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Large numbers of lumpfish are produced for the Norwegian salmon industry and are used to combat sea lice infestations. The present work tested the efficacy of three anaesthetic chemicals on lumpfish fries (average weight of 0.97 g).

A survey of the Kapisillit River system was conducted in 2005 and 2012 to study the only indigenous Atlantic salmon Salmo salar population in Greenland. Little is known about its characteristics or its relationship with other S. salar populations across the species range. Juvenile S. salar were captured in all stations surveyed within the lower river with the highest densities lower in the river and decreasing densities with increasing distance from the river mouth. Captured juveniles ranged from 0+ to 7+ years old and the predominant smolt age was between 4 and 6 years. Median length of 0+ and 1+ juveniles in August-September was 38.8 and 70.4 mm, respectively. The proportion of mature male parr increased from 4% for 1+ year old fish to 95% for fish greater than 2 years old. Genetic analysis using 96 single nucleotide polymorphisms (SNP) revealed a high degree of genetic similarity between collections, extremely low genetic diversity and low estimates of effective population size (Ne = 28.7; 95% CI = 19.7-42.4). Genetic comparison to range-wide S. salar populations demonstrated that the Kapisillit River S. salar is an outgroup of the eastern Atlantic stock complex, which is consistent with the hypothesised colonisation from the east. River morphology and the absence of glacier runoff are hypothesised to be the main reasons for the relatively high river temperatures supporting this self-sustaining population of S. salar. Given its uniqueness and persistence, this population represents an important part of range-wide biodiversity of S. salar.

The duration of hypo-osmoregulatory capacity in downstream migrating Atlantic salmon Salmo salar L smolts previously stocked as startfed young-of-the year (YOY) parr was tested in the River Dalaa from mid-May to late-June 1999. Hypo-osmoregulatory capacity, measured as plasma osmolality and chloride, was assessed after seawater (SW) challenge tests (168 h, salinity = 35). All S. salar exhibited sufficient hypo-osmoregulatory capacity at the initiation of downstream migration in mid-May. Migrating S. salar smolts caught in mid-May and retained in fresh water displayed no signs of de-smoltification as they maintained hypo-osmoregulatory capacity through June. This indicates a physiological smolt window that lasts a minimum of 6 weeks (330 degree days; D°) for hatchery-produced S. salar smolts stocked as YOY parr. Based on the observed river migration speeds, it can be assumed that the S. salar smolts entered SW 2-4 weeks after initiation of migration in the upper parts of the River Dalaa. Hence, based on smolt migration and SW tolerance, it is suggested that stocking of YOY parr is a viable enhancement strategy in the River Dalaa.

This study investigated the development of hypo-osmoregulatory capacity and timing of downstream migration in wild Atlantic salmon Salmo salar smolts from the River Stjordalselva and stocked young-of-the-year (YOY), derived S. salar smolts from the tributary River Dalaa. Both wild and stocked S. salar smolts developed seawater (SW) tolerance in early May, persisting through June, measured as their ability to regulate plasma osmolality and chloride following 24 h SW (salinity = 35) exposure. Although the majority of downstream migration among the stocked S. salar smolts occurred later than observed in their wild counterparts, the development of SW tolerance occurred concurrently. The wild S. salar from Stjordalselva and stocked YOY smolts from the River Dalaa started to migrate on the same cumulative day-degrees (D°). The study revealed no downstream migration before development of SW tolerance. This emphasizes the importance of incorporating physiological status when studying environmental triggers for downstream migration of S. salar smolts. Overall, these findings suggest that the onset of smolt migration in stocked S. salar smolts was within the smolt window from an osmoregulatory point of view.

