Evidence for increases in Antarctic blue whales based on Bayesian modelling

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dc.contributor.authorBranch, Trevor A
dc.contributor.authorMatsuoka, Koji
dc.contributor.authorMiyashita, Tomio
dc.date.accessioned2016-02-26T06:50:16Z
dc.date.available2016-02-26T06:50:16Z
dc.date.issued2004
dc.date.updated2016-02-25T09:09:46Z
dc.description.abstractAntarctic blue whales (Balaenoptera musculus intermedia) are the largest and formerly most abundant blue whale subspecies, but were hunted to near extinction last century. Estimated whaling mortality was unsustainable from 1928 to 1972 (except during 1942–1944), depleting them from 239,000 (95% interval 202,000–311,000) to a low of 360 (150–840) in 1973. Obtaining statistical evidence for subsequent increases has proved difficult due to their scarcity. We fitted Bayesian models to three sighting series (1968–2001), constraining maximum rates of increase to 12% per annum. These models indicated that Antarctic blue whales are increasing at a mean rate of 7.3% per annum (1.4%–11.6%). Informative priors based on blue whale biology (4.3%, SD = 1.9%) and a Bayesian hierarchical meta-analysis of increase rates in other blue whale populations (−3%, SD = 11.6%), suggest plausible increase rates are lower (although the latter has wide intervals), but a meta-analysis of other mysticetes obtains similar rates of increase (6.7%, SD = 4.0%). Possible biases affecting the input abundance estimates are discussed. Although Antarctic blue whales appear to have been increasing since Sovier illegal whaling ended in 1972, they still need to be protected-their estimated 1996 population size, 1,700 (860–2,900), was just 0.7% (0.3%–1.3%) of the pre-exploitation level.en_ZA
dc.identifierhttp://dx.doi.org/10.1111/j.1748-7692.2004.tb01190.x
dc.identifier.apacitationBranch, T. A., Matsuoka, K., & Miyashita, T. (2004). Evidence for increases in Antarctic blue whales based on Bayesian modelling. <i>Marine Mammal Science</i>, http://hdl.handle.net/11427/17262en_ZA
dc.identifier.chicagocitationBranch, Trevor A, Koji Matsuoka, and Tomio Miyashita "Evidence for increases in Antarctic blue whales based on Bayesian modelling." <i>Marine Mammal Science</i> (2004) http://hdl.handle.net/11427/17262en_ZA
dc.identifier.citationBranch, T. A., Matsuoka, K., & Miyashita, T. (2004). Evidence for increases in Antarctic blue whales based on Bayesian modelling. Marine Mammal Science, 20(4), 726-754.en_ZA
dc.identifier.issn0824-0469en_ZA
dc.identifier.ris TY - Journal Article AU - Branch, Trevor A AU - Matsuoka, Koji AU - Miyashita, Tomio AB - Antarctic blue whales (Balaenoptera musculus intermedia) are the largest and formerly most abundant blue whale subspecies, but were hunted to near extinction last century. Estimated whaling mortality was unsustainable from 1928 to 1972 (except during 1942–1944), depleting them from 239,000 (95% interval 202,000–311,000) to a low of 360 (150–840) in 1973. Obtaining statistical evidence for subsequent increases has proved difficult due to their scarcity. We fitted Bayesian models to three sighting series (1968–2001), constraining maximum rates of increase to 12% per annum. These models indicated that Antarctic blue whales are increasing at a mean rate of 7.3% per annum (1.4%–11.6%). Informative priors based on blue whale biology (4.3%, SD = 1.9%) and a Bayesian hierarchical meta-analysis of increase rates in other blue whale populations (−3%, SD = 11.6%), suggest plausible increase rates are lower (although the latter has wide intervals), but a meta-analysis of other mysticetes obtains similar rates of increase (6.7%, SD = 4.0%). Possible biases affecting the input abundance estimates are discussed. Although Antarctic blue whales appear to have been increasing since Sovier illegal whaling ended in 1972, they still need to be protected-their estimated 1996 population size, 1,700 (860–2,900), was just 0.7% (0.3%–1.3%) of the pre-exploitation level. DA - 2004 DB - OpenUCT DP - University of Cape Town J1 - Marine Mammal Science LK - https://open.uct.ac.za PB - University of Cape Town PY - 2004 SM - 0824-0469 T1 - Evidence for increases in Antarctic blue whales based on Bayesian modelling TI - Evidence for increases in Antarctic blue whales based on Bayesian modelling UR - http://hdl.handle.net/11427/17262 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/17262
dc.identifier.vancouvercitationBranch TA, Matsuoka K, Miyashita T. Evidence for increases in Antarctic blue whales based on Bayesian modelling. Marine Mammal Science. 2004; http://hdl.handle.net/11427/17262.en_ZA
dc.languageengen_ZA
dc.publisherWileyen_ZA
dc.publisher.departmentMarine Resource Assessment and Management Groupen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.sourceMarine Mammal Scienceen_ZA
dc.source.urihttp://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1748-7692
dc.subject.otherAntarctic blue whales
dc.subject.othertrue blue whales
dc.subject.otherBalaenoptera musculus intermedia
dc.titleEvidence for increases in Antarctic blue whales based on Bayesian modellingen_ZA
dc.typeJournal Articleen_ZA
uct.subject.keywordsAntarctic blue whalesen_ZA
uct.subject.keywordstrue blue whalesen_ZA
uct.subject.keywordsBalaenoptera rnusculus intermediaen_ZA
uct.subject.keywordsBalaenoptera rnu.rculu brevicaudaen_ZA
uct.subject.keywordsmeta-analysisen_ZA
uct.subject.keywordsBayesian modelsen_ZA
uct.subject.keywordsrate of increaseen_ZA
uct.subject.keywordsSouthern Hemisphereen_ZA
uct.subject.keywordspopulation assessmenten_ZA
uct.subject.keywordsabundance estimateen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceArticleen_ZA
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