Journal articles: 'Arctic char Arctic char'

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Dennert, A. M., S. L. May-McNally, M. H. Bond, T. P. Quinn, and E. B. Taylor. "Trophic biology and migratory patterns of sympatric Dolly Varden (Salvelinus malma) and Arctic char (Salvelinus alpinus)." Canadian Journal of Zoology 94, no. 8 (August 2016): 529–39. http://dx.doi.org/10.1139/cjz-2016-0004.

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The trophic ecology (diet and head morphology) and migration patterns of two closely related salmonid fishes, Arctic char (Salvelinus alpinus (L., 1758)) and Dolly Varden (Salvelinus malma (Walbaum, 1792)), were examined in tributaries of Lake Aleknagik, southwestern Alaska, to test for differentiation between species. Schoener’s index of proportional overlap and multivariate analyses of diets suggested that these species had significantly different trophic niches. Arctic char and the largest individuals of both species had the most diverse diets, and sockeye salmon (Oncorhynchus nerka (Walbaum, 1792)) eggs dominated the diet of both species, especially Arctic char. Arctic char had larger jaws and wider heads than Dolly Varden of similar body length, which may contribute to interspecific diet difference. The species also differed in migration patterns; otolith microchemistry indicated that juvenile Arctic char were produced by nonanadromous mothers, whereas the mothers of the Dolly Varden had been to sea in the season prior to spawning. The species also segregate in spawning habitat (Arctic char in the lakes and Dolly Varden in streams), as well as in juvenile rearing habitat. Our study provides the first evidence of divergent feeding and migratory ecology between sympatric juvenile Arctic char and Dolly Varden, differences that may constrain hybridization and introgression between them.

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Baker, Timothy T., and L. Saree Timmons. "Precision of Ages Estimated from Five Bony Structures of Arctic Char (Salvelinus alpinus) from the Wood River System, Alaska." Canadian Journal of Fisheries and Aquatic Sciences 48, no. 6 (June 1, 1991): 1007–14. http://dx.doi.org/10.1139/f91-118.

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Ages of 32 Arctic char (Salvelinus alpinus) were estimated from otoliths (surface-examined and broken-and-burned), vertebrae, cleithra, opercula, and subopercula. Six readers examined each structure three times, and the precision of these estimates among structures and readers was compared with means, aging differences, and analyses of variance. Surface-examined otoliths provided the most precise age estimates and were one of the easiest structures to prepare and read. Broken-and-burned otoliths produced less precise estimates for larger, older Arctic char than for smaller, younger Arctic char. Based on lack of precision, cleithra should probably not be used to age Arctic char. Although mean estimates for the five structures were not significantly different, surface-examined otoliths produced older age estimates than break and burn otoliths. We feel that surface-examined otoliths are best for precise estimation of age of Arctic char but recommend that both otolith methods be compared when aging Arctic char older than 8 yr. Scales were also examined from 30 Arctic char but were not included in the analyses after preliminary examination because age was difficult to interpret (circuli were clear on all scales, but only two or three annuli of uncertain significance could be distinguished).

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Kanagasabai, Lenin. "Real power loss reduction by arctic char algorithm." International Journal of Advances in Applied Sciences 9, no. 4 (December 1, 2020): 261. http://dx.doi.org/10.11591/ijaas.v9.i4.pp261-264.

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This work presents Arctic Char Algorithm (ACA) for solving optimal reactive power problem. In North America movement of Arctic char phenomenon is one among the twelve-monthly innate actions. Deeds of Arctic char have been imitated to design the algorithm. In stochastic mode solutions are initialized with one segment on every side of to the route ascendancy; particularly in between lower bound and upper bounds. Previous to the movement, Arctic char come to a decision about the passageway based on their perception. This implies stochastic mix up of control parameters to push the Arctic char groups (preliminary solution) in mutual pathway (evolutionary operators). Projected Arctic Char Algorithm (ACA) has been tested in standard IEEE 14,300 bus test system and simulation results show the projected algorithm reduced the real power loss extensively.

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Kornfield, Irv, and Frederick W. Kircheis. "Mitochondrial DNA and Conservation of an Aboriginal Arctic Char (Salvelinus alpinus oquassa) from Floods Pond, Maine." Canadian Journal of Fisheries and Aquatic Sciences 51, no. 1 (January 1, 1994): 62–67. http://dx.doi.org/10.1139/f94-008.

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Periods of low water in Floods Pond, Maine, USA, during spawning seasons for an endemic population of landlocked Arctic char, Salvelinus alpinus oquassa, have contributed to several year-class failures. To determine the genetic uniqueness of these fish, samples of Arctic char from five isolated lakes in New England and eastern Canada were examined by restriction endonuclease analysis of mitochondrial DNA (mtDNA) and compared with samples of lake trout (Salvelinus namaycush) and Arctic char from Scandinavia. Results suggest that (1) Arctic char of eastern North America should all be considered members of Salvelinus alpinus oquassa, (2) char from Floods Pond possess a unique mtDNA banding pattern for one restriction enzyme not observed in fish from any other sampled locality (this difference delineates a distinct lineage of Arctic char whose preservation is warranted on genetic grounds), and (3) unique banding patterns did not characterize any other studied char population, including geographic variants (these populations may be viewed as genetically homogeneous, and none warrant individual protection based upon our genetic characterizations). We contend that genetically identified lineages in the early stages of divergence warrant preservation.

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Persson, Lennart, Per Arne Amundsen, André M. De Roos, Rune Knudsen, Raul Primicerio, and Anders Klemetsen. "Density-dependent interactions in an Arctic char – brown trout system: competition, predation, or both?" Canadian Journal of Fisheries and Aquatic Sciences 70, no. 4 (April 2013): 610–16. http://dx.doi.org/10.1139/cjfas-2012-0175.

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In the study of mechanisms structuring fish communities, mixed competition–predation interactions where large predators feed on prey fish versus those in which small predators compete with prey fish for a shared prey have been the focus of substantial research. We used a long-term data set from a system inhabited by brown trout (Salmo trutta) (predator) and Arctic char (Salvelinus alpinus) (prey) to evaluate whether mixed interspecific interactions were present in this system as suggested in other studies focusing on this species pair. We found no evidence for a negative interspecific density dependence in individual performance in either Arctic char or brown trout. In contrast, a negative intraspecific density dependence was present, especially in Arctic char. Furthermore, large brown trout condition showed a positive response to encounter rate with Arctic char (related to the density of small Arctic char). The most parsimonious interaction module to explain the Arctic char – brown trout interaction patterns in the studied system does therefore not need to include interspecific competition. We suggest that size-structured mixed competition–predation interactions in different systems are realized as being either mainly structured through interspecific predation or by competition depending on species life history characteristics and environmental conditions.

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Finstad, Anders G., Peder A. Jansen, and Arnfinn Langeland. "Gillnet selectivity and size and age structure of an alpine Arctic char (Salvelinus alpinus) population." Canadian Journal of Fisheries and Aquatic Sciences 57, no. 8 (August 1, 2000): 1718–27. http://dx.doi.org/10.1139/f00-071.