Due to extensive cannibalism, Arctic char (Salvelinus alpinus (L.)) often represent the two highest trophic levels in Arctic freshwater ecosystem where Arctic char often is the only freshwater fish present. There is a general lack of char stock size and production estimates from Arctic lakes although high catchability and late maturation of large piscivorous individuals raise considerable management challenges because large growing forms are a valued resource. Here, we use mark-recapture to estimate the biomass of both invertebrate feeding dwarfs (60–150 mm) and their cannibalistic conspecifics (>150 mm) in a small Arctic lake at Bear Island (74.5°N, 19.0°E; 11.3 ha; mean depth 1.8 m). Biomass was 10.1 and 2.0 kg ha−1 and production was 2.1 and 0.5 kg ha−1 yr−1 for dwarfs and cannibals, respectively. All the production of invertebrate feeding small char was removed by the cannibals. The low production of the Arctic lake ecosystems combined with high catchability of large piscivorous char indicates that these stocks may be particularly vulnerable to exploitation. We finally point out the similarity between Arctic and sub-arctic alpine populations of Arctic char in production and life-history parameters.

Anadromous juvenile Arctic charr (Salvelinus alpinus) were caught in the Sila River (66°21′N, 13°10′E, Nordland County, Norway) by use of a fish trap during their migration towards the sea in May/June. The absence of tags (not captured before) and examination of otoliths from sacrificed fish revealed that none of the experimental charr had previously encountered seawater. During 4 days of exposure to seawater, only minor changes in blood plasma osmolality, and blood plasma concentrations of Na+, Cl– and Mg2+ were detected. An increase in Na+-K+-ATPase activity was measured during the exposure period. These results verified that first-time migrants exhibit hypoosmoregulatory capacity similar to that of smoltified Atlantic salmon (Salmo salar). Accordingly, the Arctic charr first-time migratory behaviour, including late descent and a possible stay within an estuary, cannot be taken as evidence of a poorly developed seawater tolerance.

This study was carried out to test the effects of acute stress on the primary and the secondary antibody responses in Atlantic salmon (Salmo salar L.). Fish received a primary immunization with sheep red blood cells (SRBC) and received a second immunization 11 weeks later. At priming, a group of fish was stressed by water level reduction for 30 min (moderate stress), and another group was stressed severely by applying the stressor twice, with an interval of 6 h, 3 days in a row (severe stress). At the time of the booster, another two groups of previously unstressed, primed fish were treated likewise. Unstressed fish mounted a primary antibody response to SRBC and a secondary response, which was improved compared with the primary response., The primary antibody response against SRBC was impaired by severe, but not moderate, acute stress at priming, whereas the secondary antibody response was unaffected. Both moderate and severe stress at the time of the booster was immunosuppressive in fish that had been primed under non-stress conditions. It is concluded that cortisol release as a result of stress exposure is most immunosuppressive at the time of the second immunization.

Arctic char Salvelinus alpinus, in the high-Arctic archipelago of Svalbard, entered the Dieset River (79°10′N) immediately after ice breakup in late June (1991–1993), and within 48 h almost half the migrating population had left the lakes where they spent the winter. The majority of the anadromous char descended into the sea within 3 weeks of the melt. The temporal pattern of emigration was independent of body size. The average residence time at sea of the char was 33.6 d, and the maximum was 56 d. The duration of the seawater sojourn was independent of body size. However, the combined time of downstream migration and marine residence was inversely related to body length in early migrating char. Fish that migrated to the sea early tended to stay there longer. The overall return rate ranged from 33.3% for the smallest (15.1–20 cm) to 75.0% for the largest (45.1–50 cm) char, averaging 51.5%. The average return rate for fish shorter than 25.1 cm (first-time migrants) was 42.5%. The upstream run star...

In order to elucidate the immune responses of Arctic charr in relation to temperature, groups were acclimated to a moderate (9°C) and a cold temperature regime (4°C), as well as subjected to a temperature decrease (from 9 to 4°C) immediately prior to an immunization with sheep red blood cells. The charr kept at 9°C responded with increased primary and secondary antibody titres, as seen by direct haemagglutination, while fish at 4°C, as well as the fish subjected to a temperature reduction, displayed lower and lowest antibody titres, respectively, and only after a second immunization. It is concluded that Arctic charr can respond to a cellular antigen with a humoral immune response typical for other teleosts, but that the immune response is delayed and diminished at low temperatures. This temperature-induced immune suppression is intensified if the fish have not been acclimated to cold water prior to immunization.

