Arnoldus Blix

Arnoldus Blix
  • UiT The Arctic University of Norway

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214
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Publications

Publications (214)
Article
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Norsk Moskus A/S was, for good or worse, Alfred Henningsen’s own private eterprise. It was by many, probably also by Henningsen himself, judged as a failure. That is hardly the full story. The project was inspired from USA, where a similar project was already under way with the purpose to domesticate the muskox to improve the economic and social co...
Chapter
After the Viking era (~800–1100 AD), the state of Norway fell into disrepair and was, from about 1400 to 1814, under Danish rule. This period is, in Norway, called the 400-year night, economically and culturally, and it was not until 1811 that our first university in Christiania (now Oslo) was established. Moreover, in 1814, after the Napoleonic wa...
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Understanding the determinants of poorly studied species’ spatial ecology is fundamental to understanding climate change impacts on those species and how to effectively prioritise their conservation. Ross seals (Ommatophoca rossii) are the least studied of the Antarctic pinnipeds with a limited knowledge of their spatial ecology. We present the lar...
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Southern Ocean ecosystems are under pressure from resource exploitation and climate change1,2. Mitigation requires the identification and protection of Areas of Ecological Significance (AESs), which have so far not been determined at the ocean-basin scale. Here, using assemblage-level tracking of marine predators, we identify AESs for this globally...
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The Retrospective Analysis of Antarctic Tracking Data (RAATD) is a Scientific Committee for Antarctic Research project led jointly by the Expert Groups on Birds and Marine Mammals and Antarctic Biodiversity Informatics, and endorsed by the Commission for the Conservation of Antarctic Marine Living Resources. RAATD consolidated tracking data for mul...
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The Retrospective Analysis of Antarctic Tracking Data (RAATD) is a Scientific Committee for Antarctic Research project led jointly by the Expert Groups on Birds and Marine Mammals and Antarctic Biodiversity Informatics, and endorsed by the Commission for the Conservation of Antarctic Marine Living Resources. RAATD consolidated tracking data for mul...
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In terrestrial mammals, the respiratory turbinate bones within the nasal cavity are employed to conserve heat and water. In order to investigate whether environmental temperature affects respiratory turbinate structure in phocids, we used micro-computed tomography to compare maxilloturbinate bone morphology in polar seals, grey seals and monk seals...
Article
It is suggested that an orienting response to loud sound causes apnea, which, in already asphyxic infants, triggers a maximal secondary chemoreceptor response, with massive vagal stimulation of the heart, which causes heart arrest.
Article
This Review focuses on the original papers that have made a difference to our thinking and were first in describing an adaptation to diving, and less on those that later repeated the findings with better equipment. It describes some important anatomical peculiarities of phocid seals, as well as their many physiological responses to diving. In so do...
Article
At temperate latitudes, the annual cycle of day length synchronizes circannual rhythms, and, in mammals, this is mediated via nocturnal production of the pineal hormone melatonin, proportional to the length of the night. Here, we studied circannual synchronization in an arctic species, the reindeer (Rangifer tarandus tarandus), which ceases to prod...
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The Antarctic Pack Ice Seal (APIS) Program was initiated in 1994 to estimate the abundance of four species of Antarctic phocids: the crabeater seal Lobodon carcinophaga, Weddell seal Leptonychotes weddellii, Ross seal Ommatophoca rossii and leopard seal Hydrurga leptonyx and to identify ecological relationships and habitat use patterns. The Atlanti...
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Fahlman and associates (2016) have emphasized the importance of proper physiological insight when modelling energy expenditure in large cetaceans. Here we argue that they have themselves failed in this endeavour.
Article
The pressure-volume relationship in the ascending aorta (“windkessel”) of the hooded seal was determined and the morphology of its vasa vasorum described in some detail. We found that the ascending aorta has a high compliance and can easily accommodate the entire stroke volume when the peripheral vascular resistance becomes much increased and maint...
Article
This Review presents a broad overview of adaptations of truly Arctic and Antarctic mammals and birds to the challenges of polar life. The polar environment may be characterized by grisly cold, scarcity of food and darkness in winter, and lush conditions and continuous light in summer. Resident animals cope with these changes by behavioural, physica...
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This paper describes the significant direct and indirect contributions to science made by the Norwegian polar explorer Roald Amundsen in the period 1897–1924. It documents that his expeditions through the North-west Passage (1903–06) with Gjøa, to the South Pole (1910–12) with Fram and through the North-east Passage (1918–1920) and the Chukchi and...
