Long-term Experiments on the Stability of Two Fish Populations in Previously Unexploited Arctic Lakes

1994 ◽  
Vol 51 (1) ◽  
pp. 209-225 ◽  
Author(s):  
Lionel Johnson
Keyword(s):  
Energy Flow ◽  
Environmental Variability ◽  
Salvelinus Alpinus ◽  
Stable State ◽  
Arctic Char ◽  
Arctic Lakes ◽  
System Stability ◽  
Fish Populations ◽  
Ecosystem Structure ◽  
Energy Flows

Previous research indicated that fish populations in arctic lakes maintain a constant size distribution and abundance in the face of the environmental variability experienced over their recent history. Such stability was tested over 15 seasons in Little Nauyuk and Gavia lakes (Northwest Territories) which contained previously undisturbed populations of Arctic char (Salvelinus alpinus). Initially, the length–frequency distribution of Arctic char in Little Nauyuk Lake was bell shaped, and in Gavia Lake, it could be described by a negative logarithmic expression. Initial sampling of Gavia Lake removed the largest fish, allowing a well-defined mode to develop (cf. Little Nauyuk Lake). In both lakes the modal value remained constant throughout the exploitation phase. When fishing ceased the populations returned to their original state without evident oscillation. The stable state of the dominant population is considered to be one of "least dissipation". It is hypothesized that ecosystem structure depends on countervailing forces, one tending to decelerate energy flow through the ecosystem and the second tending to accelerate it. For ecosystems to exist, the tendency to decelerate energy flow must dominate system behaviour over ecological time. An ecosystem is regarded as a hemeorhetic system, stability seeking through the stabilization of energy flows.

Anadromy in Arctic populations of lake trout (Salvelinus namaycush): otolith microchemistry, stable isotopes, and comparisons with Arctic char (Salvelinus alpinus)

2010 ◽  
Vol 67 (5) ◽  
pp. 842-853 ◽  
Author(s):  
Heidi K. Swanson ◽  
Karen A. Kidd ◽  
John A. Babaluk ◽  
Rick J. Wastle ◽  
Panseok P. Yang ◽  
...  
Keyword(s):  
Lake Trout ◽  
Salvelinus Alpinus ◽  
Salt Water ◽  
Salvelinus Namaycush ◽  
Otolith Microchemistry ◽  
Scientific Data ◽  
Arctic Char ◽  
Arctic Lakes ◽  
Size Dependent ◽  
The Family

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.

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.

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.

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