Causes of mortality of Atlantic salmon ( Salmo salar) and brown trout ( Salmo trutta) smolts in a restored river and its estuary
Abstract During October 2000 to August 2002, the River Skjern Nature Project was implemented by removing dykes and re‐meandering 20.5 km of the lower canalized river. As a consequence the length of the river stretch increased to 23 km. A lake of 250 ha developed in the river valley 5 km upstream fro...
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crwiley:10.1002/rra.894 2024-06-02T08:03:19+00:00 Causes of mortality of Atlantic salmon ( Salmo salar) and brown trout ( Salmo trutta) smolts in a restored river and its estuary Koed, Anders Baktoft, Henrik Bak, Brian Daniel 2005 http://dx.doi.org/10.1002/rra.894 https://onlinelibrary.wiley.com/doi/pdf/10.1002/rra.894 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor River Research and Applications volume 22, issue 1, page 69-78 ISSN 1535-1459 1535-1467 journal-article 2005 crwiley https://doi.org/10.1002/rra.894 2024-05-03T11:33:53Z Abstract During October 2000 to August 2002, the River Skjern Nature Project was implemented by removing dykes and re‐meandering 20.5 km of the lower canalized river. As a consequence the length of the river stretch increased to 23 km. A lake of 250 ha developed in the river valley 5 km upstream from the river mouth because of subsiding soils caused by reclamation and drainage since the 1960s. Using radiotelemetry, the mortality of wild Atlantic salmon ( Salmo salar ) and brown trout ( Salmo trutta ) smolts in the River Skjern and its estuary was investigated prior to and after the implementation of the project. Altogether, 77 Atlantic salmon and 66 brown trout smolts were caught, tagged and released in the river upstream of the restoration project during the spring of 2000 and 2002. The in‐river smolt mortality was more than double in 2002 for both Atlantic salmon and brown trout compared with 2000. This was primarily due to bird predation in 2002 which was not observed in 2000. The in‐river bird predation in 2002 was mediated by the new lake, which quickly became an important bird rest area. Estuarine mortality mainly caused by cormorants ( Phalacrocorax carbo sinensis ) differed significantly between species, but was high for both Atlantic salmon (39%) and brown trout (12%) in both years of investigation. The aggregated smolt mortality in the river and in the estuary (48%) may threaten an indigenous self‐sustaining Atlantic salmon population in the River Skjern. When planning river restoration projects, caution should be used, especially where permanently flooded floodplains (lakes) develop due to subsiding soil. In situations where rivers pass directly through newly developed lakes, migratory species such as Atlantic salmon and brown trout may be severely affected due to increased exposure to predation from predatory fish and birds. Copyright © 2006 John Wiley & Sons, Ltd. Article in Journal/Newspaper Atlantic salmon Salmo salar Wiley Online Library New Lake ENVELOPE(-109.468,-109.468,62.684,62.684) River Research and Applications 22 1 69 78 |
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Open Polar |
collection |
Wiley Online Library |
op_collection_id |
crwiley |
language |
English |
description |
Abstract During October 2000 to August 2002, the River Skjern Nature Project was implemented by removing dykes and re‐meandering 20.5 km of the lower canalized river. As a consequence the length of the river stretch increased to 23 km. A lake of 250 ha developed in the river valley 5 km upstream from the river mouth because of subsiding soils caused by reclamation and drainage since the 1960s. Using radiotelemetry, the mortality of wild Atlantic salmon ( Salmo salar ) and brown trout ( Salmo trutta ) smolts in the River Skjern and its estuary was investigated prior to and after the implementation of the project. Altogether, 77 Atlantic salmon and 66 brown trout smolts were caught, tagged and released in the river upstream of the restoration project during the spring of 2000 and 2002. The in‐river smolt mortality was more than double in 2002 for both Atlantic salmon and brown trout compared with 2000. This was primarily due to bird predation in 2002 which was not observed in 2000. The in‐river bird predation in 2002 was mediated by the new lake, which quickly became an important bird rest area. Estuarine mortality mainly caused by cormorants ( Phalacrocorax carbo sinensis ) differed significantly between species, but was high for both Atlantic salmon (39%) and brown trout (12%) in both years of investigation. The aggregated smolt mortality in the river and in the estuary (48%) may threaten an indigenous self‐sustaining Atlantic salmon population in the River Skjern. When planning river restoration projects, caution should be used, especially where permanently flooded floodplains (lakes) develop due to subsiding soil. In situations where rivers pass directly through newly developed lakes, migratory species such as Atlantic salmon and brown trout may be severely affected due to increased exposure to predation from predatory fish and birds. Copyright © 2006 John Wiley & Sons, Ltd. |
format |
Article in Journal/Newspaper |
author |
Koed, Anders Baktoft, Henrik Bak, Brian Daniel |
spellingShingle |
Koed, Anders Baktoft, Henrik Bak, Brian Daniel Causes of mortality of Atlantic salmon ( Salmo salar) and brown trout ( Salmo trutta) smolts in a restored river and its estuary |
author_facet |
Koed, Anders Baktoft, Henrik Bak, Brian Daniel |
author_sort |
Koed, Anders |
title |
Causes of mortality of Atlantic salmon ( Salmo salar) and brown trout ( Salmo trutta) smolts in a restored river and its estuary |
title_short |
Causes of mortality of Atlantic salmon ( Salmo salar) and brown trout ( Salmo trutta) smolts in a restored river and its estuary |
title_full |
Causes of mortality of Atlantic salmon ( Salmo salar) and brown trout ( Salmo trutta) smolts in a restored river and its estuary |
title_fullStr |
Causes of mortality of Atlantic salmon ( Salmo salar) and brown trout ( Salmo trutta) smolts in a restored river and its estuary |
title_full_unstemmed |
Causes of mortality of Atlantic salmon ( Salmo salar) and brown trout ( Salmo trutta) smolts in a restored river and its estuary |
title_sort |
causes of mortality of atlantic salmon ( salmo salar) and brown trout ( salmo trutta) smolts in a restored river and its estuary |
publisher |
Wiley |
publishDate |
2005 |
url |
http://dx.doi.org/10.1002/rra.894 https://onlinelibrary.wiley.com/doi/pdf/10.1002/rra.894 |
long_lat |
ENVELOPE(-109.468,-109.468,62.684,62.684) |
geographic |
New Lake |
geographic_facet |
New Lake |
genre |
Atlantic salmon Salmo salar |
genre_facet |
Atlantic salmon Salmo salar |
op_source |
River Research and Applications volume 22, issue 1, page 69-78 ISSN 1535-1459 1535-1467 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/rra.894 |
container_title |
River Research and Applications |
container_volume |
22 |
container_issue |
1 |
container_start_page |
69 |
op_container_end_page |
78 |
_version_ |
1800747812959289344 |