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The Saimaa ringed seal (Pusa hispida saimensis) is a subspecies of ringed seal, landlocked in Lake Saimaa, Finland. The small population of less than 500 seals is facing many human-induced threats, including chemical contaminants. Mercury, in particular, has previously been suggested to be one of the chemicals affecting the viability of this endangered population. We analysed mercury concentrations from placentas and lanugo pup tissues (blubber, brain, kidney, liver, and muscle) to determine current prenatal exposure levels. These pups were found dead in or near birth lairs and were less than 3 months old. Additionally, we used threshold values available in the literature to estimate the potential mercury toxicity to the Saimaa ringed seal. We also determined selenium concentrations for its potential to alleviate the adverse effects of mercury. We further supplemented our study with brain samples collected from various seal age classes. These seals were found dead by either natural causes or by being caught in gillnets. The analysed chemicals were present in all tissues. For lanugo pups, mercury concentrations were the highest in the kidney and liver, whereas the highest selenium to mercury molar ratio was observed in placentas. The toxicity evaluation suggested that, in severe cases, mercury may cause adverse effects in lanugo and older pups. In these cases, the selenium concentrations were low and selenium to mercury ratio was below 1:1 threshold ratio and thus unlikely to provide adequate protection from the adverse effects of mercury. Furthermore, adverse effects are more likely to occur in adult seals, as mercury bioaccumulates, leading to higher concentrations in older individuals. Placental mercury concentrations correlated to those in the livers and muscle tissues of lanugo pups. This, together with the fact that placentas can be collected non-invasively and in good condition, provides a potential novel method for biomonitoring mercury exposure in Saimaa ringed seals. [ABSTRACT FROM AUTHOR]

Genetic analyses of host‐specific parasites can elucidate the evolutionary histories and biological features of their hosts. Here, we used population‐genomic analyses of ectoparasitic seal lice (Echinophthirius horridus) to shed light on the postglacial history of seals in the Arctic Ocean and the Baltic Sea region. One key question was the enigmatic origin of relict landlocked ringed seal populations in lakes Saimaa and Ladoga in northern Europe. We found that that lice of four postglacially diverged subspecies of the ringed seal (Pusa hispida) and Baltic gray seal (Halichoerus grypus), like their hosts, form genetically differentiated entities. Using coalescent‐based demographic inference, we show that the sequence of divergences of the louse populations is consistent with the geological history of lake formation. In addition, local effective population sizes of the lice are generally proportional to the census sizes of their respective seal host populations. Genome‐based reconstructions of long‐term effective population sizes revealed clear differences among louse populations associated with gray versus ringed seals, with apparent links to Pleistocene and Holocene climatic variation as well as to the isolation histories of ringed seal subspecies. Interestingly, our analyses also revealed ancient gene flow between the lice of Baltic gray and ringed seals, suggesting that the distributions of Baltic seals overlapped to a greater extent in the past than is the case today. Taken together, our results demonstrate how genomic information from specialized parasites with higher mutation and substitution rates than their hosts can potentially illuminate finer scale population genetic patterns than similar data from their hosts. [ABSTRACT FROM AUTHOR]

Understanding the acoustic repertoire of a species is crucial for comprehending its ecology and can also provide a valuable tool in the analysis of passive acoustic monitoring data. Despite being the most abundant seal species in the Arctic, the call repertoire of ringed seals (Pusa hispida) remains poorly studied. This paper aims to provide a comprehensive and quantitative description of the calls produced by ringed seals. Data collection occurred in May 2022 near Ulukhaktok in the Western Canadian Arctic. Acoustic recorders were deployed in cracks in the sea ice that were regularly used by ringed seals as haul-out areas. All calls were counted and classified into one of three categories: yelps, barks and growls. High-quality calls were further analysed with ten acoustic parameters calculated for each signal. Cluster and classification and regression tree (CART) analyses were used to assess if the visual classification of calls was supported by the acoustic parameters calculated. The cluster and CART analyses affirmed the presence of all three distinct call types in the ringed seal acoustic repertoire. Classification of unseen calls using the CART model demonstrated an accuracy of 98%. The findings presented here serve as foundational information on the acoustic repertoire of ringed seals. [ABSTRACT FROM AUTHOR]

Ice-associated seals rely on sea ice for a variety of activities, including pupping, breeding, molting, and resting. In the Arctic, many of these activities occur in spring (April through June) as sea ice begins to melt and retreat northward. Rapid acceleration of climate change in Arctic ecosystems is therefore of concern as the quantity and quality of suitable habitat is forecast to decrease. Robust estimates of seal population abundance are needed to properly monitor the impacts of these changes over time. Aerial surveys of seals on ice are an efficient method for counting seals but must be paired with estimates of the proportion of seals out of the water to derive population abundance. In this paper, we use hourly percent-dry data from satellite-linked bio-loggers deployed between 2005 and 2021 to quantify the proportion of seals hauled out on ice. This information is needed to accurately estimate abundance from aerial survey counts of ice-associated seals (i.e., to correct for the proportion of animals that are in the water, and so are not counted, while surveys are conducted). In addition to providing essential data for survey 'availability' calculations, our analysis also provides insights into the seasonal timing and environmental factors affecting haul-out behavior by ice-associated seals. We specifically focused on bearded (Erignathus barbatus), ribbon (Histriophoca fasciata), and spotted seals (Phoca largha) in the Bering and Chukchi seas. Because ringed seals (Phoca (pusa) hispida) can be out of the water but hidden from view in snow lairs analysis of their 'availability' to surveys requires special consideration; therefore, they were not included in this analysis. Using generalized linear mixed pseudo-models to properly account for temporal autocorrelation, we fit models with covariates of interest (e.g., day-of-year, solar hour, age and sex class, wind speed, barometric pressure, temperature, precipitation) to examine their ability to explain variation in haul-out probability. We found evidence for strong diel and within-season patterns in haul-out behavior, as well as strong weather effects (particularly wind and temperature). In general, seals were more likely to haul out on ice in the middle of the day and when wind speed was low and temperatures were higher. Haul-out probability increased through March and April, peaking in May and early June before declining again. The timing and frequency of haul-out events also varied based on species and age-sex class. For ribbon and spotted seals, models with year effects were highly supported, indicating that the timing and magnitude of haul-out behavior varied among years. However, we did not find broad evidence that haul-out timing was linked to annual sea-ice extent. Our analysis emphasizes the importance of accounting for seasonal and temporal variation in haul-out behavior, as well as associated environmental covariates, when interpreting the number of seals counted in aerial surveys. [ABSTRACT FROM AUTHOR]