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The aim of the present study was to address possible implications of biased sampling for the commonly adopted uni- and bi-modal size structures and unimodal age structures in Arctic char (Salvelinus alpinus) populations. Multimesh gill nets were used to sample an allopatric population of Arctic char in an alpine lake in central Norway. Direct estimates of gillnet selectivity for different length-classes of Arctic char were obtained by mark-recapture experiments and by successive removal methods. The observed size and age structure in gillnet samples was significantly different from the estimated size and age structure of the Arctic char population when catches were corrected for gillnet selectivity. An observed unimodal size and age structure was a direct result of gillnet selectivity, as smaller and younger fish were underrepresented in gillnet catches. Moreover, an abrupt increase in gillnet selectivity for large Arctic char was related to a niche shift to cannibalism. A model that explains bimodal size distributions in gillnet catches as a result of ontogenetic behavioural change is presented. Complex ontogenetic growth and mortality patterns that have been suggested to be essential in structuring modal Arctic char populations were superfluous in explaining the observed modal population structure in the present study.

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Petersen, Karina, Maria T. Hultman, Jenny Bytingsvik, Mikael Harju, Anita Evenset, and Knut Erik Tollefsen. "Characterizing cytotoxic and estrogenic activity of Arctic char tissue extracts in primary Arctic char hepatocytes." Journal of Toxicology and Environmental Health, Part A 80, no. 16-18 (September 1, 2017): 1017–30. http://dx.doi.org/10.1080/15287394.2017.1357277.

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Hara, Toshiaki J., Torarinn Sveinsson, Robert E. Evans, and Dorthy A. Klaprat. "Morphological and functional characteristics of the olfactory and gustatory organs of three Salvelinus species." Canadian Journal of Zoology 71, no. 2 (February 1, 1993): 414–23. http://dx.doi.org/10.1139/z93-058.

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Morphological features and response characteristics of the olfactory and gustatory organs were studied in three char species, Arctic char (Salvelinus alpinus), brook char (S. fontinalis), and lake char (S. namaycush). In brook, lake, and Norwegian-stock Arctic chars the olfactory rosette consisted of 12–16 primary olfactory lamellae radiating from the rostro-caudally oriented raphe, with the secondary folding typical of salmonids. Nauyuk-stock Arctic char had fewer (7–9) olfactory lamellae without secondary folding. Electro-olfactogram response characteristics to L-cysteine, L-arginine, and L-glutamate, representing neutral, basic and acidic amino acids, respectively, were similar, with threshold concentrations of 10−9–10−8 M. Structure–activity relationship studies showed that the amino acid spectrum for Arctic char differed from those of brook and lake chars. Most characteristic was that esterification of the carboxyl group of L-arginine enhanced its effectiveness. The taste buds were generally distributed in rows oriented anterior–posterior in the palate. Each species showed distinct distribution patterns, and the highest densities (up to 40/mm2) of palatal taste buds were counted in brook char. The palatine nerve of the three species responded specifically to L-proline, hydroxy-L-proline, and L-alanine. Adaptation to L-proline eliminated responses to hydroxy-L-proline and L-alanine. No response was registered to betaine, one of the most potent gustatory stimulants for teleosts. Tetrodotoxin, quinine, and strychnine were potent gustatory stimulants in the three species. The detection threshold for tetrodotoxin was lower than for L-proline in Arctic char. We conclude that the three char species have only one main palatine gustatory amino acid receptor, that for L-proline.

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Salisbury, Sarah J., Connor Booker, Gregory R. McCracken, Tom Knight, Donald Keefe, Robert Perry, and Daniel E. Ruzzante. "Genetic divergence among and within Arctic char (Salvelinus alpinus) populations inhabiting landlocked and sea-accessible sites in Labrador, Canada." Canadian Journal of Fisheries and Aquatic Sciences 75, no. 8 (August 2018): 1256–69. http://dx.doi.org/10.1139/cjfas-2017-0163.

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Anadromous, resident, and landlocked Arctic char (Salvelinus alpinus) differentially experience drift and gene flow, making them ideal for studying incipient divergence. We investigated genetic divergence within and among char occupying landlocked and sea-accessible sites in Labrador, Canada, using 11 microsatellites. Unlike anadromous char, landlocked char were highly genetically differentiated. Genetic subgroups were detected within landlocked and sea-accessible sites. Within Ramah Lake (a sea-accessible site containing two subgroups), one subgroup matured at a small size, and both subgroups had equal proportions of males to females. These findings refute residency as a sneaker male tactic and instead suggest the presence of reproductively isolated resident and anadromous char. Subgroups demonstrated equal frequencies of Atlantic and Arctic lineage mtDNA haplotypes, suggesting their genetic differences were not due to allopatry during the last glacial maximum. Our results are therefore consistent with the sympatric genetic divergence of resident and anadromous Arctic char morphs.

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Adler, Paul R., and Lawrence J. Sikora. "Mesophilic Composting of Arctic Char Manure." Compost Science & Utilization 13, no. 1 (January 2005): 34–42. http://dx.doi.org/10.1080/1065657x.2005.10702215.

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11

Hammar, Johan, J. Brian Dempson, and Eric Verspoor. "Natural Hybridization between Arctic Char (Salvelinus alpinus) and Brook Trout (S. fontinalis): Evidence from Northern Labrador." Canadian Journal of Fisheries and Aquatic Sciences 48, no. 8 (August 1, 1991): 1437–45. http://dx.doi.org/10.1139/f91-171.

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Electrophoretic analysis of successive samples of Salvelinus collected in the Fraser River watershed of northern Labrador in 1984 and 1986 revealed the existence of natural hybrids between Arctic char (Salvelinus alpinus) and brook trout (S. fontinalis). We examined 11 electrophoretic loci in liver tissue; 10 loci were informative and six were diagnostic of the two species and their hybrids. The electrophoretic phenotypes of some hybrid specimens sugested that they were second-generation hybrids and/or backcrosses to the parental species. Hybrids were represented by six different year classes, indicating that crossing between the species in the system is a regular occurrence. The hybrids, although visually difficult to distinguish from brook trout, were meristicaîly intermediate or more closely resembled Arctic char. The observations raise a number of questions regarding the ecological circumstances promoting hybridization in the evolution of Arctic char and brook trout populations. The results stress the need for restrictions on introducing brook trout into systems with original populations of Arctic char. Further, Arctic char from the Fraser River are commonly used for aquaculture research and development; therefore, there is a clear need to screen fish carefully to determine whether or not they represent introgressed gene pools.

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Jensen, Arne Johan, Ola Håvard Diserud, Bengt Finstad, Peder Fiske, and Audun Håvard Rikardsen. "Between-watershed movements of two anadromous salmonids in the Arctic." Canadian Journal of Fisheries and Aquatic Sciences 72, no. 6 (June 2015): 855–63. http://dx.doi.org/10.1139/cjfas-2015-0015.

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A long-term study in the River Halselva in the Arctic region of Norway demonstrated that movements between watersheds were considerably higher in anadromous brown trout (Salmo trutta) than anadromous Arctic char (Salvelinus alpinus). Fourteen smolt year classes of both species were captured in a fish trap, individually tagged, and thereafter registered each time they passed the trap during their migration between the sea and fresh water every summer. Annual mean survival (i.e., recovery rate) after the first entry to sea as smolts was estimated as 31.4% in Arctic char and 26.6% in brown trout. Most surviving Arctic char returned to the River Halselva to overwinter after the same summer that they migrated to sea as smolts. However, several brown trout overwintered one to four times in other watersheds, mainly the considerably larger River Altaelva, before most eventually returned to the River Halselva upon maturation. The substantial difference in movement rate between watersheds between Arctic char (2.2%) and brown trout (39.6%) is expected to be a consequence of local geographic conditions combined with different habitat preferences of the two species.

