Polar Research (E-Journal)
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Seasonality of social behaviour among immature belugas (Delphinapterus leucas) in managed care
No full textBelugas (Delphinapterus leucas) in managed care have been reported to show seasonal variation in socio-sexual behaviour, hormone levels and respiration rates; however, little is known about the social interactions of wild belugas when they are not in summer, near-shore congregations. To better understand if belugas show seasonal variation in social interactions, this study recorded the behaviour of 10 belugas (five females, five males, ranging from birth to 10 years of age) housed in managed care. Social interactions typically peaked in the summer months but persisted at very low levels during the rest of the year. Seasonal variation was most dramatic for socio-sexual behaviour but was generally mirrored in pattern by agonistic and affiliative interactions. Subjects closer to maturity displayed more seasonal variation than younger subjects, and males displayed more seasonal variation compared to females. The peak in social interactions found in this study aligns rather closely with wild belugas’ summer, near-shore congregations, where belugas have increased opportunities for socializing. Although belugas in managed care do not experience a seasonal change in habitat, they do show seasonal changes in social behaviour, which are likely driven by seasonal fluctuations in hormone levels. It is therefore expected that wild beluga populations would show similar behavioural patterns if they were observed throughout the remainder of the year. This research has applications for belugas in managed care and may provide a framework for understanding the social behaviour of wild belugas
The immune response and diving: conservation considerations for belugas (Delphinapterus leucas) in a changing Arctic environment
No full textDiving is a critical behaviour of marine mammals, including belugas, which dive to forage and travel under Arctic sea ice. While the limitations of dive behaviour and physiological dive adaptations have been the focus of several studies, cellular adaptations, particularly those of the immune system, have been little considered. However, diving itself presents several challenges that can impact immune responses, leading to disease or injury. As beluga dive their behaviour changes in response to human activity or environmental shifts. It is necessary to better understand how the beluga’s immune system functions during diving. This review provides a brief overview of what is known about beluga’s diving behaviour and physiology and discusses the first efforts to understand the link between diving and health via immune function in belugas. This new area of research is an important consideration regarding potential sub-lethal impacts of a rapidly changing Arctic environment on beluga’s diving behaviour, health and disease susceptibility
Beluga whale stewardship and collaborative research practices among Indigenous peoples in the Arctic
No full textBeluga whales (Delphinapterus leucas) are an integral part of many Arctic Indigenous cultures and contribute to food security for communities from Greenland, across northern Canada and Alaska to Chukotka, Russia. Although the harvesting and stewardship practices of Indigenous peoples vary among regions and have shifted and adapted over time, central principles of respect for beluga and sharing of the harvest have remained steadfast. In addition to intra-community cooperation to harvest, process and use beluga whales, rapid environmental change in the Arctic has underscored the need for inter-regional communication as well as collaboration with scientists and managers to sustain beluga populations and their cultural and nutritional roles in Arctic communities. Our paper, written by the overlapping categories of researchers, hunters, and managers, first provides an overview of beluga hunting and collaborative research in seven regions of the Arctic (Greenland; Nunatsiavut, Nunavik, Nunavut, and the Inuvialuit Settlement Region, Canada; Alaska; and Chukotka). Then we present a more detailed case study of collaboration, examining a recent research and management project that utilizes co-production of knowledge to address the conservation of a depleted population of beluga in Nunavik, Canada. We conclude that sustaining traditional values, establishing collaborative management efforts, the equitable inclusion of Indigenous Knowledge, and respectful and meaningful collaborations among hunters, researchers and managers are essential to sustaining healthy beluga populations and the peoples who live with and depend upon them in a time of rapid social and environmental change