Throughout the Arctic, ice‐affiliated marine mammals constitute local subsistence resources but detrimental effects of declines in their sea ice habitats create a need for harvest sustainability assessments in light of climate change. At the same time, empirical data required for thorough population analysis of these species are often sparse at best, as illustrated by the focal species in this study, ringed seals in Svalbard: the last population survey took place two decades ago (2002–2003), demographic data are limited to age, sex, and reproductive status of a small subset of shot individuals, and harvest reporting is patchy and incomplete. Data sparsity is one of the main reasons why potential biological removal (PBR) became a commonly used tool for assessing sustainability of marine mammal harvests. Herein, we calculated PBR for Svalbard ringed seals using both recommended default parameters and population‐specific parameters obtained from an integrated population model (IPM). PBR estimates were highly uncertain, suggesting the number of sustainably harvestable individuals could lie anywhere between 0 and 91, with a substantial chance of any harvest being unsustainable under current environmental conditions and trends. Subsequent population viability analyses (PVAs) further confirmed that the current harvest was likely unsustainable, even in a scenario in which sea ice conditions would not deteriorate (and therefore lower pup survival) further. However, uncertainty in population projections was high, and forecasts thus not ideal for formulating management advice. Better forecasts will require more frequent population surveys and obtaining more knowledge regarding the links between vital rates and environmental conditions, both of which may be facilitated by the adoption of novel technology (e.g., drone monitoring, genetic studies). The modeling framework created in this study can be readily updated with new data as they become available, and can serve as a tool for adaptive management of this and other marine mammal populations. [ABSTRACT FROM AUTHOR]

The endangered Saimaa ringed seal (Pusa hispida saimensis) is an endemic freshwater subspecies inhabiting Lake Saimaa in Finland. The Baltic ringed seal (Pusa hispida botnica) inhabits the brackish Baltic Sea, which is almost entirely landlocked. Recent research shows that Saimaa and Baltic ringed seals may be genetically even further apart from each other than from other ringed seal subspecies. We documented histologically the integument microstructure of Saimaa and Baltic ringed seals to determine whether the geographic and genetic isolation was manifested as variation in the integument microstructure of these subspecies adapted to icy aquatic environments. The skin structures of these subspecies were similar to those of other phocids. The association of the sweat glands with hair follicles in both subspecies suggested that they were small apocrine sweat glands described previously in terrestrial or aquatic mammals. None of the apocrine glands had large lumina, and some of the ducts were relatively straight and short. Further studies analysing the mode of secretion, for example, apocrine versus eccrine, in the sweat glands are necessary to confirm the types of sweat glands in seals. [ABSTRACT FROM AUTHOR]

Simple Summary: The ringed seal is part of the daily diet for local Inuits in Greenland, and therefore, the contents of trace elements are being monitored bi-annually under the AMAP CORE Programme. In this study Hg, Cd and Se concentrations were measured in ringed seal livers, along with pathological changes in both the liver and the kidneys of the seals. The oldest seals had the highest concentrations of the three trace elements, while the content was the same in both sexes. In more than half of the livers, we found mononuclear cell infiltration (94.7%) and portal cell infiltration (68.4%), while glomerular mesangial deposits (54.1%) were the predominant finding in the kidney. Ringed seals are consumed in Greenland and are therefore included as a key biomonitoring species with the focus on pollution exposure and health effects. Ringed seals in Central West Greenland (Qeqertarsuaq) and in North West Greenland (Qaanaaq) were analyzed for metal concentrations in the liver and histological changes in the liver and kidney. The mean liver concentration of mercury in Qaanaaq was 3.73 ± 5.01 µg/g ww (range: 0.28–23.29 µg/g ww), and the mean cadmium concentration was 7.80 ± 8.95 µg/g ww (range: 0.013–38.79 µg/g ww). For Qeqertarsuaq, the liver concentration of mercury was 1.78 ± 1.70 µg/g ww (range: 0.45–8.00 µg/g ww) and the mean cadmium concentration was 11.58 ± 6.32 µg/g ww (range: 0.11–25.45 µg/g ww). Age had a positive effect on the liver concentrations of metals, while no effect was found for sex or histological changes. The prevalence of histological changes in liver tissue decreased in the following order: random pattern mononuclear cell infiltration (92.1%), portal cell infiltration (68.4%), hepatic intracellular fat (18.4%), portal fibrosis (7.9%), focal hepatic fibrosis (7.9%), bile duct hyperplasia/fibrosis (7.9%) and lipid granuloma (2.6%). For kidney tissue, the prevalence of histological changes decreased in the following order: glomerular mesangial deposits (54.1%) > glomerular basement membrane thickening (45.9%) > THD (40%) > tubular hyaline casts (14.0%) > glomerular atrophy (13.5%) > dilated tubules (13.5%) > glomerular hyper-cellularity (10.8%) > mononuclear cell infiltrations (8.1%). [ABSTRACT FROM AUTHOR]

Feature selection (FS) is a critical step in many data science-based applications, especially in text classification, as it includes selecting relevant and important features from an original feature set. This process can improve learning accuracy, streamline learning duration, and simplify outcomes. In text classification, there are often many excessive and unrelated features that impact performance of the applied classifiers, and various techniques have been suggested to tackle this problem, categorized as traditional techniques and meta-heuristic (MH) techniques. In order to discover the optimal subset of features, FS processes require a search strategy, and MH techniques use various strategies to strike a balance between exploration and exploitation. The goal of this research article is to systematically analyze the MH techniques used for FS between 2015 and 2022, focusing on 108 primary studies from three different databases such as Scopus, Science Direct, and Google Scholar to identify the techniques used, as well as their strengths and weaknesses. The findings indicate that MH techniques are efficient and outperform traditional techniques, with the potential for further exploration of MH techniques such as Ringed Seal Search (RSS) to improve FS in several applications. [ABSTRACT FROM AUTHOR]

The physiological properties of marine mammal skeletal muscle are foundational in defining diving and foraging capacities. Further, these parameters can be useful when assessing the behavioral flexibility of species faced with environmental change or disturbance. Herein, we define species- and age-specific muscle physiology for three ice-associated seal species experiencing Arctic warming. Specifically, we evaluated myoglobin content ([Mb]), nonbicarbonate buffering capacity (p), and fiber type profiles of a major locomotor muscle, the longissimus dorsi. Muscle samples were obtained from subsistence harvested ringed (Pusa hispida; n = 11), bearded (Erignathus barbatus; n = 41), and spotted (Phoca largha; n = 12) seals of all ages in the Bering and Chukchi Seas. Adult ringed seals had the highest [Mb] (6.67 ± 0.20 g 100 g wet tissue-1), followed by spotted (5.38 ± 0.29 g 100 g wet tissue-1) and bearded (4.55 ± 0.07 g 100 g wet tissue-1) seals. [Mb] increased with age for all species, but rates of increase differed by species. In contrast, p was similar for all species and age classes. We documented higher proportions of fast-twitch relative to slow-twitch fibers in these species, and fiber type proportions did not differ significantly with age. Adult bearded seals exhibited the greatest proportion of fast-twitch fibers (68.7 ± 1.5%), followed by ringed (59.0 ± 4.8%) and spotted (55.1 ± 2.1%) seals. Overall, our data suggest a strong link between muscle physiology, diving behavior, and life history strategies, and provide insight into the physiological capacities of these potentially vulnerable species. [ABSTRACT FROM AUTHOR]

We investigated trophic transfer of cadmium (Cd) through an Arctic marine food web in Hudson Bay and compared it with mercury (Hg), a metal known to strongly biomagnify. We evaluated blue mussel, sea urchin, common eider, sculpin, Arctic cod, and ringed seal for the influence of dietary and biological variables on variation in Cd and Hg concentrations. Age and size influenced metal concentrations among individuals within a vertebrate species. Consumer carbon and sulfur isotope values were correlated with their Cd and Hg concentrations, indicating habitat-specific feeding influenced metal bioaccumulation. Trophic transfer patterns for Cd depended on the vertebrate tissue, with food web biodilution observed for the muscle but not the liver. Liver Cd concentrations were higher in ringed seal and some common eider relative to prey. In contrast, we observed mercury biomagnification for both tissues. Tissue- and species-specific physiology can explain discrepancies of Cd trophic transfer in this Arctic marine food web. [ABSTRACT FROM AUTHOR]

