Marine temperature and depth use by anadromous Arctic char correlates to body size and diel period

2020 ◽  
Vol 77 (5) ◽  
pp. 882-893 ◽  
Author(s):  
Ingeborg M. Mulder ◽  
Corey J. Morris ◽  
J. Brian Dempson ◽  
Ian A. Fleming ◽  
Michael Power
Keyword(s):  
Body Size ◽  
Salvelinus Alpinus ◽  
Activity Patterns ◽  
Dive Duration ◽  
Arctic Char ◽  
Ontogenetic Changes ◽  
Thermal Habitat ◽  
Physiological Processes ◽  
Thermal Preferences ◽  
Depth Use

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.

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.

Diurnal and nocturnal feeding activity in Arctic char (Salvelinus alpinus) and rainbow trout (Oncorhynchus mykiss)

1997 ◽  
Vol 54 (12) ◽  
pp. 2894-2900 ◽  
Author(s):  
Anders Alanärä ◽  
Eva Brännäs
Keyword(s):  
Rainbow Trout ◽  
Oncorhynchus Mykiss ◽  
Salvelinus Alpinus ◽  
Feeding Activity ◽  
Activity Patterns ◽  
Arctic Char ◽  
Diel Activity ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Nocturnal Feeding ◽  
Nocturnal Fish

When food is limited and competition for it is high, individual fish may adopt different diel activity patterns. We followed individual feeding activity in groups of 10 Arctic char (Salvelinus alpinus) and rainbow trout (Oncorhynchus mykiss) using a combined self-feeding and PIT-tag system. Food was supplied at low and high rewards to five replicate groups of Arctic char and rainbow trout. Four categories were identified in both species: high-triggering diurnal (diurnal fish with the highest self-feeding activity), low-triggering diurnal, nocturnal, and nontriggering fish. On average, the photophase proportion of the total daily activity was approx 90% in diurnal and approx 20% in nocturnal individuals. Rainbow trout offered high rewards did not show any diel preferences. Diurnal Arctic char and rainbow trout with the highest self-feeding activity were initially larger and had the highest growth rates, indicating a high social position. Nocturnal fish were initially smaller and their proportion of trigger actuations much lower than the high-triggering diurnal fish. These still grew successfully whereas nontriggering fish grew significantly less. Thus, some individuals with a low social status may apply an alternative strategy to attain adequate growth by feeding at night when dominant individuals are less aggressive. This may be referred to as concurrent dualism (diurnalism and nocturnalism).

Experimental assessment of the bioenergetic and behavioural differences between two morphologically distinct populations of Arctic char (Salvelinus alpinus)

2010 ◽  
Vol 67 (3) ◽  
pp. 580-595 ◽  
Author(s):  
Guillaume Guénard ◽  
Daniel Boisclair ◽  
Ola Ugedal ◽  
Torbjørn Forseth ◽  
Bror Jonsson ◽  
...  
Keyword(s):  
Food Consumption ◽  
Salmo Trutta ◽  
Salvelinus Alpinus ◽  
Activity Patterns ◽  
Arctic Char ◽  
Winter Period ◽  
Fish Community Structure ◽  
Spatial And Temporal Patterns ◽  
Functional Differences ◽  
Environment Experiment

A common environment experiment was conducted to assess the magnitude of the difference in growth, consumption, activity rate, and spatial and temporal patterns of habitat use between morphologically different populations of Arctic char ( Salvelinus alpinus ) originating from two Norwegian lakes. These two lakes contrasted sharply in terms of surface area, depth, elevation, length of the winter period, and fish community structure (presence–absence of brown trout, Salmo trutta ). The experimental framework encompassed four littoral enclosures (average volume, 146 m3) stocked with char from either of the two populations with duplicated treatments. Char morphology was quantified with numerical image analysis, food consumption was estimated using caesium analysis (133Cs), and activity cost and patterns were determined using video cameras. Char populations were morphologically distinct and reacted differently in growth (1.9-fold difference between populations), food consumption (3-fold difference), and spatial activity patterns (20-fold difference) to the conditions prevailing in the enclosures. The results highlight that functional differences between morphologically distinct char may drive important differences in their bioenergetic and behavioural responses when exposed to similar environmental conditions. Such functional differences should be incorporated when developing habitat or trophic cascade models.

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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