Can you hear me? Impacts of underwater noise on communication space of adult, sub-adult and calf contact calls of endangered St. Lawrence belugas (Delphinapterus leucas)
No full textNoise and anthropogenic disturbances from vessel traffic are an important threat to the recovery of the endangered St. Lawrence Estuary (SLE) beluga population. The consequences of acoustic masking could be particularly adverse in the case of critical vocalizations that maintain contact between mothers and their dependent but mobile calves. This study models the communication range of adults, sub-adults and newborn beluga contact calls in the presence and absence of vessels in an important summering area for this population. Ambient noise measurements, a composite beluga audiogram and apparent source levels of adult/sub-adult and newborn calls, informed the model. Apparent source levels were estimated from received levels of contact calls produced by four individuals carrying digital acoustic tags in the SLE, Canada, and from received levels of calls recorded from two adults and a newborn calf at an aquarium, at known distances from a calibrated hydrophone. The median communication ranges were over 18 times larger for SLE adult and sub-adult calls than for newborn calls, with a 57 and 53% reduction in range in the presence of vessel noise, respectively. For newborn calls, this results in a median range of 170 m in vessel noise. These first estimates of the communication range of beluga vocalizations with a known function suggest that masking of the quiet calls of newborns by anthropogenic noise could impair mother–calf contact
The surface energy balance of Austre Lovénbreen, Svalbard, during the ablation period in 2014
No full textThe ability to simulate the surface energy balance is key to studying land–atmosphere interactions; however, it remains a weakness in Arctic polar sciences. Based on the analysis of meteorological data from 1 June to 30 September 2014 from an automatic weather station on the glacier Austre Lovénbreen, near Ny–Ålesund, Svalbard, we established a surface energy balance model to simulate surface melt. The results reveal that the net shortwave radiation accounts for 87% (39 W m–2) of the energy sources, and is controlled by cloud cover and surface albedo. The sensible heat equals 6 W m–2 and is a continuous energy source at the glacier surface. Net longwave radiation and latent heat account for 31% and 5% of heat sinks, respectively. The simulated summer mass balance equals –793 mm w.e., agreeing well with the observation by an ultrasonic ranger
Marine debris on two Arctic beaches in the Russian Far East
No full textIn August 2005, marine debris was counted on two Arctic beaches in the Russian Far East. On the north coast of the Chukchi Peninsula east of Kolyuchin Bay, a beach stretch of ca. 2.4 km held a total of 736 items, 0.024 items m‑2, while no more than 0.0011 items m‑2, 12 items in total, were found on a beach stretch of ca. 1.2 km on southern Wrangel Island. The likely explanation for this difference is that the area around the mainland beach is ice-free for a longer period each year, but a contributing factor may be that late spring ice movement removed plastic from the beach on Wrangel Island. The language on the few items with identifiable labels was for the most part Russian or English, making the Chukchi Sea a possible source region. Beaches at the same latitude in the Atlantic may hold more debris on account of the higher human population density, more shipping and transport of floating debris unhindered by a narrow strait that is ice-covered much of the year. Fishing gear blown across the tundra is suggested as a potential threat to reindeer and other terrestrial wildlife
Modelling polar bear maternity den habitat in east Svalbard
No full textWe evaluated a novel tool that predicts possible maternity den habitat of the polar bear (Ursus maritimus) based on a physical snow transport model, a digital terrain model and weather data. We observed and compared den locations in three important denning areas in east Svalbard (Kongsøya, n = 288; Svenskøya, n = 86; Hopen, n = 115) with modelled snowdrift distributions for 24 years. Accounting for a likely position uncertainty of 100 m, 69% of all dens were located within year-specific modelled snowdrifts. These covered on average 1.8%, 2.1% and 24.7% of the three study islands, respectively. Our snowdrift model accurately predicted maternity den positions (R2 = 0.42, area under the receiving operating characteristic curve [AUC] = 0.85). A model based on slope and altitude, also predicted den positions reasonably well (R2 = 0.35, AUC = 0.88). Habitat maps identifying both current and future areas for maternity denning will become important in managing the Barents Sea population as well as other Arctic populations where changes in sea-ice conditions alter the accessibility to traditional denning areas
