Environmental factors drive differences in activity between sexes of a large marine predator

Abstract

Fluctuations in environmental conditions can induce changes in animal behaviour, influence annual migrations for food or reproduction, and alter physiology. Additionally daily shifts in behaviour in response to short-term environmental change can vary across different spatial and temporal scales. Traditional acoustic tracking methods typically quantify the geographical movements of animals, without considering the changes in activity that can occur spatially, temporally, and in response to environmental conditions. We quantified spatial, temporal, and environmental factors that drive the acceleration of a top marine predator in a near-shore habitats. We deployed acoustic accelerometer tags on 504 white sharks (Carcharodon carcharias) between 2020 and 2023 in New South Wales, Australia. Generalised Additive Mixed Models were then used to assess the influence of spatial, temporal, and environmental factors on shark activity levels. Considerable individual variation was observed in both male and female sharks while male sharks exhibit higher acceleration than females. Male white sharks demonstrated higher acceleration equatorward of 33°S between 1000 and 1500 h, while female sharks had higher acceleration poleward of 33°S between 0900 and 1300 h, and 2100 and 0200 h. This research highlights the importance of moving beyond traditional acoustic tracking studies to explore the complex interplay of factors influencing animal behaviour and movement. Our findings will inform non-lethal shark management programs to better protect water users, helping reduce the risk of negative human-shark interactions.