Animal re‐identification remains a challenging problem due to the cost of tagging systems and the difficulty of permanently attaching a physical marker to some animals, such as sea stars. Due to these challenges, photo identification is a good fit to solve this problem whether evaluated by humans or through machine learning. Accurate machine learning methods are an improvement over manual identification as they are capable of evaluating a large number of images automatically and recent advances have reduced the need for large training datasets.This study aimed to create an accurate, robust, general purpose machine learning framework for individual animal re‐identification using images both from publicly available data as well as two groups of sea stars of different species under human care. Open‐source code was provided to accelerate work in this space. Images of two species of sea star (Asterias rubens and Anthenea australiae) were taken using a consumer‐grade smartphone camera and used as original datasets to train a machine learning model to re‐identify an individual animal using few examples. The model's performance was evaluated on these original sea star datasets which contained between 39–54 individuals and 983–1204 images, as well as using six publicly available re‐identification datasets for tigers, beef cattle noses, chimpanzee faces, zebras, giraffes and ringed seals ranging between 45–2056 individuals and 829–6770 images.Using time aware‐splits, which are a data splitting technique ensuring that the model only sees an individual's images from a previous collection event during training to avoid information leaking, the model achieved high (>99%) individual re‐identification mean average precision for the top prediction (mAP@1) for the two species of sea stars. The re‐identification mAP@1 for the mammalian datasets was more variable, ranging from 83% to >99%. However, this model outperformed published state‐of‐the‐art re‐identification results for the publicly available datasets.The reported approach for animal re‐identification is generalizable, with the same machine learning framework achieving good performance in two distinct species of sea stars with different physical attributes, as well as seven different mammalian species. This demonstrates that this methodology can be applied to nearly any species where individual re‐identification is required. This study presents a precise, practical, non‐invasive approach to animal re‐identification using only basic image collection methods. [ABSTRACT FROM AUTHOR]

The various models used in gross anatomical studies to improve the visualization of blood vessels differ in the amount of manual labour, cost, equipment and time involved. This study aimed to compare chemical and enzymatic maceration processes for soft‐tissue removal from arterial silicone casts on skull scaffolds using ringed seal (Pusa hispida) skull specimens. Both processes produced specimens that covered all anatomical aspects required to visualize the intracranial arterial arrangement on a bone scaffold. Overall, the enzyme maceration process was better for production of such specimens, as this process is easy and safe to perform, is less harmful to the bony parts of the specimen, and the resulting specimens are visually more appealing for display and teaching. Compared with previously published models, the end result varied in the amount of dissolved bone tissue and the visual presentation of the model. [ABSTRACT FROM AUTHOR]

An adult female ringed seal died suddenly and was subsequently examined for diagnostic purposes. The animal's lungs demonstrated mild non-collapsibility and multifocal white to yellow patches. Histopathological examination revealed multifocal pulmonary histiocytosis. Alveoli were filled with numerous foamy macrophages cytoplasm and scattered multinucleated giant cells containing cholesterol clefts. The foamy cytoplasm of the macrophages stained with oil red O stain. Further, lipid droplets within the cytoplasm were detected by electron microscopy. To the author's knowledge, this is the first case report describing the histochemical staining and electron microscopic findings associated with endogenous lipid pneumonia in ringed seal. [ABSTRACT FROM AUTHOR]

Environmental change in the Arctic has impacted the composition and structure of marine food webs. Tracking feeding ecology changes of culturally-valued Arctic char (Salvelinus alpinus) and ringed seals (Pusa hispida) can provide an indication of the ecological significance of climate change in a vulnerable region. We characterized how changes in sea ice conditions, sea surface temperature (SST), and primary productivity affected the feeding ecology of these two keystone species over a 13- and 18-year period, respectively, in northern Labrador, Canada. Arctic char fed consistently on pelagic resources (δ13C) but shifted over time to feeding at a higher trophic level (δ15N) and on more marine/offshore resources (δ34S), which correlated with decreases in chlorophyll a concentration. A reduction in Arctic char condition factor and lipid content was associated with higher trophic position. Ringed seals also shifted to feeding at a higher trophic level, but on more pelagic resources, which was associated with lower SST and higher chlorophyll a concentrations. Years with abnormally high SSTs and reduced sea ice concentrations resulted in large isotopic niche sizes for both species, suggesting abrupt change can result in more variable feeding. Changes in abundance and distribution of species long valued by the Inuit of Labrador could diminish food security. [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]

Seal populations in Canadian waters provide sustenance to coastal communities. There is potential for pathogenic and/or antimicrobial‐resistant bacteria to transfer to humans through inadvertent faecal contamination of seal products. The objective of this study was to investigate the occurrence and potential antimicrobial resistance of Salmonella spp., Escherichia coli and Listeria monocytogenes in faecal samples collected from grey seals (Halichoerus grypus) in the Gulf of St. Lawrence and from ringed seals (Pusa hispida) in Frobisher Bay and Eclipse Sound, Nunavut, Canada. Grey seals were harvested during commercial hunts or during scientific sampling; ringed seals were collected by Inuit hunters during subsistence harvests. Virulence genes defining pathogenic E. coli were identified by PCR, and antimicrobial susceptibility testing was performed on recovered isolates. In grey seals, E. coli was detected in 34/44 (77%) samples, and pathogenic E. coli (extraintestinal E. coli [ExPEC], enteropathogenic E. coli [EPEC] or ExPEC/EPEC) was detected in 13/44 (29%) samples. Non‐susceptibility to beta‐lactams and quinolones was observed in isolates from 18 grey seals. In ringed seals from Frobisher Bay, E. coli was detected in 4/45 (9%) samples; neither virulence genes nor antimicrobial resistance was detected in these isolates. In ringed seals from Eclipse Sound, E. coli was detected in 8/50 (16%) samples and pathogenic E. coli (ExPEC and ExPEC/EPEC) in 5/50 (10%) samples. One seal from Eclipse Sound had an E. coli isolate resistant to beta‐lactams. A monophasic Salmonella Typhimurium was recovered from 8/50 (16%) seals from Eclipse Sound. All Salmonella isolates were resistant to ampicillin, streptomycin, sulfisoxazole and tetracycline. L. monocytogenes was not detected in any sample. These findings suggest that seals may act as important sentinel species and as reservoirs or vectors for antimicrobial‐resistant and virulent E. coli and Salmonella species. Further characterization of these isolates would provide additional insights into the source and spread of antimicrobial resistance and virulence genes in these populations of free‐living seals. [ABSTRACT FROM AUTHOR]

The article focuses on a study that analyzes the sensitivity of narwhals or Monodon monoceros to human-made noise and the negative impact of noise stressors on these Niche-conservative species. It found that deep diving is avoided by narwhals with simultaneous reduction of foraging, increasing shallow diving activity and reducing forage activity as a reaction to either the noise of ship alone or ship sound with simultaneous seismic airgun pulse.

