Harp Seals Research Articles

Prosthetic Soul Mates: Sex Robots as Media for Companionship

Prosthetic Soul Mates: Sex Robots as Media for Companionship

Effects of health status on pressure-induced changes in phocid immune function and implications for dive ability

The ability of marine mammals to cope with environmental challenges is a key determining factor in strandings and successful release of rehabilitated animals. Dive behavior is related to foraging and thus survival. While dive adaptations have been well studied, it is unknown how the immune system responds to diving and whether health status impacts immune function during diving. This study investigated the functional response of ex situ immune cells from stranded phocids to in vitro increased pressure, over the course of rehabilitation. Blood samples were drawn from stranded harbor seals (Phoca vitulina), gray seals (Halichoerus grypus) and harp seals (Phoca groenlandica) at the time of admit to the Mystic Aquarium, Mystic, CT and again after rehabilitation (pre-release). Phagocytosis, lymphocyte proliferation and immune cell activation were measured in vitro, with and without exposure to 2000 psi (simulated dive depth of 1360 m). Plasma epinephrine and norepinephrine, and serum cortisol were measured in vivo. All hormone values decreased between admit and release conditions. Under admit or release conditions, pressure exposures resulted in significant changes in granulocyte and monocyte phagocytosis, granulocyte expression of CD11b and lymphocyte expression of the IL2 receptor (IL2R). Overall, pressure exposures resulted in decreased phagocytosis for admit conditions, but increased phagocytosis in release samples. Expression of leukocyte activation markers, CD11b and IL2R, increased and the response did not differ between admit and release samples. Specific hematological and serum chemistry values also changed significantly between admit and release and were significantly correlated with pressure-induced changes in immune function. Results suggest (1) dive duration affects the response of immune cells, (2) different white blood cell types respond differently to pressure and (3) response varies with animal health. This is the first study describing the relationship between diving, immune function and health status in phocids.

“Seal scrapers” from Šventoji – In search of their possible function

During the excavations carried out at the complex of Subneolitic-Neolithic sites in Šventoji, coastal Lithuania (sites 1, 4, 6 and 23), 27 unique bone products have been discovered. Due to the character of the use-wear and technological traces which are macroscopically readable on their surface they have been defined as scrapers. Dated to ca. 3000 cal BC, these tools are made of harp seal tibia, about 75% of them from right side bones. This article describes the procedure that was conducted in order to interpret the technology of production, ways of use and possible functions of these tools, and includes the experimental program directed to the activities which could have been carried out with such products within the specialized camps of Šventoji, such as processing of animal hides (including seal) with admixture of ochre or ash and fish scraping. The basis for the interpretations is the results of traceological and chemical (SEM-EDX) analysis of the artefacts and experimental tools. As a result of the conducted studies, it was found that the analysed tools were most probably used for scraping the hides with the use of an ochre admixture. The presented research probably concludes a long period of speculations about the functions of these unique objects.

Diet and isotopic niche overlap elucidate competition potential between seasonally sympatric phocids in the Canadian Arctic

Interspecific interactions may be altered as a result of poleward species range shifts caused by climate change. In recent decades, Cumberland Sound, Nunavut, in the Canadian Arctic, has undergone concurrent increases in the availability of the forage fish capelin (Mallotus villosus) and the number of migratory harp seals (Pagophilus groenlandicus) during the open-water period; however, the impacts of these changes on endemic Arctic species, such as ringed seals (Pusa hispida), have received little attention. We coupled stomach contents with stable isotope analysis (δ13C and δ15N) of muscle and liver to determine the extent of potential competition between ringed seals (n = 91) and harp seals (n = 39) in Cumberland Sound. Isotopic niche breadth was greater for ringed seals (95% ellipse: 10.08‰2) than for harp seals (95% ellipse: 8.00‰2), and harp seal isotopic niche overlapped more with ringed seal isotopic niche than vice versa, suggesting asymmetrical competition potential. Although there was high overlap in isotopic niche breadth (range 50.3–91.0%) and prey species consumed (Schoener’s Index 0.60), stomach content analysis revealed differences in prey species proportions and size composition, thereby reducing the degree of realized niche overlap. Harp seals consumed a higher biomass of fish (66.7%) than did ringed seals (31.9%), and harp seals also consumed larger capelin (64–200 mm), polar cod (Boreogadus saida; 28–194 mm), and Liparidae (55–115 mm) than ringed seals (63–154 mm, 20–189 mm, and 16–128 mm, respectively). With climate change and range shifts predicted to continue into the future, our results provide an important baseline for future studies examining interspecific interactions.

