Multiscale movements of golden perch (Percichthyidae: Macquaria ambigua) in the River Murray, Australia

Abstract

AbstractUnderstanding the spatio‐temporal characteristics of animal movement is integral to effective conservation and management. Golden perch (Macquaria ambigua) is a potamodromous species known to undertake long‐distance movements, putatively in response to elevated flow in spring and summer. In this study, 52 adult golden perch from the lower River Murray were surgically implanted with radio transmitters and passive integrated transponder (PIT) tags, and tracked for 2 years. Strong site fidelity was common, with 19 fish (~36%) remaining at the site of capture throughout the study. This included a spawning season (spring‐summer) and a period of elevated flow. Eighteen fish (35%) made small‐ to medium‐scale (2–22 km) movements that included the establishment of new home sites. Fifteen fish (29%) migrated long distances (33–270 km) upstream in spring–summer, coincident with steady, falling and rising flows. These movements were correlated with seasonal variation in mean daily water temperature, and to a lesser extent, short‐term (10‐day) flow variability, and did not coincide with spawning or recruitment during the year of migration. This contrasts previous studies that have associated long‐distance movements of golden perch with increased flows and spawning. Upstream migration continued until passage was blocked by a weir, or fish were captured by anglers. Our results highlight the need for a broad spatio‐temporal perspective when investigating the movement of long‐lived potamodromous fishes, to integrate the range of behaviours exhibited by individuals and population contingents. We advocate that life history models that incorporate behavioural plasticity and a river‐scale perspective will advance conservation.