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Jensen, Arne J., Bengt Finstad, Peder Fiske, Nils Arne Hvidsten, Audun H. Rikardsen, and Laila Saksgård. "Timing of smolt migration in sympatric populations of Atlantic salmon (Salmo salar), brown trout (Salmo trutta), and Arctic char (Salvelinus alpinus)." Canadian Journal of Fisheries and Aquatic Sciences 69, no. 4 (April 2012): 711–23. http://dx.doi.org/10.1139/f2012-005.

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A study over a 22-year period of first-time migrants (smolts) of three sympatric salmonids (Atlantic salmon ( Salmo salar ), brown trout ( Salmo trutta ), and Arctic char ( Salvelinus alpinus )) in a watercourse in northern Norway demonstrated that although there was considerable overlap in smolt migration timing among the species, Atlantic salmon migrated first, followed by Arctic char, and finally brown trout. The migration period of Arctic char had a smaller range and less annual variation than those of the two other species, possibly partly related to their more lake-dwelling habitat preference. For all species, water flow was important in explaining day-to-day variations in smolt runs. Water flow was most important for brown trout, change in flow for Atlantic salmon, whereas photoperiod was most important for Arctic char. These results suggest that both age and size of smolts and the timing of the smolt migration have been shaped by the different habitat preferences of these species both in fresh water and sea through local selection.

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Maier, Kris W. C., Neil J. Mochnacz, Robert Bajno, Andrew J. Chapelsky, Peter Rodger, and James D. Reist. "Range Extension of Northern Form Dolly Varden (Salvelinus malma malma) to the Upper Arctic Red River Watershed, Northwest Territories, Canada." ARCTIC 74, no. 1 (March 16, 2021): 42–50. http://dx.doi.org/10.14430/arctic72138.

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Northern form Dolly Varden is an anadromous char with significant ecological value found in high-gradient rivers of the Western Arctic. Because of declines in population abundance, Dolly Varden was recently designated as “Special Concern” under the federal Species at Risk Act. This species is also of great cultural and dietary significance to Indigenous Peoples of many communities in the Western Arctic; thus, expanding knowledge of the distribution, biology, and essential habitat is an important priority. We present results of a fisheries survey in the headwaters of the Arctic Red River, Northwest Territories, that focused on confirming the presence of Dolly Varden. Of 143 fish captured among 12 sampling locations, two were Arctic grayling (Thymallus arcticus), 33 were slimy sculpin (Cottus cognatus), and 108 were char identified using qualitative and quantitative morphological features. A subsample of 44 char voucher specimens were frozen whole and later identified using a linear discriminant function (LDF) based on meristic counts and morphological measurements, and a mitochondrial DNA genetic marker. LDF scores indicated that char collected in the Arctic Red River were northern form Dolly Varden. Genetic analysis showed that all but one char possessed mitochondrial DNA sequences common in northern form Dolly Varden from Canada. Our results confirm the presence of Dolly Varden in the Arctic Red River headwaters, extending the confirmed known distribution of this taxon in the Northwest Territories approximately 450 km south and 100 km east of previously delimited areas.

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Jansen, Peder A., Henning Slettvold, Anders G. Finstad, and Arnfinn Langeland. "Niche segregation between Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta): an experimental study of mechanisms." Canadian Journal of Fisheries and Aquatic Sciences 59, no. 1 (January 1, 2002): 6–11. http://dx.doi.org/10.1139/f01-184.

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Interactive competition has been suggested to be an important mechanism by which brown trout (Salmo trutta) and Arctic char (Salvelinus alpinus) segregate into benthic vs. pelagic niches. According to the interactive competition hypotheses, Arctic char and brown trout should have the same preference for prey. We tested this by studying foraging performance when char and trout were offered small pelagic Daphnia longispina and (or) large epibenthic Gammarus lacustris in 10-min foraging experiments with solitary fish and with fish competing pairwise. There were obvious behavioural differences between char and trout. Trout were profoundly more aggressive than char. In comparison, char chose small pelagic daphnids and were superior daphnid foragers. Trout chose large epibenthic gammarids and were superior gammarid foragers. When competing, char and trout segregated such that rate of feeding on the chosen prey type was similar to solitary foraging fish, whereas rate of feeding on the alternative prey type was close to zero. We suggest that the observed selective differences in foraging behaviour, choice of prey, and feeding rates play an important role in niche segregation between Arctic char and brown trout. Hence, our results conform more closely with selective processes, rather than interactive processes, as the founding mechanisms for such segregation.

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Pleyte, Kay A., Ruth B. Phillips, and Sheila E. Hartley. "Q-band chromosomal polymorphisms in arctic char (Salvelinus alpinus)." Genome 32, no. 1 (February 1, 1989): 129–33. http://dx.doi.org/10.1139/g89-419.

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Stock-specific variation in the number and location of quinacrine-staining chromosomal bands was found in North American and European stocks of arctic char (Salvelinus alpinus). The mean number of bands per genome varied from 5.8 ± 5.3 in the Northwest Territories stock to 15.4 ± 2.1 in the Scottish stock. These bands appear to represent a subset of heterochromatin since they stain darkly with the C-band technique. Since the four stocks examined were each distinguishable on the basis of their Q-band patterns, these chromosome markers should be useful in genetic comparisons between different arctic char stocks and populations.Key words: Q banding, chromosomes, polymorphisms, arctic char, Salvelinus alpinus.

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Bystriansky, J. S., and J. S. Ballantyne. "Gill Na+-K+-ATPase activity correlates with basolateral membrane lipid composition in seawater- but not freshwater-acclimated Arctic char (Salvelinus alpinus)." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 292, no. 2 (February 2007): R1043—R1051. http://dx.doi.org/10.1152/ajpregu.00189.2005.

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The successful migration of euryhaline teleost fish from freshwater to seawater requires the upregulation of gill Na+-K+-ATPase, an ion transport enzyme located in the basolateral membrane (BLM) of gill chloride cells. Following 39 days of seawater exposure, Arctic char had similar plasma sodium and chloride levels as individuals maintained in freshwater, indicating they had successfully acclimated to seawater. This acclimation was associated with an eightfold increase in gill Na+-K+-ATPase activity but only a threefold increase in gill Na+-K+-ATPase protein number, suggesting that other mechanisms may also modulate gill Na+-K+-ATPase activity. We therefore investigated the influence of membrane composition on Na+-K+-ATPase activity by examining the phospholipid, fatty acid, and cholesterol composition of the gill BLM from freshwater- and seawater-acclimated Arctic char. Mean gill BLM cholesterol content was significantly lower (∼22%) in seawater-acclimated char. Gill Na+-K+-ATPase activity in individual seawater Arctic char was negatively correlated with BLM cholesterol content and positively correlated with %phosphatidylethanolamine and overall %18:2n6 (linoleic acid) content of the BLM, suggesting gill Na+-K+-ATPase activity of seawater-acclimated char may be modulated by the lipid composition of the BLM and may be especially sensitive to those parameters known to influence membrane fluidity. Na+-K+-ATPase activity of individual freshwater Arctic char was not correlated to any membrane lipid parameter measured, suggesting that different lipid-protein interactions may exist for char living in each environment.