Predation of Harp Seals, <i>Pagophilus groenlandicus</i>, by Polar Bears, <i>Ursus maritimus</i>, in Svalbard

Harp seals (Pagophilus groenlandicus) that breed in February and March in the White Sea migrate to open water around Svalbard and Franz Josef Land in the Barents Sea, feeding pelagically while following the receding ice edge northward to the edge of the polar pack. Although harp seals are present throughout the area during the summer, they are primarily pelagic and do not appear to be extensively preyed upon by polar bears (Ursus maritimus). However, occasionally, large numbers of harp seals may haul out and rest on the pack ice or feed in the water below the ice and surface to breathe between the floes. When approached by a polar bear while on the ice, harp seals do not exhibit the instant flight response characteristic of the polar bear’s primary prey species, ringed (Pusa hispida) and bearded seals (Erignathus barbatus). In this situation, polar bears may make multiple kills without either consuming their own prey or scavenging seals killed by other bears. This behavior appears not to frighten other nearby harp seals, whether hauled out on the ice or in the water below the floes. These unusual concentrations of harp seals hauled out on sea ice may be related to the distribution and abundance of fish or other epontic prey. Their lack of an escape response to predators on the surface of the sea ice is probably a result of briefly hauling out in large numbers in spring while whelping on the sea ice in areas where the consequences of potential polar bear predation are insignificant. The rare events of harp seal mortality from bears killing them on the surface of pack ice during the summer do not appear to have a significant impact at the population level of either species.

A comparison of diet estimates of captive beluga whales using fatty acid mixing models with their true diets

Beluga whales (Delphinapterus leucas) are sentinel species for Arctic environmental change; however, whether belugas are resilient to anticipated changes in prey dynamics remains uncertain, partly due to a lack of dietary information. Mixing models are promising tools to evaluate the diets of marine mammals, using dietary tracers such as fatty acid signatures. Additionally, captive feeding trials are useful to test the effectiveness of these tools for application to wild populations. In our study, we compared the ability of two models, quantitative fatty acid signature analysis in R (QFASAR) and Fatty Acid Source Tracking Algorithm in R (FASTAR) to reconstruct the diets of captive beluga whales that had been fed a long-term diet consisting mostly of Pacific herring (Clupea harengus pallasi), and in smaller proportions, capelin (Mallotus villosus) and squid (Doryteuthis opalescens). To account for fatty acid metabolism, we compared a suite of calibration coefficients derived from captive feeding trials of American mink (Mustela vison), harp seal (Pagophilus groenlandicus), harbour seal (Phoca vitulina richardsi), and grey seal (Halichoerus grypus) fed monotypic diets. For both methods, diets estimated using calibration coefficients derived from feeding trials of mink fed herring and/or seal oil were able to correctly identify herring as the dominant prey source of belugas. In addition, there was higher precision among diet estimates using these calibration coefficients in comparison to those generated using calibration coefficients derived from feeding trials of pinnipeds or mink fed poultry. QFASAR more accurately approximated the diet proportions of the whales than FASTAR, possibly because of the greater robustness to errors in the calibration coefficients. Based on QFASAR, diet estimates best reflect the whales' true dietary proportions consumed approximately two weeks to one month prior to sampling, similar to timeframes seen in previous studies of harbour seals. We recommend caution when using these models with prey that have high within-species variability in fatty acid signatures or small sample sizes, as well as prey with similar fatty acid signatures. The application of mixing models is promising to identify the prey of wild beluga whales and other marine mammals.

Alternative bait trials in the Barents Sea snow crab fishery.

