in blood levels of ∑PCB between the two other samples was 720% (from 201 to 1447 ng/g lipid). Blubber levels of OCs from the animals in the wild were significantly higher in the thin seals compared with the fat animals. In addition, the blubber levels of OCs were significantly higher than blood levels of OCs only for the fat seals. This study demonstrates the extreme variability present in the concentrations of OCs in blood of seals in response to change in condition. Since the natural variation in condition is extreme during phocid seals’ annual cycles, we recommend that blood should not be used in studies of OCs where the aim of the study is to monitor OC levels for comparative purposes or time-trend analysis. [Copyright &y& Elsevier]

Investigates physiological and behavioral aspects of diving development in pups of the harbor seal Phoca vitulina. Correlation between the U shape proportion of dives and age; Effect of blood oxygen stores on the rate of neonatal dive development; Consideration of behavioral modification as a rate-limiting factor for ontogeny of diving skills.

Investigates the discoloration of furs from bearded and ringed seals. Element analysis of samples of rust-colored and normal fur from bearded and ringed seals collected in Svalbard, Norway in spring of 1997; Elements with the largest differences in concentration between rust-colored and normal fur of subjects; How seals acquire elements responsible for the coloration of their fur.

Investigates the reproductive behavior and energetics of bearded seals. Characteristics of birth sites; Prenatal molting in bearded seals; Organization of the prenatally shed hair of bearded seals; Prenatal molt-early swimming pattern among phocid seals; Difference in structuring of the molted hair in the womb of harbor versus hooded seals.

Focuses on a study by scientists examining the activities of seven Halichoerus grypus, the lactating ice-breeding grey seals, from the Gulf of St Lawrence in Canada. Prior studies on the subject; Methods and results of the study; Discussion on the results.

Documents the behavior of lactating female harp seals. Use of time-depth recorders; Diving behavior; Dive duration; Haul-out periods; Mass transfer efficiency; Correlation of mass transfer efficiency with maternal behavior patterns.

Insight into animal movements is essential for understanding habitat use by individuals as well as population processes and species life-history strategies. In this study, we instrumented 25 fin whales with ARGOS satellite-transmitters in Svalbard, Norway, to study their movement patterns and behaviour (Area Restricted Search (ARS), transiting or unknown) during boreal autumn/early winter. Ten of the whales stayed in the tagging area (most northerly location: 81.68°N) for their entire tracking periods (max 45 days). The other 15 whales moved in a south-westerly direction; the longest track ended off the coast of northern Africa (> 5000 km from the tagging location) after 96 days. The whales engaged in ARS behaviour intermittently throughout their southward migrations. During transit phases the whales moved quickly; one individual maintained an average horizontal speed of 9.3 km/h (travelling 223 km per day) for a period of a week. This study documents that: (1) some fin whales might remain at high latitudes during winter; (2) the whales that do migrate probably feed along the way; (3) they can maintain high transiting speed for long periods and; (4) one breeding area for this species is likely located in deep, warm water some 100 km west of Morocco. [ABSTRACT FROM AUTHOR]

Despite the well-documented, broad global distribution of sperm whales (Physeter macrocephalus), their distributional patterns remain poorly known in Arctic regions, where year-round monitoring is challenging. Adult male sperm whales are known to migrate seasonally between nutrient-rich high latitude waters and low latitude breeding grounds. However, knowledge is limited regarding fine-scale distribution and seasonal presence at high latitudes. To investigate the acoustic occurrence of this vocally active species in the High Arctic of the Northeast Atlantic, this study combined automated and manual click detection methods to analyze passive acoustic data collected at eight locations around the Svalbard Archipelago, Norway, between 2012 and 2021. The results revealed the presence of sperm whales at six recording sites and demonstrated sperm whale "hotspots" in ice-free areas in eastern Fram Strait along the shelf break and close to the west coast of Spitsbergen from May–January, with some variation between years and locations. Although acoustic presence decreased with increasing latitude, even the northern-most location (81° N) recorded sperm whale vocal activity between August and January. This study provides a baseline for sperm whale acoustic presence in the High Arctic, which will be essential in the context of detecting future changes and also for predicting future distribution patterns in the rapidly changing Arctic marine environment. [ABSTRACT FROM AUTHOR]

