High-resolution mapping of shark movements from drone footage at Queensland beaches improves risk assessment for beach safety

Abstract

Shark interactions with water users can, on rare occasions, lead to shark bites. The sporadic nature of these events and their rarity has complicated efforts to understand the underlying causes, with many contributing factors implicated. Understanding shark presence and movement patterns near beaches is critical to developing a better appraisal of risk for shark bites. Recent advancements in Unmanned Aerial Vehicle (UAV, or drones) technology has provided new opportunities to observe and monitor sharks in coastal areas, offering real-time safety benefits and research insights. This research uses four years of data from the Queensland SharkSmart drone trial to investigate shark presence and movement behaviour at three beaches in Southeast Queensland. The research aimed to evaluate high-resolution shark tracks to analyse key metrics including proximity to shore and water users, time spent in the area and signs of active foraging. By bringing these and other data together, the study sought to develop a risk assessment matrix to inform risk to water users at these beaches and provide criteria to assist drone pilots decide when to evacuate beaches when risk is higher. Results showed that shark species, total length, proximity to water users and prey presence were key aspects determining the risk to water users associated with shark sighting events. Areas with abundant prey or near river mouths were more likely to attract potentially dangerous sharks. Understanding shark patterns at these beaches will facilitate predictions of higher-risk shark occurrences, thereby contributing to risk management and improvement of SharkSmart education for water users.