Data
The Antarctic Pack Ice Seal (APIS) Program was initiated in 1994 to estimate the abundance of four species of Antarctic phocids: the crabeater seal Lobodon carcinophaga, Weddell seal Leptonychotes weddellii, Ross seal Ommatophoca rossii and leopard seal Hydrurga leptonyx and to identify ecological relationships and habitat use patterns. The Atlanti...
Article
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We compared the morphology and thermal characteristics of winter pelage from two Siberian musk deer Moschus moschiferus (aged 5 and 41 mo.; 5.7 and 9.5 kg) and two Eurasian reindeer Rangifer tarandus tarandus (aged >48 mo.; 73 and 79 kg). The depth of the fur over the back of musk deer was less (approximately 30 mm) than in reindeer (approximately...
Chapter
All seals are dependent on land or ice to breed upon, and many species of seals spend their entire life in close proximity to the coast or the edge of ice, where they can be observed and collected throughout the year. However, several species of phocid seals are pelagic outside the short breeding and moulting periods, and it was not until the inven...
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Whales are unique in that the supply of blood to the brain is not by the internal carotid arteries, but by way of thoracic and intra-vertebral arterial retia. We found in the harbour porpoise (Phocoena phocoena) that these retia split up into smaller anastomosing vessels and thin-walled sinusoid structures that are embedded in fat. The solubility o...
Article
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Hooded seals (Cystophora cristata) rely on large stores of oxygen, either bound to hemoglobin or myoglobin (Mb), to support prolonged diving activity. Pups are born with fully developed hemoglobin stores, but their Mb levels are only 25-30% of adults. We measured changes in muscle Mb concentration [Mb] from birth until one year of age in two groups...
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To characterise the functional morphology of the nasal microcirculation in humans in comparison with reindeer as a means of testing the hypothesis that the luminous red nose of Rudolph, one of the most well known reindeer pulling Santa Claus's sleigh, is due to the presence of a highly dense and rich nasal microcirculation. Observational study. Tro...
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Information on health parameters, such as antibody prevalences and serum chemistry that can reveal exposure to pathogens, disease, and abnormal physiologic conditions, is scarce for Antarctic seal species. Serum samples from Antarctic fur seals (Arctocephalus gazella, n=88) from Bouvetøya (2000-2001 and 2001-2002), and from Weddell seals (Leptonych...
Article
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A total of four barren adult female muskoxen (Ovibos moschatus) were used over a period of 2 years for the purpose of the present study. During the first year, the natural changes in appetite (ad libitum intake of standard pelleted reindeer feed) and body mass were determined in two of the animals. During the second year, the effect of reduced food...
Data
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The development of models of marine ecosystems in the Southern Ocean is becoming increasingly important as a means of understanding and managing impacts such as exploitation and climate change. Collating data from disparate sources, and understanding biases or uncertainties inherent in those data, are important first steps for improving ecosystem m...
Article
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Reindeer (Rangifer tarandus) are protected against the Arctic winter cold by thick fur of prime insulating capacity and hence have few avenues of heat loss during work. We have investigated how these animals regulate brain temperature under heavy heat loads. Animals were instrumented for measurements of blood flow, tissue temperatures and respirato...
Article
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The structural features of the venous system of seals, including such specialties as a caval sphincter, a huge posterior caval vein and hepatic sinuses, venous plexuses and a huge extradural intravertebral vein, are described and functional aspects of these features in relation to diving habits are discussed. A number of old concepts are discarded...
Article
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One hundred and thirty three "wild" muskoxen, 81 of which of known body mass, were successfully immobilized using etorphine (M99), and xylazine (Rompun®), delivered by use of a dart gun. A dose of 0.05 mg/kg M99, supplemented by 0.15 mg/kg Rompun was found to be very effective. This dose is much higher than currently recommended e.g. by Handbook of...
Article
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Experiences from the management of a semi-domesticated herd of muskoxen, mostly on an island outside Tromsø (~70º N; 19º E), over a period of 40 years have been collected, and data on husbandry practices, reproduction, diseases and longevity are presented and discussed.
Chapter
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The sections in this article are:
Article
Direct evidence that the mammalian neocortex is an important generator of intrinsic activity comes from isolated neocortical slices that spontaneously generate multiple rhythms including those in the beta, delta and gamma range. These oscillations are also seen in intact animals where they interact with other areas including the hippocampus, thalam...