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Jørgensen, Even H., and Johannes Wolkers. "Effect of temperature on the P4501A response in winter- and summer-acclimated Arctic char (Salvelinus alpinus) after oral benzo[a]pyrene exposure." Canadian Journal of Fisheries and Aquatic Sciences 56, no. 8 (August 1, 1999): 1370–75. http://dx.doi.org/10.1139/f99-075.

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In this study, the time-dependent P450 response to oral benzo[a]pyrene exposure at 1 and 10°C was investigated in winter- and summer-acclimated Arctic char (Salvelinus alpinus). In both seasons, a strong induction of CYP1A activities and protein levels (measured only in the winter experiment) were seen at both 1 and 10°C. At 1°C, the responses were delayed and more long-lasting than at 10°C. No within-season difference between 1 and 10°C in the magnitude of the induction response was found, but due to elevated baseline CYP1A activities, the induction response was seven times lower in winter- as compared with the response in summer-acclimated Arctic char. The results show that the CYP1A enzymes of the Arctic char respond to temperature changes in a compensatory way, and they are promising with respect to the applicability of the P450 enzyme system of the Arctic char as a biomarker for monitoring polycyclic aromatic hydrocarbon contamination in high-latitude environments. More studies are needed, however, to reveal seasonal differences in the biomarker response to pollutants.

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Nilsson, J. "Genetics of Growth of Juvenile Arctic Char." Transactions of the American Fisheries Society 123, no. 3 (May 1994): 430–34. http://dx.doi.org/10.1577/1548-8659(1994)123<0430:gogoja>2.3.co;2.

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Heggberget, Tor G., Per Grotnes, Anders Klemetsen, Roger Richardsen, and Ola Ugedal. "Culture of Arctic Char-Possibilities in Norway." Transactions of the American Fisheries Society 123, no. 3 (May 1994): 435–44. http://dx.doi.org/10.1577/1548-8659(1994)123<0435:coacpi>2.3.co;2.

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Makhrov, A. A., I. N. Bolotov, V. M. Spitsyn, M. Yu Gofarov, and V. S. Artamonova. "Resident and anadromous forms of arctic charr (Salvelinus alpinus) from North-East Europe: an example of high ecological variability without speciation." Доклады Академии наук 485, no. 2 (May 20, 2019): 242–46. http://dx.doi.org/10.31857/s0869-56524852242-246.

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Samples from 11 populations of the Arctic char of the North-European part of Russia belonging to the anadromous and resident forms and two samples from Lake Sobach'e (Taimyr) were studied. The nucleotide sequence of the mitochondrial COI gene was determined in 60 individuals. In the majority of populations, the same COI haplotype was found. In some populations of the resident chars, haplotypes differing from the widespread haplotype in a single nucleotide substitution were found. The obtained genetic data give no reason to distinguish the resident form of the Arctic char from lakes of Karelia and the Kola Peninsula as an independent species, Salvelinus lep- echini. The adaptation of the Arctic char to the unstable environmental conditions is ensured primarily by its phenotypic plasticity.

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Gyselman, E. C. "Fidelity of Anadromous Arctic Char (Salvelinus alpinus) to Nauyuk Lake, N.W.T., Canada." Canadian Journal of Fisheries and Aquatic Sciences 51, no. 9 (September 1, 1994): 1927–34. http://dx.doi.org/10.1139/f94-194.

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The estimated fidelity of anadromous Arctic char (Salvelinus alpinus) returning to Nauyuk Lake from 1974 to 1978 was low (53%). Seven percent of the fish were absent for 1 or 2 yr before returning. Fidelity was also size dependant. Intermediate-sized fish (35–65 cm) had the highest estimated fidelity, while smaller and larger fish had lower rates. The char leaving Nauyuk Lake each spring were categorized into three groups: postspawning char, char that had been observed returning to Nauyuk Lake at least once, and char that had not shown any fidelity to Nauyuk Lake in the past. The char that had shown fidelity to Nauyuk Lake previously had the highest fidelity rate (75%), while the postspawning char and those that had not shown any previous fidelity to Nauyuk Lake both had a fidelity rate of 45%. The low fidelity of the postspawning char was attributed to a higher mortality rate. Fidelity could not be correlated with the length of time a fish was at sea or when it left Nauyuk Lake in the spring.

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Curtis, Mark A., Michel Bérubé, and Andreas Stenzel. "Parasitological evidence for specialized foraging behavior in lake-resident Arctic char (Salvelinus alpinus)." Canadian Journal of Fisheries and Aquatic Sciences 52, S1 (August 1, 1995): 186–94. http://dx.doi.org/10.1139/f95-526.

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Analyses of statistical associations between the stomach contents and endoparasites of Arctic char, Salvelinus alpinus, from a small (9 ha) lake in northern Quebec revealed that food items found in fish stomachs at the time of capture frequently consisted of intermediate hosts for the parasites infecting the fish. Thus the stomach contents of Arctic char infected by Diphyllobothrium ditremum, D. dendriticum, and Eubothrium salvelini tended to include copepods, while fish infected by the digenean Crepidostomum farionis more frequently contained insect larvae (ephemeropterans) and fish infected by the acanthocephalan Echinorhynchus lateralis most often had amphipods in their stomachs. Moreover, strong quantitative associations were evident between parasites utilizing intermediate hosts from either the benthic or the limnetic zone of the lake. This suggests that some degree of persistent feeding specialization was present among members of the Arctic char population over an extended period of time, with individual fish predominantly feeding upon prey organisms in either limnetic or benthic habitats. In this manner an allopatric Arctic char population may function analogously to more diverse fish communities, where specialist foraging behavior is developed to most efficiently exploit the food web.

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Hobson, Keith A., and Harold E. Welch. "Cannibalism and trophic structure in a high Arctic lake: insights from stable-isotope analysis." Canadian Journal of Fisheries and Aquatic Sciences 52, no. 6 (June 1, 1995): 1195–201. http://dx.doi.org/10.1139/f95-116.

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Stable-nitrogen (15N/14N) isotope ratios (from 2.1‰ in moss to 14.5‰ in Arctic char, Salvelinus alpinus), showed enrichment with trophic level in the food web of Char Lake, Northwest Territories, and may be used to infer trophic position. The average 15N enrichment of 1.5‰ between moss or algae and invertebrates suggests input to the food web of isotopically lighter nitrogen than that measured for these sources of primary production. Stable-carbon (13C/12C) isotope ratios differed between moss and algae by almost 10‰ and indicate that carbon in the Char Lake food web is derived from a blend of these sources of primary production. Arctic char δ15N values for muscle tissue were positively correlated with fork length and clustered into three distinct groups: small fish (1–3 cm, mean δ15N = 5.7‰), which possibly consumed more benthic particles than previously assumed; intermediate-size fish (10–35 cm, mean δ15N = 10‰), which likely depended on larval char as well as their primary zooplankton and chironomid prey; and larger Arctic char, which showed a mean stepwise increase in δ15N of 3.7‰. This suggests that complete cannibalism in this population generally occurs abruptly and is exercised by a relatively small number of large individuals.