Commercial harvesting of snow crab (Chionoecetes opilio) in the Barents Sea started in 2012 by Norwegian fishing vessels. This new fishery has significant bait requirements, representing an emerging conservation challenge. In this study, we evaluate the performance of five alternative (natural) baits manufactured from the waste stream of existing and sustainably managed harp seal (Pagophilus groenlandicus) and minke whale (Balaenoptera acutorostrata) capture. Five different types of new bait were evaluated, including seal fat (SF), seal fat with skin (SFS), seal meat with bone (SMB), whale fat with skin (WFS), and whale meat with fat (WMF). A comparative fishing experiment was conducted onboard a commercial snow crab fishing vessel in the Barents Sea (May–June, 2016) to evaluate the performance of traditional bait (squid, Illexs spp.) and alternative baits at catching snow crabs. Performance of the different baits were compared on the basis of the number of commercial crab caught per trap haul catch per unit effort (CPUE) and carapace width (CW). Our results showed that SF and SFS performed equally well to traditional bait, with no statistical difference in CPUE (p-value = 0.325 and 0.069, respectively). All of the other experimental baits significantly decreased CPUE, when compared to squid. No significant effect of bait treatment on CW was detected and the cumulative distribution of CW was the same between control traps and each of the bait treatments. Overall the results indicated that SF and SFS represent a viable alternative to replace traditional bait, addressing a key conservation challenge in this bait intensive snow crab fishery.

Does Vibrissal Innervation Patterns and Investment Predict Hydrodynamic Trail Following Behavior of Harbor Seals (Phoca vitulina)?

Our understanding of vibrissal function in pinnipeds is poor due to the lack of comparative morphological, neurobiological, and psychophysical performance data. In contrast, the function of terrestrial mammalian vibrissae is better studied. Pinnipeds have the largest vibrissae of all mammals, and phocids may have the most modified vibrissae. The tactile performance for pinniped vibrissae is well known for harbor seals (Phoca vitulina). Harbor seals display at least two types of tactile behavior involving their mystacial vibrissae: a fine discriminatory capability using active touch and hydrodynamic trail following (the ability to detect and follow turbulent trails). This study investigated innervation patterns of harbor seal follicle-sinus complexes (F-SCs) to test the hypothesis that the whiskers used in hydrodynamic trail following possess increased innervation investment compared to other phocids. Therefore, the most lateral vibrissae from five harbor seals were histologically processed so that morphometric measurements and axon counts could be collected. Vibrissae from one harbor seal were immunolabeled with anti-protein gene product (PGP 9.5) to document the pattern of deep vibrissal nerve innervation of the F-SCs. Overall, harbor seals showed an innervation pattern (axons/F-SC and axons/muzzle) similar to other phocids. The ventrolateral vibrissae, involved in hydrodynamic trail following, have greater axon density in harbor seals than harp seals, suggesting harbor seal F-SC innervation patterns could explain their performance at trail following. The combination of microstructural, innervation investment, and behavioral data provides a foundation for functional inference regarding this tactile behavior in harbor seals and also facilitates future comparative work for other pinniped species. Anat Rec, 302:1837-1845, 2019. © 2019 American Association for Anatomy.

From ice to ocean: changes in the thermal function of harp seal pelt with ontogeny.

Many animals exhibit ontogenetic changes associated with adaptations for survival. Harp seals (Pagophilus groenlandicus) live in the Arctic and rely on thick insulation to maintain thermal homeostasis. Adult harp seals primarily use blubber for insulation, but newborn harp seals rely on a lanugo pelt while nursing, as their blubber layer develops and their first-year pelage grows. This study compared ontogenetic changes in the thermal properties of harp seal pelts in water and in air. Thermal conductivity, pelt thickness, and thermal resistance were measured in water for pelts of harp seal neonates (1 day old), thin whitecoats (4 day old), fat whitecoats (9 day old), ragged jackets (2 week old), beaters (3 week old), and adults and compared to previously published measurements made on the same pelts in air. Pelt conductivity was significantly higher in water than air for pre-molt and molting pups (P ≤ 0.031). Unlike adult pelage, which flattened underwater, lanugo hairs lifted underwater, a phenomenon that has not been reported previously. Thermal resistance of the pelt was significantly reduced in water compared to air for neonates and thin whitecoats (P ≤ 0.0001). A mathematical model of conductive heat transfer for an ellipsoid bodyshowed volume-specific heat loss in water decreased and then stabilized as harp seals aged (P = 0.0321) and was significantly higher for neonates, thin whitecoats, and ragged jackets in water than in air (P ≤ 0.0089). Overall, pelt function is reduced in water for harp seal pups with lanugo, and this renders neonates and thin whitecoats particularly vulnerable to heat loss if submerged.