Article
Controlled exposure experiments on captive hooded seals (Cystophora cristata) were made to examine behavioural and physiological effects of sonar signals. The animals were instrumented with data loggers recording heart rate, dive depth, and swimming activity, and then released into a 1,200 m(3) net-cage in the ocean. The exposure consisted of three...
Article
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Brain (T(brain)), intra-aorta (T(aorta)), latissimus dorsi muscle (T(m)) and rectal temperature (T(r)) were measured in harp (Pagophilus groenlandicus) and hooded (Cystophora cristata) seals during experimental dives in 4 degrees C water. The median brain cooling was about 1 degrees C during 15 min diving, but in some cases it was as much as 2.5 de...
Article
Newborn hooded seals (Cystophora cristata) have smaller weight-specific oxygen stores than adults, but nothing is known about how this affects their diving behaviour. Here, we present data on the diving behaviour and migrations of seven weaned hooded seal pups of the Greenland Sea stock during their first year of life, as collected by use of satell...
Article
Reindeer (Rangifer tarandus) eat and utilize lichens as an important source of energy and nutrients in winter. Lichens synthesize and accumulate a wide variety of phenolic secondary compounds, such as usnic acid, as a defense against herbivores and to protect against damage by UV-light in solar radiation. We have examined where and to what extent t...
Chapter
Most People Know That Seals Spend Most Of Their Time, And Whales All Of Their Time, In Water, But Research Over The Last Few Decades Has Shown That Several Species Of Both Orders Of These Air-Breathing Mammals Spend As Much As 80–90% Of The Time Under Water. Moreover, Sperm Whales (Physeter Catodon) (Watkins 1985) And Southern Elephant Seals (Mirou...
Article
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Forsøkene (viste) at tilleggsforing av underernærte simler i siste del av drektighetsperioden kun synes å ha effekt på fødselsvekten for kalvene forutsatt at simlene får høyverdig ernæring etter kalving. Den forskjellige ernæringsbakgrunn før kalving synes således ikke å innvirke på melkeproduksjon/kvalitet, da vektutviklingen for alle grupper av k...
Article
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p>A group of 35 pregnant reindeer (Rangifcr tarandus) was divided into two groups in mid-February. Until calving in May one of the groups (L) received lichen ad lib., while the other group (IN) received an improved diet, rich in protein and minerals. After calving both groups received the same improved diet. In both groups it was distinguished betw...
Article
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p>Three Norwegian reindeer were first fed lichen ad libitum for 40 days, then they were starved for 3 days, and thereafter offered a commercially available mill «waste product» (AB-84) ad libitum. One animal refused to eat AB-84 and was excluded. When eating lichen average daily dry matter intake was 1.1 ± 0.4 kg, while when eating AB-84 after the...
Article
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p>Total body water and water turnover were measured at different times throughout the year in 3 captive Norwegian reindeer, using a tritiated water dilution method (Holleman et al. 1982). Total body water (percent of body weight) increased during late autumn and winter, from 59.1 ± 1.5 % in October to 72.5 ± 2.0 % in April. Using the equatation by...
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p>A method is described whereby it is possible to alter total body core temperature independently of environmetal temperature and/or exercise in conscious reindeer. The method employs the use of a simple heat exchanger introduced through a permanent rumen fistula. The heat exchanger consists of a 7 m long coil of flexible plastic tubing (OD, 10.0 m...
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Resultatene er derfor hittil negative når det gjelder vår hypotese om at stress påvirkervommiljøet og dermed kjøttkvaliteten. Det er imidlertid tvilsomt om dyrene som var slaktet i Kautokeino var tilstrekkelig stresset til å gi et klart utslag. Det bør i denne sammenheng fremheves at det ikke ble påvist dårlig lukt eller andre subjektive tegn på då...
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Selective cooling of the brain during hyper-thermia has been demonstrated in several species of mammals (Baker 1979, 1982). Such cooling is achieved by heat exchange between the cooled venous blood returning from the nasal mucosa and the warmer arterial blood entering the brain via the carotid rete. Spot measurements of brain temperature (Tbr) and...
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Report of preventing damage on reindeer caused by radioactivity fall out from Chernobyl. Including a short discussion.
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In an attempt to find practical solutions to the treatment of radiocesium contaminated reindeer, 8 adult female reindeer were fed naturally radiocesium contaminated lichen ad lib. for 35 days. The lichen contained on average 45 000 Bq/kg, and the food intake of lichen was on average 2 kg dry matter per day. Determination of radiocesium contaminatio...