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Harris, Les N., David A. Bogsuski, Colin P. Gallagher, and Kimberly L. Howland. "Genetic Stock Identification and Relative Contribution of Arctic Char (Salvelinus alpinus) from the Hornaday and Brock Rivers to Subsistence Fisheries in Darnley Bay, Northwest Territories + Supplementary Appendix Tables S1 to S4 (See Article Tools)." ARCTIC 69, no. 3 (September 2, 2016): 231. http://dx.doi.org/10.14430/arctic4578.

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Where anadromous fishes occur in the Canadian Arctic, they provide the mainstay of local subsistence fisheries of varying intensities. Many of these fisheries harvest a mixture of stocks at discrete locations and it is often not known which stocks, specifically, are being harvested and to what extent. In the Darnley Bay area of the Northwest Territories, Arctic char, Salvelinus alpinus, in particular have long provided an important subsistence resource to residents of Paulatuk, and char from two systems (the Hornaday and Brock Rivers) are thought to contribute to the coastal fishery for this species. Genetic mixed-stock analysis (GMA) is routinely applied for resolving stock contributions to such fisheries, yet studies incorporating GMA to understand specifically which stocks are being harvested in the Canadian Arctic, and to what extent, are relatively scarce. In this study, we assayed microsatellite DNA variation among 987 Arctic char from two important coastal subsistence fisheries and several inland sampling locations in the Darnley Bay area to (1) assess the degree of genetic structuring between the Hornaday and Brock Rivers and (2) resolve the proportional contributions of these stocks to coastal mixed-stock fisheries in the region using GMA. Overall, genetic differentiation was relatively high and significant (θ = 0.117; 95% C.I. = 0.097–0.142) among baseline sampling locations. Overall patterns of genetic stock structure also support previous hypotheses that additional life history types (e.g., landlocked or freshwater-resident char, or both) exist in the Hornaday system, as indicated by elevated levels of genetic differentiation between some of our sampling locations. The GMA suggested that, while both river systems contribute to the coastal fishery, catches were dominated by Arctic char from the Hornaday River, which highlights the importance of this system. All told, our results may be relevant to the management of the subsistence fishery in Darnley Bay and for furthering the collective understanding of char biodiversity and life history variation in the Canadian Arctic.

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Swanson, Heidi K., Karen A. Kidd, and James D. Reist. "Quantifying importance of marine prey in the diets of two partially anadromous fishes." Canadian Journal of Fisheries and Aquatic Sciences 68, no. 11 (November 2011): 2020–28. http://dx.doi.org/10.1139/f2011-111.

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The importance of marine prey sources for partially anadromous fishes has received little study and is complicated by considerable plasticity in life history. We determined proportional contributions of marine, freshwater benthic, and freshwater pelagic prey to anadromous and resident Arctic char (Salvelinus alpinus) and lake trout (Salvelinus namaycush) from several partially anadromous populations in the Canadian Arctic. Bayesian mixing models (MixSIR) applied to δ34S and δ13C ratios in lake-specific models indicated that marine prey accounted for 90%–91% of anadromous Arctic char diet and 60%–66% of anadromous lake trout diet. When these estimates were combined with proportion of anadromous individuals in partially anadromous populations, marine food sources accounted for 31%–44% of Arctic char population productivity and 16%–26% of lake trout population productivity. Although future research is needed to refine and quantify variability around these estimates, our results will allow better predictions of the effects of anthropogenic stressors on partially anadromous fishes.

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Holm, Jens Chr. "Mono- and Duoculture of juvenile Atlantic Salmon (Salmo salar) and Arctic Char (Salvelinus alpinus)." Canadian Journal of Fisheries and Aquatic Sciences 46, no. 4 (April 1, 1989): 697–704. http://dx.doi.org/10.1139/f89-088.

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In a duoculture experiment with Atlantic salmon parr (Salmo salar) and two Arctic char (Salvelinus alpinus) strains, both species showed increased growth rates compared with monoculture. In duoculture, salmon dispersed more evenly than in monoculture, maintaining positions among the char. Less frequent occurrence of dorsal fin rot was observed in duoculture salmon, probably indicating decreased intraspecific aggression, compared with monoculture salmon. It is suggested that shading and increased dispersion allowed a decrease in intraspecific salmon aggression. Arctic char social hierarchy, indicated by variance of mean inter-renal cell nucleus area, was changed in the presence of salmon, favouring the largest individuals belonging to one of the strains. Different ecological adaptations and size differences can explain the difference in growth gain from duoculture between the char strains. Temperature is suggested as a behavioural regulator in salmon–char duoculture.

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Harris, Les N., Jean-Sébastien Moore, Robert Bajno, and Ross F. Tallman. "Genetic Stock Structure of Anadromous Arctic Char in Canada’s Central Arctic: Potential Implications for the Management of Canada’s Largest Arctic Char Commercial Fishery." North American Journal of Fisheries Management 36, no. 6 (November 2016): 1473–88. http://dx.doi.org/10.1080/02755947.2016.1227399.

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Laakkonen, Mika VM, and Heikki Hirvonen. "Is boldness towards predators related to growth rate in naïve captive-reared Arctic char (Salvelinus alpinus)?" Canadian Journal of Fisheries and Aquatic Sciences 64, no. 4 (April 1, 2007): 665–71. http://dx.doi.org/10.1139/f07-041.

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Previous studies have shown that the antipredator responsiveness of fish degenerates through generations in captive breeding. However, detailed knowledge of the underlying mechanism is still largely lacking. We tested the hypothesis that hatchery fish supposedly selected for faster growth in the hatchery environment are bolder towards predators than their slower-growing conspecifics. This was examined by comparing the antipredator behavior of predator- naïve fast- and slow-growing individuals of a captive-bred Arctic char (Salvelinus alpinus) population to chemical cues from natural predators burbot (Lota lota) and pikeperch (Sander lucioperca). As behavioral responses depended on char body size, we compared boldness towards predators of size-matched fast- and slow-growing char. We found no differences in four behavioral antipredator traits between size-matched groups of fast- and slow-growing char. According to these results, boldness to predator cues is not related to individual growth rate in captive-bred Arctic char.

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Finstad, Anders Gravbrøt, Peder Andreas Jansen, and Heikki Hirvonen. "Bimodal size distributions in Arctic char, Salvelinus alpinus: artefacts of biased sampling." Canadian Journal of Fisheries and Aquatic Sciences 60, no. 9 (September 1, 2003): 1104–10. http://dx.doi.org/10.1139/f03-089.

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Bimodal population size and age distributions in Arctic char (Salvelinus alpinus (L.)) and hypotheses on growth patterns generating bimodality have drawn considerable attention during the last decade. However, such bimodality has also been suggested to be an artefact of biased sampling. We examined published data sets reporting bimodal size distributions in gill-net samples of Arctic char in order to confront hypotheses on growth patterns generating bimodal population size distributions. Growth patterns were derived from published length-at-age data. Simulations revealed that the observed growth patterns evidently could not generate a bimodal population size distribution. The basic reason for this was that growth did not stagnate strongly enough in the largest size classes of Arctic char. The reliability of growth approximations from length-at-age data was supported by empirical data on back-calculated growth trajectories. Furthermore, differences in year-class strength cannot explain all of the observed bimodal size and age distributions in gill-net samples, as they have been reported to persist over time. Thus, bias in the sampling procedure, which overestimates the frequency of old and large fish, is retained as the only plausible explanation for stable bimodal size distributions often observed in Arctic char gill-net samples.