Migration and growth by parr of Arctic char Salvelinus alpinus were studied in the high-Arctic Dieset watercourse (79°10′N) on Spitsbergen Island, Svalbard, Norway. Our results showed a rapid parr emigration from the lake into the river during the ice breakup in late June. The habitat change was almost completed by mid-July for parr with body lengths ranging from 70 to 180 mm. Migrating parr were 2–8 years of age and 63–200 mm in length, whereas parr remaining in the lake were 0–4 years old and 23–116 mm in length. Parr migrating into the river were significantly larger than lake-dwelling parr of corresponding age. The migrating parr exhibited a mean daily increase in body weight from 1.22% (age 3 years) to 0.37% (age 8 years). Our results indicated that an early descent into the river is favorable for a body weight increase.

This investigation examines the influence of implants containing 11-ketotestosterone (11KT), 17β-estradiol (E2), and 3,5,3′-triiodo-l-thyronine (T3) on astaxanthin metabolism in sexually immature individually tagged Arctic charr. The fish (initial average weight 427 g) were maintained in freshwater for 40 days, and weekly implanted intraperitoneally with oil-based injections containing either 11 KT, E2 or T3 at levels of 0.1, 1.0 and 0.1 mg (100 g body weight (BW))−1, respectively. The control fish were given the oil medium alone (0.2 ml 100 g BW−1). The diet contained ca. 50 mg astaxanthin kg−1. Carotenoid composition was monitored in plasma, fillet, liver and skin, and 11 KT, E2 and testosterone (T) levels in plasma. All hormone treatments reduced plasma T compared to the control. E2-treated fish had a higher (p

Migrating Arctic charr (Salvelinus alpinus) parr (118 ± 34.4 mm) were caught close to the rivermouth of the Dieset river on Spitsbergen (79°10′N), Svalbard. When subjected to a seawater tolerance test (34 ppt at 6°C) their blood plasma osmolality and sodium and magnesium concentrations increased significantly. After 90 h of exposure, average plasma osmolality was 410 (±54.1) mOsmol. Corresponding sodium and magnesium concentrations were 207 (±35.9) mmol l−1 and 2.7 (±1.36) mmol l−1, respectively. Survival at this time was only 12.5%. When smaller fish (96 ± 26.6 mm) were exposed to seawater, mortality was 100% within 72 h. We conclude that small-sized Svalbard charr may survive only short periods in seawater. Therefore, the lack of adequate hypoosmoregulatory capacity limits their access to marine food resources.

Anadromous Arctic charr (Salvelinus alpinus L.) were caught on their way to and from the sea with the use of a fish trap placed in the Dieset watercourse located on the Spitsbergen Island (79 degrees 10' Northern latitude) within the high-Arctic Svalbard archipelago. When subjected to a seawater challenge test (34 parts/thousand at 4-5 degrees C), charr on their way to the sea showed only minor and temporary changes in blood plasma osmolality and Na+ and Mg2+ concentrations. The seawater tests also revealed good hypoosmoregulatory capacity for Arctic charr returning from the marine environment 4 wk later. A progressive decrease in seawater tolerance was first documented 7-11 days after their return to the freshwater habitat. Thus the Svalbard charr, being the northernmost anadromous salmonid and probably a direct descendant from the first Salvelinus immigrants to freshwater systems, undergoes a preparatory increase of hypoosmoregulatory capacity (smoltification) before entering the oceanic water bodies. Furthermore, the termination of their short annual seawater stay is probably elicited by factors controlling body systems other than osmoregulation.

