Behavioural ontogeny of bearded seals Erignathus barbatus through the first year of life

Funding was provided by the Norwegian Research Council (MARE programme, grant number 164940). C.D.H. was funded by the Norwegian Polar Institute’s Centre for Ice, Climate and Ecosystems.Pinniped pups face special ontogenetic challenges as they are born and receive maternal care on solid substrates (land or ice) but must transition to feeding aquatically following weaning. In this study, Satellite Relay Data Loggers were used to study behavioural ontogeny of bearded seal Erignathus barbatus pups (n = 13) through their first year in Svalbard, Norway. Pups occupied shallow, coastal habitats and were found in areas with intermediate ice concentrations (in seasons with sea ice - late-autumn/winter). Most pups showed exploratory movement patterns that peaked in the weeks following weaning; maximum home range size occurred at 31 to 60 days of age. Thereafter, home range size decreased with pups settling into areas along the coast. Time spent diving, dive duration, dive depth and time at the bottom of dives increased during the first weeks of independence, stabilizing when pups were ~50 d old. Dive depth subsequently decreased to depths comparable to adult bearded seals (by the time pups were ~175 d old). Record maximum dive depth (368 m) and duration (16.5 min) were performed by pups that were 66 and 224 d old, respectively. Time spent hauled out decreased after weaning, with pups hauling out only sporadically after they were 75 d old. Bearded seals pups seem to be physiologically and behaviourally well developed by the time they are two months old. Pups did not display the individually specialized diving behaviour seen in adults, which suggests that they continue to fine-tune their aquatic and other life-skills well past the end of the first year of life.Publisher PDFPeer reviewe

Marine mammal hotspots across the circumpolar Arctic

Aim: Identify hotspots and areas of high species richness for Arctic marine mammals. Location: Circumpolar Arctic. Methods: A total of 2115 biologging devices were deployed on marine mammals from 13 species in the Arctic from 2005 to 2019. Getis-Ord Gi* hotspots were calculated based on the number of individuals in grid cells for each species and for phyloge-netic groups (nine pinnipeds, three cetaceans, all species) and areas with high spe-cies richness were identified for summer (Jun-Nov), winter (Dec-May) and the entire year. Seasonal habitat differences among species’ hotspots were investigated using Principal Component Analysis. Results: Hotspots and areas with high species richness occurred within the Arctic continental-shelf seas and within the marginal ice zone, particularly in the “Arctic gateways” of the north Atlantic and Pacific oceans. Summer hotspots were generally found further north than winter hotspots, but there were exceptions to this pattern, including bowhead whales in the Greenland-Barents Seas and species with coastal distributions in Svalbard, Norway and East Greenland. Areas with high species rich-ness generally overlapped high-density hotspots. Large regional and seasonal dif-ferences in habitat features of hotspots were found among species but also within species from different regions. Gap analysis (discrepancy between hotspots and IUCN ranges) identified species and regions where more research is required. Main conclusions: This study identified important areas (and habitat types) for Arctic marine mammals using available biotelemetry data. The results herein serve as a benchmark to measure future distributional shifts. Expanded monitoring and teleme-try studies are needed on Arctic species to understand the impacts of climate change and concomitant ecosystem changes (synergistic effects of multiple stressors). While efforts should be made to fill knowledge gaps, including regional gaps and more com-plete sex and age coverage, hotspots identified herein can inform management ef-forts to mitigate the impacts of human activities and ecological changes, including creation of protected areas

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Distribution and habitat characteristics of pinnipeds and polar bears in the Svalbard Archipelago, 2005–2018

