Applying the direct duplicate method to simulated IDCR/SOWER survey data

dc.contributor.authorBranch, Trevor A
dc.contributor.authorButterworth, Doug S
dc.date.accessioned2016-03-11T13:43:51Z
dc.date.available2016-03-11T13:43:51Z
dc.date.issued2005
dc.date.updated2016-03-08T09:13:39Z
dc.description.abstractThe direct duplicate method (Palka, 1994) was applied to simulated IDCR/SOWER survey data. Estimates of whale density were generally negative biased, but less so than estimates obtained using the standard method. The mean bias across scenarios was -11% (range -31% to 8%) for the “2004” scenarios and -5% (range -19% to 10%) for the “2005” scenarios. Negative bias was more pronounced when a density gradient was present, when the detection function used to generate the simulated sightings excluded school size but included weather as a covariate, when errors in recorded school size were introduced, when weather and density were correlated, and when surveys were conducted in IO mode only. This method shows promise although further development is desirable to reduce the associated bias further, perhaps by including weather and school size as covariates.en_ZA
dc.identifier.apacitationBranch, T. A., & Butterworth, D. S. (2005). <i>Applying the direct duplicate method to simulated IDCR/SOWER survey data</i> University of Cape Town ,Faculty of Science ,Marine Resource Assessment and Management Group. Retrieved from http://hdl.handle.net/11427/17642en_ZA
dc.identifier.chicagocitationBranch, Trevor A, and Doug S Butterworth <i>Applying the direct duplicate method to simulated IDCR/SOWER survey data.</i> University of Cape Town ,Faculty of Science ,Marine Resource Assessment and Management Group, 2005. http://hdl.handle.net/11427/17642en_ZA
dc.identifier.citationBranch, T. A., & Butterworth, D. (2005). Applying the direct duplicate method to simulated IDCR/SOWER survey data. IWC Paper SC/57/IA15: 10pp.en_ZA
dc.identifier.ris TY - Working Paper AU - Branch, Trevor A AU - Butterworth, Doug S AB - The direct duplicate method (Palka, 1994) was applied to simulated IDCR/SOWER survey data. Estimates of whale density were generally negative biased, but less so than estimates obtained using the standard method. The mean bias across scenarios was -11% (range -31% to 8%) for the “2004” scenarios and -5% (range -19% to 10%) for the “2005” scenarios. Negative bias was more pronounced when a density gradient was present, when the detection function used to generate the simulated sightings excluded school size but included weather as a covariate, when errors in recorded school size were introduced, when weather and density were correlated, and when surveys were conducted in IO mode only. This method shows promise although further development is desirable to reduce the associated bias further, perhaps by including weather and school size as covariates. DA - 2005 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2005 T1 - Applying the direct duplicate method to simulated IDCR/SOWER survey data TI - Applying the direct duplicate method to simulated IDCR/SOWER survey data UR - http://hdl.handle.net/11427/17642 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/17642
dc.identifier.vancouvercitationBranch TA, Butterworth DS. Applying the direct duplicate method to simulated IDCR/SOWER survey data. 2005 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/17642en_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.titleApplying the direct duplicate method to simulated IDCR/SOWER survey dataen_ZA
dc.typeWorking Paperen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceResearch paperen_ZA
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