Seafloor habitat, depth and diel patterns influencing prey encounter and hunting success in a large marine predator, the Australian fur seal

Determining the environmental factors driving the foraging behaviour of marine top predators is crucial for assessing their ecological roles and resilience to environmental variability. This study examines the foraging strategies of female Australian fur seals (Arctocephalus pusillus doriferus; AUFS) during the austral autumn and winter (2008–2018) at Kanowna Island, south-eastern Australia, a region increasingly threatened by anthropogenic activities and environmental changes. Using animal-borne video cameras, GPS tracking, and dive behaviour loggers, encounters and captures of prey were analysed across 2022 recorded dives from 22 adult females provisioning pups. Benthic invertebrate cover was a key predictor of capture success, with the highest probabilities in densely covered areas, despite these not being the most frequently visited habitats. Encounter rates increased with depth, suggesting greater prey availability in deeper waters. Time of day significantly affected both encounters and captures with nocturnal periods showing the highest rates. These findings demonstrate that seafloor habitat complexity, depth and diel cycles simultaneously shape the prey fields of AUFS. The identification of specific habitat features linked to foraging behaviour improves the understanding of the ecological requirements of this central-place forager in a region undergoing rapid environmental change driven by anthropogenic pressures. Such insights are critical to anticipate potential impacts on prey availability and, consequently, on foraging efficiency and the ability of the species to adapt to future conditions.