The ice flux to the Lambert Glacier and Amery Ice Shelf along the Chinese inland traverse and implications for mass balance of the drainage basins, East Antarctica
No full textStudy of the mass balance of the Antarctic Ice Sheet is critical to estimate its potential contribution to global sea-level rise in the future. As the largest drainage system, the Lambert Glacier–Amery Ice Shelf drainage system plays an important role in the mass balance of the Antarctic Ice Sheet. In this study, the ice thickness measured by airborne ice-penetrating radar with high spatial resolution and accuracy and accurate ice velocity measured by in situ GPS stations along the route of the Chinese National Antarctic Research Expedition inland traverse were used to calculate the ice flux with unprecedented accuracy. This transverse is from Zhongshan Station to Dome A, passing through the east side of the Lambert Glacier and the smaller coastal glacier in the C-Cp basin. The results show that the ice flux across the entire traverse is 24.7 ± 2.8 Gt a−1, along which the section in drainage basin B–C (Lambert Glacier) has an ice flux of 20.9 ± 1.9 Gt a−1 and the section in drainage basin C–Cp (basin adjacent to Lambert Glacier) contributed 3.8 ± 0.4 Gt a−1. The ice flux values in both regions are coincident with the mass balance calculated from the Ice, Cloud, and Land Elevation Satellite, Earth Observing System. Meanwhile, the C–Cp basin shows an ice flux value of 6.6 ± 0.8 Gt a−1 across the grounding line
Revisiting the extended Svalbard Airport monthly temperature series, and the compiled corresponding daily series 1898–2018
No full textThe Svalbard Airport composite series spanning the period from 1898 to the present represents one of very few long-term instrumental temperature series from the High Arctic. A homogenized monthly temperature series is available since 2014. Here we increase the resolution from a monthly to daily basis, and further digitization of historical data has reduced the uncertainty of the series. The most pronounced changes in the 120-year record occur during the last three decades. For the 1991–2018 period the number of days warmer than 0 and 5 °C has increased by 25 (21%) and 22 (59%), respectively, per year compared to the 1961–1990 standard normal. Likewise, comparing the same periods, the number of days colder than −10 and −20 °C has decreased by 42 (32%) and 27 (62%), respectively. During the entire time span of the series, the western Spitsbergen climate has gone through stepwise changes, alternating between cold and warm regimes: 1899–1929 was cold, 1930–1961 warm, 1962–1998 cold and 1999–2018 warm. The latest cold regime was 1.0 °C warmer than the first cold one, and the latest warm regime was 1.7 °C warmer than the previous warm one. For the whole series the linear trend for annual means amounts to 0.32°C/decade, which is about 3.5 times the increase of the global mean temperature for the same period. Since 1991, the rate of warming at Svalbard Airport is 1.7 °C/decade, which is more than twice the Arctic average (0.8 °C/decade, north of 66 °N) and about seven times the global average for the same period
Unusual drift behaviour of multi-year sea ice in the Beaufort Sea during summer 2018
No full textIn summer 2018, thick sea ice blocked the mouth of the Amundsen Gulf (AG), Canada, obstructing shipping through the North-west Passage. This study analysed multi-year ice motion to investigate the source of this thick ice and the reasons for its unusual movement. For this purpose, a daily multi-year ice distribution product was generated by ice tracking using gridded daily sea-ice velocities (2003–2018) derived from the AMSR-E and AMSR-2 data. From autumn 2017 to summer 2018, the area of multi-year ice extended westward to the Beaufort Sea and then migrated towards the AG mouth. The primary cause of the unusual ice cover was anomalous AG-ward wind in September 2018. It is known that multi-year ice has become increasingly moveable over the past decades, as indicated by the increasing wind factor (i.e., ratio of ice-drift speed and wind speed), but the unusual ice motion in the summer of 2018 cannot be explainable by the wind factor alone. Accurately, predicting monthly wind and monitoring old thick ice will reduce the risk posed by thick Arctic sea ice to shipping