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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f89-097 ◽

1989 ◽

Vol 46 (5) ◽

pp. 786-789 ◽

Cited By ~ 30

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.

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f2011-127 ◽

2011 ◽

Vol 68 (12) ◽

pp. 2090-2100 ◽

Cited By ~ 14

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.

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Between-watershed movements of two anadromous salmonids in the Arctic

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2015-0015 ◽

2015 ◽

Vol 72 (6) ◽

pp. 855-863 ◽

Cited By ~ 13

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.

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