Inter-annual and seasonal trends in cetacean distribution, density and abundance off southern California
The article of record as published may be located at https://doi.org/10.1016/j.dsr2.2014.10.008 Funded by Naval Postgraduate School Trends in cetacean density and distribution off southern California were assessed through visual line- transect surveys during thirty-seven California Cooperative Ocean...
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ftnavalpschool:oai:calhoun.nps.edu:10945/71779 2024-06-09T07:44:56+00:00 Inter-annual and seasonal trends in cetacean distribution, density and abundance off southern California Campbell, Gregory S. Thomas, Len Whitaker, Katherine Douglas, Annie B. Calambokidis, John Hildebrand, John A. Naval Postgraduate School 2021 15 p. application/pdf https://hdl.handle.net/10945/71779 unknown Elsevier Funded by Naval Postgraduate School Campbell, Gregory S., et al. "Inter-annual and seasonal trends in cetacean distribution, density and abundance off southern California." Deep Sea Research Part II: Topical Studies in Oceanography 112 (2015): 143-157. https://hdl.handle.net/10945/71779 Copyright is reserved by the copyright owner. Cetaceans Line transect Density Abundance Distribution Trends Southern California CalCOFI Article 2021 ftnavalpschool 2024-05-15T00:45:41Z The article of record as published may be located at https://doi.org/10.1016/j.dsr2.2014.10.008 Funded by Naval Postgraduate School Trends in cetacean density and distribution off southern California were assessed through visual line- transect surveys during thirty-seven California Cooperative Oceanic Fisheries Investigations (CalCOFI) cruises from July 2004–November 2013. From sightings of the six most commonly encountered cetacean species, seasonal, annual and overall density estimates were calculated. Blue whales (Balaenoptera musculus), fin whales (Balaenoptera physalus) and humpback whales (Megaptera novaeangliae) were the most frequently sighted baleen whales with overall densities of 0.91/1000 km2 (CV 1⁄4 0.27), 2.73/ 1000 km2 (CV 1⁄4 0.19), and 1.17/1000 km2 (CV 1⁄4 0.21) respectively. Species specific density estimates, stratified by cruise, were analyzed using a generalized additive model to estimate long-term trends and correct for seasonal imbalances. Variances were estimated using a non-parametric bootstrap with one day of effort as the sampling unit. Blue whales were primarily observed during summer and fall while fin and humpback whales were observed year-round with peaks in density during summer and spring respectively. Short-beaked common dolphins (Delphinus delphis), Pacific white-sided dolphins (Lagen- orhynchus obliquidens) and Dall’s porpoise (Phocoenoidesdalli) were the most frequently encountered small cetaceans with overall densities of 705.83/1000 km2 (CV1⁄40.22), 51.98/1000 km2 (CV1⁄40.27), and 21.37/1000 km2 (CV 1⁄4 0.19) respectively. Seasonally, short-beaked common dolphins were most abun- dant in winter whereas Pacific white-sided dolphins and Dall’s porpoise were most abundant during spring. There were no significant long-term changes in blue whale, fin whale, humpback whale, short- beaked common dolphin or Dall’s porpoise densities while Pacific white-sided dolphins exhibited a significant decrease in density across the ten-year study. The results from this study were ... Article in Journal/Newspaper Balaenoptera musculus Balaenoptera physalus baleen whales Blue whale Fin whale Humpback Whale Megaptera novaeangliae Naval Postgraduate School: Calhoun Pacific |
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Naval Postgraduate School: Calhoun |
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ftnavalpschool |
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topic |
Cetaceans Line transect Density Abundance Distribution Trends Southern California CalCOFI |
spellingShingle |
Cetaceans Line transect Density Abundance Distribution Trends Southern California CalCOFI Campbell, Gregory S. Thomas, Len Whitaker, Katherine Douglas, Annie B. Calambokidis, John Hildebrand, John A. Inter-annual and seasonal trends in cetacean distribution, density and abundance off southern California |
