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

Towner, Alison V., Wcisel, Michelle A., Reisinger, Ryan R., Edwards, David and Jewell, Oliver J.D. (2013) Correction: Gauging the threat: The first population estimate for white sharks in South Africa using photo identification and automated software. PLoS ONE, 8 (6), [10.1371/annotation/2ac91258-bfcc-40f4-adee-3f855b1a4be7]. (doi:10.1371/annotation/bb25e7cb-12f7-42e4-9d26-07b9bda87ecc).

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 openpopulation 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.

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Contributors

Author: Ryan R. Reisinger

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