Gauging the threat: the first population estimate for white sharks in South Africa using photo identification and automated software

 

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dc.contributor.author Towner, Alison V en_ZA
dc.contributor.author Wcisel, Michelle A en_ZA
dc.contributor.author Reisinger, Ryan R en_ZA
dc.contributor.author Edwards, David en_ZA
dc.contributor.author Jewell, Oliver J D en_ZA
dc.date.accessioned 2015-11-16T04:14:11Z
dc.date.available 2015-11-16T04:14:11Z
dc.date.issued 2013 en_ZA
dc.identifier.citation Towner, A. V., Wcisel, M. A., Reisinger, R. R., Edwards, D., & Jewell, O. J. (2012). Gauging the threat: the first population estimate for white sharks in South Africa using photo identification and automated software. PloS one, 8(6), e66035-e66035. doi:10.1371/journal.pone.0066035 en_ZA
dc.identifier.uri http://hdl.handle.net/11427/15032
dc.identifier.uri http://dx.doi.org/10.1371/journal.pone.0066035
dc.description.abstract South Africa is reputed to host the world’s largest remaining population of white sharks, yet no studies have accurately determined a population estimate based on mark-recapture of live individuals. We used dorsal fin photographs (fin IDs) to identify white sharks in Gansbaai, South Africa, from January 2007 - December 2011. We used the computer programme DARWIN to catalogue and match fin IDs of individuals; this is the first study to successfully use the software for white shark identification. The programme performed well despite a number of individual fins showing drastic changes in dorsal fin shape over time. Of 1682 fin IDs used, 532 unique individuals were identified. We estimated population size using the open-population POPAN parameterisation in Program MARK, which estimated the superpopulation size at 908 (95% confidence interval 808-1008). This estimated population size is considerably larger than those described at other aggregation areas of the species and is comparable to a previous South African population estimate conducted 16 years prior. Our assessment suggests the species has not made a marked recovery since being nationally protected in 1991. As such, additional international protection may prove vital for the long-term conservation of this threatened species. en_ZA
dc.language.iso eng en_ZA
dc.publisher Public Library of Science en_ZA
dc.rights This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. en_ZA
dc.rights.uri http://creativecommons.org/licenses/by/4.0 en_ZA
dc.source PLoS One en_ZA
dc.source.uri http://journals.plos.org/plosone en_ZA
dc.subject.other Sharks en_ZA
dc.subject.other Computer applications en_ZA
dc.subject.other Computer software en_ZA
dc.subject.other Marine fish en_ZA
dc.subject.other South Africa en_ZA
dc.subject.other Confidence intervals en_ZA
dc.subject.other Eyes en_ZA
dc.subject.other Marine environments en_ZA
dc.title Gauging the threat: the first population estimate for white sharks in South Africa using photo identification and automated software en_ZA
dc.type Journal Article en_ZA
dc.rights.holder © 2013 Towner et al en_ZA
uct.type.publication Research en_ZA
uct.type.resource Article en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Science en_ZA
dc.publisher.department Department of Biological Sciences en_ZA
uct.type.filetype Text
uct.type.filetype Image


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This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Except where otherwise noted, this item's license is described as This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.