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Swanson, Heidi K., Karen A. Kidd, John A. Babaluk, Rick J. Wastle, Panseok P. Yang, Norman M. Halden, and James D. Reist. "Anadromy in Arctic populations of lake trout (Salvelinus namaycush): otolith microchemistry, stable isotopes, and comparisons with Arctic char (Salvelinus alpinus)." Canadian Journal of Fisheries and Aquatic Sciences 67, no. 5 (May 2010): 842–53. http://dx.doi.org/10.1139/f10-022.

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In the family Salmonidae, lake trout ( Salvelinus namaycush ) are considered the least tolerant of salt water. There are, however, sporadic reports of lake trout in coastal, brackish habitats in the Canadian Arctic. Otolith microchemistry analyses conducted on lake trout and Arctic char ( Salvelinus alpinus ) from four Arctic lakes in the West Kitikmeot region of Nunavut, Canada, revealed that 37 of 135 (27%) lake trout made annual marine migrations. Anadromous lake trout were in significantly better condition (K = 1.17) and had significantly higher C:N ratios (3.71) than resident lake trout (K = 1.05 and C:N = 3.34). Anadromous lake trout also had significantly higher δ15N (mean = 16.4‰), δ13C (mean = –22.3‰), and δ34S (mean = 13.43‰) isotope ratios than resident lake trout (means = 12.84‰, –26.21‰, and 1.93‰ for δ15N, δ13C, and δ34S, respectively); results were similar for Arctic char and agree with results from previous studies. Mean age of first migration for lake trout was 13 years, which was significantly older than that for Arctic char (5 years). This could be a reflection of size-dependent salinity tolerance in lake trout, but further research is required. These are the first detailed scientific data documenting anadromy in lake trout.

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Borgen, Anders R., Martin Schlabach, Roland Kallenborn, and Eirik Fjeld. "Polychlorinated Alkanes in Fish from Norwegian Freshwater." Scientific World JOURNAL 2 (2002): 136–40. http://dx.doi.org/10.1100/tsw.2002.82.

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Short-chain polychlorinated alkanes (sPCAs) have been measured in freshwater fish samples from different lakes all over Norway and from the Norwegian Arctic. The analyses were performed with high-resolution GC coupled to high-resolution MS in electron capture negative ion mode. The species investigated were trout, Arctic char, and burbot (Lota lota). Muscle tissue in the lake trout and Arctic char, and liver in burbot, were selected for analyses because of their high lipid content. ∑sPCA concentration ranged from 108 to 3700 ng/g fat. The highest value was found in the south of Norway near an industrial area.

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Bérubé, Michel, and Mark A. Curtis. "Transmission of Diphyllobothrium ditremum to Arctic Char (Salvelinus alpinus) in Two Subarctic Quebec lakes." Canadian Journal of Fisheries and Aquatic Sciences 43, no. 8 (August 1, 1986): 1626–34. http://dx.doi.org/10.1139/f86-201.

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Diphyllobothrium ditremum (Cestoda: Pseudophyllidea) transmission to arctic char (Salvelinus alpinus) was investigated at two small (<10 ha) lakes in northern Quebec, where the char populations exhibit a marked difference in plerocercoid prevalence (78 vs. 18%) and abundance (27.7 vs. 1.2 plerocercoids/fish). The highly infected char population was characterized by slow growth and poor feeding conditions. Feeding behavior of char in the two lakes differed principally in the fall, when consumption of benthos significantly decreased in the highly infected population as char fed more on copepods or sticklebacks (Gasterosteus aculeatus). Presence of these two food items in char stomachs was associated with high abundance of D. ditremum. The availability of alternative foods, such as larval insects and amphipods, appears to prevent char from acquiring heavy infections of D. ditremum, even in circumstances where all potential hosts are present.

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34

Berg, Ole Kristian, and Magnus Berg. "Sea Growth and Time of Migration of Anadromous Arctic Char (Salvelinus alpinus) from the Vardnes River, in Northern Norway." Canadian Journal of Fisheries and Aquatic Sciences 46, no. 6 (June 1, 1989): 955–60. http://dx.doi.org/10.1139/f89-123.

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The annual seaward migration of Arctic char (Salvelinus alpinus) from the Vardnes River, northern Norway usually takes place early in summer, between the end of May and the beginning of June. A period of very fast growth was recorded immediately following the entry of char into the sea. Mean daily growth rates of both small and large char decreased with increasing length of time spent at sea, particularly after the end of June. Almost no further increase in length took place in the sea after the beginning of July. Sea temperature was low during this early growth period, rising to above 10 °C during the period when sea char growth declined. Char appeared to be especially well adapted to low temperatures, since their growth rate during this early period was from two to four times faster than that recorded for sympatric sea trout (Salmo trutta). The results support the hypothesis that sea temperature may be one of the factors that control the southern distribution of anadromous Arctic char.

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BYSTRÖM, PÄR. "Recruitment pulses induce cannibalistic giants in Arctic char." Journal of Animal Ecology 75, no. 2 (March 31, 2006): 434–44. http://dx.doi.org/10.1111/j.1365-2656.2006.01064.x.

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36

Boyer, J. N., and W. Van Toever. "Reconditioning of Arctic char (Salvelinus alpinus) after spawning." Aquaculture 110, no. 3-4 (March 1993): 279–84. http://dx.doi.org/10.1016/0044-8486(93)90376-a.

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37

Christensen, B. "Uptake and release of fluoride in arctic char." Environmental Toxicology and Chemistry 6, no. 7 (July 1987): 529–33. http://dx.doi.org/10.1002/etc.5620060705.

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38

Bernatchez, Louis, J. Brian Dempson, and Sylvain Martin. "Microsatellite gene diversity analysis in anadromous arctic char, Salvelinus alpinus, from Labrador, Canada." Canadian Journal of Fisheries and Aquatic Sciences 55, no. 5 (May 1, 1998): 1264–72. http://dx.doi.org/10.1139/f97-325.

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We analysed six loci among 257 Arctic char (Salvelinus alpinus) representing seven locations in Labrador and Newfoundland to provide a first assessment of microsatellites gene diversity in anadromous char and to determine the geographic scale of population structuring within the species. The number of alleles per locus varied between 9 and 48, and gene diversity ranged from 0.190 to 0.968. Significant FST and differences in allele frequencies were observed among most samples, as well as heterozygous deficiency, which was indicative of a Wahlund's effect. These results implied the existence of genetically distinct populations on a microgeographic scale (less than 10 km) and that our samples represented an admixture of char from those populations that interchange among rivers for owerwintering, in congruence with tagging investigations. These results indicate that microsatellites potentially offer more sensitivity than allozymes and mitochondrial DNA to infer fine-scale population structure in anadromous arctic char.

