Environmental drivers of humpback whale foraging behavior in the remote Southern Ocean

Satellite telemetry and animal movement models advance our ability to remotely monitor the behavior of wide-ranging species. Understanding how different behaviors (e.g. foraging) are shaped by dynamic environmental features is fundamental to understanding ecological interactions and the impact of variability. In this study we deployed satellite-linked tags on humpback whales (Megaptera novaeangliae) and used state-space models to estimate locations and to infer underlying behavioral states. We then modelled the association between whale behavior (e.g. foraging or transiting) and environmental variables using linear mixed-effect models. We identified the importance of two recently discovered Southern Ocean feeding areas for Oceania humpback whales as well as the key environmental drivers affecting whale behavior. We detected behavioral differences between whales utilizing the two adjacent feeding regions (~2000 km apart), which were likely caused by animals trying to efficiently locate prey in relation to the dynamic environmental characteristics of each habitat. We observed a seasonal pattern in foraging behavior, with the peak occurring in the middle of summer. Whales also foraged more intensively with increasing proximity to areas from which the ice edge had recently retreated, suggesting heightened productivity in these areas. The relationship between the animals and the physical features of the seascape, as well as the behavioral plasticity observed, could have implications for the future recovery of these whales in a changing Southern Ocean.