AERIAL CENSUS OF PACIFIC WALRUSES IN THE CHUKCHI SEA, 1985
Abstract The U.S. Fish and Wildlife Service conducted a survey of the walruses in the pack ice of the Chukchi Sea between 16 September and 2 October 1985, as part of a joint effort with the Soviet Union to estimate the size of the Pacific walrus population. American observers conducted censuses from...
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crwiley:10.1111/j.1748-7692.1989.tb00211.x 2023-12-03T10:20:23+01:00 AERIAL CENSUS OF PACIFIC WALRUSES IN THE CHUKCHI SEA, 1985 Gilbert, James R 1989 http://dx.doi.org/10.1111/j.1748-7692.1989.tb00211.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1748-7692.1989.tb00211.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1748-7692.1989.tb00211.x en eng Wiley http://onlinelibrary.wiley.com/termsAndConditions#vor Marine Mammal Science volume 5, issue 1, page 17-28 ISSN 0824-0469 1748-7692 Aquatic Science Ecology, Evolution, Behavior and Systematics journal-article 1989 crwiley https://doi.org/10.1111/j.1748-7692.1989.tb00211.x 2023-11-09T13:59:53Z Abstract The U.S. Fish and Wildlife Service conducted a survey of the walruses in the pack ice of the Chukchi Sea between 16 September and 2 October 1985, as part of a joint effort with the Soviet Union to estimate the size of the Pacific walrus population. American observers conducted censuses from two aircraft along randomly selected north–south lines over the pack ice. The observers counted walruses within a constant viewing angle that corresponded to a total strip width of 1.38 km at an altitude of 152 m. In nine days of flying, 15,312 walruses were observed, of which 10,140 were on 5,764 km 2 of census strips. Few walruses were observed east of 161°W longitude or west of 170°W longitude, hence the census effort was stratified. Walrus concentrations between 161° and 170° shifted slightly westward during the 2‐wk duration of the censuses. The differences among days in observed walrus density were due to changes in the numbers of walruses on the ice within 37 km of the ice edge. The number of observable walruses in pack ice of the eastern Chukchi Sea was estimated to be 62,177 (SD = 19,480), based on censuses conducted on 29 and 30 September and 1 October. At that time there were also at least 15,238 in Bristol Bay, Bering Sea. The Soviets counted 39,572 on the shores of the western Chukchi and Bering seas and estimated 115,531 in pack ice of the western Chukchi Sea. Summing U.S. and Soviet estimates, the total population of Pacific walruses in 1985 was 232,518. This number was comparable with earlier estimates from censuses conducted jointly by the U.S. and the Soviets. However, information on fraction hauled out, segregation, and movements is needed for more precise estimates. Article in Journal/Newspaper Bering Sea Chukchi Chukchi Sea walrus* Wiley Online Library (via Crossref) Bering Sea Chukchi Sea Pacific Marine Mammal Science 5 1 17 28 |
institution |
Open Polar |
collection |
Wiley Online Library (via Crossref) |
op_collection_id |
crwiley |
language |
English |
topic |
Aquatic Science Ecology, Evolution, Behavior and Systematics |
spellingShingle |
Aquatic Science Ecology, Evolution, Behavior and Systematics Gilbert, James R AERIAL CENSUS OF PACIFIC WALRUSES IN THE CHUKCHI SEA, 1985 |
topic_facet |
Aquatic Science Ecology, Evolution, Behavior and Systematics |
description |
Abstract The U.S. Fish and Wildlife Service conducted a survey of the walruses in the pack ice of the Chukchi Sea between 16 September and 2 October 1985, as part of a joint effort with the Soviet Union to estimate the size of the Pacific walrus population. American observers conducted censuses from two aircraft along randomly selected north–south lines over the pack ice. The observers counted walruses within a constant viewing angle that corresponded to a total strip width of 1.38 km at an altitude of 152 m. In nine days of flying, 15,312 walruses were observed, of which 10,140 were on 5,764 km 2 of census strips. Few walruses were observed east of 161°W longitude or west of 170°W longitude, hence the census effort was stratified. Walrus concentrations between 161° and 170° shifted slightly westward during the 2‐wk duration of the censuses. The differences among days in observed walrus density were due to changes in the numbers of walruses on the ice within 37 km of the ice edge. The number of observable walruses in pack ice of the eastern Chukchi Sea was estimated to be 62,177 (SD = 19,480), based on censuses conducted on 29 and 30 September and 1 October. At that time there were also at least 15,238 in Bristol Bay, Bering Sea. The Soviets counted 39,572 on the shores of the western Chukchi and Bering seas and estimated 115,531 in pack ice of the western Chukchi Sea. Summing U.S. and Soviet estimates, the total population of Pacific walruses in 1985 was 232,518. This number was comparable with earlier estimates from censuses conducted jointly by the U.S. and the Soviets. However, information on fraction hauled out, segregation, and movements is needed for more precise estimates. |
format |
Article in Journal/Newspaper |
author |
Gilbert, James R |
author_facet |
Gilbert, James R |
author_sort |
Gilbert, James R |
title |
AERIAL CENSUS OF PACIFIC WALRUSES IN THE CHUKCHI SEA, 1985 |
title_short |
AERIAL CENSUS OF PACIFIC WALRUSES IN THE CHUKCHI SEA, 1985 |
title_full |
AERIAL CENSUS OF PACIFIC WALRUSES IN THE CHUKCHI SEA, 1985 |
title_fullStr |
AERIAL CENSUS OF PACIFIC WALRUSES IN THE CHUKCHI SEA, 1985 |
title_full_unstemmed |
AERIAL CENSUS OF PACIFIC WALRUSES IN THE CHUKCHI SEA, 1985 |
title_sort |
aerial census of pacific walruses in the chukchi sea, 1985 |
publisher |
Wiley |
publishDate |
1989 |
url |
http://dx.doi.org/10.1111/j.1748-7692.1989.tb00211.x https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1748-7692.1989.tb00211.x https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1748-7692.1989.tb00211.x |
geographic |
Bering Sea Chukchi Sea Pacific |
geographic_facet |
Bering Sea Chukchi Sea Pacific |
genre |
Bering Sea Chukchi Chukchi Sea walrus* |
genre_facet |
Bering Sea Chukchi Chukchi Sea walrus* |
op_source |
Marine Mammal Science volume 5, issue 1, page 17-28 ISSN 0824-0469 1748-7692 |
op_rights |
http://onlinelibrary.wiley.com/termsAndConditions#vor |
op_doi |
https://doi.org/10.1111/j.1748-7692.1989.tb00211.x |
container_title |
Marine Mammal Science |
container_volume |
5 |
container_issue |
1 |
container_start_page |
17 |
op_container_end_page |
28 |
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1784267804801761280 |