Gauging the threat: the first population estimate for white sharks in South Africa using photo identification and automated software.
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, fro...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2013-01-01
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| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC3680411?pdf=render |
| _version_ | 1818161754323025920 |
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| author | Alison V Towner Michelle A Wcisel Ryan R Reisinger David Edwards Oliver J D Jewell |
| author_facet | Alison V Towner Michelle A Wcisel Ryan R Reisinger David Edwards Oliver J D Jewell |
| author_sort | Alison V Towner |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-12-11T16:22:48Z |
| format | Article |
| id | doaj.art-2d2ffcb589054ffcb28928767b8305ba |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-11T16:22:48Z |
| publishDate | 2013-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-2d2ffcb589054ffcb28928767b8305ba2022-12-22T00:58:48ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-0186e6603510.1371/journal.pone.0066035Gauging the threat: the first population estimate for white sharks in South Africa using photo identification and automated software.Alison V TownerMichelle A WciselRyan R ReisingerDavid EdwardsOliver J D JewellSouth 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.http://europepmc.org/articles/PMC3680411?pdf=render |
| spellingShingle | Alison V Towner Michelle A Wcisel Ryan R Reisinger David Edwards Oliver J D Jewell Gauging the threat: the first population estimate for white sharks in South Africa using photo identification and automated software. PLoS ONE |
| title | Gauging the threat: the first population estimate for white sharks in South Africa using photo identification and automated software. |
| title_full | Gauging the threat: the first population estimate for white sharks in South Africa using photo identification and automated software. |
| title_fullStr | Gauging the threat: the first population estimate for white sharks in South Africa using photo identification and automated software. |
| title_full_unstemmed | Gauging the threat: the first population estimate for white sharks in South Africa using photo identification and automated software. |
| title_short | Gauging the threat: the first population estimate for white sharks in South Africa using photo identification and automated software. |
| title_sort | gauging the threat the first population estimate for white sharks in south africa using photo identification and automated software |
| url | http://europepmc.org/articles/PMC3680411?pdf=render |
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