Phylogenomic insights to the origin and spread of phocine distemper virus in European harbour seals in 1988 and 2002.

The 1988 and 2002 phocine distemper virus (PDV) outbreaks in European harbour seals Phoca vitulina are among the largest mass mortality events recorded in marine mammals. Despite its large impact on harbour seal population numbers, and 3 decades of studies, many questions regarding the spread and temporal origin of PDV remain unanswered. Here, we sequenced and analysed 7123 bp of the PDV genome, including the coding and non-coding regions of the entire P, M, F and H genes in tissues from 44 harbour seals to shed new light on the origin and spread of PDV in 1988 and 2002. The phylogenetic analyses trace the origin of the PDV strain causing the 1988 outbreak to between May 1987 and April 1988, while the origin of the strain causing the 2002 outbreak can be traced back to between June 2001 and May 2002. The analyses further point to several independent introductions of PDV in 1988, possibly linked to a southward mass immigration of harp seals in the winter and spring of 1987-1988. The vector for the 2002 outbreak is unknown, but the epidemiological analyses suggest the subsequent spread of PDV from the epicentre in the Kattegat, Denmark, to haul-out sites in the North Sea through several independent introductions.

Persistent organic pollutants in the Pechora Sea walruses

Until 2011, walrus (Odobenus rosmarus rosmarus) population inhabiting the Pechora Sea remained among the less-studied parts of the Atlantic subspecies. Composition and level of anthropogenic pollutants in these walruses have never been studied before the present work. We collected samples of skin and subcutaneous tissues from 15 adult males in the Pechora Sea and from 1 adult female from adjacent White Sea during the years 2011–2017. These samples were analyzed for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides. The highest concentrations were found for PCBs (∑PCB: \(\stackrel{-}{x}\) ± SE = 5700 ± 3090 ng g−1 lipid; range 40–50,400 ng g−1 lipid, n = 16), followed by pesticides oxychlordane (\(\stackrel{-}{x}\) ± SE = 1090 ± 412 ng g−1 lipid; range 31–5070 ng g−1 lipid, n = 16), and 4,4′-DDE (\(\stackrel{-}{x}\) ± SE = 460 ± 300 ng g−1 lipid; range 2.5–4920 ng g−1 lipid, n = 16). PBDEs showed the lowest concentrations (∑PBDE: \(\stackrel{-}{x}\) ± SE = 13 ± 6.5 ng g−1 lipid; range 0.7–104 ng g−1 lipid, n = 16). Compared with walruses from Svalbard, the studied animals have considerably lower levels of oxychlordane, comparable levels of PBDEs, and exceeding burden of PCBs. Concentrations found in walruses are closer to polar bears than to other pinnipeds from this region (ringed and harp seals). Although all walruses in the sample group were mature males with exception of one mature female from the same location, concentrations of pollutants varied in very broad range. Three groups of walruses were distinguished by concentrations of analyzed persistent organic pollutants (POPs): low POP concentrations; high POP concentrations; intermediate POP concentrations.

Dairy Farmers and Seal Hunters: Subsistence on a Norse Farm in the Eastern Settlement, Greenland

The paper presents the results of the zooarchaeological investigation of a large bone sample from a stratified bog deposit situated next to the dwelling of a Norse farm in South Greenland, ca. 6 km NNW of the presumed political centre of the Landnam period in the Eastern Settlement. The bog layers containing cultural remains cover a period of at least 300 years. The stratigraphical analyses show no dramatic changes in species composition through time, indicating a rather conservative economic system. The age structure of slaughtered cattle reflects a focus on a dairy economy. Investigations of the bones of the small ruminants show that almost equal numbers of lambs and kids were born at the farm, but that the adult population contained twice as many sheep as goats. Pigs were eaten occasionally, but no bones from adults have been found to document the presence of a local breeding stock. Finds of several bones of cat add this species for the first time to the domestic stock in Norse Greenland. Eleven species of wild mammals make up a little less than half of all identified bones of mammals. The seals dominate and the majority are from harp seal and hood ed seal.

