Applying the direct duplicate method to simulated IDCR/SOWER survey data
| dc.contributor.author | Branch, Trevor A | |
| dc.contributor.author | Butterworth, Doug S | |
| dc.date.accessioned | 2016-03-11T13:43:51Z | |
| dc.date.available | 2016-03-11T13:43:51Z | |
| dc.date.issued | 2005 | |
| dc.date.updated | 2016-03-08T09:13:39Z | |
| dc.description.abstract | 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. | en_ZA |
| dc.identifier.apacitation | Branch, 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/11427/17642 | en_ZA |
| dc.identifier.chicagocitation | Branch, 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/11427/17642 | en_ZA |
| dc.identifier.citation | Branch, 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.uri | http://hdl.handle.net/11427/17642 | |
| dc.identifier.vancouvercitation | Branch 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/11427/17642 | en_ZA |
| dc.language | eng | en_ZA |
| dc.publisher.department | Marine Resource Assessment and Management Group | en_ZA |
| dc.publisher.faculty | Faculty of Science | en_ZA |
| dc.publisher.institution | University of Cape Town | |
| dc.title | Applying the direct duplicate method to simulated IDCR/SOWER survey data | en_ZA |
| dc.type | Working Paper | en_ZA |
| uct.type.filetype | Text | |
| uct.type.filetype | Image | |
| uct.type.publication | Research | en_ZA |
| uct.type.resource | Research paper | en_ZA |