Bottom‐up forcing and the decline of Steller sea lions (Eumetopias jubatus) in Alaska: assessing the ocean climate hypothesis
Declines of Steller sea lion (Eumetopias jubatus) populations in the Aleutian Islands and Gulf of Alaska could be a consequence of physical oceanographic changes associated with the 1976-77 climate regime shift. Changes in ocean climate are hypothesized to have affected the quantity, quality, and ac...
Published in: | Fisheries Oceanography |
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eScholarship, University of California
2007
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Online Access: | https://escholarship.org/uc/item/09n0h140 https://escholarship.org/content/qt09n0h140/qt09n0h140.pdf https://doi.org/10.1111/j.1365-2419.2006.00408.x |
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ftcdlib:oai:escholarship.org:ark:/13030/qt09n0h140 2024-09-15T18:41:25+00:00 Bottom‐up forcing and the decline of Steller sea lions (Eumetopias jubatus) in Alaska: assessing the ocean climate hypothesis TRITES, ANDREW W MILLER, ARTHUR J MASCHNER, HERBERT DG ALEXANDER, MICHAEL A BOGRAD, STEVEN J CALDER, JOHN A CAPOTONDI, ANTONIETTA COYLE, KENNETH O DI LORENZO, EMANUELE FINNEY, BRUCE P GREGR, EDWARD J GROSCH, CHESTER E HARE, STEVEN R HUNT, GEORGE L JAHNCKE, JAIME KACHEL, NANCY B KIM, HEY‐JIN LADD, CAROL MANTUA, NATHAN J MARZBAN, CAREN MASLOWSKI, WIESLAW MENDELSSOHN, ROY NEILSON, DOUGLAS J OKKONEN, STEPHEN R OVERLAND, JAMES E REEDY‐MASCHNER, KATHERINE L ROYER, THOMAS C SCHWING, FRANKLIN B WANG, JULIAN XL WINSHIP, ARLISS J 46 - 67 2007-01-01 application/pdf https://escholarship.org/uc/item/09n0h140 https://escholarship.org/content/qt09n0h140/qt09n0h140.pdf https://doi.org/10.1111/j.1365-2419.2006.00408.x unknown eScholarship, University of California qt09n0h140 https://escholarship.org/uc/item/09n0h140 https://escholarship.org/content/qt09n0h140/qt09n0h140.pdf doi:10.1111/j.1365-2419.2006.00408.x CC-BY Fisheries Oceanography, vol 16, iss 1 Aleutian Islands climate regime shift Gulf of Alaska Steller sea lion Oceanography Fisheries Sciences Fisheries article 2007 ftcdlib https://doi.org/10.1111/j.1365-2419.2006.00408.x 2024-06-28T06:28:19Z Declines of Steller sea lion (Eumetopias jubatus) populations in the Aleutian Islands and Gulf of Alaska could be a consequence of physical oceanographic changes associated with the 1976-77 climate regime shift. Changes in ocean climate are hypothesized to have affected the quantity, quality, and accessibility of prey, which in turn may have affected the rates of birth and death of sea lions. Recent studies of the spatial and temporal variations in the ocean climate system of the North Pacific support this hypothesis. Ocean climate changes appear to have created adaptive opportunities for various species that are preyed upon by Steller sea lions at mid-trophic levels. The east-west asymmetry of the oceanic response to climate forcing after 1976-77 is consistent with both the temporal aspect (populations decreased after the late 1970s) and the spatial aspect of the decline (western, but not eastern, sea lion populations decreased). These broad-scale climate variations appear to be modulated by regionally sensitive biogeographic structures along the Aleutian Islands and Gulf of Alaska, which include a transition point from coastal to open-ocean conditions at Samalga Pass westward along the Aleutian Islands. These transition points delineate distinct clusterings of different combinations of prey species, which are in turn correlated with differential population sizes and trajectories of Steller sea lions. Archaeological records spanning 4000 yr further indicate that sea lion populations have experienced major shifts in abundance in the past. Shifts in ocean climate are the most parsimonious underlying explanation for the broad suite of ecosystem changes that have been observed in the North Pacific Ocean in recent decades. © 2007 Blackwell Publishing Ltd. Article in Journal/Newspaper Alaska Aleutian Islands University of California: eScholarship Fisheries Oceanography 16 1 46 67 |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Aleutian Islands climate regime shift Gulf of Alaska Steller sea lion Oceanography Fisheries Sciences Fisheries |
spellingShingle |
Aleutian Islands climate regime shift Gulf of Alaska Steller sea lion Oceanography Fisheries Sciences Fisheries TRITES, ANDREW W MILLER, ARTHUR J MASCHNER, HERBERT DG ALEXANDER, MICHAEL A BOGRAD, STEVEN J CALDER, JOHN A CAPOTONDI, ANTONIETTA COYLE, KENNETH O DI LORENZO, EMANUELE FINNEY, BRUCE P GREGR, EDWARD J GROSCH, CHESTER E HARE, STEVEN R HUNT, GEORGE L JAHNCKE, JAIME KACHEL, NANCY B KIM, HEY‐JIN LADD, CAROL MANTUA, NATHAN J MARZBAN, CAREN MASLOWSKI, WIESLAW MENDELSSOHN, ROY NEILSON, DOUGLAS J OKKONEN, STEPHEN R OVERLAND, JAMES E REEDY‐MASCHNER, KATHERINE L ROYER, THOMAS C SCHWING, FRANKLIN B WANG, JULIAN XL WINSHIP, ARLISS J Bottom‐up forcing and the decline of Steller sea lions (Eumetopias jubatus) in Alaska: assessing the ocean climate hypothesis |
