Knowledge of spatial and temporal variation in abundance is critical for the implementation of effective protective measures for organisms that are both naturally rare and vulnerable to exploitation. The development of management and conservation strategies for elasmobranchs depends on accurate assessment and monitoring of the distribution and abundance of target species in the eld, but detecting species occurrences is often even more challenging in the aquatic environment than on land (Webb and Mindel, 2015). Consequently, as is the case for many large, mobile and rare vertebrates, shark detection is inherently difcult.