Spatial aggregations of seabirds and their prey on the continental shelf off SW Vancouver Island
We investigated the spatial scales at which seabirds aggregate and associate with prey over the continental shelf off southwest Vancouver Island, British Columbia. Bird densities and hydroacoustic measures of prey abundance were recorded in all seasons from 1993 to 1995 from a vessel moving along fi...
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ftmemorialuniv:oai:research.library.mun.ca:530 2024-09-15T18:40:04+00:00 Spatial aggregations of seabirds and their prey on the continental shelf off SW Vancouver Island Burger, Alan E. Hitchcock, Christine L. Davoren, Gail K. 2004-11-30 application/pdf https://research.library.mun.ca/530/ https://research.library.mun.ca/530/1/spatial_aggregations.pdf https://research.library.mun.ca/530/3/spatial_aggregations.pdf http://www.int-res.com/abstracts/meps/v283/p279-292/ en eng Inter-Research https://research.library.mun.ca/530/1/spatial_aggregations.pdf https://research.library.mun.ca/530/3/spatial_aggregations.pdf Burger, Alan E. <https://research.library.mun.ca/view/creator_az/Burger=3AAlan_E=2E=3A=3A.html> and Hitchcock, Christine L. <https://research.library.mun.ca/view/creator_az/Hitchcock=3AChristine_L=2E=3A=3A.html> and Davoren, Gail K. <https://research.library.mun.ca/view/creator_az/Davoren=3AGail_K=2E=3A=3A.html> (2004) Spatial aggregations of seabirds and their prey on the continental shelf off SW Vancouver Island. Marine Ecology Progress Series, 283. pp. 279-292. ISSN 1616-1599 cc_by_nc QH301 Biology Article PeerReviewed 2004 ftmemorialuniv 2024-07-10T03:16:00Z We investigated the spatial scales at which seabirds aggregate and associate with prey over the continental shelf off southwest Vancouver Island, British Columbia. Bird densities and hydroacoustic measures of prey abundance were recorded in all seasons from 1993 to 1995 from a vessel moving along fixed strip transects (mean distance 93 km; minimum spatial units 250 m). We used the neighbour K analysis to determine the spatial scale (patch radius) and number of birds (crowding) associated with aggregations of birds. Birds were grouped into 3 guilds: divers (dominated by common murres Uria aalge and other alcids), surface-feeders (dominated by California gulls Larus californicus and other gulls) and shearwaters (mainly sooty shearwaters Puffinus griseus). Flying birds occurred in smaller aggregations spread over a wider area than birds on the water. For birds on the water, patch radii were usually 2 to 8 km, and crowding averaged 574, 143 and 50 birds per patch for surface-feeders, shearwaters and divers, respectively. Patch radii showed few significant differences among bird species and guilds, and remained relatively constant throughout the year for most species, despite large seasonal changes in density and mean crowding. Abundance of prey (small schooling fish and euphausiids) was highest in the upper 10 m, declining progressively with deeper depths and showed marked seasonal trends (mean scores 4 to 5x higher in summer than in winter). Significant associations between birds and prey were usually within patch radii of 2 to 8 km. The appropriate scale to map and monitor seabirds and seabird-prey associations, for oil spill assessments and other reasons, would therefore be 1 to 10 km. Article in Journal/Newspaper Uria aalge uria Memorial University of Newfoundland: Research Repository |
institution |
Open Polar |
collection |
Memorial University of Newfoundland: Research Repository |
op_collection_id |
ftmemorialuniv |
language |
English |
topic |
QH301 Biology |
spellingShingle |
QH301 Biology Burger, Alan E. Hitchcock, Christine L. Davoren, Gail K. Spatial aggregations of seabirds and their prey on the continental shelf off SW Vancouver Island |
topic_facet |
QH301 Biology |
description |
We investigated the spatial scales at which seabirds aggregate and associate with prey over the continental shelf off southwest Vancouver Island, British Columbia. Bird densities and hydroacoustic measures of prey abundance were recorded in all seasons from 1993 to 1995 from a vessel moving along fixed strip transects (mean distance 93 km; minimum spatial units 250 m). We used the neighbour K analysis to determine the spatial scale (patch radius) and number of birds (crowding) associated with aggregations of birds. Birds were grouped into 3 guilds: divers (dominated by common murres Uria aalge and other alcids), surface-feeders (dominated by California gulls Larus californicus and other gulls) and shearwaters (mainly sooty shearwaters Puffinus griseus). Flying birds occurred in smaller aggregations spread over a wider area than birds on the water. For birds on the water, patch radii were usually 2 to 8 km, and crowding averaged 574, 143 and 50 birds per patch for surface-feeders, shearwaters and divers, respectively. Patch radii showed few significant differences among bird species and guilds, and remained relatively constant throughout the year for most species, despite large seasonal changes in density and mean crowding. Abundance of prey (small schooling fish and euphausiids) was highest in the upper 10 m, declining progressively with deeper depths and showed marked seasonal trends (mean scores 4 to 5x higher in summer than in winter). Significant associations between birds and prey were usually within patch radii of 2 to 8 km. The appropriate scale to map and monitor seabirds and seabird-prey associations, for oil spill assessments and other reasons, would therefore be 1 to 10 km. |
format |
Article in Journal/Newspaper |
author |
Burger, Alan E. Hitchcock, Christine L. Davoren, Gail K. |
author_facet |
Burger, Alan E. Hitchcock, Christine L. Davoren, Gail K. |
author_sort |
Burger, Alan E. |
title |
Spatial aggregations of seabirds and their prey on the continental shelf off SW Vancouver Island |
title_short |
Spatial aggregations of seabirds and their prey on the continental shelf off SW Vancouver Island |
title_full |
Spatial aggregations of seabirds and their prey on the continental shelf off SW Vancouver Island |
title_fullStr |
Spatial aggregations of seabirds and their prey on the continental shelf off SW Vancouver Island |
title_full_unstemmed |
Spatial aggregations of seabirds and their prey on the continental shelf off SW Vancouver Island |
title_sort |
spatial aggregations of seabirds and their prey on the continental shelf off sw vancouver island |
publisher |
Inter-Research |
publishDate |
2004 |
url |
https://research.library.mun.ca/530/ https://research.library.mun.ca/530/1/spatial_aggregations.pdf https://research.library.mun.ca/530/3/spatial_aggregations.pdf http://www.int-res.com/abstracts/meps/v283/p279-292/ |
genre |
Uria aalge uria |
genre_facet |
Uria aalge uria |
op_relation |
https://research.library.mun.ca/530/1/spatial_aggregations.pdf https://research.library.mun.ca/530/3/spatial_aggregations.pdf Burger, Alan E. <https://research.library.mun.ca/view/creator_az/Burger=3AAlan_E=2E=3A=3A.html> and Hitchcock, Christine L. <https://research.library.mun.ca/view/creator_az/Hitchcock=3AChristine_L=2E=3A=3A.html> and Davoren, Gail K. <https://research.library.mun.ca/view/creator_az/Davoren=3AGail_K=2E=3A=3A.html> (2004) Spatial aggregations of seabirds and their prey on the continental shelf off SW Vancouver Island. Marine Ecology Progress Series, 283. pp. 279-292. ISSN 1616-1599 |
op_rights |
cc_by_nc |
_version_ |
1810484391790510080 |