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39

Arbour, J. H., D. C. Hardie, and J. A. Hutchings. "Morphometric and genetic analyses of two sympatric morphs of Arctic char (Salvelinus alpinus) in the Canadian High Arctic." Canadian Journal of Zoology 89, no. 1 (January 2011): 19–30. http://dx.doi.org/10.1139/z10-100.

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Multivariate morphometric analyses were used to examine variation in head, body, and fin shape between two sympatric morphotypes of Arctic char ( Salvelinus alpinus (L., 1758)) from Lake Hazen, Ellesmere Island, Nunavut, Canada. Population structure of the Lake Hazen Arctic char was examined using five microsatellite loci. The “small” morph was found to have a larger (primarily deeper) head, larger and more elongate fins, and a deeper lateral profile than the “large” morph. The morphs also differed in allometric growth patterns. The large and small morphs do not appear to represent genetically distinct populations. The head morphology of the Lake Hazen small and large morphs exhibited similarities to benthic and pelagic morphs (respectively) from other lakes. We hypothesize that the large morph may be adapted to high-efficiency swimming and that the small morph may be adapted to low-efficiency, high-acceleration swimming. Such functional trade-offs are not uncommon among fish specializing in dispersed or mobile prey (fish and plankton) and benthic prey, respectively. The lack of apparent genetic differentiation between the morphs may suggest that the morphological differences result, to some extent, from phenotypic plasticity. Based on these results and previous analyses, it seems reasonable to conclude that Lake Hazen Arctic char represent a resource polymorphism.

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Mulder, Ingeborg M., Corey J. Morris, J. Brian Dempson, Ian A. Fleming, and Michael Power. "Overwinter thermal habitat use in lakes by anadromous Arctic char." Canadian Journal of Fisheries and Aquatic Sciences 75, no. 12 (December 2018): 2343–53. http://dx.doi.org/10.1139/cjfas-2017-0420.

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Anadromous Arctic char (Salvelinus alpinus) migrate back to fresh water in late summer to spawn and (or) overwinter. Upon freshwater entry, feeding is reduced or absent, and movement activity is restricted. While the physiological responses to low temperatures (e.g., growth, metabolism) are understood, specifics of the use of thermal habitat for overwintering remains poorly characterized. This study used acoustic and archival telemetry data from two lakes in southern Labrador, Canada, to study thermal habitat use during the ice-covered period. Results showed that lake-dwelling anadromous Arctic char predominantly occupied a narrow range of temperatures (0.5–2 °C) and used cooler temperatures available within the middle and upper water column. Use of the selected temperatures is likely a strategy that lowers metabolic costs and minimizes energy expenditure, preserving stored lipids for overwinter survival and the energetic costs of preparation for seaward migration. As Arctic char are visual feeders, use of the upper water column is also thought to aid foraging efficiency by increasing the likelihood of prey capture.

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41

Bernatchez, Louis, Hélène Glémet, Chris C. Wilson, and Roy G. Danzmann. "Introgression and fixation of Arctic char (Salvelinus alpinus) mitochondrial genome in an allopatric population of brook trout (Salvelinus fontinalis)." Canadian Journal of Fisheries and Aquatic Sciences 52, no. 1 (January 1, 1995): 179–85. http://dx.doi.org/10.1139/f95-018.

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Although mitochondrial introgression between taxa has been increasingly documented, interspecific replacement of mtDNA is rare, particularly when the donor species is absent. We document evidence for a population of brook trout (Salvelinus fontinalis) in which all individuals possess the mitochondrial genome of Arctic char (S. alpinus) despite the present-day absence of the latter species in the watershed where the population is located. The mitochondrial genotype of 48 brook trout from Lake Alain (Québec) was characterized by RFLP analysis performed over the entire mtDNA molecule and/or a 2.5-kb PCR-amplified segment of the ND-5/6 region. Although the fish examined were morphologically indistinguishable from typical brook trout and homozygous for the diagnostic alleles characteristic of brook trout, the mtDNA of all individuals was identical to the Québec Arctic char haplotype. Together, these results indicate that the mtDNA haplotype observed in Lake Alain brook trout has resulted from ancient introgression with Arctic char rather than ancestral polymorphism or convergent evolution. They also demonstrate that introgressive hybridization between those two species can have significant and long-term effects on their genetic composition.

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42

Gunnarsson, Guðmundur Smári, and Stefán Óli Steingrímsson. "Contrasting patterns of territoriality and foraging mode in two stream-dwelling salmonids, Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta)." Canadian Journal of Fisheries and Aquatic Sciences 68, no. 12 (December 2011): 2090–100. http://dx.doi.org/10.1139/f2011-127.

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Territoriality and foraging behaviour play major roles in determining the abundance and distribution of mobile animals. To date, territorial behaviour of young-of-the-year (YOY) salmonids is typically described for sit-and-wait individuals that defend territories from one foraging station, but rarely for more mobile fish. We examined the territorial behaviour and foraging mode of 31 YOY Arctic char ( Salvelinus alpinus ) and 30 YOY brown trout ( Salmo trutta ) in relation to ecological factors in six rivers in northern Iceland. Arctic char used larger territories than brown trout, corresponding with high and low mobility prior to attacking prey, respectively. Within species, more mobile fish also used larger territories. Territory size increased with body size and declined with increased food abundance as predicted, but surprisingly increased with rising intruder pressure. Finally, Arctic char territories overlapped more and were less exclusively defended than brown trout territories. This study shows that territories of mobile individuals may not always pertain to the same rules as single central-place territories and highlights that territorial behaviour, and its role in population regulation, may vary between salmonid species.

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43

Halačka, Karel, Radovan Kopp, Ondřej Klíma, and Jan Mareš. "Epidermis structure in the brook trout (Salvelinus fontinalis) and its Arctic char (Salvelinus alpinus) hybrid." Acta Veterinaria Brno 84, no. 2 (2015): 159–66. http://dx.doi.org/10.2754/avb201584020159.

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Brook trout (Salvelinus fontinalis) is a species of fish native to North-East America. Brook trout are also commercially raised in large numbers for food production. Skin infection and/or parasite outbreaks can have a serious economics effect on aquaculture businesses. For this reason, it has been hybridized with the more resistant Arctic char (Salvelinus alpinus). The aim of this study was an examination of the epidermal structure and dynamic in brook trout and its Arctic char hybrid which is less sensitive to skin infection. The samples of fish (72 brook trout, 72 brook trout × Arctic char hybrid) from fish farm in Pravíkov (49°19’10”N, 15°5’40”E) were collected five times during the year 2011. Absolute and relative epidermal thickness (in relation to body size) and relative proportion of secretory cells in a given volume of epidermis were measured. The epidermis structure of brook trout and brook trout × Arctic char hybrid both display similar seasonal dynamics, with a decrease in absolute and relative epidermal thickness and a reduction in the relative percentage of mucous secretory cells over the summer. On the other hand, the lower absolute (mean 103 µm (range 84–146 µm) in brook trout; 88 µm (range 68–115 µm) in hybrids) and relative epidermal thickness (mean 4.8 (range 3.6–6.8) in brook trout; 4.4 (range 2.9–6.4) in hybrids) and lower volume of secretory cells was observed to the hybrid (mean 28% (range 19–33%) in brook trout; 23% (range 10–30%) in hybrids). It can interrelate with their higher resistance to infection and/or parasite outbreaks.