This study presents comprehensive mapping of the current distribution of pinnipeds and polar bears (Ursus maritimus) around Svalbard based on a regional marine mammal sightings programme and explores time-trends (2005–2018). Walruses (Odobenus rosmarus) were observed with high frequency and in high numbers around previously identified haul-out sites. At-sea walruses were seen close to the coast in shallow waters. Ringed seals (Pusa hispida) were observed in coastal areas throughout Svalbard, often in association with tidewater glacier fronts. There was no increase in the mean latitude for ringed seal observations, but there was an increased frequency of observations at around 82°N, which reflects their following a northward shift in the ice edge during summer foraging trips. Bearded seals (Erignathus barbatus) were observed frequently in north-western Spitsbergen and shared many habitat features with ringed seals. There was a slight increase in the mean latitude of bearded seal observations and a decreased frequency of observation in the southern parts of the archipelago, suggesting that this species might be shifting its distribution. Harbour seal (Phoca vitulina) observations within fjords have increased, likely as a consequence of increased inflow of Atlantic water into west coast fjords. Harp seals (Pagophilus groenlandicus) were observed with high frequency north of Svalbard. Hooded seals (Cystophora cristata) were observed only rarely. Polar bears were reported most frequently, undoubtedly as a result of an effort bias favouring this species. In spite of biases, citizen-based observations are useful for assessing broad distributional patterns of marine mammals through time

Summer habitat selection by ringed seals (Pusa hispida) in the drifting sea ice of the northern Barents Sea

Ringed seals are a central component of the Arctic ecosystem; they have a circumpolar distribution and are both important predators of lower trophic animals (invertebrates and fishes) and prey for polar bears and coastal human populations. They depend on sea ice for reproduction, moulting and resting, and they consume significant amounts of ice-associated prey. The population of ringed seals in Svalbard, Norway, uses both coastal and offshore habitats, the latter being important during seasonal migrations undertaken by some animals, mostly juveniles. This study examined habitat preferences of 18 satellite-tracked ringed seals (mostly young animals, but also a few adults) during late summer/autumn migrations to the drift ice in the northern Barents Sea. Resource selection functions showed that ringed seals preferred being close to the 50% sea-ice concentration threshold; a 120 km increase in the distance to the 50% sea-ice concentration threshold halved the probability of selection of a given area. In addition, higher sea-ice concentrations (80–100%) were between 1.4 and 2.2 times as likely to be selected as lower sea-ice concentrations or open water. Ringed seals use the marginal ice zone of the Barents Sea during summer/autumn. This offshore habitat has shifted northward during recent decades, which is likely causing negative effects on ringed seals by increasing the energetic cost of offshore migrations

Haul-out behaviour indices vs solar hour.

<p>GAMM smooth curves (A, C, E - mean (solid lines) ±95% CI (dashed lines)) showing impacts of solar hour on haul-out probability and hazard ratios from Cox Proportional Hazard (CPH) models (B, D, F) for the months where there is a day and night cycle (A,B), for the months of polar night (C,D) and for the months of midnight sun (E,F) for 60 harbour seals equipped with Satellite-Relay Data Loggers (SRDLs) in 2009 and 2010 in Svalbard, Norway. [Hazard ratios beneath one indicate a decreased risk of ending a haul-out event and hazard ratios above one indicate an increased risk of ending a haul-out event.]</p

Map of Svalbard, Norway.

<p>Map of Svalbard, Norway, showing the location of Prins Karls Forland, the core area for the harbour seal population, and Forlandsøyane, the major capture area for the 60 harbour seals equipped with Satellite-Relay Data Loggers (SRDLs) in 2009 and 2010. The red and black dots show the location of the tidal and weather stations, respectively, that were used in the analyses of haul-out behaviour.</p

Non-terrestrial haul-out sites.

<p>Maps showing the location of non-terrestrial haul-out events performed by 60 harbour seals equipped with Satellite-Relay Data Loggers (SRDLs) in 2009 and 2010 in Svalbard, Norway. The seals hauled out on either shore-fast ice, drifting pack-ice or on floating glacier ice pieces (yellow dots in inset maps) in fjords, when annually formed sea ice was not available.</p

Proportion of haul-out events on off-shore ice.

<p>Smooth curves from a GAMM model, showing the proportion of haul-out events (mean (solid lines) ±95% CI (dotted lines)) performed by 60 harbour seals, equipped with Satellite-Relay Data Loggers (SRDLs) in Svalbard, Norway, which took place on off-shore ice, by month during 2009 and 2010.</p