Seasonal changes in diel haul‐out patterns of the lacustrine Saimaa ringed seal (Pusa hispida saimensis) were studied using a combination of satellite telemetry and camera traps during 2007–2015. We found the haul‐out activity patterns to vary seasonally. Our results show that during the ice‐covered winter period before the seals start their annual molt, the peak in haul‐out generally occurs at midnight. Similarly, during the postmolt season of summer and autumn when the lake is free of ice, the haul‐out is concentrated in the early hours of the morning. In contrast, over the spring molting period, Saimaa ringed seals tend to haul out around the clock. The spring molt is also the only period when a slight difference in haul‐out behavior between the sexes is observed, with females having a haul‐out peak at nighttime while the males have a less visible diel pattern. According to our results, the diel haul‐out patterns of Saimaa ringed seals are similar to the ones of marine ringed seals. Gathering information on haul‐out activity is important in order to safeguard the natural patterns of Saimaa ringed seals in areas that are prone to disturbance from human activities. [ABSTRACT FROM AUTHOR]

The article presents the discussion on resting being an important behavioral and metabolic function for all animals. Topics include relaxed immobility being typically reserved for recovery and thermoregulation, and the resting metabolic rate (RMR) comprising the largest daily activity budget for human; and on-land resting periods being exposed to external stimuli posing threats during their recovery.

Fragmentation of isolated populations increases the risk of inbreeding and loss of genetic diversity. The endemic Saimaa ringed seal (Pusa hispida saimensis) is one of the most endangered pinnipeds in the world with a population of only ~ 400 individuals. The current genetic diversity of this subspecies, isolated in Lake Saimaa in Finland for ca. 1000 generations, is alarmingly low. We performed whole-genome sequencing on Saimaa ringed seals (N = 30) and analyzed the level of homozygosity and genetic composition across the individual genomes. Our results show that the Saimaa ringed seal population has a high number of runs of homozygosity (RoH) compared with the neighboring Baltic ringed seal (Pusa hispida botnica) reference population (p < 0.001). There is also a tendency for stillborn seal pups to have more pronounced RoH. Since the population is divided into semi-isolated subpopulations within the Lake Saimaa exposing the population to deleterious genomic effects, our results support augmented gene flow as a genetic conservation action. Based on our results suggesting inbreeding depression in the population, we recommend Pihlajavesi as a potential source and Southern Saimaa as a potential recipient subpopulation for translocating individuals. The Saimaa ringed seal is a recognized subspecies and therefore translocations should be considered only within the lake to avoid an unpredictable risk of disease, the introduction of deleterious alleles, and severe ecological issues for the population. [ABSTRACT FROM AUTHOR]

To estimate abundance, surveys of marine mammals often rely on samples of satellite‐tagged individuals to correct counts for the proportion of animals that are unavailable to be detected. However, naïve application of this correction relies on the key assumption that availability of the tagged sample resembles that of the population. Here, we show how matrix population models can be used to estimate stable age‐ and stage‐proportions, and how these can be used to adjust aerial survey correction factors so that they represent population‐level availability. We illustrate this procedure using data from ice‐associated seals in the Bering, Chukchi, and Beaufort Seas. After compiling life history data for bearded (Erignathus barbatus), ribbon (Histriophoca fasciata), ringed (Pusa hispida), and spotted seals (Phoca largha), we find that correction factors ignoring age‐sex composition can positively bias spotted seal abundance by an average of 13% and negatively bias ribbon seal abundance by an average of 5%. Note that we did not examine potential bias for bearded or ringed seals due to low sample sizes; as such, we urge caution in interpretation of abundance estimates for these species. [ABSTRACT FROM AUTHOR]

Sea ice loss is fundamentally altering the Arctic marine environment. Yet there is a paucity of data on the adaptability of food webs to ecosystem change, including predator–prey interactions. Polar bears (Ursus maritimus) are an important subsistence resource for Indigenous people and an apex predator that relies entirely on the under‐ice food web to meet its energy needs. In this study, we assessed whether polar bears maintained dietary energy density by prey switching in response to spatiotemporal variation in prey availability. We compared the macronutrient composition of diets inferred from stable carbon and nitrogen isotopes in polar bear guard hair (primarily representing summer/fall diet) during periods when bears had low and high survival (2004–2016), between bears that summered on land versus pack ice, and between bears occupying different regions of the Alaskan and Canadian Beaufort Sea. Polar bears consumed diets with lower energy density during periods of low survival, suggesting that concurrent increased dietary proportions of beluga whales (Delphinapterus leucas) did not offset reduced proportions of ringed seals (Pusa hispida). Diets with the lowest energy density and proportions from ringed seal blubber were consumed by bears in the western Beaufort Sea (Alaska) during a period when polar bear abundance declined. Intake required to meet energy requirements of an average free‐ranging adult female polar bear was 2.1 kg/day on diets consumed during years with high survival but rose to 3.0 kg/day when survival was low. Although bears that summered onshore in the Alaskan Beaufort Sea had higher‐fat diets than bears that summered on the pack ice, access to the remains of subsistence‐harvested bowhead whales (Balaena mysticetus) contributed little to improving diet energy density. Because most bears in this region remain with the sea ice year round, prey switching and consumption of whale carcasses onshore appear insufficient to augment diets when availability of their primary prey, ringed seals, is reduced. Our results show that a strong predator–prey relationship between polar bears and ringed seals continues in the Beaufort Sea. The method of estimating dietary blubber using predator hair, demonstrated here, provides a new metric to monitor predator–prey relationships that affect individual health and population demographics. [ABSTRACT FROM AUTHOR]

Historically, the seals and harbour porpoises of the Baltic Sea and North Sea have been subjected to hunting, chemical pollutants and repeated mass mortalities, leading to significant population fluctuations. Despite the conservation implications and the zoonotic potential associated with viral disease outbreaks in wildlife, limited information is available on the circulation of viral pathogens in Baltic Sea seals and harbour porpoises. Here, we investigated the presence of the influenza A virus (IAV), the phocine distemper virus (PDV) and the cetacean morbillivirus (CeMV) in tracheal swabs and lung tissue samples from 99 harbour seals, 126 grey seals, 73 ringed seals and 78 harbour porpoises collected in the Baltic Sea and North Sea between 2002–2019. Despite screening 376 marine mammals collected over nearly two decades, we only detected one case of PDV and two cases of IAV linked to the documented viral outbreaks in seals in 2002 and 2014, respectively. Although we find no evidence of PDV and IAV during intermediate years, reports of isolated cases of PDV in North Sea harbour seals and IAV (H5N8) in Baltic and North Sea grey seals suggest introductions of those pathogens within the sampling period. Thus, to aid future monitoring efforts we highlight the need for a standardized and continuous sample collection of swabs, tissue and blood samples across Baltic Sea countries. [ABSTRACT FROM AUTHOR]

