The allocation of an organism’s time and energy to different behaviours can impact survival and fitness, and ultimately influence population dynamics. As such, the rate at which animals expend energy is a key component to understanding how they interact with their surrounding environment. Activity, primarily derived through locomotion, represents the principal energy cost in addition to basic metabolism, although is rarely quantified in the field. In this PhD project, you will explore the biotic and abiotic drivers of field activity rates in Australia’s largest freshwater fish, the iconic Murray cod. In doing so, you will test theories on energy budgets and incorporate new information into bioenergetics models. During this project you will have the opportunity to undertake both laboratory and field studies, and gain new skills in fish biology, ecology, physiology, biotelemetry and multivariate modelling. Working in collaboration with State government agencies, you will plan and communicate your research so that it is directly applicable to conservation and management.