Article
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Arctic ungulates usually neither freeze nor starve to death despite the rigours of winter. Physiological adaptations enable them to survive and reproduce despite long periods of intense cold and potential undernutrition. Heat conservation is achieved by excellent insulation combined with nasal heat exchange. Seasonal variation in fasting metabolic...
Article
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Simultaneous measurements of metabolic rate, respiratory minute volume, respiratory frequency, and oxygen extraction from the inspired air were obtained during treadmill exercise in Svalbard reindeer (Rangifer tarandus platyrhynchus) and Norwegian reindeer (Rangifer tarandus tarandus). The experiments were carried out both in summer and winter at a...
Article
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Resting metabolic rate (RMR) in two 12 yrs., semidomesticated, female muskoxen was 0.86 ± 0.10 W • kg-1 in winter, and 1.74 ± 0.27 W • kg-1 in summer, (p<0.001). After 6 days of starvation RMR was down to 0.62 + 0.07 W • kg-1 and 0.77 ± 0.03 W • kg-1 (p<0.001) in winter and summer, respectively. RMR during starvation in winter was 19% below predict...
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We model two time and space scales discrete observations by using a unique continuous diffusion process with time dependent coefficient. We define new parameters for the large scale model as functions of the small scale distribution cumulants. We use the non - uniform distribution of the observation time intervals to obtain consistent and unbiased...
Article
Deep diving mammals have developed strategies to cope with limited oxygen availability when submerged. These adaptations are associated with an increased neuronal hypoxia tolerance. Brain neurons of the hooded seal Cystophora cristata remain much longer active in hypoxic conditions than those of mice. To understand the cellular basis of neuronal hy...
Article
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Pinnipeds rely on muscle oxygen stores to help support aerobic diving, therefore muscle maturation may influence the behavioral ecology of young pinnipeds. To investigate the pattern of muscle development, myoglobin concentration ([Mb]) and acid buffering ability (beta) was measured in ten muscles from 23 harp and 40 hooded seals of various ages. A...
Article
The anatomy of the gastrointestinal system of Northeastern Atlantic minke whales (Balaenoptera acutorostrata) was investigated. The stomach consisted of four compartments. The first chamber, or forestomach, was non-glandular and was lined with a keratinized stratified squamous epithelium. The tissue wet weight of the forestomach represented 10.4 ±...
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Two adult female leopard seals (Hydrurga leptonyx) were tagged with satellite-linked dive recorders off Queen Maud Land, Antarctica, just after moulting in mid-February. The transmitters transmitted for 80 and 220days, respectively. Both seals remained within the pack ice relatively close to the Antarctic Continent until early May, when contact was...
Article
Two acceleration data loggers, each measuring surging and heaving acceleration, were attached to the head and mandible of three captive hooded seals, Cystophora cristata, for detection of underwater feeding events. Three sizes of prey: Atlantic herring (large), capelin (medium), and half a capelin (small) were tested. A highpass frequency-filtering...
Article
Arctic reindeer exhibit marked seasonal changes in fat deposition and mobilization. At intervals throughout the year, therefore, we have measured feed intake of both Svalbard (SR) and Norwegian reindeer (NR) together with the seasonal changes in size, lipogenic and lipolytic capacity of isolated adipocytes from both sub-species. Feed intake of both...
Article
Seals cope with regular exposure to diving hypoxia by storing oxygen in blood and skeletal muscles and by limiting the distribution of blood-borne oxygen to all but the most hypoxia vulnerable tissues (brain, heart), through dramatic cardiovascular adjustments. Still, arterial oxygen tension of freely diving seals regularly drops to levels that wou...
Article
Eight adult female harp seals (Pagophilus groenlandicus) of the White Sea–Barents Sea stock were tagged with satellite-linked dive recorders during the nursing period and followed from breeding in late February 1995 until moulting in late April 1995. Another ten adult harp seals of both sexes were tagged and followed from moult in early May 1996 un...
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The Ross seal (Ommatophoca rossii) is the least studied of the Antarctic ice-breeding phocids. In particular, estimating the population status of the Ross seal has proved extremely difficult. The Protocol on Environmental Protection to the Antarctic Treaty currently designates the Ross seal as a ‘Specially Protected Species’, contrasting with the I...
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Six out of ten adult Ross seals that were tagged with Argos satellite-linked dive recorders off Queen Maud Land, just after the moult in February, provided data on location and diving activity throughout a year. Shortly after tagging, the animals headed 2,000km north and stayed pelagic in the area south of the Antarctic Polar Front, until October w...
