scholarly journals The cost of anadromy: marine and freshwater mortality rates in anadromous Arctic char and brown trout in the Arctic region of Norway

2019 ◽  
Vol 76 (12) ◽  
pp. 2408-2417 ◽  
Author(s):  
Arne Johan Jensen ◽  
Bengt Finstad ◽  
Peder Fiske
Keyword(s):  
Fresh Water ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Reproductive Output ◽  
Energy Use ◽  
Salvelinus Alpinus ◽  
Arctic Region ◽  
Mortality Rates ◽  
Arctic Char ◽  
The Arctic

It is hypothesized that in diadromous fish, migrations may occur because of differences in the availability of food in marine and freshwater habitats. The benefits of migration to sea may be increased growth opportunities and reproductive output, while the costs may be increased mortality and increased energy use. Here we examine mortality rates of anadromous Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta) in fresh water and at sea over a 25-year period to test these hypotheses. Daily mortality rates were 5–15 times higher at sea than in fresh water, with highest rates for first-time migrants, inferring a clear trade-off between increased mass gain and mortality risk during the sea migration. Descending smolts were caught in a trap at the outlet of the river, individually tagged, and thereafter recorded each time they passed through the trap on their annual migration between the river and the sea. Brown trout females seemed to benefit to a higher degree from migrating to sea than did female Arctic char, probably because of the higher growth rate at sea, and hence higher reproductive output.

Between-watershed movements of two anadromous salmonids in the Arctic

2015 ◽  
Vol 72 (6) ◽  
pp. 855-863 ◽  
Author(s):  
Arne Johan Jensen ◽  
Ola Håvard Diserud ◽  
Bengt Finstad ◽  
Peder Fiske ◽  
Audun Håvard Rikardsen
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Salvelinus Alpinus ◽  
Habitat Preferences ◽  
Arctic Region ◽  
Arctic Char ◽  
The Arctic ◽  
Long Term Study ◽  
Brown Trout Salmo Trutta

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.

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.

Temperature Requirements in Atlantic Salmon (Salmo salar), Brown Trout (Salmo trutta), and Arctic Char (Salvelinus alpinus) from Hatching to Initial Feeding Compared with Geographic Distribution

1989 ◽  
Vol 46 (5) ◽  
pp. 786-789 ◽  
Author(s):  
Arne J. Jensen ◽  
Bjørn O. Johnsen ◽  
Laila Saksgård
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Geographic Distribution ◽  
Brown Trout ◽  
Salmo Trutta ◽  
Development Time ◽  
Salvelinus Alpinus ◽  
Arctic Char ◽  
Atlantic Salmon Salmo Salar ◽  
Brown Trout Salmo Trutta

Development time at different temperatures from hatching to 50% feeding was studied in Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) alevins. Live animals were used as food. In both species the development time decreased with increasing temperature, and these relationships were described by power curves. The results were compared with similar data for Arctic char (Salvelinus alpinus). At temperatures above about 8 °C, the development time to 50% feeding was the same for all three species. However, at lower temperatures Atlantic salmon alevins needed more time to reach the stage of initial feeding than did Arctic char. Brown trout were intermediate. These results are in accordance with the known optimum temperature ranges for the three species and their geographic distribution.

Contrasting patterns of territoriality and foraging mode in two stream-dwelling salmonids, Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta)

2011 ◽  
Vol 68 (12) ◽  
pp. 2090-2100 ◽  
Author(s):  
Guðmundur Smári Gunnarsson ◽  
Stefán Óli Steingrímsson
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Salvelinus Alpinus ◽  
Ecological Factors ◽  
Central Place ◽  
Arctic Char ◽  
Territory Size ◽  
Territorial Behaviour ◽  
Foraging Mode ◽  
Brown Trout Salmo Trutta

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.