The Atlantic salmon (Salmo salar) stress response was examined by measuring plasma cortisol, glucose and chloride in fish after water level reduction within rearing tanks. Maximum plasma cortisol levels (366±43 (SD) nM and 534±280 nM for Groups 1 and 2, respectively) were observed 20 min after application of the stressor. Cortisol levels were down to control levels 24 h later. The pattern for cortisol changes observed within these two groups were comparable. Plasma glucose and chloride concentrations did not change significantly in either of the experimental groups. The fish in group 2 were then repeatedly subjected to the same stressor every third day. After the fifth exposure to the stressor, blood was obtained from fish at times corresponding to sampling after the first exposure. Their maximum plasma cortisol level only reached 223 (±96) nM, and was down to prestress levels within 2 h. Plasma glucose and chloride concentrations did not change significantly in this second experiment. This challenge test revealed an acute primary response in Atlantic salmon without any apparent harmful secondary responses, that may thus serve as a standardized reference stressor using other fish groups under comparable conditions.

Anadromous Arctic charr, Salvelinus alpinus (L.), from the River Halselva in Finnmark, northern Norway, were used as broodstock for the production of smolts. During the smolting period the fish were either shielded from normal working routines, subjected to normal work routines, or exposed to excessive work routines (stress) within the hatchery. None of the handling routines affected the gill-Na-K-ATPase activity, or the hypoosmoregulatory capacity of the charr. Compared with normal handling, neither stress nor shielding caused any significant difference in the migratory behaviour of the charr, in the duration of the sea residence, or in homing success. However, the stressed group did show a lymphocytopenia at end of the rearing period.

Atlantic salmon parr (58 g) in fresh water at 5.0 °C and adult salmon (1130g) in sea water at 7.7 °C were exposed to water containing different concentrations of metomidate in the range 1 to 10 mg 1 −1 . Metomidate was efficacious in inducing anaesthesia (hypnosis), and efficacy increased with concentration over the interval tested. The anaesthetic was more potent in the adult salmon acclimated to sea water than in freshwater parr. Metomidate at 3 mg 1 −1 or higher completely prevented any plasma cortisol increase after a handling stressor when stressor and anaesthetic were applied concomitantly. The lack of a cortisol response seemed to be due to a blockage at the level of the interrenal cell, since exogenous ACTH injected intraperitoneally did not produce a cortisol increase in metomidate-anaesthetized fish but did in those anaesthetized with MS-222. Blood lactate levels and haematocrit increased in fish during metomidate anaesthesia.

Increase in weight and length of lower leg of Arctic foxes ( Alopex lagopus ), captured in Svalbard, Norway, from 25 days of age to maturity were described using the Gompertz growth model. The asymptotic values of length of calf were 14.3 cm in females and 15.2 cm in males. The asymptotic values of body weight were 3,102 g in females and 3,583 g in males. Males grew larger than females mainly by growing for a longer time. Absolute growth rates were ca. 50% greater than were predicted from the established regression between growth rate and body weight in carnivores. Growth ceased when foxes were 6–7 months of age. Differences in body mass and lengths of body, tail, and calf among juvenile, yearling, and adult foxes caught in December–March were not significant. From measurements on a sample of trapped foxes ( n = 848), males were significantly larger than females in body weight (19%) and lengths of body (4%), calf (6%), and tail (4%). The high rate of growth for Arctic foxes is consistent with the observed rates of other canids and, consequently, is not an adaptation to a living in a more seasonal, Arctic environment. Sexual dimorphism was documented for Arctic foxes.