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Pinnipeds rely primarily on oxygen stores in blood and muscles to support aerobic diving; therefore rapid development of body oxygen stores (TBO(2)) is crucial for pups to transition from nursing to independent foraging. Here, we investigate TBO(2) development in 45 harp (Pagophilus groenlandicus) and 46 hooded (Cystophora cristata) seals ranging i...
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All mammals and birds must develop effective strategies to cope with reduced oxygen availability. These animals achieve tolerance to acute and chronic hypoxia by (a) reductions in metabolism, (b) the prevention of cellular injury, and (c) the maintenance of functional integrity. Failure to meet any one of these tasks is detrimental. Birds and mamma...
Article
A bstract Food intake (PI), body mass ( BM ), and compartmental growth were recorded for 12 mo in four captive 2–4‐yr‐old male harp seals ( Phoca groenlandica ), exposed to an artificial light regime that closely resembled natural day length at 69°. In early May before molting, both FZ and BM decreased in all four animals. Total body fat ( TBF ) de...
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A bstract Gross energy intake (GEI), apparent digestible efficiency (%DE), and body‐mass change were studied both in recently weaned and in subadult harp seals fed capelin ( Mallotus villosus ) and crustaceans ( Parathemisto libellula and Thysanoessa sp.) ad lib. The median %DE of Parathemisto libellula (with a wet‐weight energy density (ED) of 3.9...
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Metabolic rates of four resting, post-absorptive male adult summer- and winter-adapted captive arctic foxes (Alopex lagopus) were recorded. Basal metabolic rates (BMR) varied seasonally with a 36% increase from winter to summer, while body mass was reduced by 17% in the same period. The lower critical temperature (T 1c) of the winter-adapted arctic...
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The light/dark cycle of day and night synchronizes an internal 'biological clock' that governs daily rhythms in behaviour, but this form of regulation is denied to polar animals for most of the year. Here we demonstrate that the continuous lighting conditions of summer and of winter at high latitudes cause a loss in daily rhythmic activity in reind...
Article
The mammalian response to hypothermia is increased metabolic heat production, usually by way of muscular activity, such as shivering. Seals, however, have been reported to respond to diving with hypothermia, which in other mammals under other circumstances would have elicited vigorous shivering. In the diving situation, shivering could be counterpr...
Article
A solitary skin lesion was found on the neck of a Weddell seal (Leptonychotes weddellii), chemically immobilized in Queen Maud Land (70 degrees 09'S, 05 degrees 22'E) Antarctica 2001. The lesion was elevated and 3cm in diameter, consisting of partly fresh and partly necrotic tissue, and proliferative papilloma-like structures were seen. Electron mi...
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Conspicuous sonic click sounds were recorded in the presence of cod (Gadus morhua), together with either harp seals (Pagophilus groenlandicus), hooded seals (Cystophora cristata) or a human diver in a pool. Similar sounds were never recorded in the presence of salmon (Salmo salar) together with either seal species, or from either seal or fish speci...
Article
The distribution and diving behaviour of 16 adult harp seals (Pagophilus groenlandicus) from the Greenland Sea stock were studied in 1993 and 1999, using satellite-linked dive recorders (SDRs). The seals remained near the pack-ice edge in the Greenland Sea between breeding and moulting (April/May 1993; 6F) and during the first 7weeks after moulting...
Article
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Two minke whales were tagged with satellite-linked radio transmitters off the coast of northern Norway in order to obtain data on daily locations, movements and swimming speed. One whale was tagged in September 1994, south of Lofoten at the entrance to the Vestfjorden, and one whale was tagged in August 1999 just north of Vesterålen. The whale tagg...
Article
This study tested the hypothesis that the annual cycle in heart rate (HR) in reindeer is, at least in part, a consequence of seasonal fluctuation in voluntary-food intake. Heart rate and daily dry matter voluntary-food intake (DDMVFI) were recorded in two captive female reindeer (Rangifer tarandus tarandus) from April 1995 to August 1996. Heart rat...
Article
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Two winter-insulated Norwegian reindeer (Rangifer tarandus tarandus) were exposed to air temperatures of 10, 20, 30, and 38 degrees C while standing at rest in a climatic chamber. The direction of airflow through nose and mouth, and the total and the nasal minute volumes, respectively, were determined during both closed- and open-mouth panting. The...
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Physical model experiments, as well as simulations of the effects of grenade harpooning on anaesthetized pigs fully immersed in water suggest that the shock effect of the blast from the currently used grenades is relatively minor. Also the animals are not stunned to death, but loose consciousness and subsequently die from hemorrhage. Survival time...