The Arctic is a global warming 'hot‐spot' that is experiencing rapid increases in air and ocean temperatures and concomitant decreases in sea ice cover. These environmental changes are having major consequences on Arctic ecosystems. All Arctic endemic marine mammals are highly dependent on ice‐associated ecosystems for at least part of their life cycle and thus are sensitive to the changes occurring in their habitats. Understanding the biological consequences of changes in these environments is essential for ecosystem management and conservation. However, our ability to study climate change impacts on Arctic marine mammals is generally limited by the lack of sufficiently long data time series. In this study, we took advantage of a unique dataset on hooded seal (Cystophora cristata) movements (and serum samples) that spans more than 30 years in the Northwest Atlantic to (i) investigate foraging (distribution and habitat use) and dietary (trophic level of prey and location) habits over the last three decades and (ii) predict future locations of suitable habitat given a projected global warming scenario. We found that, despite a change in isotopic signatures that might suggest prey changes over the 30‐year period, hooded seals from the Northwest Atlantic appeared to target similar oceanographic characteristics throughout the study period. However, over decades, they have moved northward to find food. Somewhat surprisingly, foraging habits differed between seals breeding in the Gulf of St Lawrence vs those breeding at the "Front" (off Newfoundland). Seals from the Gulf favoured colder waters while Front seals favoured warmer waters. We predict that foraging habitats for hooded seals will continue to shift northwards and that Front seals are likely to have the greatest resilience. This study shows how hooded seals are responding to rapid environmental change and provides an indication of future trends for the species—information essential for effective ecosystem management and conservation. [ABSTRACT FROM AUTHOR]

Male bearded seals (Erignathus barbatus) use vocal displays to attract females and to compete with other males during the mating season. This makes it possible to monitor breeding populations of this species using passive acoustic monitoring (PAM). This study analysed year-round acoustic data records from AURAL instruments in Svalbard (Norway) to investigate seasonal variation in the acoustic presence of male bearded seals and the phenology of different call types (long, step and sweep trills) at three sites representing a variety of habitats with varied ice conditions. Male bearded seals vocalized for an extended period at a drift-ice site (Atwain; January–July) north of Spitsbergen, while the vocal season was shorter at a High Arctic land-fast-ice site (Rijpfjorden; February–June) and shorter yet again at a west-coast site that has undergone dramatic reductions in sea ice cover over the last 1.5 decades (Kongsfjorden; April–June). Generalized Additive Models showed marked seasonal segregation in the use of different trill types at Atwain, where call rates reached 400 per h, with long trills being the most numerous call type. Modest segregation of trill types was seen at Rijpfjorden, where call rates reached 300 per h, and no segregation occurred in Kongsfjorden (peak call rate 80 per h). Sea ice cover was available throughout the vocal season at Atwain and Rijpfjorden, while at Kongsfjorden peak vocal activity (May–June) occurred after the sea ice disappeared. Ongoing climate warming and sea ice reductions will likely increase the incidence of such mismatches and reduce breeding habitat for bearded seals. [ABSTRACT FROM AUTHOR]