topic_facet |
Cetaceans Line transect Density Abundance Distribution Trends Southern California CalCOFI |
description |
The article of record as published may be located at https://doi.org/10.1016/j.dsr2.2014.10.008 Funded by Naval Postgraduate School Trends in cetacean density and distribution off southern California were assessed through visual line- transect surveys during thirty-seven California Cooperative Oceanic Fisheries Investigations (CalCOFI) cruises from July 2004–November 2013. From sightings of the six most commonly encountered cetacean species, seasonal, annual and overall density estimates were calculated. Blue whales (Balaenoptera musculus), fin whales (Balaenoptera physalus) and humpback whales (Megaptera novaeangliae) were the most frequently sighted baleen whales with overall densities of 0.91/1000 km2 (CV 1⁄4 0.27), 2.73/ 1000 km2 (CV 1⁄4 0.19), and 1.17/1000 km2 (CV 1⁄4 0.21) respectively. Species specific density estimates, stratified by cruise, were analyzed using a generalized additive model to estimate long-term trends and correct for seasonal imbalances. Variances were estimated using a non-parametric bootstrap with one day of effort as the sampling unit. Blue whales were primarily observed during summer and fall while fin and humpback whales were observed year-round with peaks in density during summer and spring respectively. Short-beaked common dolphins (Delphinus delphis), Pacific white-sided dolphins (Lagen- orhynchus obliquidens) and Dall’s porpoise (Phocoenoidesdalli) were the most frequently encountered small cetaceans with overall densities of 705.83/1000 km2 (CV1⁄40.22), 51.98/1000 km2 (CV1⁄40.27), and 21.37/1000 km2 (CV 1⁄4 0.19) respectively. Seasonally, short-beaked common dolphins were most abun- dant in winter whereas Pacific white-sided dolphins and Dall’s porpoise were most abundant during spring. There were no significant long-term changes in blue whale, fin whale, humpback whale, short- beaked common dolphin or Dall’s porpoise densities while Pacific white-sided dolphins exhibited a significant decrease in density across the ten-year study. The results from this study were ... |
author2 |
Naval Postgraduate School |
format |
Article in Journal/Newspaper |
author |
Campbell, Gregory S. Thomas, Len Whitaker, Katherine Douglas, Annie B. Calambokidis, John Hildebrand, John A. |
author_facet |
Campbell, Gregory S. Thomas, Len Whitaker, Katherine Douglas, Annie B. Calambokidis, John Hildebrand, John A. |
author_sort |
Campbell, Gregory S. |
title |
Inter-annual and seasonal trends in cetacean distribution, density and abundance off southern California |
title_short |
Inter-annual and seasonal trends in cetacean distribution, density and abundance off southern California |
title_full |
Inter-annual and seasonal trends in cetacean distribution, density and abundance off southern California |
title_fullStr |
Inter-annual and seasonal trends in cetacean distribution, density and abundance off southern California |
title_full_unstemmed |
Inter-annual and seasonal trends in cetacean distribution, density and abundance off southern California |
title_sort |
inter-annual and seasonal trends in cetacean distribution, density and abundance off southern california |
publisher |
Elsevier |
publishDate |
2021 |
url |
https://hdl.handle.net/10945/71779 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Balaenoptera musculus Balaenoptera physalus baleen whales Blue whale Fin whale Humpback Whale Megaptera novaeangliae |
genre_facet |
Balaenoptera musculus Balaenoptera physalus baleen whales Blue whale Fin whale Humpback Whale Megaptera novaeangliae |
op_relation |
Funded by Naval Postgraduate School Campbell, Gregory S., et al. "Inter-annual and seasonal trends in cetacean distribution, density and abundance off southern California." Deep Sea Research Part II: Topical Studies in Oceanography 112 (2015): 143-157. https://hdl.handle.net/10945/71779 |
op_rights |
Copyright is reserved by the copyright owner. |
_version_ |
1801373831957315584 |