Plasma levels of thyroxine, prolactin, and cortisol in migrating and resident wild arctic char, Salvelinus alpinus

1997 ◽  
Vol 54 (12) ◽  
pp. 2947-2954 ◽  
Author(s):  
Helga Rachel Høgåsen ◽  
Patrick Prunet
Keyword(s):  
Thyroid Hormones ◽  
Salvelinus Alpinus ◽  
Gonadosomatic Index ◽  
Downstream Migration ◽  
Plasma Cortisol Level ◽  
Arctic Char ◽  
Plasma Prolactin ◽  
Seaward Migration ◽  
Energy Stores ◽  
Prevailing View

The study was performed on 14-49 cm wild arctic char, Salvelinus alpinus. Plasma thyroxine concentration was twice as high in upstream and downstream migrants (3.8 and 4.0 ng/mL, respectively) as in non-migrants (1.7 ng/mL), supporting the prevailing view that thyroid hormones are stimulatory to both upstream and downstream migration in wild anadromous salmonids. The stimulation of downstream migration by thyroid hormones is suggested to depend on the low feeding state of wild smolts. Plasma prolactin concentration was lower in downstream migrants (10.3 ng/mL) than in non-migrants sampled during the period of downstream migration (16.2 ng/mL), suggesting a possible role for this hormone in repressing seaward migration. Plasma cortisol level was twice as high in upstream migrants (464 ng/mL) as in downstream migrants (244 ng/mL) trapped in a standardized manner. Higher interrenal capacity or responsiveness in upstream migrants may increase their ability to mobilize energy stores. In upstream-migrating females, plasma prolactin concentration was positively correlated with the gonadosomatic index, suggesting a role for prolactin in early sexual maturation. Body length, which was correlated with numbers of migrations, was found to be related only to plasma thyroxine concentration in downstream migrants.

Overwinter thermal habitat use in lakes by anadromous Arctic char

2018 ◽  
Vol 75 (12) ◽  
pp. 2343-2353 ◽  
Author(s):  
Ingeborg M. Mulder ◽  
Corey J. Morris ◽  
J. Brian Dempson ◽  
Ian A. Fleming ◽  
Michael Power
Keyword(s):  
Habitat Use ◽  
Water Column ◽  
Prey Capture ◽  
Salvelinus Alpinus ◽  
Late Summer ◽  
Arctic Char ◽  
Foraging Efficiency ◽  
Thermal Habitat ◽  
Metabolic Costs ◽  
Seaward Migration

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.

Feeding and Migratory Habits of Arctic Char, Salvelinus alpinus, Indicated by the Presence of the Swimbladder Nematode Cystidicola cristivomeri White

1978 ◽  
Vol 35 (11) ◽  
pp. 1488-1491 ◽  
Author(s):  
S. B. Eddy ◽  
M. W. Lankester
Keyword(s):  
Intermediate Host ◽  
Salvelinus Alpinus ◽  
Arctic Char ◽  
Shallow Waters ◽  
Small Fish ◽  
Swim Bladder ◽  
Mysis Relicta ◽  
Seaward Migration ◽  
Slow Growing ◽  
Feeding Migration

The presence of Cystidicola cristivomeri White 1941 in the swim bladder of char indicates the fish have fed on infected, freshwater Mysis relicta which is the essential intermediate host of this parasite. Char younger than 5 yr occur in shallow waters in Stanwell-Fletcher Lake and apparently feed rarely on Mysis as indicated by infrequent infection with C. cristivomeri. Older fish that adopt a migratory habit and go to sea for the summer appear to feed little on Mysis when they return to overwinter in the lake. Small, slow-growing char present in the lake during summer were commonly infected with C. cristivomeri indicating they feed heavily on Mysis. These small fish, which are as old as many migrants, may not participate regularly in the seaward migration. Key words: Arctic char, feeding, migration, nematodes, Cystidicola cristivomeri

Sea Growth and Time of Migration of Anadromous Arctic Char (Salvelinus alpinus) from the Vardnes River, in Northern Norway

1989 ◽  
Vol 46 (6) ◽  
pp. 955-960 ◽  
Author(s):  
Ole Kristian Berg ◽  
Magnus Berg
Keyword(s):  
Salmo Trutta ◽  
Salvelinus Alpinus ◽  
Early Period ◽  
Growth Period ◽  
Arctic Char ◽  
Daily Growth ◽  
Sea Temperature ◽  
Northern Norway ◽  
Sea Trout ◽  
Seaward Migration

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.

First confirmation of salmonid alphavirus infection in Arctic char Salvelinus alpinus and in Austria

2018 ◽  
Vol 130 (1) ◽  
pp. 71-76
Author(s):  
E Lewisch ◽  
T Frank ◽  
H Soliman ◽  
O Schachner ◽  
A Friedl ◽  
...  
Keyword(s):  
Salvelinus Alpinus ◽  
Arctic Char ◽  
Alphavirus Infection

scholarly journals Investigating the morphological and genetic divergence of arctic char ( Salvelinus alpinus) populations in lakes of arctic Alaska

2021 ◽  
Author(s):  
Stephen L. Klobucar ◽  
Jessica A. Rick ◽  
Elizabeth G. Mandeville ◽  
Catherine E. Wagner ◽  
Phaedra Budy
Keyword(s):  
Genetic Divergence ◽  
Salvelinus Alpinus ◽  
Arctic Char ◽  
Arctic Alaska

Influence of Parr Growth, Lake Morphology, and Freshwater Parasites on the Degree of Anadromy in Different Populations of Arctic Char (Salvelinus alpinus) in Northern Norway