Aim: Greenland is one of the places on Earth where the effects of climate change are most evident. The retreat of sea ice has made East Greenland more accessible for longer periods during the year. East Greenland fjords have been notoriously difficult to study due to their remoteness, dense sea ice conditions and lack of infrastructure. As a result, biological monitoring across latitudinal gradients is scarce in East Greenland and relies on sporadic research cruises and trawl data from commercial vessels. We here aim to investigate the transition in fish and marine mammal communities from South to Northeast Greenland using environmental DNA (eDNA). Location: South to Northeast Greenland. Methods: We investigated the transition in fish and marine mammal communities from South to Northeast Greenland using eDNA metabarcoding of seawater samples. We included both surface and mesopelagic samples, collected over approximately 2400 km waterway distance, by sampling from Cape Farewell to Ella Island in August 2021. Results: We demonstrate a clear transition in biological communities from south to northeast, with detected fish and mammal species matching known distributions. Samples from the southern areas were dominated by capelin (Mallotus villosus) and redfish (Sebastes), whereas northeastern samples were dominated by polar cod (Boreogadus saida), sculpins (Myoxocephalus) and ringed seal (Pusa hispida). We provide newly generated 12S rRNA barcodes from 87 fish species, bringing the public DNA database closer to full taxonomic coverage for Greenlandic fish species for this locus. Main Conclusions: Our results demonstrate that eDNA sampling can detect latitudinal shifts in marine biological communities of the Arctic region, which can supplement traditional fish surveys in understanding species distributions and community compositions of marine vertebrates. Importantly, sampling of eDNA can be a feasible approach for detecting northward range expansions in remote areas as climate change progresses. [ABSTRACT FROM AUTHOR]

The Saimaa ringed seal (Pusa hispida saimensis) is endemic to Lake Saimaa in Finland. The subspecies is thought to have originated when parts of the ringed seal population of the Baltic region were trapped in lakes emerging due to postglacial bedrock rebound around 9000 years ago. During the 20th century, the population experienced a drastic human‐induced bottleneck. Today encompassing a little over 400 seals with extremely low genetic diversity, it is classified as endangered. We sequenced sections of the mitochondrial control region from 60 up to 125‐years‐old museum specimens of the Saimaa ringed seal. The generated dataset was combined with publicly available sequences. We studied how genetic variation has changed through time in this subspecies and how it is phylogenetically related to other ringed seal populations from the Baltic Sea, Lake Ladoga, North America, Svalbard, and the White Sea. We observed temporal fluctuations in haplotype frequencies and loss of haplotypes accompanied by a recent reduction in female effective population size. In apparent contrast with the traditionally held view of the Baltic origin of the population, the Saimaa ringed seal mtDNA variation also shows affinities to North American ringed seals. Our results suggest that the Saimaa ringed seal has experienced recent genetic drift associated with small population size. The results further suggest that extant Baltic ringed seal is not representative of the ancestral population of the Saimaa ringed seal, which calls for re‐evaluation of the deep history of this subspecies. [ABSTRACT FROM AUTHOR]

Fish and marine mammals are an important traditional subsistence and cultural resource for residents of Ulukhaktok, a community within the Inuvialuit Settlement Region, Northwest Territories. Community-based harvest surveys were conducted monthly out of Ulukhaktok, between 2004 and 2015, to enumerate fish and marine mammal subsistence harvest. Anadromous Arctic Char (annual average: 3,464 fish), Lake Trout (annual average: 2,114 fish), and Ringed Seals (annual average: 256 seals) continue to be the most abundantly harvested fish and marine mammal species 2004-2015, with landlocked Arctic Char (annual average: 203 fish), whitefish (annual average: 74 fish), cod (annual average: 136 fish), and Bearded Seals (annual average: 8) also reported. Accessibility to harvesting areas and availability of fish and marine mammals were strongly linked to seasonal cycles. Following concerns regarding the population status of Kuujjua River (i.e., Tatik Lake) Arctic Char, and to support the sustainable management of all Arctic Char subsistence and commercial fisheries in the area, the Ulukhaktok Char Working Group (UCWG) was established in 1996. The UCWG implemented a community fishing plan with voluntary management measures and fishery guidelines supported by harvest data provided by monitoring programs. In response to the observed decline in stock status, the UCWG established a voluntary subsistence harvest level of 1,000 fish from Tatik Lake which has not been surpassed in recent years (2003-2015); however, the total number of Kuujjua River Arctic Char harvested is unknown due to the uncertainty regarding contributions to the coastal mixed-stock harvest. Total annual harvest of anadromous Arctic Char from respective management zones 1988-2015 varied as follows: a) between 486 and 6,297 fish in coastal waters; b) between 0 (voluntary community closure) and 4,386 fish from the Kuujjua River; and c) between 0 and 5,502 fish from rivers in Prince Albert Sound. Co-management partners consider all available information collected through harvest surveys, monitoring programs, Indigenous Knowledge and observations, and scientific research to support the adaptive comanagement of these important fish and marine mammal species in a changing climate. [ABSTRACT FROM AUTHOR]

Arctic foxes are significant predators of pups in lairs in much of the geographic range of ringed seals (Smith, [25]; Smith et al., [29]). Arctic fox predation of ringed seals occurs on pups at lairs in spring (Smith, [25], [26]; Smith & Lydersen, [30]; Stirling, [32]; Stirling & Archibald, [33]). During unusual warm temperatures and rain events on southeast Baffin Island in April 1972, lairs collapsed prematurely and pups exposed in their subnivean lairs experienced elevated rates of bear and fox predation (Stirling & Smith, [35]). During spring, polar bear predation of ringed seals in the fast ice is focused on pups in lairs (Smith, [25], [26]; Smith & Lydersen, [30]; Stirling, [32]; Stirling & Archibald, [33]). [Extracted from the article]

To understand the impact of underwater anthropogenic noise on marine life, it is crucial to collect more data about the onset of behavioural reactions of marine species. Three free-ranging ringed seals (Phoca hispida botnica) were marked with GPS tags to track their movements in the Baltic Sea. The tracking data showed that ringed seals regularly transit between their haul-outs in the Väinameri and foraging areas in the southern part of the Gulf of Riga. On their way, the ringed seals pass through the Suur väin (Suur Strait) and have to cross the Virtsu--Kuivastu ferry route, where they are likely exposed to underwater ship-borne noise. Ringed seals' dive profiles were studied for the presence of avoidance reactions in response to ship-radiated noise. As a result, some dive profile irregularities were noticed in the form of deep dives or multiple surfacings. The received level (RL) causing the disturbance in ringed seals' behaviour was estimated based on sound propagation modelling. The obtained results are generally in line with previously reported studies on captive harbour seals and free-ranging grey seals. However, behavioural reactions observed in the current study are unlikely to adversely affect the energy budgets of ringed seals due to the short exposure time. [ABSTRACT FROM AUTHOR]

The correction notice in the journal "Environmental Science & Pollution Research" addresses an oversight in acknowledging partners in a study on mercury exposure in ringed seals in Lake Saimaa, Finland. The authors failed to include Metsähallitus, Parks and Wildlife Finland in the acknowledgements section for their assistance in sample collection. The original article has been updated to include this acknowledgment. [Extracted from the article]

