A proposed model transformation to circumvent problems encountered with the sex-ratio approach to obtain lower confidence limits for the abundance of West Greenland minke whales

dc.contributor.authorBrandão, Anabela
dc.contributor.authorButterworth, Doug S
dc.date.accessioned2016-04-21T14:24:46Z
dc.date.available2016-04-21T14:24:46Z
dc.date.issued2011
dc.date.updated2016-04-21T14:23:21Z
dc.description.abstractAn illustrative example is given of a transformation applied to the sex-ratio approach which operates in a way that for population sizes much greater than are realistic, the impact of catches of females on abundance is damped. This leads to finite estimates of carrying capacity K even in circumstances where the trend over time in the proportion of whales in the catch that are male is decreasing (as is the case for West Greenland minke whales). The example is shown to produce positively biased estimates of the lower 5% confidence interval for current population size. However the concern with which this should be viewed is difficult to assess since the estimator is positively biased even in circumstances where the proportion of the catches that are male does not trend downwards over time.en_ZA
dc.identifier.apacitationBrandão, A., & Butterworth, D. S. (2011). <i>A proposed model transformation to circumvent problems encountered with the sex-ratio approach to obtain lower confidence limits for the abundance of West Greenland minke whales</i> University of Cape Town ,Faculty of Science ,Marine Resource Assessment and Management Group. Retrieved from http://hdl.handle.net/11427/19108en_ZA
dc.identifier.chicagocitationBrandão, Anabela, and Doug S Butterworth <i>A proposed model transformation to circumvent problems encountered with the sex-ratio approach to obtain lower confidence limits for the abundance of West Greenland minke whales.</i> University of Cape Town ,Faculty of Science ,Marine Resource Assessment and Management Group, 2011. http://hdl.handle.net/11427/19108en_ZA
dc.identifier.citationBrandão, A., & Butterworth, D. S. A proposed model transformation to circumvent problems encountered with the sex-ratio approach to obtain lower confidence limits for the abundance of West Greenland minke whales. MARAM: University of Cape Town.en_ZA
dc.identifier.ris TY - Working Paper AU - Brandão, Anabela AU - Butterworth, Doug S AB - An illustrative example is given of a transformation applied to the sex-ratio approach which operates in a way that for population sizes much greater than are realistic, the impact of catches of females on abundance is damped. This leads to finite estimates of carrying capacity K even in circumstances where the trend over time in the proportion of whales in the catch that are male is decreasing (as is the case for West Greenland minke whales). The example is shown to produce positively biased estimates of the lower 5% confidence interval for current population size. However the concern with which this should be viewed is difficult to assess since the estimator is positively biased even in circumstances where the proportion of the catches that are male does not trend downwards over time. DA - 2011 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2011 T1 - A proposed model transformation to circumvent problems encountered with the sex-ratio approach to obtain lower confidence limits for the abundance of West Greenland minke whales TI - A proposed model transformation to circumvent problems encountered with the sex-ratio approach to obtain lower confidence limits for the abundance of West Greenland minke whales UR - http://hdl.handle.net/11427/19108 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/19108
dc.identifier.vancouvercitationBrandão A, Butterworth DS. A proposed model transformation to circumvent problems encountered with the sex-ratio approach to obtain lower confidence limits for the abundance of West Greenland minke whales. 2011 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/19108en_ZA
dc.languageengen_ZA
dc.publisher.departmentMarine Resource Assessment and Management Groupen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.titleA proposed model transformation to circumvent problems encountered with the sex-ratio approach to obtain lower confidence limits for the abundance of West Greenland minke whalesen_ZA
dc.typeWorking Paperen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceResearch paperen_ZA
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