Hypoosmoregulatory capacity was examined in anadromous Arctic char, Salvelinus alpinus (L.), caught whilst migrating towards the sea in the river A-elva, northern Norway (69°04′N and 17°00′E). Metacercariae of the marine digenean Cryptocotyle lingua (Creplin) were found on 47% of the fish investigated, demonstrating that they had been in brackish or sea water on at least one previous occasion. The fish were randomly divided into three groups, and exposed to sea water (35 ppt salinity at 5–6°C) for 7 days- one group immediately after capture, and the other two groups after 16 days of acclimation in fresh water and brackish water (15–17ppt), respectively. Blood plasma osmolality, Na+ and Mg2+ levels showed only a small and transient rise during seawater exposure, and there were only minor changes in muscle water content, irrespective of prior treatment. A slight, but insignificant, reduction in hypoosmoregulatory capacity appeared to occur in the groups retained in fresh water or brackish water for 16 days prior to seawater exposure. The results did not indicate that the fish show any improvement of hypoosmoregulatory capacity following a period of acclimation in brackish water. The hypoosmoregulatory capacity of seaward-migrating Arctic char is well developed before they enter the sea, and may be comparable to that seen in salmonids which undergo a parr-smolt transformation. There was a negative correlation between blood plasma electrolyte levels and both body length and weight, indicating that hypoosmoregulatory capacity was affected by the size of the fish. The effects of body size upon the development of hypoosmoregulatory capacity are discussed with respect to estuarine residence and the constraints placed upon the survival of small fish in full-strength sea water.

Two groups of Arctic char (Salvelinus alpinus) were reared in freshwater (5–6 °C) under either continuous light (LDL) from first feeding (March) or LDL until July and then natural photoperiod (NDL, 70°N). Direct transfer to seawater (5.5 °C, 35 ppt) in February resulted in both groups exhibiting increases in blood plasma osmolality, Na+, and Mg2+concentrations and a significant decrease in muscle water content. When tested in May, an improvement in seawater tolerance was evident in both groups. In June, only the NDL fish showed further improvements in hypoosmoregulatory capacity, since they exhibited only minor fluctuations in plasma constituents and muscle water content following direct transfer to seawater. Increased body size could partially explain the improved seawater tolerance in the experimental groups. Acclimation to brackish water prior to transfer to 35 ppt seawater in June improved seawater tolerance only in fish reared under continuous light. The results indicate that the seasonal increase in photoperiod stimulates the development of hypoosmoregulatory capacity whilst the fish are still resident in freshwater.

A sex steroid-binding protein (SBP) that binds 17beta-estradiol with high affinity and moderate capacity was identified in the plasma from Arctic charr (Salvelinus alpinus L.) sampled during the early stage of gonadal maturation in June and prior to spawning in October. Maximum specific binding (B(max)) and equilibrium dissociation constant (K(d)) of males (B(max) = 2122 fmol E(2)/mg protein, K(d) = 1.9 nM), females (B(max) = 4115 fmol E(2)/mg protein, K(d) = 3.0 nM), and juveniles (B(max) = 4355 fmol E(2)/mg protein, K(d) = 1.8 nM) resembled binding characteristics of SBP from related species. The early-maturing females displayed both B(max) and K(d) values significantly higher than those of males (June samples). No significant differences in binding characteristics between fully matured males or females and immature juveniles were observed in the October samples. Interestingly, despite large individual variations there was a strong correlation between SBP levels and affinity. The association rate for 17beta-estradiol was rapid (t(1/2) approximately 1-2 min) compared with the dissociation rate (t(1/2) approximately 3 h). Several native hormones (estrogens, androgens, and progesterone) were able to compete with tritiated 17beta-estradiol for the binding site. Gel filtration chromatography demonstrated a peak of estradiol binding at approximately 60 kDa, when eluted on a Sephadex S-200 HR column.

Three arctic charr ( Salvelinus alpinus ) morphs coexist within the Dieset watercourse (79°10'N, 11°20'E) on Spitsbergen, Svalbard. Small freshwater resident charr exhibited a very slow growth rate, while large freshwater resident charr grew at a rate comparable to that reported for cannibalistic charr elsewhere. First-time sea migrants of the anadromous charr were similar in size to their more southern-living Norwegian conspecifics, but on average two years older. The average number of sea runs before first-time spawning was 3.6 for males and 4.4 for females. Veteran migrants displayed growth comparable to that of anadromous charr from more southern populations. In all three morphs, sex ratio did not differ from unity. The short-lived small residents matured from an age of 4 years, 3 to 4 years earlier than did large residents and anadromous charr. The majority of small resident and anadromous charr spawn a maximum of three times, while large resident charr may spawn up to seven times. Although 69% of large resident charr were older than 15 years, only 5.7% of reproductive anadromous charr exceeded this age. This divergence may indicate different reproductive strategies between the two morphs. There was no evidence of reproductive isolation between these High Arctic charr morphs. Key words: anadromous, Arctic charr, High Arctic, life-history, resident, Salvelinus alpinus , Spitsbergen, Svalbard