This study uses telemetry and stomach content analysis to describe the ringed seals’ dive pattern and prey selection within Kangia (Ilulissat Icefjord), Greenland, where the ringed seals are known to be exceptionally large and genetically distinct. Data from twenty-four ringed seals (Pusa hispida) tagged in Kangia, with satellite relay data loggers from 2012 to 2020, were used to describe the dive patterns. The transmitters were active between 28 and 270 days and showed that subadults most frequently dove to around 150 m. Adult males frequently dove to this depth, but they also had a second frequently visited depth at around 400 m, some adults significantly deeper. Adult males generally dove deeper than females and adult seals showed deeper dives during the winter, a feature that was less prominent in subadults. The stomach content from ringed seals (n = 108) harvested in Kangia by subsistence hunters revealed that polar cod (Boreogadus saida), capelin (Mallotus villosus), mysids (Mysis oculata, M. littoralis, M. Polaris) and shrimps (mainly Pandalus borealis) were the dominant prey. Shrimps were observed more often in adults, likely due to the frequently visited dive depth of around 400 m, whereas mysids were more observed in small subadult seals. The stomach content from harp seals (Pagophilus groenlandicus) and Greenland halibut (Reinhardtius hippoglossoides) caught in Kangia also showed a strong niche overlap with the ringed seals. These findings outline the unique ecological adaptations and the importance of Kangia as a critical habitat of ringed seals. [ABSTRACT FROM AUTHOR]

The purpose of the research is study of pinniped helminth fauna in Chukotka, and the analysis of the fish of the main commercial families infected with pathogens of helminthozoonoses based on modern literature.Materials and methods. The helminths were collected in autumn of 2019 from pinnipeds caught in the Mechigmenskaya Guba of the Bering Sea in the Chukotka Autonomous Okrug by the method of partial helminthological dissection per Skryabin (gastrointestinal tract). Samples were examined from 6 walruses and 26 seals (13 spotted seals and 13 ringed seals). The helminths found were fixed in 70% alcohol. The helminth species were identified at the Department of Parasitology and Veterinary and Sanitary Examination of the MVA named after K. I. Skryabin using reference literature.Results and discussion. All pinnipeds were infected with nematodes of the family Anisakidae. Mature Pseudoterranova desipiens were found in the walrus (Infection Prevalence = 16.7% with Infection Intensity = 3 specimens/animal), mature Ps. desipiens, as well as Contracoecum osculatum and Anisakis simplex larvae (IP = 30.8% with II from 5 to 57 specimens) were found in the spotted seal, and Ps. desipiens larvae and mature Ps. desipiens were found in the ringed seal (IP = 15.4% with II from 1 to 4 specimens). Thus, only Ps. desipiens were represented by mature stages (females and males), and two other species of anisakids, C. osculatum and A. simplex, were found in the seals in the larval stage.

Wildlife camera traps and crowd-sourced image material provide novel possibilities to monitor endangered animal species. The massive data volumes call for automatic methods to solve various tasks related to population monitoring, such as the re-identification of individual animals. The Saimaa ringed seal (Pusa hispida saimensis) is an endangered subspecies only found in Lake Saimaa, Finland, and is one of the few existing freshwater seal species. Ringed seals have permanent pelage patterns that are unique to each individual and that can be used for the identification of individuals. A large variation in poses, further exacerbated by the deformable nature of seals, together with varying appearance and low contrast between the ring pattern and the rest of the pelage makes the Saimaa ringed seal re-identification task very challenging, providing a good benchmark by which to evaluate state-of-the-art re-identification methods. Therefore, we make our Saimaa ringed seal image (SealID) dataset (N = 57) publicly available for research purposes. In this paper, the dataset is described, the evaluation protocol for re-identification methods is proposed, and the results for two baseline methods—HotSpotter and NORPPA—are provided. The SealID dataset has been made publicly available. [ABSTRACT FROM AUTHOR]

Host‐specialist parasites of endangered large vertebrates are in many cases more endangered than their hosts. In particular, low host population densities and reduced among‐host transmission rates are expected to lead to inbreeding within parasite infrapopulations living on single host individuals. Furthermore, spatial population structures of directly‐transmitted parasites should be concordant with those of their hosts. Using population genomic approaches, we investigated inbreeding and population structure in a host‐specialist seal louse (Echinophthirius horridus) infesting the Saimaa ringed seal (Phoca hispida saimensis), which is endemic to Lake Saimaa in Finland, and is one of the most endangered pinnipeds in the world. We conducted genome resequencing of pairs of lice collected from 18 individual Saimaa ringed seals throughout the Lake Saimaa complex. Our analyses showed high genetic similarity and inbreeding between lice inhabiting the same individual seal host, indicating low among‐host transmission rates. Across the lake, genetic differentiation among individual lice was correlated with their geographic distance, and assignment analyses revealed a marked break in the genetic variation of the lice in the middle of the lake, indicating substantial population structure. These findings indicate that movements of Saimaa ringed seals across the main breeding areas of the fragmented Lake Saimaa complex may in fact be more restricted than suggested by previous population‐genetic analyses of the seals themselves. [ABSTRACT FROM AUTHOR]

Since the 1990s, scientists and Indigenous peoples have worked together across Inuit Nunangat (Inuit homeland in Canada) to conduct research on contaminants in ringed seals (Pusa hispida; natsiq, natchiq or ᓇᑦᓯᖅ in Inuktut), a species of high cultural, economic and nutritional importance among Inuit. Developing innovative ways of engaging Indigenous communities in research has become essential. Here we examine a science outreach and knowledge mobilization project that was developed as part of a long-term contaminant monitoring program on ringed seals in the Canadian Arctic. This project engaged Inuit school students, youth and communities through workshops on ringed seal ecology and contaminants. We present our approach to workshop planning and delivery, discuss results from a workshop assessment, and reflect on lessons learned and best practices. We also assess the potential of school workshops that braid Western science and Inuit knowledge to support the meaningful engagement of Inuit youth in environmental research. [ABSTRACT FROM AUTHOR]

As a high trophic-level species, ringed seals (Pusa hispida) and beluga whales (Delphinapterus leucas) are particularly vulnerable to elevated concentrations of biomagnifying contaminants, such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and mercury (Hg). These species also face climate-change-related impacts which are leading to alterations in their diet and associated contaminant exposure. The metabolomic profile of marine mammal tissues and how it changes to environmental stressors is poorly understood. This study characterizes the profiles of 235 metabolites across plasma, liver, and inner and outer blubber in adult ringed seals and beluga whales and assesses how these profiles change as a consequence of contaminants and dietary changes. In both species, inner and outer blubber were characterized by a greater proportion of lipid classes, whereas the dominant metabolites in liver and plasma were amino acids, carbohydrates, biogenic amines and lysophosphatidylcholines. Several metabolite profiles in ringed seal plasma correlated with δ13C, while metabolite profiles in blubber were affected by hexabromobenzene in ringed seals and PBDEs and Hg in belugas. This study provides insight into inter-matrix similarities and differences across tissues and suggests that plasma and liver are more suitable for studying changes in diet, whereas liver and blubber are more suitable for studying the impacts of contaminants. [ABSTRACT FROM AUTHOR]

