Movement patterns of Murray cod (Maccullochella peelii) and golden perch (Macquaria ambigua) in a northern Murray-Darling Basin dryland river

Context. Dryland rivers are unique ecosystems, where drought and flood play an important role in shaping the ecosystem. River regulation has altered the natural flow regime in many of these systems, affecting migration cues and connectivity for many species. Aims. To quantify the discharge-related movements of Murray cod and golden perch within the Condamine-Balonne River subject to differing levels of river regulation. Methods. We quantified flow regime variability, river regulation and fish movement to develop generalised additive mixed models to predict movement probability for Murray cod and golden perch. Results. Both species showed strong positive relationships between discharge and movement. Murray cod did not show any association with river regulation; however, medium-sized individuals were significantly more likely to move than were smaller or larger fish. Golden perch movements varied among levels of regulation, were more likely to move as body weight increased and showed seasonality of movement, moving less during winter. Conclusions. This study presents the largely unobserved movement behaviours of fish across a gradient of river regulation and environmental conditions in the northern Murray-Darling Basin. Implications. This information is valuable for informing policy and management decisions that may affect species' life-history requirements in analogous river systems.