Samples of liver (n = 78) and kidney (n = 60) from Svalbard reindeer (Rangifer tarandus platyrhynchus Vrolik) collected at four different seasons in Svalbard were analysed for their content of Cd, Pb, Cu, Zn, Mn, and Se. The study shows that when animals are exposed to large seasonal variations in both the quality and quantity of food, it is crucial to relate element concentrations to the physiological condition of the animal, e.g., to look at seasonal fluctuations in the total element content of the different organs.

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

We studied the seasonal variation in body composition of arctic foxes (Alopex lagopus) to determine the adaptive significance of fat deposition in this species. Homogenates of 75 minced fox carcasses were analyzed. On a large sample of animals trapped in 1982-89, the thickness of subcutaneous fat was measured, and the amount of fat was indexed subjectively. Fat was deposited both subcutaneously and viscerally in September-October, and it reached a maximum of about 20% of the skinned carcass mass in November. The amount of fat deposited did not decline between November and March of any year. The fat deposits were depleted from March through May, reaching about 6% of the carcass mass by the summer. Fifteen percent of the trapped foxes did not have any subcutaneous or visceral fat deposits in winter

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 ambient temperatures and running speeds ranging from +12 to -30 °C and 3.7 to 9.0 knvh1, respectively. We found that respiratory minute volume was generally lower in summer than in winter for a similar ambient temperature, and also that respiratory minute volume was reduced at low ambient temperature both in summer and winter. The change in respiratory minute volume was inversely related to oxygen extraction, the latter being at its highest at the lowest ambient temperature and running speed in summer. Reduction of respiratory minute volume, and hence respiratory water loss, at low ambient temperature is likely to contribute significantly to the survival of these species, particularly in winter when the animals can only replace body water with snow at low temperature.

Groups of Arctic charr,Salvelinus alpinus, which had been acclimated to water with a salinity of 7 g·l−1 and natural temperature and photoperiod, were exposed to water with different salinities and temperatures in June, September and February. At a salinity of 15 g·l−1, plasma osmolality, plasma Na+, Cl−, Mg2+ concentrations and the activity of gill Na-K-ATPase were stable, irrespective of temperature and season. In June, the charr were able to regulate blood plasma ionic levels within narrow limits when exposed to a salinity of 34 g·l−1 (sea water) and a temperature of 8°C. The hypo-osmoregulatory capacity was less, but sufficient if the temperature was only 1°C during the seawater exposure. At the start of the experiment, the gill Na-K-ATPase activity was significantly higher in June than corresponding enzyme activities in September and February. Furthermore, an increase in gill Na-K-ATPase activity during the seawater exposure (8°C) was seen in June. Irrespective of ambient temperature and salinity, no fish died during the June experiments. In September and February, exposure to sea water produced marked increases in plasma osmolality and plasma ion concentrations. There were no changes in gill Na-K-ATPase activity. Consequently, the fish became dehydrated and were moribund after a short period of seawater exposure. Highest mortality was recorded when charr were exposed to winter sea conditions (34 g·l−1 and 1°C) in February. The results indicate that an increase in daylength induce a hypo-osmoregulatory capacity in the Arctic charr during summer. In fall and winter, however, reduced daylength are accompanied by poor hypo-osmoregulatory capacity. This leads to high mortality as a result of increased electrolyte levels and dehydration.