The timing and effect of a range of environmental variables on the annual molt of ringed seals (Pusa hispida saimensis) in Lake Saimaa were studied in 2013–2019. Molting patterns were investigated by mixed models run on photoidentification data collected by camera trapping and digital camera surveys. Photoperiod was the predominant environmental variable affecting the molt but molting of females was also linked to air temperature and ice thickness. The cumulative proportion of molting seals peaked around the 18th–20th May, when day length reached 18 h. The main molting season, when most of the seals were hauled out at the same time, lasted on average for 16 days with considerable inter‐annual differences in the duration (range 11–22 days). The results provide important baseline information on Saimaa ringed seal molt. Continued monitoring is important as the molt is an energetically demanding period for the seals, and any changes in molting behavior may indicate changes in habitat or in environmental conditions. [ABSTRACT FROM AUTHOR]

Nest boxes and other human‐made constructions have been widely and successfully used as conservation tools to increase nest‐availability for hollow‐dependent fauna, especially birds and some small and medium mammals.This study applies, for the first time, this recovery technique to a large aquatic mammal, aiming to improve resting, birthing and nursing sites of endangered Saimaa ringed seals (Pusa hispida saimensis) by developing artificial nest boxes. This landlocked subspecies' breeding habitat is severely affected by climate change. Because of mild winters, sufficient ice and snow habitat for subnivean lairs is lacking.In this study, floating nest boxes were developed. It was found that free‐ranging ringed seals accept nest boxes as sites for resting, birthing and nursing. Thirty‐four boxes in total were offered during six successive breeding seasons. Almost half (47%) of the available boxes were used by seals, and two pups were born and reared in the boxes during the 6‐year study.Our study indicates that this innovative technique can be a valuable tool for the Saimaa ringed seal conservation in the changing climate. [ABSTRACT FROM AUTHOR]

Data on the seasonal distribution and ecology of ringed seals (Pusa hispida) were obtained from the results of seal tagging with satellite telemetry transmitters (STT) in the White Sea. STT "Pulsar" worked in the Argos system. Catching and tagging of ringed seals were carried out in the Dvina Bay of the White Sea in autumn 2008 and 2016 and in the summer of 2020. 5 tags were installed on seals of different ages. It was shown in the summer the ringed seals did not make long movements and remained on the littoral. The seals moved long distances in autumn, the average daily distance between observation points was 43 km per day. The ringed seal preferred areas with open water and the sea edge of landfast ice in winter. The ringed seal could stay for more than two months in the pelagic zone above the depth of 20 m. Priority directions of movement haven’t been identified. We suggest this feature of the seals' behavior in the White Sea is associated with the seasonal distribution of food. [ABSTRACT FROM AUTHOR]

Shipping is increasing in Arctic regions, exposing marine mammals to increased underwater noise. Noise analyses often use unweighted broadband sound pressure levels (SPL) to assess noise impacts, but this does not account for the animals' hearing abilities at different frequencies. In 2018 and 2019, noise levels were recorded at five and three sites, respectively, along a shipping route in an inlet of Northern Baffin Island, Canada. Broadband SPLs (10 Hz–25 kHz), unweighted and with auditory weighing functions from three marine mammal groups, were compared between times ore carriers (travelling < 9 knots) were present or absent. Clearly audible distances of shipping noise and exposure durations were estimated for each weighting function relative to vessel direction, orientation, and year. Auditory weighting functions had significant effects on the potential perception of shipping noise. Bowhead whales (Balaena mysticetus) experienced similar SPLs to unweighted levels. Narwhals (Monodon monoceros) and ringed seals (Pusa hispida) experienced lower SPLs. Narwhals were unlikely to clearly perceive shipping noise unless ships were in close proximity (<3 km) and ambient noise levels were low. Detectability propagation models of presumed noise exposure from shipping must be based on the hearing sensitivities of each species group when assessing noise impacts on marine mammals. [ABSTRACT FROM AUTHOR]

The enzyme-linked immunosorbent assay (ELISA) was applied to detect antibodies against Brucella abortus in serum samples from four seal species at nine coastal locations of Hokkaido, Japan. These antibodies were detected in 27% (32/118) of Western Pacific harbor seals (Phoca vitulina stejnegeri) at Cape Erimo. The antibodies were observed in spotted seals (P. largha) in one out of six at Nemuro, in two out of three at Rebun Island, in one out of two at Bakkai, and in examined one at Soya. They were also found in respective examined one ribbon seal (Histriophoca fasciata) and one ringed seal (Pusa hispida) at Akkeshi. Harbor seals that tested positive were mostly yearlings (35%, 20/57) and juveniles (45%, 10/22), while only one pup (1/13) and one subadult (1/5) tested positive with low titers of the antibody; no antibodies were observed in adults (n=21). These results suggest that Brucella mainly infected harbor seals from the environment while weaning, and the bacteria were cleared during the early life stage of the seals. In spotted seals, however, antibodies were also detected in adults, suggesting that spotted seals could become infected with Brucella even as adults. It is also possible that a different, more persistent strain of Brucella may have infected the spotted seals. [ABSTRACT FROM AUTHOR]

The anatomical architecture of the hip and stifle joints of the Saimaa ringed seal was determined by dissection to be similar to that of the Baltic ringed seal. There was no ligament of the femoral head in the hip joint. The lateral side of the stifle joint lacked a collateral ligament but the collateral ligament on the medial side was of considerable size. The medial meniscus was larger and thicker than the lateral meniscus. The asymmetrical anatomical architecture allows for much lateral movement during aquatic motion, but it is poorly adapted to terrestrial locomotion. [ABSTRACT FROM AUTHOR]

Warming ocean temperatures and loss of Arctic sea ice have contributed to shifts in the distribution of endemic forage species important to the diets of marine carnivores, such as ringed seals (Pusa hispida). Given the heterogeneous way in which these changes are projected to occur throughout the Arctic, it is important to gain an understanding of predator diets and how they may change over time and space. We present the first study of ringed seal foraging ecology in the Gulf of Boothia, located in the central Canadian Arctic, using three diet estimation techniques: stomach contents, stable isotopes, and fatty acid signature analyses. Samples of ringed seal blubber and muscle were collected during subsistence harvests in Kugaaruk, Nunavut, Canada between 2012 and 2016. Stomach contents were collected in 2012 and differed amongst seals of different age classes, with polar cod (Boreogadus saida) comprising the largest proportion of both adult and juvenile seal diets. Mysids (Mysis oculata) were the main prey consumed by young of the year. Overall, FA signatures differed amongst age classes and exhibited significant interannual variation, but were not influenced by sea ice phenology, whilst values of δ13C, an indication of foraging habitat, changed in relation to the dates of annual sea ice breakup and freeze-up. Our results offer novel insights into the foraging habits of ringed seals in the Gulf of Boothia and demonstrate that ringed seal diets vary temporally, although not solely in response to sea ice concentration, which remains relatively high in this region of the central Canadian Arctic. [ABSTRACT FROM AUTHOR]