topic_facet |
Aleutian Islands climate regime shift Gulf of Alaska Steller sea lion Oceanography Fisheries Sciences Fisheries |
description |
Declines of Steller sea lion (Eumetopias jubatus) populations in the Aleutian Islands and Gulf of Alaska could be a consequence of physical oceanographic changes associated with the 1976-77 climate regime shift. Changes in ocean climate are hypothesized to have affected the quantity, quality, and accessibility of prey, which in turn may have affected the rates of birth and death of sea lions. Recent studies of the spatial and temporal variations in the ocean climate system of the North Pacific support this hypothesis. Ocean climate changes appear to have created adaptive opportunities for various species that are preyed upon by Steller sea lions at mid-trophic levels. The east-west asymmetry of the oceanic response to climate forcing after 1976-77 is consistent with both the temporal aspect (populations decreased after the late 1970s) and the spatial aspect of the decline (western, but not eastern, sea lion populations decreased). These broad-scale climate variations appear to be modulated by regionally sensitive biogeographic structures along the Aleutian Islands and Gulf of Alaska, which include a transition point from coastal to open-ocean conditions at Samalga Pass westward along the Aleutian Islands. These transition points delineate distinct clusterings of different combinations of prey species, which are in turn correlated with differential population sizes and trajectories of Steller sea lions. Archaeological records spanning 4000 yr further indicate that sea lion populations have experienced major shifts in abundance in the past. Shifts in ocean climate are the most parsimonious underlying explanation for the broad suite of ecosystem changes that have been observed in the North Pacific Ocean in recent decades. © 2007 Blackwell Publishing Ltd. |
format |
Article in Journal/Newspaper |
author |
TRITES, ANDREW W MILLER, ARTHUR J MASCHNER, HERBERT DG ALEXANDER, MICHAEL A BOGRAD, STEVEN J CALDER, JOHN A CAPOTONDI, ANTONIETTA COYLE, KENNETH O DI LORENZO, EMANUELE FINNEY, BRUCE P GREGR, EDWARD J GROSCH, CHESTER E HARE, STEVEN R HUNT, GEORGE L JAHNCKE, JAIME KACHEL, NANCY B KIM, HEY‐JIN LADD, CAROL MANTUA, NATHAN J MARZBAN, CAREN MASLOWSKI, WIESLAW MENDELSSOHN, ROY NEILSON, DOUGLAS J OKKONEN, STEPHEN R OVERLAND, JAMES E REEDY‐MASCHNER, KATHERINE L ROYER, THOMAS C SCHWING, FRANKLIN B WANG, JULIAN XL WINSHIP, ARLISS J |
author_facet |
TRITES, ANDREW W MILLER, ARTHUR J MASCHNER, HERBERT DG ALEXANDER, MICHAEL A BOGRAD, STEVEN J CALDER, JOHN A CAPOTONDI, ANTONIETTA COYLE, KENNETH O DI LORENZO, EMANUELE FINNEY, BRUCE P GREGR, EDWARD J GROSCH, CHESTER E HARE, STEVEN R HUNT, GEORGE L JAHNCKE, JAIME KACHEL, NANCY B KIM, HEY‐JIN LADD, CAROL MANTUA, NATHAN J MARZBAN, CAREN MASLOWSKI, WIESLAW MENDELSSOHN, ROY NEILSON, DOUGLAS J OKKONEN, STEPHEN R OVERLAND, JAMES E REEDY‐MASCHNER, KATHERINE L ROYER, THOMAS C SCHWING, FRANKLIN B WANG, JULIAN XL WINSHIP, ARLISS J |
author_sort |
TRITES, ANDREW W |
title |
Bottom‐up forcing and the decline of Steller sea lions (Eumetopias jubatus) in Alaska: assessing the ocean climate hypothesis |
title_short |
Bottom‐up forcing and the decline of Steller sea lions (Eumetopias jubatus) in Alaska: assessing the ocean climate hypothesis |
title_full |
Bottom‐up forcing and the decline of Steller sea lions (Eumetopias jubatus) in Alaska: assessing the ocean climate hypothesis |
title_fullStr |
Bottom‐up forcing and the decline of Steller sea lions (Eumetopias jubatus) in Alaska: assessing the ocean climate hypothesis |
title_full_unstemmed |
Bottom‐up forcing and the decline of Steller sea lions (Eumetopias jubatus) in Alaska: assessing the ocean climate hypothesis |
title_sort |
bottom‐up forcing and the decline of steller sea lions (eumetopias jubatus) in alaska: assessing the ocean climate hypothesis |
publisher |
eScholarship, University of California |
publishDate |
2007 |
url |
https://escholarship.org/uc/item/09n0h140 https://escholarship.org/content/qt09n0h140/qt09n0h140.pdf https://doi.org/10.1111/j.1365-2419.2006.00408.x |
op_coverage |
46 - 67 |
genre |
Alaska Aleutian Islands |
genre_facet |
Alaska Aleutian Islands |
op_source |
Fisheries Oceanography, vol 16, iss 1 |
op_relation |
qt09n0h140 https://escholarship.org/uc/item/09n0h140 https://escholarship.org/content/qt09n0h140/qt09n0h140.pdf doi:10.1111/j.1365-2419.2006.00408.x |
op_rights |
CC-BY |
op_doi |
https://doi.org/10.1111/j.1365-2419.2006.00408.x |
container_title |
Fisheries Oceanography |
container_volume |
16 |
container_issue |
1 |
container_start_page |
46 |
op_container_end_page |
67 |
_version_ |
1810485814342189056 |