LARSEN, T.S. & NILSSEN, K.J. 1985. On the hormonal regulation of lipolysis in isolated reindeer adipocytes. Acta Physiol Scand125, 547–552. Received 19 December 1984ac cepted 12 June 1985. ISSN 0001–6772. Department of Arctic Biology and Department of Physiology, Institute of Medical Biology, University of Tromso, Norway. The effects of insulin and bovine growth hormone (bGH) on lipolysis (basal and/or adrenaline-stimulated) were investigated in isolated adipocytes from the Norwegian reindeer. Addition of 100 nmol 1-1 adrenaline to the cells increased lipolysis 20-fold above basal lipolytic rate. Insulin (0.1 and 1 nmol l-1) depressed lipolysis significantly at submaximal adrenaline stimulation but had no effect when lipolysis was stimulated maximally. Bovine GH (25 and 100 ng ml-1) inhibited basal lipolysis during the first 2 h of incubation, whereas refractoriness to this action was induced during the third and fourth hour of incubation. These effects were not influenced by inclusion of a small amount of glucocorticoid (dexamethasone, 25 ng ml-1). Addition of 0.1 and 1 nmol 1-1 insulin together with bGH (100 ng ml-1) prevented the initial antilipolytic effect of the latter and resulted in the expression of normal basal lipolytic rates. Preincubation with bGH (100 ng ml-1) for 2 h did not alter the lipolytic response of the adipocytes to adrenaline. These findings lend support to the conclusion that insulin exerts a major control of lipolysis in reindeer adipose tissue. The significance of the antilipolytic effect of bGH is difficult to evaluate since this effect was transient and was abolished during the third and fourth hour of incubation.

Exhaled air temperature (Te), respiratory frequency (f), and rectal temperature (Tb) were measured in two reindeer before, during and after running for 45 min at a constant speed of 9.2 km X hr-1 on a level treadmill at different ambient temperatures (Ta), in summer with fur insulation at a minimum and in winter with fur insulation at its prime. Before and immediately after the 45-min running period, skin temperature (Tsk) and radiative surface temperature (Tr) were also measured. Te, Tsk and Tr decreased at rest with decreasing Ta both summer and winter Tb was elevated during running except at low Ta in summer. During running Tsk, Te and f were higher in winter than in summer, while Tr was higher in summer than in winter. The changes in Tr and Tsk in response to running were more pronounced on the legs than on the trunk. It is suggested that in the running reindeer the body surface is an effective avenue of heat loss during summer, while heat dissipation by way of the respiratory tract attains increased importance in winter, when fur insulation is at its best.

Mössbauer spectra have been obtained from samples of the liver of Spitsbergen reindeer at different times of the year. Most of the iron is in a very similar form to that of the iron storage materials ferritin and haemosiderin. The data reflect the large differences in the amount of iron found in the liver at different times of the year and also indicate that there are only relatively small differences in the chemical and physical form of the iron found in the liver at different times of the year.

Changes in liver iron concentration in relation to seasonal body weight variations and food iron intake have been investigated in 77 Svalbard reindeer by chemical and histological methods. During the winter season the body weight decreased about 43% in females and 39% in males. Liver weight was reduced about 65% in both sexes. The liver iron concentration showed little or no difference between the sexes and was 29 +/- 13 mg iron/100 g wet weight in the autumn. The concentration increased in late winter to 291 +/- 52 mg iron/100 g in animals eating iron-rich forage plants, and to 165 +/- 92 mg iron/100 g in animals eating forage plants with a normal iron content. Starving animals with a very high iron concentration of the rumen content usually had massive siderosis in both parenchymal and nonparenchymal cells of the liver. In contrast, siderosis was restricted to nonparenchymal cells in starving animals with normal rumen iron concentration. Transferrin saturation was significantly higher in animals eating iron-rich forage plants than in those eating forage plants with a normal content. Therefore it is proposed that seasonal liver siderosis is a result of a) translocation of iron from catabolized blood and lean tissue that is recovered in nonparenchymal cells and b) high uptake of food iron with deposition in the parenchymal cells.