The interview survey conducted in Ilulissat, Ilimanaq, and Qasigiannguit in Greenland during March–April 2019 showed that the local fishers are changing fishing strategies and adapting to a changing environment caused by climate change. The main fjord of Ilulissat Icefjord is usually filled with icebergs year-round, making it impossible to navigate. Currently, there are more ice clearing events in Ilulissat Icefjord during the winter than previously. The traditional pattern of going fishing using dogsled is changing and fishing from boats occurs, whenever the main fjord clears of ice. The poorer sea ice conditions in the southern branch of the fjord system, combined with the fact that it is increasingly challenging to reach fishing sites, have resulted in fishers from Qasigiannguit not going to the Icefjord as much as they used to. Ilulissat Icefjord is by any means considered important fishing and hunting ground by locals, as both Greenland halibut and ringed seals are known to be of larger size inside the fjord system, when compared to those caught in Disco Bay. The locals use Ilulissat Icefjord during a limited period of the year, and the fjord is therefore said to be protected from overexploitation. They observe the immediate effects of climate change from changes in the ice conditions, a change in the fjord's accessibility, and the occurrence of Atlantic cod, which were not present in the fjord system in such numbers before. [ABSTRACT FROM AUTHOR]

Arctic sea ice loss has direct consequences for predators. Climate‐driven distribution shifts of native and invasive prey species may exacerbate these consequences. We assessed potential changes by modelling the prey base of a widely distributed Arctic predator (ringed seal; Pusa hispida) in a sentinel area for change (Hudson Bay) under high‐ and low‐greenhouse gas emission scenarios from 1950 to 2100. All changes were relatively negligible under the low‐emission scenario, but under the high‐emission scenario, we projected a 50% decline in the abundance of the well‐distributed, ice‐adapted and energy‐rich Arctic cod (Boreogadus saida) and an increase in the abundance of smaller temperate‐associated fish in southern and coastal areas. Furthermore, our model predicted that all fish species declined in mean body size, but a 29% increase in total prey biomass. Declines in energy‐rich prey and restrictions in their spatial range are likely to have cascading effects on Arctic predators. [ABSTRACT FROM AUTHOR]

Induced pluripotent stem (iPS) cells have been produced just for a few species among order Carnivora: snow leopard, Bengal tiger, serval, jaguar, cat, dog, ferret, and American mink. We applied the iPS cell derivation protocol to the ringed seal (Phoca hispida) fibroblasts. The resulting cell line had the expression of pluripotency marker gene Rex1. Differentiation in embryoid body-like structures allowed us to register expression of AFP, endoderm marker, and Cdx2, trophectoderm marker, but not neuronal (ectoderm) markers. The cells readily differentiated into adipocytes and osteocytes, mesoderm cell types of origin. Transcriptome analysis allowed us to conclude that the cell line does not resemble human pluripotent cells, and, therefore, most probably is not pluripotent. Thus, we produced ringed seal multipotent stem cell line capable of differentiation into adipocytes and osteocytes. [ABSTRACT FROM AUTHOR]

The inaugural data from the first systematic program of sea-ice observations in Kotzebue Sound, Alaska, in 2018 coincided with the first winter in living memory when the Sound was not choked with ice. The following winter of 2018–19 was even warmer and characterized by even less ice. Here we discuss the mass balance of landfast ice near Kotzebue (Qikiqtaġruk) during these two anomalously warm winters. We use in situ observations and a 1-D thermodynamic model to address three research questions developed in partnership with an Indigenous Advisory Council. In doing so, we improve our understanding of connections between landfast ice mass balance, marine mammals and subsistence hunting. Specifically, we show: (i) ice growth stopped unusually early due to strong vertical ocean heat flux, which also likely contributed to early start to bearded seal hunting; (ii) unusually thin ice contributed to widespread surface flooding. The associated snow ice formation partly offset the reduced ice growth, but the flooding likely had a negative impact on ringed seal habitat; (iii) sea ice near Kotzebue during the winters of 2017–18 and 2018–19 was likely the thinnest since at least 1945, driven by a combination of warm air temperatures and a persistent ocean heat flux. [ABSTRACT FROM AUTHOR]

Results of studies on technology of natural canned meat of ringed seal (akiba) are presented. The frozen seal meat was used for canning without subcutaneous fat that was removed after slaughter. Protein content in the muscle tissue was 22.50 ± 0.71 %, fat content — 8.20 ± 0.20 %, minerals — 1.20 ± 0.10 %, its energy value was 167.4 ± 5.6 kcal/100 g. After defrosting, pieces of the seal meat were kept in fresh water at temperature of 15–18 oC for 2 to 3 hours, then onion and flavorings were added. The spiced meet was packed to cans № 6 and sterilized under temperature of 120 oC. The finished canned food had a meaty taste and smell, without extraneous smacks and smells. The broth was transparent with brown tint and small amount of suspended protein substances. Protein content in the finished canned food was 17.0 %, fat content 7.0 %, protein composition was close to the standard protein by amount and ratio of essential amino acids. Monounsaturated fatty acids dominated in lipids of the canned food (58.08 % of total lipids), mainly oleic (18:1 n-9) and palmitooleic (16:1 n-7) acids; portion of polyunsaturated fatty acids was 22.17 %, including omega-3 fatty acids (18.56 % of PUFA). High content of iron (6.6 mg/100 g), zinc (2.3 mg/100 g) and selenium (80 μg/100 g) was detected in the canned food that partially or completely maintained daily requirements of human body for these elements.

Abstract Arctic ecosystem dynamics are shifting in response to warming temperatures and sea ice loss. Such ecosystems may be monitored by examining the diet of upper trophic level species, which varies with prey availability. To assess interannual variation in the Beaufort Sea ecosystem, we examined spatial and temporal trends in ringed seal (Pusa hispida) δ13C and δ15N in claw growth layers grown from 1964 to 2011. Stable isotopes were correlated with climate indices, environmental conditions, seal population productivity, and geographic location. Sex and age did not influence stable isotopes. Enriched 13C was linked to cyclonic circulation regimes, seal productivity, and westward sampling locations. Higher δ15N was linked to lower sea surface temperatures, a higher percentage of pups in the subsistence harvest, and sample locations that were eastward and further from shore. From the 1960s to 2000s, ringed seal niche width expanded, suggesting a diversification of diet due to expansion of prey and/or seal space use. Overall, trends in ringed seal stable isotopes indicate changes within the Beaufort Sea ecosystem affected by water temperatures and circulation regimes. We suggest that continued monitoring of upper trophic level species will yield insights into changing ecosystem structure with climate change.

Historically, the seals and harbour porpoises of the Baltic Sea and North Sea have been subjected to hunting, chemical pollutants and repeated mass mortalities, leading to significant population fluctuations. Despite the conservation implications and the zoonotic potential associated with viral disease outbreaks in wildlife, limited information is available on the circulation of viral pathogens in Baltic Sea seals and harbour porpoises. Here, we investigated the presence of the influenza A virus (IAV), the phocine distemper virus (PDV) and the cetacean morbillivirus (CeMV) in tracheal swabs and lung tissue samples from 99 harbour seals, 126 grey seals, 73 ringed seals and 78 harbour porpoises collected in the Baltic Sea and North Sea between 2002–2019. Despite screening 376 marine mammals collected over nearly two decades, we only detected one case of PDV and two cases of IAV linked to the documented viral outbreaks in seals in 2002 and 2014, respectively. Although we find no evidence of PDV and IAV during intermediate years, reports of isolated cases of PDV in North Sea harbour seals and IAV (H5N8) in Baltic and North Sea grey seals suggest introductions of those pathogens within the sampling period. Thus, to aid future monitoring efforts we highlight the need for a standardized and continuous sample collection of swabs, tissue and blood samples across Baltic Sea countries.