Article
Ronald et al. (1977) suggested that blood flow in the caudal/lumbar sections of the extradural intravertebral vein (EIV) of seals changes direction from running towards the head before diving, to the opposite during diving. The possible advantage would be that the oxygen-depleted venous effluent from the brain is routed via the EIV to the posterior...
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The 10th Arctic Ungulate Conference was organised by the Department of Arctic Biology and held at the University of Tromsø, Norway, 9-13 August 1999. The conference continued a series of nine conferences devoted to Arctic ungulates, including five International Reindeer/Caribou Symposia, two International Muskox Symposia and two Arctic Ungulate Con...
Article
Full-text available
Physical model experiments, as well as simulations of the effects of grenade harpooning on anaesthetized pigs fully immersed in water suggest that the shock effect of the blast from the currently used grenades is relatively minor. Also the animals are not stunned to death, but loose consciousness and subsequently die from hemorrhage. Survival time...
Article
Full-text available
Minke whales consume large amounts of pelagic crustaceans. Digestion of the prey is initiated by indigenous bacteria in a rumen-like forestomach system. A major structural component of the crustacean exoskeleton is chitin, the beta-1,4-linked polymer of N-acetyl-D-glucosamine. The exoskeletons appear to dissolve completely in the non-glandular fore...
Article
Three adult harp seals (Phoca groenlandica) were fed different daily amounts of capelin (Mallotus villosus), and their body composition determined by use of the tritiated water method at different levels of fattening. Basal metabolic rate (BMR) was measured after 5 days of fasting by indirect calorimetry, and was on average 1.1 W.kg-1 when 45% of b...
Article
The mammalian spleen consists of white and red pulp and serves at least the dual purpose of immunological functions and filtration, and subsequent lysis of abnormal red blood cells (RBCs) from the blood. Seals are known to have very large spleens with a mass that, when fully dilated, amounts to about 2–4% of body mass. The red pulp in these animals...
Article
Satellite-linked dive recorders were used to collect data on depths and durations of ∼120,000 dives by 16 hooded seals (Cystophora cristata). Following tagging after moult (four males, eight females) and breeding (four females) off east Greenland, seals dispersed widely in the northeast Atlantic during 172 ± 97 days (mean satellite-linked dive reco...
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Hypothermia may limit asphyxic damages to the brain, and many small homeotherms have been shown to use anapyrexic strategies when exposed to asphyxic conditions. Larger homeotherms do not seem to use the same strategy, but could save oxygen and prevent hypoxic brain damage by employing selective brain cooling (SBC) in connection with asphyxia. To t...
Article
Isolated ring preparations of arteries and veins from hooded seal spleens were subjected in vitro to adrenaline (A), noradrenaline (NA), isoprenaline (Iso), and acetylcholine (ACh), alone or in combination with the blockers phentolamine (Phe), propranolol (Pro), and atropine (Atr). Both arteries and veins constricted in response to A (the estimated...
Article
The southern elephant seal (Mirounga leonina) has the ability to dive for 2 h and reach depths of 1200 m. This creature is also exceptional in having a small intestine that is 25 times body length. Krockenberger and Bryden advanced the hypothesis that the long small intestine has developed to compensate for the extended periods with reduced or even...
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Volume changes in the spleens of hooded seals (Cystophora cristata) and harp seals (Phoca groenlandica) were measured plethysmographically in vitro in response to epinephrine, norepinephrine, isoprenaline, phentolamine, and acetylcholine. Dilated spleens contracted forcefully within 1-3 min of alpha-adrenoceptor activation with 1.0-5.0 micrograms e...
Article
Various heat loss models have been used to predict metabolic rates or lower critical temperatures of marine mammals. We have evaluated the accuracy of four models by making detailed measurements of all input parameters, while simultaneously recording the metabolic rate in two resting harp seals (Phoca groenlandica) in ice water. We subtracted respi...
Article
Heart rate (HR) and dry matter voluntary food intake (DMVFI) were recorded in two captive female reindeer (Rangifer tarandus tarandus) from April 1995 to July 1996. The relationship between HR and DMVFI was also investigated by experimentally manipulating the level of feeding while recording HR in August. Average (modal) daily HR and DMVFI fluctuat...
Article
Reindeer calves(Rangifer tarandus tarandus) were used in parallel feeding trials with two different qualities of round-bale timothy silage in September 1992 (summer) and April 1993 (winter) in northern Norway, to determine the effect of season on their food intake and ability to utilize silage of different fibre contents. The silages were prepared...

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