Separating pygmy and Antarctic blue whales using long-forgotten ovarian data
Pygmy blue whales (Balaenoptera musculus brevicauda) are ≤24.1 m and are generally found north of 52°S in summer, whereas the more southerly Antarctic blue whales (B. m. intermedia) may exceed 30 m. Previous assessments have assumed that catches and recent surveys south of 60°S recorded Antarctic bl...
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ftunivcapetownir:oai:open.uct.ac.za:11427/17413 2024-09-15T17:41:01+00:00 Separating pygmy and Antarctic blue whales using long-forgotten ovarian data Branch, Trevor A Mikhalev, Y A Kato, H 2009 application/pdf http://hdl.handle.net/11427/17413 eng eng Wiley Marine Resource Assessment and Management Group Faculty of Science University of Cape Town http://hdl.handle.net/11427/17413 Marine Mammal Science http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1748-7692 Balaenoptera musculus Balaenoptera musculus indica Bayesian models corpora lutea mixture models statistical models subspecies identification true blue whales Journal Article 2009 ftunivcapetownir https://doi.org/10.1111/(ISSN)1748-7692 2024-06-25T03:33:35Z Pygmy blue whales (Balaenoptera musculus brevicauda) are ≤24.1 m and are generally found north of 52°S in summer, whereas the more southerly Antarctic blue whales (B. m. intermedia) may exceed 30 m. Previous assessments have assumed that catches and recent surveys south of 60°S recorded Antarctic blue whales, but these may have included pygmy blue whales. Here, we use ovarian corpora, which accumulate with ovulations and hence with length, to separate these subspecies. The resulting Bayesian mixture model, applied to 1,380 Northern Region (north of 52°S and 35°–180°E) and 3,844 Southern Ocean (south of 52°S) blue whales, estimated that only 0.1% (95% credibility intervals 0.0%–0.4%) of the Antarctic region blue whales were pygmy blue whales and, unexpectedly, found significantly lower lifetime ovulation counts for pygmy blue whales than for Antarctic blue whales (7.6 vs. 13.6). Over four decades, despite substantial depletion of Antarctic blue whales, there was no trend in the estimated proportion of pygmy blue whales in the Antarctic. Several lines of investigation found no evidence for sizeable numbers of pygmy blue whales in ovarian corpora data collected in the 1930s, as was previously hypothesized. Article in Journal/Newspaper Antarc* Antarctic Balaenoptera musculus Southern Ocean University of Cape Town: OpenUCT Marine Mammal Science |
institution |
Open Polar |
collection |
University of Cape Town: OpenUCT |
op_collection_id |
ftunivcapetownir |
language |
English |
topic |
Balaenoptera musculus Balaenoptera musculus indica Bayesian models corpora lutea mixture models statistical models subspecies identification true blue whales |
spellingShingle |
Balaenoptera musculus Balaenoptera musculus indica Bayesian models corpora lutea mixture models statistical models subspecies identification true blue whales Branch, Trevor A Mikhalev, Y A Kato, H Separating pygmy and Antarctic blue whales using long-forgotten ovarian data |
topic_facet |
Balaenoptera musculus Balaenoptera musculus indica Bayesian models corpora lutea mixture models statistical models subspecies identification true blue whales |
description |
Pygmy blue whales (Balaenoptera musculus brevicauda) are ≤24.1 m and are generally found north of 52°S in summer, whereas the more southerly Antarctic blue whales (B. m. intermedia) may exceed 30 m. Previous assessments have assumed that catches and recent surveys south of 60°S recorded Antarctic blue whales, but these may have included pygmy blue whales. Here, we use ovarian corpora, which accumulate with ovulations and hence with length, to separate these subspecies. The resulting Bayesian mixture model, applied to 1,380 Northern Region (north of 52°S and 35°–180°E) and 3,844 Southern Ocean (south of 52°S) blue whales, estimated that only 0.1% (95% credibility intervals 0.0%–0.4%) of the Antarctic region blue whales were pygmy blue whales and, unexpectedly, found significantly lower lifetime ovulation counts for pygmy blue whales than for Antarctic blue whales (7.6 vs. 13.6). Over four decades, despite substantial depletion of Antarctic blue whales, there was no trend in the estimated proportion of pygmy blue whales in the Antarctic. Several lines of investigation found no evidence for sizeable numbers of pygmy blue whales in ovarian corpora data collected in the 1930s, as was previously hypothesized. |
format |
Article in Journal/Newspaper |
author |
Branch, Trevor A Mikhalev, Y A Kato, H |
author_facet |
Branch, Trevor A Mikhalev, Y A Kato, H |
author_sort |
Branch, Trevor A |
title |
Separating pygmy and Antarctic blue whales using long-forgotten ovarian data |
title_short |
Separating pygmy and Antarctic blue whales using long-forgotten ovarian data |
title_full |
Separating pygmy and Antarctic blue whales using long-forgotten ovarian data |
title_fullStr |
Separating pygmy and Antarctic blue whales using long-forgotten ovarian data |
title_full_unstemmed |
Separating pygmy and Antarctic blue whales using long-forgotten ovarian data |
title_sort |
separating pygmy and antarctic blue whales using long-forgotten ovarian data |
publisher |
Wiley |
publishDate |
2009 |
url |
http://hdl.handle.net/11427/17413 |
genre |
Antarc* Antarctic Balaenoptera musculus Southern Ocean |
genre_facet |
Antarc* Antarctic Balaenoptera musculus Southern Ocean |
op_source |
Marine Mammal Science http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1748-7692 |
op_relation |
http://hdl.handle.net/11427/17413 |
op_doi |
https://doi.org/10.1111/(ISSN)1748-7692 |
container_title |
Marine Mammal Science |
_version_ |
1810487077725274112 |