Assessing the effect of visual isolation on the population density of Atlantic salmon ( Salmo salar) using GIS
Abstract Few studies investigate the behavioural response of organisms to stream enhancement schemes. One behavioural process that is rarely examined in enhancement studies is the visual isolation created by adding boulders on the river bed. The objective of this research is to use a Geographic Info...
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crwiley:10.1002/rra.1024 2024-06-02T08:03:26+00:00 Assessing the effect of visual isolation on the population density of Atlantic salmon ( Salmo salar) using GIS Dolinsek, Ivan J. Biron, Pascale M. Grant, James W. A. 2007 http://dx.doi.org/10.1002/rra.1024 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Frra.1024 https://onlinelibrary.wiley.com/doi/pdf/10.1002/rra.1024 en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor River Research and Applications volume 23, issue 7, page 763-774 ISSN 1535-1459 1535-1467 journal-article 2007 crwiley https://doi.org/10.1002/rra.1024 2024-05-03T11:28:16Z Abstract Few studies investigate the behavioural response of organisms to stream enhancement schemes. One behavioural process that is rarely examined in enhancement studies is the visual isolation created by adding boulders on the river bed. The objective of this research is to use a Geographic Information Systems (GIS) viewshed analysis to determine if the increase in density of Atlantic salmon observed in boulder‐added zones is related to visual isolation or, alternatively, the presence of a velocity refuge. Eight study sites were established on Catamaran Brook and Little Southwest Miramichi River (New Brunswick, Canada). Each reach was divided into three quadrats of 3 m × 2 m. In one of the quadrats, 36 boulders ( D 50 = 0.20 m) were added to increase visual isolation. Boulders were removed from another adjacent quadrat whereas a third quadrat was left in a natural state. A detailed Digital Elevation Model (DEM) was created for all the sites with a total station. Atlantic salmon were observed by snorkelling on several occasions during two summers. Their position was recorded with the total station and the snout and average velocity was measured. A GIS viewshed analysis was performed to determine the visible area for each fish and to verify whether the surrounding fish were visible or not. Results suggest that the primary mechanism responsible for the observed increase in Atlantic salmon population density in the experimental quadrats is a reduction in the field of view of individuals, through an increase in habitat heterogeneity, which is consistent with the visual isolation hypothesis. There was also no change in the snout velocity of salmon among the three treatments, suggesting that the increase in density is not consistent with the velocity‐refuge hypothesis. Copyright © 2007 John Wiley & Sons, Ltd. Article in Journal/Newspaper Atlantic salmon Salmo salar Wiley Online Library Canada River Research and Applications 23 7 763 774 |
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Wiley Online Library |
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description |
Abstract Few studies investigate the behavioural response of organisms to stream enhancement schemes. One behavioural process that is rarely examined in enhancement studies is the visual isolation created by adding boulders on the river bed. The objective of this research is to use a Geographic Information Systems (GIS) viewshed analysis to determine if the increase in density of Atlantic salmon observed in boulder‐added zones is related to visual isolation or, alternatively, the presence of a velocity refuge. Eight study sites were established on Catamaran Brook and Little Southwest Miramichi River (New Brunswick, Canada). Each reach was divided into three quadrats of 3 m × 2 m. In one of the quadrats, 36 boulders ( D 50 = 0.20 m) were added to increase visual isolation. Boulders were removed from another adjacent quadrat whereas a third quadrat was left in a natural state. A detailed Digital Elevation Model (DEM) was created for all the sites with a total station. Atlantic salmon were observed by snorkelling on several occasions during two summers. Their position was recorded with the total station and the snout and average velocity was measured. A GIS viewshed analysis was performed to determine the visible area for each fish and to verify whether the surrounding fish were visible or not. Results suggest that the primary mechanism responsible for the observed increase in Atlantic salmon population density in the experimental quadrats is a reduction in the field of view of individuals, through an increase in habitat heterogeneity, which is consistent with the visual isolation hypothesis. There was also no change in the snout velocity of salmon among the three treatments, suggesting that the increase in density is not consistent with the velocity‐refuge hypothesis. Copyright © 2007 John Wiley & Sons, Ltd. |
format |
Article in Journal/Newspaper |
author |
Dolinsek, Ivan J. Biron, Pascale M. Grant, James W. A. |
spellingShingle |
Dolinsek, Ivan J. Biron, Pascale M. Grant, James W. A. Assessing the effect of visual isolation on the population density of Atlantic salmon ( Salmo salar) using GIS |
author_facet |
Dolinsek, Ivan J. Biron, Pascale M. Grant, James W. A. |
author_sort |
Dolinsek, Ivan J. |
title |
Assessing the effect of visual isolation on the population density of Atlantic salmon ( Salmo salar) using GIS |
title_short |
Assessing the effect of visual isolation on the population density of Atlantic salmon ( Salmo salar) using GIS |
title_full |
Assessing the effect of visual isolation on the population density of Atlantic salmon ( Salmo salar) using GIS |
title_fullStr |
Assessing the effect of visual isolation on the population density of Atlantic salmon ( Salmo salar) using GIS |
title_full_unstemmed |
Assessing the effect of visual isolation on the population density of Atlantic salmon ( Salmo salar) using GIS |
title_sort |
assessing the effect of visual isolation on the population density of atlantic salmon ( salmo salar) using gis |
publisher |
Wiley |
publishDate |
2007 |
url |
http://dx.doi.org/10.1002/rra.1024 https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Frra.1024 https://onlinelibrary.wiley.com/doi/pdf/10.1002/rra.1024 |
geographic |
Canada |
geographic_facet |
Canada |
genre |
Atlantic salmon Salmo salar |
genre_facet |
Atlantic salmon Salmo salar |
op_source |
River Research and Applications volume 23, issue 7, page 763-774 ISSN 1535-1459 1535-1467 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1002/rra.1024 |
container_title |
River Research and Applications |
container_volume |
23 |
container_issue |
7 |
container_start_page |
763 |
op_container_end_page |
774 |
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1800747959537631232 |