Sacciform cells in the epidermis of the brown trout, Salmo trutta, and the Arctic char, Salvetinus alpinus

1987 ◽  
Vol 247 (2) ◽  
Author(s):  
A.D. Pickering ◽  
J.M. Fletcher
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Arctic Char ◽  
The Arctic ◽  
Brown Trout Salmo Trutta

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.

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.

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.

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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