Since 2000, the CSS team (Sharks Studies Center), as part of the project: “Ecology and Ethology of the Great White Shark”, has been collecting ethological data during Scientific Expeditions organized in South Africa in Gansbaai, 200 km east of Cape Town. In Gansbaai Bay and around Dyer Island and Geyser rock, there is a large population of White Sharks that can be observed thanks to the support of local ecotourism operators authorized to reach the best field observation sites. Research activities about ethological and ecotoxicological analyses, covered between 2003 and 2019, were developed in collaboration with: University of Calabria and Siena in Italy and Stellenbosch University in South Africa. In order to enable proper data collection, it was necessary to develop techniques to identify white sharks that consist mainly of the collection of various biometric and environmental data in special sheets, as well as photographs of animals with special attention to the dorsal fins. After the first years of optimization of the techniques and of staff involved, it was necessary to identify the individual specimens and, between 2009 and 2019, it was possible to create a db. Since 2009 to 2019, between march and may, 423 different white sharks were catalogued for a total of 440 hours of field observations from the boat and 220 hours of observations from the cage, including 99 photographs of unique dorsal fins. In this work the preliminary results, related to the trends of the population present in Gansbaai Bay are presented and discussed.