The Earth's polar regions are low rates of inter‐ and intraspecific diversification. An extreme mammalian example is the Arctic ringed seal (Pusa hispida hispida), which is assumed to be panmictic across its circumpolar Arctic range. Yet, local Inuit communities in Greenland and Canada recognize several regional variants; a finding supported by scientific studies of body size variation. It is however unclear whether this phenotypic variation reflects plasticity, morphs or distinct ecotypes. Here, we combine genomic, biologging and survey data, to document the existence of a unique ringed seal ecotype in the Ilulissat Icefjord (locally 'Kangia'), Greenland; a UNESCO World Heritage site, which is home to the most productive marine‐terminating glacier in the Arctic. Genomic analyses reveal a divergence of Kangia ringed seals from other Arctic ringed seals about 240 kya, followed by secondary contact since the Last Glacial Maximum. Despite ongoing gene flow, multiple genomic regions appear under strong selection in Kangia ringed seals, including candidate genes associated with pelage coloration, growth and osmoregulation, potentially explaining the Kangia seal's phenotypic and behavioural uniqueness. The description of 'hidden' diversity and adaptations in yet another Arctic species merits a reassessment of the evolutionary processes that have shaped Arctic diversity and the traditional view of this region as an evolutionary freezer. Our study highlights the value of indigenous knowledge in guiding science and calls for efforts to identify distinct populations or ecotypes to understand how these might respond differently to environmental change. [ABSTRACT FROM AUTHOR]

Studies on host–parasite systems that have experienced distributional shifts, range fragmentation, and population declines in the past can provide information regarding how parasite community richness and genetic diversity will change as a result of anthropogenic environmental changes in the future. Here, we studied how sequential postglacial colonization, shifts in habitat, and reduced host population sizes have influenced species richness and genetic diversity of Corynosoma (Acanthocephala: Polymorphidae) parasites in northern European marine, brackish, and freshwater seal populations. We collected Corynosoma population samples from Arctic, Baltic, Ladoga, and Saimaa ringed seal subspecies and Baltic gray seals, and then applied COI barcoding and triple‐enzyme restriction‐site associated DNA (3RAD) sequencing to delimit species, clarify their distributions and community structures, and elucidate patterns of intraspecific gene flow and genetic diversity. Our results showed that Corynosoma species diversity reflected host colonization histories and population sizes, with four species being present in the Arctic, three in the Baltic Sea, two in Lake Ladoga, and only one in Lake Saimaa. We found statistically significant population‐genetic differentiation within all three Corynosoma species that occur in more than one seal (sub)species. Genetic diversity tended to be high in Corynosoma populations originating from Arctic ringed seals and low in the landlocked populations. Our results indicate that acanthocephalan communities in landlocked seal populations are impoverished with respect to both species and intraspecific genetic diversity. Interestingly, the loss of genetic diversity within Corynosoma species seems to have been less drastic than in their seal hosts, possibly due to their large local effective population sizes resulting from high infection intensities and effective intra‐host population mixing. Our study highlights the utility of genomic methods in investigations of community composition and genetic diversity of understudied parasites. [ABSTRACT FROM AUTHOR]

The extent, thickness and age of Arctic sea ice has dramatically declined since the late 1990s, and these trends are predicted to continue. Exploring the habitat use of sea‐ice‐dependent species can help us understand which resources they use and how their distribution responds to a changing environment. The goal of this study was to develop predictive models of the habitat use of an Arctic apex predator. Polar bear Ursus maritimus habitat use in the Barents Sea subpopulation was modelled with seasonal resource selection functions (RSFs) using satellite‐linked telemetry data from 294 collars deployed on female polar bears between 1991 and 2015. Polar bears selected habitat in the Marginal Ice Zone, with a preference for intermediate sea ice concentrations (40–80%). They spent most time in areas with relatively short travel distances to 15 or 75% ice concentration, and during spring and autumn they exhibited a preference for sea ice areas over the continental shelf or over shallower bathymetry). Predictions of the distribution of polar bears in the Barents Sea area can be made for specific sea ice scenarios using these models. Two such predictive distribution maps based on the autumn seasonal model were made and validated against two independent polar bear survey datasets collected in August 2004 and August 2015. The distribution of optimal polar bear habitat has shifted strongly northwards in all seasons of the year during the 25 yr study period. [ABSTRACT FROM AUTHOR]