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Dahl-Hansen, Geir A. P., Stein H. Rubach, and Anders Klemetsen. "Selective Predation by Pelagic Arctic Char on Crustacean Plankton in Takvatn, Northern Norway, before and after Mass Removal of Arctic Char." Transactions of the American Fisheries Society 123, no. 3 (May 1994): 385–94. http://dx.doi.org/10.1577/1548-8659(1994)123<0385:spbpac>2.3.co;2.

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45

Poléo, Antonio BS, and Frode Bjerkely. "Effect of unstable aluminium chemistry on Arctic char (Salvelinus alpinus)." Canadian Journal of Fisheries and Aquatic Sciences 57, no. 7 (July 1, 2000): 1423–33. http://dx.doi.org/10.1139/f00-084.

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Arctic char (Salvelinus alpinus) were exposed to a non-steady-state Al-rich medium (pH 5.8, total Al 480 µg·L-1, total organic C 3.0 mg C·L-1, Ca2+ 2.9 mg·L-1, temperature 7.5°C). An Al-poor medium (pH 5.2 and 5.8, total Al 99 µg·L-1, total organic C 3.0 mg C·L-1, Ca2+ 2.9 mg·L-1, temperature 8.0°C) acted as control. The Al-rich medium was acutely toxic to the Arctic char. Total mortality (percent) and mortality rate (LT50) were highest in fish exposed to the Al-rich medium immediately after mixing and decreased systematically with water residence time (e.g., from 65 h at 1 min to 124 h at 3 min to more than 400 h at 15 min). Gill morphology changes, Al gill deposition, and haematological parameters revealed significant effects of Al, which all correlated with water residence time. Signs of acclimation or high difference in Al tolerance between individuals were observed. This indicates that effects of Al in fish are dependent on the degree of Al polymerisation and supports earlier indications that Arctic char are relatively tolerant of acidic Al-rich water.

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46

Ziaja, Wieslaw. "An Arctic char observed in a glacial Spitsbergen river." Polar Record 50, no. 3 (January 20, 2014): 333–35. http://dx.doi.org/10.1017/s0032247413000879.

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ABSTRACTAn anadromous Arctic char (male) was recorded in southwestern Spitsbergen, in a very muddy glacial river, in August 2008. This is apparently the first specimen of this species observed in such an unfavourable habitat in Svalbard.

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47

Jones, Keith A., and Toshiaki J. Hara. "Behavioral Alterations in Arctic Char (Salvelinus alpinus) Briefly Exposed to Sublethal Chlorine Levels." Canadian Journal of Fisheries and Aquatic Sciences 45, no. 4 (April 1, 1988): 749–52. http://dx.doi.org/10.1139/f88-092.

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Changes in the locomotor behavior of Arctic char (Salvelinus alpinus) exposed inadvertently to sublethal chlorine concentrations (> 19μg total residual chlorine/L) for 6 d are described. Compared with their preexposure behavior, the char became hypoactive, much more strongly thigmotactic, and less responsive to a food extract during the exposure. After the high chlorine levels subsided, the char continued to be hypoactive for at least 1 wk and failed to respond positively to the food extract for 20 d. There is evidence that some individuals displayed chlorine stress behavior for at least 46 d after the return of nonstressful conditions.

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Adams, N. J., D. R. Barton, R. A. Cunjak, G. Power, and S. C. Riley. "Diel patterns of activity and substrate preference in young Arctic char from the Koroc River, northern Quebec." Canadian Journal of Zoology 66, no. 11 (November 1, 1988): 2500–2502. http://dx.doi.org/10.1139/z88-370.

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Young Arctic char (Salvelinus alpinus) were observed in a stream tank located on the bank of the Koroc river, northern Quebec. Early in the summer, char were most active from dusk to dawn, and at midday, mainly over gravel or sand. Some nocturnal feeding activity was evident. As the summer progressed, this diel periodicity in activity became less pronounced; char exhibited increasing diurnal activity, most of it over rubble substrata. Char preferred rubble for resting throughout the summer. Invertebrate drift decreased from July through August so that, although fish were active more of the time, the rate of feeding during periods of activity declined.

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Aas-Hansen, Øyvind, Mathilakath M. Vijayan, Helge K. Johnsen, Colin Cameron, and Even H. Jørgensen. "Resmoltification in wild, anadromous Arctic char (Salvelinus alpinus): a survey of osmoregulatory, metabolic, and endocrine changes preceding annual seawater migration." Canadian Journal of Fisheries and Aquatic Sciences 62, no. 1 (January 1, 2005): 195–204. http://dx.doi.org/10.1139/f04-186.

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Anadromous Arctic char (Salvelinus alpinus) migrate to seawater every summer for feeding and spend the rest of the year overwintering in fresh water. We investigated whether annual seawater migration is preceded by changes in hyposmoregulatory capacity, intermediary metabolism, and the plasma levels of hormones known to play a role in salmonid seawater preadaptation (smoltification). Wild, anadromous Arctic char were sampled in their overwintering lake in April and May and during the period of downstream migration in June. Our results demonstrate a fourfold seasonal increase in gill Na+/K+ ATPase activity, with maximum levels in descending migrants that also displayed prime hyposmoregulatory capacity. Hepatosomatic index and activities of key liver enzymes also increased during spring, indicating a general increase in liver metabolic capacity. These changes were accompanied by increased plasma cortisol and thyroxine levels, decreased plasma growth hormone levels, and unchanged plasma levels of insulin-like growth factor-I and 3,5,3′-triiodothyronine. Our results indicate that wild, anadromous Arctic char resmoltify every spring, and this involves a shift from an energy-conserving overwintering state to a state where they become osmotically and metabolically prepared for their annual feeding migration to seawater.

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Mulder, Ingeborg M., Corey J. Morris, J. Brian Dempson, Ian A. Fleming, and Michael Power. "Marine temperature and depth use by anadromous Arctic char correlates to body size and diel period." Canadian Journal of Fisheries and Aquatic Sciences 77, no. 5 (May 2020): 882–93. http://dx.doi.org/10.1139/cjfas-2019-0097.

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Acoustic and archival telemetry were used to study the marine movements of 115 anadromous Arctic char (Salvelinus alpinus) at two sites in southern Labrador, Canada, in relation to daily variation in temperature and depth use, body size, and their effects on marine activity patterns. Although evidence varied between locations, Arctic char generally utilized ambient water temperatures available in the upper water column, possibly in aid of physiological processes such as digestion, whereas deeper waters were suggested to be used for feeding purposes. Size-dependent thermal preferences were evident, with larger individuals utilizing cooler water temperatures (8.5 °C) compared with smaller individuals (9.5 °C), a pattern suggestive of ontogenetic changes in thermal habitat use for the purposes of growth maximization. Diurnal patterns of diving activity were interpreted to reflect the vertical migration of prey items and (or) the visual capabilities of Arctic char. Dive duration was dependent on body size and external body temperature with smaller individuals performing shorter dives in colder water temperatures (<1 min at 5 °C) than larger fish (∼2 min at 5 °C), likely to maintain their core temperature and abilities to both effectively capture prey and avoid predation.

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Journal articles on the topic 'Arctic char Arctic char'

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