Preliminary Observations on the Ionic Regulation of the Arctic Char Salvelinus Alpinus

1971 ◽  
Vol 55 (1) ◽  
pp. 213-222
Author(s):  
R. A. ROBERTS
Keyword(s):  
Fresh Water ◽  
Sea Water ◽  
Potassium Concentration ◽  
Salvelinus Alpinus ◽  
Sodium Concentration ◽  
Sodium Content ◽  
Arctic Char ◽  
The Arctic ◽  
High Degree ◽  
Total Sodium

1. The degree of euryhalinity in a fresh-water resident population of the arctic char, Salvelinus alpinus, has been determined. 2. Although isolated in fresh water for c. 10000-12000 years these fish still show a high degree of salinity tolerance characteristic of their ancestral stock, but this is variably developed in individuals. 3. In fresh water, blood sodium concentration is regulated at 150 mM/l and chloride at 130 mM/l. These increase to 233 and 218 mm/l respectively in sea water. 4. Fish in sea water show a large increase in muscle sodium, although the potassium concentration is only slightly higher than that maintained in fresh water. The total sodium content of the fish reflects the increase observed in the intracellular and extracellular compartments. 5. The rate of sodium turnover in sea-water-adapted fish is some ten times higher than in fresh-water-adapted fish, although it is significantly lower than that observed in most sea-water-adapted teleosts.

scholarly journals Compromised thermal tolerance of cardiovascular capacity in upstream migrating Arctic char and brown trout—are hot summers threatening migrating salmonids?

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Giovanna Mottola ◽  
Torstein Kristensen ◽  
Katja Anttila
Keyword(s):  
Brown Trout ◽  
Oxygen Delivery ◽  
Thermal Tolerance ◽  
Salmo Trutta ◽  
Heat Waves ◽  
Salvelinus Alpinus ◽  
Arctic Char ◽  
Upstream Migration ◽  
River Temperature ◽  
Cardiovascular Capacity

Abstract Heat waves are threatening fish around the world, leading sometimes to mass mortality events. One crucial function of fish failing in high temperatures is oxygen delivery capacity, i.e. cardiovascular function. For anadromous salmonids, increased temperature could be especially detrimental during upstream migration since they need efficiently working oxygen delivery system in order to cross the river rapids to reach upstream areas. The migration also occurs during summer and early autumn exposing salmonids to peak water temperatures, and in shallow rivers there is little availability for thermal refuges as compared to thermally stratified coastal and lake habitats. In order to shed light on the mechanisms underpinning the capacity of migrating fish to face high environmental temperatures, we applied a physiological and molecular approach measuring cardiovascular capacities of migrating and resident Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta) in Northern Norway. The maximum cardiovascular capacity of migrating fish was significantly lower compared to the resident conspecifics. The onset of cardiac impairment started only 2°C higher than river temperature, meaning that even a small increase in water temperature may already compromise cardiac function. The migrating fish were also under significant cellular stress, expressing increased level of cardiac heat shock proteins. We consider these findings highly valuable when addressing climate change effect on migrating fish and encourage taking action in riverine habitat conservation policies. The significant differences in upper thermal tolerance of resident and migrating fish could also lead changes in population dynamics, which should be taken into account in future conservation plans.

scholarly journals Evidence for the linkage of survival of anadromous Arctic char and brown trout during winter to marine growth during the previous summer

2018 ◽  
Vol 75 (5) ◽  
pp. 663-672 ◽  
Author(s):  
Arne Johan Jensen ◽  
Bengt Finstad ◽  
Peder Fiske
Keyword(s):  
Brown Trout ◽  
Critical Period ◽  
Salmo Trutta ◽  
Critical Size ◽  
Salvelinus Alpinus ◽  
Salt Water ◽  
Arctic Char ◽  
Brown Trout Salmo Trutta ◽  
First Time ◽  
Previous Summer

Data from a 25-year study of anadromous Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta) in the River Halselva provided evidence that survival during winter was linked to marine growth during the previous summer. The study supported the “critical size and critical period” hypothesis, which postulates that regulation of the abundance of adult salmonids occurs in two major phases. The first phase is marine mortality that occurs shortly after smolts enter salt water, and the second is during the following winter, when individuals that have not attained a critical size are unable to meet minimum metabolic requirements and die. In the present study, growth during summer appeared to be more important to winter survival than body size. Size-selective mortality occurred both at sea during summer and in fresh water during winter and was more evident for first-time migrants than repeat migrants.

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