Identifying genetically different groups of animals, occupying specific geographical areas, is a prerequisite for conservation and management priorities. In the present study, the genetic structure of Atlantic walruses (Odobenus rosmarus rosmarus) occupying the Pechora Sea (PEC) in the western Russian Arctic, including walruses from Svalbard-Franz Josef Land (SVA-FJL) and East Greenland (EGR) regions, was investigated using 14 microsatellites (N=159) and mtDNA sequences (N=212). Bayesian-based clustering analysis identified two clusters: EGR and the other Northeast Atlantic areas. Pairwise FST analyses based on microsatellites revealed low but significant genetic differences between walruses from the PEC and SVA-FJL groups, which was supported by mtDNA analysis. FST was not significant for all sampling years, indicating a temporal effect or male-biased gene flow. Extended Bayesian Skyline Plots suggested a constant female subpopulation size (Nef) for EGR and an increase for the SVA-FJL and PEC groups that commenced around 40-30 Kyr ago, indicating different demographic histories for walruses in the EGR. Further, the evolutionary phylogenetic relationship between Atlantic and Pacific walruses (O. r. divergence), based on mtDNA sequences, showed a monophyletic Atlantic clade, suggesting that Atlantic and Pacific walruses diverged ~949 Kyr. The principal finding suggests that PEC walruses show low, but significant genetic distinction from walruses in SVA-FJL and should be managed conservatively, as a separate, small population. [ABSTRACT FROM AUTHOR]

Congener-specific transfer of polychlorinated biphenyls (PCBs) and chlorinated pesticides from female to pup was studied in harp seals from eastern Canada. Possible effects on hepatic cytochrome P450 enzymes (CYP450) due to contaminant mobilization from blubber lipids in females and ingestion of contaminated milk in pups were studied. Contaminant transfer from blubber to milk in females favored the more polar compounds (lower chlorinated PCBs, toxaphenes, hexachlorocyclohexanes, and hexachlorobenzene) relative to more lipophilic compounds (higher chlorinated PCBs, dichlorodiphenyltrichloroethane [DDT], chlordane). In spite of substantial contaminant mobilization from blubber in females and ingestion of contaminated milk by pups, CYP450 activities were low in all animals. Possibly, increased plasma estradiol concentrations, involved in breeding after lactation, suppressed CYP450 directly. Although the pups were exposed to contaminants in milk, CYP450 activities were low, resulting in low contaminant metabolism. This wasconfirmed by similar contaminant patterns in milk and pups. A strongpositive relation between CYP1A-like activities and body weight in the pups suggested not yet fully developed CYP1A enzymes. A negative association between CYP3A and pesticides in females and pups was hypothesized to be a result of metabolic inactivation of CYP450. The CYP450 enzyme activities were considered unsuitable indicators for contaminant mobilization and transfer in harp seals. [ABSTRACT FROM AUTHOR]

Harp seals (Phoca groenlandica) from the Barents Sea were analyzed for blubber levels of polychlorinated biphenyls (PCBs), polychlorinated camphenes (PCCs; toxaphenes), DDT and its metabolites, hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), and the cyclodiene pesticides, including dieldrin, endrin, and the chlordanes. Also, the hepatic cytochrome P450 (CYP) enzyme activities were measured to assess a possible relation between CYP activities and pesticide levels. Furthermore, the bioaccumulation potential and persistency of these compounds were evaluated. PCCs were the dominant contaminants, exceeding thePCB concentrations. Individual PCC congener levels (Tox 26 and 50) were fourfold greater than those in the Canadian Arctic and 20-fold greater than those in seals from the west coast of Svalbard, suggestingthat the Barents Sea is exposed to PCCs by a local source. The biomagnification factor and the metabolic index were greatest for p,p-DDT,HCB, Beta-HCH, and the chlordanes trans-nonachlor and U82. The otherpesticides showed lesser values, suggesting metabolism. The ethoxyresorufin-O-deethylation activity (CYP1A) was high and not correlated with any of the pesticides, whereas a high correlation (r2 adjusted > 50%) was found between the PCCs and testosterone 6-Beta hydroxylation activities (CYP3A). This suggests an induction of CYP3A-like activity by PCC exposure. [ABSTRACT FROM AUTHOR]