1994 ◽  
Vol 51 (6) ◽  
pp. 1229-1246 ◽  
Author(s):  
Knut Kristoffersen ◽  
Morten Halvorsen ◽  
Lisbeth Jørgensen
Keyword(s):  
Salvelinus Alpinus ◽  
Relative Size ◽  
Significant Negative Correlation ◽  
Relative Volume ◽  
Arctic Char ◽  
Northern Norway ◽  
Length Relationship ◽  
Lake Morphology ◽  
Different Populations ◽  
Profundal Zone

Anadromy of nine lake populations of Arctic char (Salvelinus alpinus) in northern Norway was scored on the following criteria: prevalence of marine parasites, fish size, and size at maturity. In general, anadromy dominated in shallow lakes and residency dominated in deep lakes. The anadromy scores of the populations were significantly higher in lakes without a profundal zone compared with lakes with a profundal zone. There was also a significant negative correlation between the relative volume of the profundal zone (RPV) and the degree of anadromy and between RPV and mean parr length at ages 2+ and 3+. However, differences in parr growth could not explain all the observed variation in anadromy, and the correlation between mean parr length at ages 2+ and 3+ and the degree of anadromy in the different populations was not significant. In addition to the effect on parr growth, lake morphology seemed to influence the degree of anadromy through the relative size of different habitats, which in turn affects the number of available niches. The parr weight/length relationship and infection with the freshwater parasites Phyllodistomum umblae and Diphyllobothrium spp. did not affect the degree of anadromy.

Respiratory development in Arctic char Salvelinus alpinus under conditions of normoxia and chronic hypoxia

1977 ◽  
Vol 55 (9) ◽  
pp. 1461-1467 ◽  
Author(s):  
D. G. McDonald ◽  
B. R. McMahon
Keyword(s):  
Heart Rate ◽  
Surface Morphology ◽  
Chronic Hypoxia ◽  
Prolonged Exposure ◽  
Salvelinus Alpinus ◽  
Ventilation Rate ◽  
Arctic Char ◽  
Adult Fish ◽  
Weighted Averages ◽  
Secondary Lamellae

Changes in surface morphology of the gills, ventilation rate, and heart rate were examined in Arctic char larvae exposed to normoxia (pO2 = 121 ± 6 (SE) mmHg) or chronic hypoxia (pO2 = 33 ± 3.5 mmHg) for 47 days after hatching. A modified weighted-averages technique was developed to measure aspects of gill morphology.Early development of the gills was characterized by rapid increases in filament size and number, and the emergence and proliferation of secondary lamellae. Variations in the dimensions of the gills, as noted in adult fish, were particularly evident in the larval fish.Hypoxia caused increases in both ventilation rate and heart rate. Prolonged exposure led to a retardation of gill growth, particularly the proliferation of secondary lamellae. However, growth of individual lamellae was stimulated between 38 and 47 days.

Annual Variations in Rheotactic Behaviour and Seawater Adaptability in Landlocked Arctic Char (Salvelinus alpinus)

1992 ◽  
Vol 49 (3) ◽  
pp. 448-452 ◽  
Author(s):  
Monika Schmitz
Keyword(s):  
Seasonal Changes ◽  
Salvelinus Alpinus ◽  
Challenge Test ◽  
Early Summer ◽  
Rapid Decrease ◽  
Arctic Char ◽  
Migratory Behaviour ◽  
Annual Variations ◽  
Seawater Tolerance ◽  
Seawater Challenge

The existence of basic smoltification characteristics, measured by means of seasonal changes in rheotactic behaviour and seawater adaptability, was studied from February to November in 1- and 2-yr-old landlocked Arctic char (Salvelinus alpinus). Up- and downstream directed movements were monitored in an annular stream tank at a water velocity of 0.2 m/s. A 48-h seawater challenge test using 25‰ seawater was performed at monthly intervals throughout the year to assess seawater adaptability. The 1-yr-old char displayed mainly nondirectional behaviour during spring, but from August onwards the movements were predominantly against the current. Seawater performance improved slightly in this group in May and June. The 2-yr-old char progressively developed a downstream behaviour and exhibited an increased seawater adaptability during spring and early summer. In late August, a marked reversal in rheotactic behaviour occurred, followed by a rapid decrease in seawater tolerance. The results demonstrate that seasonal changes in seawater adaptability and changes in migratory behaviour which were directionally consistent with smolting still exist in a population of Arctic char that has been landlocked for about 6000 yr.

Summer stream habitat preferences of Nunavik anadromous Arctic char (Salvelinus alpinus) fry and parr

2022 ◽  
Author(s):  
Véronique Dubos ◽  
André St-Hilaire ◽  
Normand E Bergeron
Keyword(s):  
Habitat Use ◽  
Salvelinus Alpinus ◽  
Habitat Preferences ◽  
Arctic Region ◽  
Arctic Char ◽  
The Arctic ◽  
Stream Habitat ◽  
Physical Habitat ◽  
High Plasticity ◽  
Slow Velocity

Arctic char is a fish species known to occupy diverse habitats within the Arctic region. However, summer habitat use during the juvenile stage of the anadromous form is largely unknown. The present study aims to characterize fry and parr summer habitat preferences. Surveys were conducted by electrofishing, associated with physical habitat characterization on several rivers of the Ungava Bay, Nunavik, Canada. At the microhabitat and station scales, fry showed significant habitat preferences for shallow water and slow velocity. At the mesohabitat scale, fry showed a significant habitat selectivity for riffles. This habitat selectivity implies that habitat models can be built to evaluate the potential of habitat suitability for Arctic char fry. However, no significant habitat selectivity was found for parr. Parr size was nonetheless positively correlated with velocity, which was found to be a limitative factor for juvenile habitat use. This first attempt at modeling juvenile anadromous Arctic char habitat in rivers emphasizes the importance of selecting an appropriate spatial scale and reiterates the fact that parr showed relatively high plasticity in stream habitat selection.

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