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

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

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Overwinter thermal habitat use in lakes by anadromous Arctic char

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2017-0420 ◽

2018 ◽

Vol 75 (12) ◽

pp. 2343-2353 ◽

Cited By ~ 10

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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Is boldness towards predators related to growth rate in naïve captive-reared Arctic char (Salvelinus alpinus)?

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f07-041 ◽

2007 ◽

Vol 64 (4) ◽

pp. 665-671 ◽

Cited By ~ 10

Author(s):

Mika VM Laakkonen ◽

Heikki Hirvonen

Keyword(s):

Growth Rate ◽

Captive Breeding ◽

Salvelinus Alpinus ◽

Antipredator Behavior ◽

Underlying Mechanism ◽

Arctic Char ◽

Individual Growth ◽

Detailed Knowledge ◽

Individual Growth Rate ◽

Slow Growing

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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Accumulation of Persistent Pollutants in Normal and Dwarfed Arctic Char (Salvelinus alpinus sp. complex)

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f93-281 ◽

1993 ◽

Vol 50 (12) ◽

pp. 2574-2580 ◽

Cited By ~ 24

Author(s):

Johan Hammar ◽

Per Larsson ◽

Maris Klavins

Keyword(s):

Growth Rate ◽

Salvelinus Alpinus ◽

Arctic Char ◽

Individual Growth ◽

The Arctic ◽

Growth Strategies ◽

Sympatric Populations ◽

Fast Growing ◽

Persistent Pollutants ◽

Slow Growing

Two extreme growth fractions of introgressed sympatric populations of the Arctic char (Salvelinus alpinus) species complex from Lake Blåsjön, northern Sweden, were sampled for individual concentrations of persistent pollutants originating from atmospheric deposition. Slow growing char (dwarfs) had significantly higher levels of SPCB (sum of PCB congeners found) and p,p-DDE (dominating DDT-compound) than fast growing char (normals). Besides demonstrating a highly divergent growth pattern the introgressed populations also inhabit a great range of depths, and the seasonal food consumption rates may differ between extreme growth fractions, although the same major invertebrates (introduced Mysis relicta and Pallasea quadrispinosa) are consumed over the year. However, of the life history parameters differing in late spring, individual growth rate was the most important factor explaining the variation in the levels of the pollutants studied. The results support the hypothesis of a biomass "dilution" of pollutants in fish, illustrated by lower levels in fast growing char and higher levels in the slow-growing dwarfs. Individuals with alternative growth strategies in sympatric conspecific communities thus provide unique opportunities to study growth rate as a variable influencing levels of persistent pollutants in fish.

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Cannibalism and trophic structure in a high Arctic lake: insights from stable-isotope analysis

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f95-116 ◽

1995 ◽

Vol 52 (6) ◽

pp. 1195-1201 ◽

Cited By ~ 94

Author(s):

Keith A. Hobson ◽

Harold E. Welch

Keyword(s):

Primary Production ◽

Food Web ◽

Salvelinus Alpinus ◽

Trophic Position ◽

Isotope Analysis ◽

Fork Length ◽

Isotope Ratios ◽

High Arctic ◽

Arctic Char ◽

Small Fish

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f97-233 ◽

1997 ◽

Vol 54 (12) ◽

pp. 2947-2954 ◽

Cited By ~ 13

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.

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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 ◽

10.1139/f89-123 ◽

1989 ◽

Vol 46 (6) ◽

pp. 955-960 ◽

Cited By ~ 53

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.

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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 ◽

10.1139/f04-186 ◽

2005 ◽

Vol 62 (1) ◽

pp. 195-204 ◽

Cited By ~ 34

Author(s):

Øyvind Aas-Hansen ◽

Mathilakath M Vijayan ◽

Helge K Johnsen ◽

Colin Cameron ◽

Even H Jørgensen

Keyword(s):

Plasma Levels ◽

Liver Enzymes ◽

Salvelinus Alpinus ◽

Arctic Char ◽

Hepatosomatic Index ◽

Plasma Growth Hormone ◽

Metabolic Capacity ◽

General Increase ◽

Energy Conserving ◽

Feeding Migration

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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