The food of Atlantic salmon Salmo salar L. and brown trout Salmo trutta L. smolts during migration in the Orkla river, Norway

Stomach analyses were carried out on 286 Atlantic salmon smolts and 163 brown trout smolts during migration in the river Orkla Central Norway (63°N, 10°E), from 1982 to 1984. Empty stomachs comprised less than 18,4% for salmon and 25,4% for trout. The food composition of both species varied little...

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Published in:Fauna Norvegica
Main Authors: Erik Garnås, Nils Arne Hvidsten
Format: Article
Language:English
Published: Norwegian University of Science and Technology 1985-12-01
Subjects:
Online Access:https://www.ntnu.no/ojs/index.php/fauna_norvegica/article/view/6112
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author Erik Garnås
Nils Arne Hvidsten
author_facet Erik Garnås
Nils Arne Hvidsten
author_sort Erik Garnås
collection DOAJ
container_title Fauna Norvegica
description Stomach analyses were carried out on 286 Atlantic salmon smolts and 163 brown trout smolts during migration in the river Orkla Central Norway (63°N, 10°E), from 1982 to 1984. Empty stomachs comprised less than 18,4% for salmon and 25,4% for trout. The food composition of both species varied little from year to year. The dominant food items of Atlantic salmon smolts were Trichoptera larvae and nymphs of Plecoptera and Ephemeroptera, each comprising from 17,7 to 31,2 % of the stomach volume. These three insect orders were also the main food of brown trout smolts in addition to Diptera pupae, varying from 17,4% to 32,3% in volume for each food item. The volume of Trichoptera larvae in the smolt stomachs decreased during the migration, while the importance of Ephemeroptera and Plecoptera nymphs as food for the smolts increased. There was a significant overlap in diet between salmon and brown trout smolts both in the different years and during the migration period in 1984.
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spelling doaj-art-33d0fa44a73b4ebaa7a0ea75cd789ac32025-08-20T00:29:52ZengNorwegian University of Science and TechnologyFauna Norvegica1502-48731891-53961985-12-01610.5324/fn.v6i0.6112The food of Atlantic salmon Salmo salar L. and brown trout Salmo trutta L. smolts during migration in the Orkla river, NorwayErik Garnås0Nils Arne Hvidsten1Direktoratet for Naturforvaltning, Tungasletta 2, NO-7000 Trondheim, NorwayDirektoratet for Naturforvaltning, Tungasletta 2, NO-7000 Trondheim, Norway Stomach analyses were carried out on 286 Atlantic salmon smolts and 163 brown trout smolts during migration in the river Orkla Central Norway (63°N, 10°E), from 1982 to 1984. Empty stomachs comprised less than 18,4% for salmon and 25,4% for trout. The food composition of both species varied little from year to year. The dominant food items of Atlantic salmon smolts were Trichoptera larvae and nymphs of Plecoptera and Ephemeroptera, each comprising from 17,7 to 31,2 % of the stomach volume. These three insect orders were also the main food of brown trout smolts in addition to Diptera pupae, varying from 17,4% to 32,3% in volume for each food item. The volume of Trichoptera larvae in the smolt stomachs decreased during the migration, while the importance of Ephemeroptera and Plecoptera nymphs as food for the smolts increased. There was a significant overlap in diet between salmon and brown trout smolts both in the different years and during the migration period in 1984. https://www.ntnu.no/ojs/index.php/fauna_norvegica/article/view/6112ActinopterygiiSalmoniformesInsectaPlecopteraTrichopteraEphemeroptera
spellingShingle Erik Garnås
Nils Arne Hvidsten
The food of Atlantic salmon Salmo salar L. and brown trout Salmo trutta L. smolts during migration in the Orkla river, Norway
Actinopterygii
Salmoniformes
Insecta
Plecoptera
Trichoptera
Ephemeroptera
title The food of Atlantic salmon Salmo salar L. and brown trout Salmo trutta L. smolts during migration in the Orkla river, Norway
title_full The food of Atlantic salmon Salmo salar L. and brown trout Salmo trutta L. smolts during migration in the Orkla river, Norway
title_fullStr The food of Atlantic salmon Salmo salar L. and brown trout Salmo trutta L. smolts during migration in the Orkla river, Norway
title_full_unstemmed The food of Atlantic salmon Salmo salar L. and brown trout Salmo trutta L. smolts during migration in the Orkla river, Norway
title_short The food of Atlantic salmon Salmo salar L. and brown trout Salmo trutta L. smolts during migration in the Orkla river, Norway
title_sort food of atlantic salmon salmo salar l and brown trout salmo trutta l smolts during migration in the orkla river norway
topic Actinopterygii
Salmoniformes
Insecta
Plecoptera
Trichoptera
Ephemeroptera
url https://www.ntnu.no/ojs/index.php/fauna_norvegica/article/view/6112
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