A computational fluid dynamics (CFD) based method for assessing the hydrodynamic impact of animal borne data loggers on host marine mammals

AbstractAnimal‐borne data loggers (ABDLs) or “tags” are regularly used to elucidate animal ecology and physiology, but current literature highlights the need to assess associated deleterious impacts including increased resistive force to motion. Previous studies have used computational fluid dynamics (CFD) to estimate this impact, but many suffer limitations (e.g., inaccurate turbulence modeling, neglecting boundary layer transition, neglecting added mass effects, and analyzing the ABDL in isolation from the animal).A novel CFD‐based method is presented in which a “tag impact envelope” is defined utilizing simulations with and without transition modeling to define upper and lower drag limits, respectively, and added mass coefficients are found via simulations with sinusoidally varying inlet velocity, with modified Navier‐Stokes conservation of momentum equations enforcing a shift to the animal's noninertial reference frame. The method generates coefficients for calculating total resistive force for any velocity and acceleration combination, and is validated against theory for a prolate spheroid. An example case shows ABDL drag impact on a harp seal of 11.21%–16.24%, with negligible influence on added mass.By considering the effects of added mass and boundary layer transition, the approach presented is an enhancement to the CFD‐based ABDL impact assessment methods previously applied by researchers.

Animal welfare, social license, and wildlife use industries

ABSTRACTMany wildlife use industries are facing criticism from animal welfare groups. In some recent cases, opposition to contentious practices (e.g., kangaroo [Macropus spp.] harvesting) has achieved widespread community support and industries have lost market access or regulatory approval. The concept of social license to operate has become an important focus for many natural resource management fields, but there is ostensibly less awareness of its role in animal industries. To regard this contemporary threat to traditional wildlife management as more than inexplicable requires some delving into social sciences. We use the example of the declining harp seal (Pagophilus groenlandicus) harvest in Canada to illustrate how poorly addressed animal welfare concerns can erode social license and decimate even ecologically sustainable wildlife use enterprises. We argue that other consumptive wildlife use industries, such as North American fur harvesting and kangaroo harvesting in Australia are at risk of loss of social license if animal welfare concerns are not addressed proactively and effectively. When faced with opposition from animal advocacy groups, many wildlife use industries have traditionally been reactive and have been reluctant to engage with stakeholders who possess seemingly irreconcilable differences. Instead, industries have often resorted to secrecy or deception, or have steadfastly defended their current approaches while attacking their critics. We suggest that a more effective approach would be for industries to proactively engage with stakeholders, establish a shared vision for how their industry should operate, and support this vision by transparently monitoring animal welfare outcomes. Proactive management of community expectations surrounding animal welfare is essential for the maintenance of social license for wildlife use enterprises. © 2018 The Wildlife Society.

Seal Occurrence and Habitat Use during Summer in Petermann Fjord, Northwestern Greenland

Ice-associated seals are considered especially susceptible and are potentially the first to modify distribution and habitat use in response to physical changes associated with the changing climate. Petermann Glacier, part of a unique ice-tongue fjord environment in a rarely studied region of northwestern Greenland, lost substantial sections of its ice tongue during major 2010 and 2012 calving events. As a result, changes in seal habitat may have occurred. Seal occurrence and distribution data were collected in Petermann Fjord and adjacent Nares Strait region over 27 days (2 to 28 August) during the multidisciplinary scientific Petermann 2015 Expedition on the icebreaker Oden. During 239.4 hours of dedicated observation effort, a total of 312 individuals were recorded, representing four species: bearded seal (Erignathus barbatus), hooded seal (Crystophora cristata), harp seal (Pagophilus groenlandicus), and ringed seal (Pusa hispida). Ringed seals were recorded significantly more than the other species (χ2 = 347.4, df = 3, p < 0.001, n = 307). We found significant differences between species in haul-out (resting on ice) behavior (χ2 = 133.1, df = 3, p < 0.001, n = 307). Bearded seals were more frequently hauled out (73.1% n = 49), whereas ringed seals were almost exclusively in water (93.9%, n = 200). Differences in average depth and ice coverage where species occurred were also significant: harp seals and bearded seals were found in deeper water and areas of greater ice coverage (harp seals: 663 ± 366 m and 65 ± 14% ice cover; bearded seals: 598 ± 259 m and 50 ± 21% ice cover), while hooded seals and ringed seals were found in shallower water with lower ice coverage (hooded seals: 490 ± 163 m and 38 ± 19% ice cover; ringed seals: 496 ± 235 m, and 21 ± 20% ice cover). Our study provides an initial look at how High Arctic seals use the rapidly changing Petermann Fjord and how physical variables influence their distribution in one of the few remaining ice-tongue fjord environments.

