Separating southern blue whale subspecies based on length frequencies of sexually mature females
When sexually mature, Antarctic (true) blue whales are substantially longer than pygmy blue whales. To estimate the proportions of these two subspecies in various regions, Bayesian mixture models were fitted to catch length frequencies of sexually mature females. The extent of rounding to 5-ft inter...
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ftunivcapetownir:oai:open.uct.ac.za:11427/17290 2024-09-15T17:42:32+00:00 Separating southern blue whale subspecies based on length frequencies of sexually mature females Branch, Trevor A Abubaker, E M N Mkango, S Butterworth, Doug S 2007 application/pdf http://hdl.handle.net/11427/17290 eng eng Wiley Marine Resource Assessment and Management Group Faculty of Science University of Cape Town http://hdl.handle.net/11427/17290 Marine Mammal Science http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1748-7692 balaenoptera musculus intermedia B. m. brevicauda blue whale mixture models Bayesian Journal Article 2007 ftunivcapetownir https://doi.org/10.1111/(ISSN)1748-7692 2024-06-25T03:38:08Z When sexually mature, Antarctic (true) blue whales are substantially longer than pygmy blue whales. To estimate the proportions of these two subspecies in various regions, Bayesian mixture models were fitted to catch length frequencies of sexually mature females. The extent of rounding to 5-ft intervals was also estimated. Antarctic blue whales dominated (99.2%) pelagic catches south of 52°S, whereas pygmy blue whales dominated (99.9%) north of 52°S and in 35°–180°E. South of 60°S, only 0.7% (95% credibility interval 0.5%–1.0%) were pygmy blue whales, lower than the 7% upper bound currently assumed. Shore-based catches from SW Africa and those before 1937 from South Georgia and the South Shetlands were estimated to contain 90%–92% Antarctic blue whales. Actual proportions were probably higher, but these data show evidence of rounding (up to 19% of records), poor length-estimation methods, and other problems. The mean length of sexually mature female Chilean blue whales (77.1 ft, 23.5 m) was intermediate between pygmy (68.9 ft, 21.0 m) and Antarctic blue whales (83.4–86.3 ft, 25.4–26.6 m). A good fit to these data was obtained only by assuming that the Chilean whales are a separate subspecies or distinctive population. This finding is also consistent with their discrete distribution, and genetic and call type differences, compared to Antarctic and pygmy blue whales. Article in Journal/Newspaper Antarc* Antarctic Balaenoptera musculus Blue whale University of Cape Town: OpenUCT Marine Mammal Science |
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Open Polar |
collection |
University of Cape Town: OpenUCT |
op_collection_id |
ftunivcapetownir |
language |
English |
topic |
balaenoptera musculus intermedia B. m. brevicauda blue whale mixture models Bayesian |
spellingShingle |
balaenoptera musculus intermedia B. m. brevicauda blue whale mixture models Bayesian Branch, Trevor A Abubaker, E M N Mkango, S Butterworth, Doug S Separating southern blue whale subspecies based on length frequencies of sexually mature females |
topic_facet |
balaenoptera musculus intermedia B. m. brevicauda blue whale mixture models Bayesian |
description |
When sexually mature, Antarctic (true) blue whales are substantially longer than pygmy blue whales. To estimate the proportions of these two subspecies in various regions, Bayesian mixture models were fitted to catch length frequencies of sexually mature females. The extent of rounding to 5-ft intervals was also estimated. Antarctic blue whales dominated (99.2%) pelagic catches south of 52°S, whereas pygmy blue whales dominated (99.9%) north of 52°S and in 35°–180°E. South of 60°S, only 0.7% (95% credibility interval 0.5%–1.0%) were pygmy blue whales, lower than the 7% upper bound currently assumed. Shore-based catches from SW Africa and those before 1937 from South Georgia and the South Shetlands were estimated to contain 90%–92% Antarctic blue whales. Actual proportions were probably higher, but these data show evidence of rounding (up to 19% of records), poor length-estimation methods, and other problems. The mean length of sexually mature female Chilean blue whales (77.1 ft, 23.5 m) was intermediate between pygmy (68.9 ft, 21.0 m) and Antarctic blue whales (83.4–86.3 ft, 25.4–26.6 m). A good fit to these data was obtained only by assuming that the Chilean whales are a separate subspecies or distinctive population. This finding is also consistent with their discrete distribution, and genetic and call type differences, compared to Antarctic and pygmy blue whales. |
format |
Article in Journal/Newspaper |
author |
Branch, Trevor A Abubaker, E M N Mkango, S Butterworth, Doug S |
author_facet |
Branch, Trevor A Abubaker, E M N Mkango, S Butterworth, Doug S |
author_sort |
Branch, Trevor A |
title |
Separating southern blue whale subspecies based on length frequencies of sexually mature females |
title_short |
Separating southern blue whale subspecies based on length frequencies of sexually mature females |
title_full |
Separating southern blue whale subspecies based on length frequencies of sexually mature females |
title_fullStr |
Separating southern blue whale subspecies based on length frequencies of sexually mature females |
title_full_unstemmed |
Separating southern blue whale subspecies based on length frequencies of sexually mature females |
title_sort |
separating southern blue whale subspecies based on length frequencies of sexually mature females |
publisher |
Wiley |
publishDate |
2007 |
url |
http://hdl.handle.net/11427/17290 |
genre |
Antarc* Antarctic Balaenoptera musculus Blue whale |
genre_facet |
Antarc* Antarctic Balaenoptera musculus Blue whale |
op_source |
Marine Mammal Science http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1748-7692 |
op_relation |
http://hdl.handle.net/11427/17290 |
op_doi |
https://doi.org/10.1111/(ISSN)1748-7692 |
container_title |
Marine Mammal Science |
_version_ |
1810489128841641984 |