Serum levels of 3,5,3′-triiodothyronine (T 3 ), free thyroxine (FT 4 ), and cortisol were determined for free-ranging Svalbard reindeer during winter (March), summer (June–July), and autumn (October). A total of 48 animals representing adult males, adult barren, pregnant, and lactating females, and calves were shot, and blood sampled from their hearts. T 3 and FT 4 were found to vary seasonally, the levels being lower in winter than in summer or autumn. Differences due to state of pregnancy, sex, or age were represented by low FT 4 levels in lactating females (summer) and rutting males (autumn), and high T 3 levels in young calves (summer). Serum cortisol levels were found to change seasonally, summer levels being higher than winter or autumn levels in all groups of animals. This finding suggests that glucocorticoids (cortisol) do not affect the deiodination from T 4 to T 3 in reindeer. The seasonal changes in T 3 and FT 4 in wild animals were similar to the changes in captive animals. It is therefore concluded that the changes in thyroidal hormone levels do not indicate changes in basal metabolic rate in this species.

The purpose of this study was to determine whether a convenient relationship could be found between heart rate (HR) and energy expenditure at rest and during running in the high arctic Svalbard reindeer (SR) and the subarctic Norwegian reindeer (NR). Measurements of HR and energy expenditure (O2 consumption) were made at different ambient temperatures, at rest, and during running at different speeds during both summer and winter. Cost of transportation (Science 177: 222-228, 1972) was 3.56 and 2.67 J X g-1 X km-1 in SR and NR, respectively. The y-intercept value obtained for NR was close to the predicted value (J. Exp. Biol. 97: 1-22, 1982), whereas that of SR was much lower. In NR the relationship between HR and energy expenditure at running speeds from 0 to 9.2 km X h-1 is, regardless of ambient temperature (in the -30 to +10 degrees C range), described by the following equations: y = 8.04x + 48.70, r = 0.92, n = 27 (summer); and y = 7.48x + 31.20, r = 0.95, n = 52 (winter). In SR, the corresponding equations were y = 7.60x + 49.20, r = 0.94, n = 29 (summer); and y = 8.90x + 32.10, r = 0.96, n = 44 (winter), where y is HR (beats X min-1) and x is metabolic rate (W X kg-1).

1. 1. Freshwater-resident Arctic charr acclimated for 2 months at 8°C, 15% were divided into four experimental groups in July and exposed to 1 and 8°C in 15 and 34% salinity. 2. 2. Only slight changes in gill Na-K-ATPase activity, blood plasma osmolality and blood plasma concentrations of Cl − and Mg 2+ were found for the fish exposed to 1 or 8°C in brackish water. 3. 3. When exposed to sea-water at 8°C, an increase in osmolality and in concentrations of Cl − and Mg 2+ took place during the first 2–3 days, after which it levelled off. 4. 4. If exposed to sea-water at 1°C, however, marked increases were found for all parameters measured and all the fish were dead within 5 days of exposure. 5. 5. These results show that freshwater-resident Arctic charr—if acclimated to brackish water—can survive in sea-water during summer if the environmental temperature is not too low.

Sixty-three adult (>1 year) Svalbard reindeer (Rangifer tarandus platyrhynchus) from the Arctic island Spitsbergen were all parasitized by abomasal nematodes of the family Trichostrongylidae. Seven species of nematodes were recorded. Of these, Grosspiculaqia occidentalis was found only in reindeer from inner parts of Nordenskiold Land, and specimens of Marshallagia marshalli were also much more abundant in this area than at the coast. These two species are, primarily, parasites of bovids, and their local distribution coincides with that of muskoxen which were introduced to Spitsbergen in 1929. The reindeer parasites Ostertagia griihneri and Skrijabinagia arctica were about equally abundant in both the inland and coastal reindeer subpopulations. The results indicate that G. occidentalis and M. marshalli may have been introduced to Spitsbergen with bovids, most probably muskoxen, and that 0. griihneri and S. arctica may have spread from the reindeer into the muskoxen population.