Изменение активности гренландского тюленя (Pagophilus groenlandicus) в весенне-летний период в условиях вольерного содержания

Изменение активности гренландского тюленя (Pagophilus groenlandicus) в весенне-летний период в условиях вольерного содержания

Исследование обоняния серых и гренландских тюленей с помощью метода оперантного обучения

Исследование обоняния серых и гренландских тюленей с помощью метода оперантного обучения

Population Structure of White Sea Harp Seals (Pagophilus groenlandicus) as an Adaptation to Habitat Conditions

The spatiotemporal distribution of harp seal pups around breeding grounds in the White Sea is considered. It is shown that spatial localization of groups of females with different terms of mass pup birth takes place. This somewhat confirms the data on the gregarious structure of White Sea harp seal population. It is possible to explain the structure of this adaptation of the seal population to different living conditions in different feeding areas.

Accumulation of PBDEs in stranded harp (Pagophilus groenlandicus) and hooded seals (Cystophora cristata) from the Northeastern United States

Polybrominated diphenyl ethers (PBDEs) are highly lipophilic components of brominated flame retardants that are environmentally persistent and bioaccumulate. PBDEs are taken up from the gastrointestinal tract and accumulate mainly in fat depots and liver tissues. Seal species inhabiting Arctic and sub-Arctic regions can have upwards of 30% of their body mass composed of blubber. When those blubber stores are mobilized for energy, stored toxicants are also released into circulation. Most studies reporting accumulation of PBDEs in seals have focused on harbor and grey seals with few examining harp and hooded seals. In this study, PBDEs concentrations were analyzed in seal blubber from 21 stranded harp and 9 stranded hooded seals sampled along the northeast coast of the U.S. (1999–2010). A PBDE congener profile was determined for each individual. The results show that both species of seals are accumulating PBDEs with BDE-47 being the dominant congener. Mean ƩPBDE concentrations in harp seals were 70.55 ± 33.59 ng/g ww and for hooded seals 94.28 ± 42.65 ng/g ww. The results of this study are consistent with previous studies reporting a decrease in bioaccumulation with an increase in bromination. For both species, BDE-47 represented the highest percentage of the ƩPBDEs, composing over 50% of the ƩPBDEs in harp seals. When compared to stranding condition code, animals found alive had overall higher PBDE concentrations than those found in a state of moderate decomposition. This difference could be due to decreased blubber levels in the decomposed animals or potential degradation of the compounds in the blubber. Almost all seals used in this study were yearlings which is the most likely age class to strand. Yearling seals are at a crucial stage of development, especially of their immune system, which can be impacted by high levels of contaminants like PBDEs and increase the susceptibility to disease.

Seroprevalence for Brucella spp. in Baltic ringed seals (Phoca hispida) and East Greenland harp (Pagophilus groenlandicus) and hooded (Cystophora cristata) seals

Zoonotic infections transmitted from marine mammals to humans in the Baltic and European Arctic are of unknown significance, despite given considerable potential for transmission due to local hunt. Here we present results of an initial screening for Brucella spp. in Arctic and Baltic seal species. Baltic ringed seals (Pusa hispida, n = 12) sampled in October 2015 and Greenland Sea harp seals (Pagophilus groenlandicus, n = 6) and hooded seals (Cystophora cristata, n = 3) sampled in March 2015 were serologically analysed for antibodies against Brucella spp. The serological analyses were performed using the Rose Bengal Test (RBT) followed by a confirmatory testing of RBT-positive samples by a competitive-enzyme linked immunosorbent assay (C-ELISA). Two of the Baltic ringed seals (a juvenile male and a juvenile female) were seropositive thus indicating previous exposure to a Brucella spp. The findings indicate that ringed seals in the Baltic ecosystem may be exposed to and possibly infected by Brucella spp. No seropositive individuals were detected among the Greenland harp and hooded seals. Although our initial screening shows a zoonotic hazard to Baltic locals, a more in-depth epidemiological investigation is needed in order to determine the human risk associated with this.