2013 journal article
Gauging the Threat: The First Population Estimate for White Sharks in South Africa Using Photo Identification and Automated Software
PLoS ONE, 8(6).
Contributors: A. Towner*, M. Wcisel*, R. Reisinger *, D. Edwards * & O. Jewell *
TL;DR:
The assessment suggests the species has not made a marked recovery since being nationally protected in 1991 and additional international protection may prove vital for the long-term conservation of this threatened species.
(via Semantic Scholar)
journals.plos.org (publisher PDF)
Source: ORCID
Added: January 29, 2024
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.