Hydrographic features and seabird foraging in Aleutian Passes
Strong tidal currents crossing over the abrupt topography of the Aleutian Passes result in regions with high horizontal property gradients. These frontal regions vary with the tidal cycle and form the boundary between vertically mixed and stratified regions. Concentrations of seabirds were associate...
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2005
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ftcdlib:oai:escholarship.org/ark:/13030/qt2g64g6gv 2023-05-15T15:43:54+02:00 Hydrographic features and seabird foraging in Aleutian Passes Ladd, C Jahncke, J Hunt, GL Coyle, KO Stabeno, PJ 178 - 195 2005-11-01 application/pdf https://escholarship.org/uc/item/2g64g6gv unknown eScholarship, University of California qt2g64g6gv https://escholarship.org/uc/item/2g64g6gv CC-BY CC-BY Fisheries Oceanography, vol 14, iss SUPPL. 1 Aleutian Islands Aleutian Passes convergences Fulmarus glacialis northern fulmar Puffinus tenuirostris seabird foraging short-tailed shearwater tidal fronts trophic transfer zooplankton Fisheries Oceanography Fisheries Sciences article 2005 ftcdlib 2020-03-20T23:55:48Z Strong tidal currents crossing over the abrupt topography of the Aleutian Passes result in regions with high horizontal property gradients. These frontal regions vary with the tidal cycle and form the boundary between vertically mixed and stratified regions. Concentrations of seabirds were associated with convergence zones in the mixed water (MW) and with the front between North Pacific (NP) water and MW. Species that were foraging by picking at prey from the surface were associated with surface convergences that appeared to be associated with Langmuir circulation cells or tidal features (all fulmar aggregations) in the central passes (Samalga, Seguam). In contrast, sub-surface foraging puffins and small alcids were mostly observed in areas of turbulent, well-mixed water near the shallow regions of the passes. Short-tailed shearwater flocks that were plunge-diving for prey were associated with the front between the NP water and MW in the passes. On our transects, we observed no significant aggregations of seabirds associated with Bering Sea water or NP water away from the frontal zones. The interaction of strong currents with bathymetric features results in zones of vertical advection, mixing, and surface convergences that make island passes attractive foraging regions for seabirds. Deep passes lacking these features, such as many of the passes in the western Aleutian Archipelago, are not as likely to facilitate trophic transfer to top predators as shallow passes, such as those found in the eastern Aleutian Islands. © 2005 Blackwell Publishing Ltd. Article in Journal/Newspaper Bering Sea Fulmarus glacialis Northern Fulmar Puffinus tenuirostris Aleutian Islands University of California: eScholarship Bering Sea Fulmar ENVELOPE(-46.016,-46.016,-60.616,-60.616) Langmuir ENVELOPE(-67.150,-67.150,-66.967,-66.967) Pacific |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Aleutian Islands Aleutian Passes convergences Fulmarus glacialis northern fulmar Puffinus tenuirostris seabird foraging short-tailed shearwater tidal fronts trophic transfer zooplankton Fisheries Oceanography Fisheries Sciences |
spellingShingle |
Aleutian Islands Aleutian Passes convergences Fulmarus glacialis northern fulmar Puffinus tenuirostris seabird foraging short-tailed shearwater tidal fronts trophic transfer zooplankton Fisheries Oceanography Fisheries Sciences Ladd, C Jahncke, J Hunt, GL Coyle, KO Stabeno, PJ Hydrographic features and seabird foraging in Aleutian Passes |
topic_facet |
Aleutian Islands Aleutian Passes convergences Fulmarus glacialis northern fulmar Puffinus tenuirostris seabird foraging short-tailed shearwater tidal fronts trophic transfer zooplankton Fisheries Oceanography Fisheries Sciences |
description |
Strong tidal currents crossing over the abrupt topography of the Aleutian Passes result in regions with high horizontal property gradients. These frontal regions vary with the tidal cycle and form the boundary between vertically mixed and stratified regions. Concentrations of seabirds were associated with convergence zones in the mixed water (MW) and with the front between North Pacific (NP) water and MW. Species that were foraging by picking at prey from the surface were associated with surface convergences that appeared to be associated with Langmuir circulation cells or tidal features (all fulmar aggregations) in the central passes (Samalga, Seguam). In contrast, sub-surface foraging puffins and small alcids were mostly observed in areas of turbulent, well-mixed water near the shallow regions of the passes. Short-tailed shearwater flocks that were plunge-diving for prey were associated with the front between the NP water and MW in the passes. On our transects, we observed no significant aggregations of seabirds associated with Bering Sea water or NP water away from the frontal zones. The interaction of strong currents with bathymetric features results in zones of vertical advection, mixing, and surface convergences that make island passes attractive foraging regions for seabirds. Deep passes lacking these features, such as many of the passes in the western Aleutian Archipelago, are not as likely to facilitate trophic transfer to top predators as shallow passes, such as those found in the eastern Aleutian Islands. © 2005 Blackwell Publishing Ltd. |
format |
Article in Journal/Newspaper |
author |
Ladd, C Jahncke, J Hunt, GL Coyle, KO Stabeno, PJ |
author_facet |
Ladd, C Jahncke, J Hunt, GL Coyle, KO Stabeno, PJ |
author_sort |
Ladd, C |
title |
Hydrographic features and seabird foraging in Aleutian Passes |
title_short |
Hydrographic features and seabird foraging in Aleutian Passes |
title_full |
Hydrographic features and seabird foraging in Aleutian Passes |
title_fullStr |
Hydrographic features and seabird foraging in Aleutian Passes |
title_full_unstemmed |
Hydrographic features and seabird foraging in Aleutian Passes |
title_sort |
hydrographic features and seabird foraging in aleutian passes |
publisher |
eScholarship, University of California |
publishDate |
2005 |
url |
https://escholarship.org/uc/item/2g64g6gv |
op_coverage |
178 - 195 |
long_lat |
ENVELOPE(-46.016,-46.016,-60.616,-60.616) ENVELOPE(-67.150,-67.150,-66.967,-66.967) |
geographic |
Bering Sea Fulmar Langmuir Pacific |
geographic_facet |
Bering Sea Fulmar Langmuir Pacific |
genre |
Bering Sea Fulmarus glacialis Northern Fulmar Puffinus tenuirostris Aleutian Islands |
genre_facet |
Bering Sea Fulmarus glacialis Northern Fulmar Puffinus tenuirostris Aleutian Islands |
op_source |
Fisheries Oceanography, vol 14, iss SUPPL. 1 |
op_relation |
qt2g64g6gv https://escholarship.org/uc/item/2g64g6gv |
op_rights |
CC-BY |
op_rightsnorm |
CC-BY |
_version_ |
1766378104797790208 |