Comparison of industry-based data to monitor white shark cage-dive tourism

Abstract

Although wildlife tourism is becoming increasingly popular worldwide, the industry has a potential to affect the fauna it targets. A variety of methods are used to monitor the activities and impacts of wildlife tourism. In South Australia, mandatory logbook reporting and the ability to photograph and identify individual sharks provides two industry-based data sources to monitor how cage-diving tourism may impact white sharks. Findings show that both methods can assess shark populations, and detect seasonal sex-biased changes in white shark abundance. Photo-ID significantly underestimates effort days and number of sharks sighted, and is considerably more labour-intensive, but allows accurate identification of individual sharks, facilitating additional analysis. The continued use of logbook reporting is the optimum long-term monitoring method, although we recommend the maintenance of a photographic database for periodic extraction of individual information. Combining these methods will facilitate an ongoing adaptive management framework, aiding the long-term sustainability of the industry.