Improve environmental water delivery to enhance recruitment, movement, and population persistence of Golden Perch (Macquaria ambigua) in Murrumbidgee floodplain lake systems (Tala and Yanga) 

My aim is to investigate how environmental water can support golden perch populations in the Murrumbidgee River floodplain, with the main focus being on the Yanga and Tala Lakes. Environmental flows are used to mimic natural floods and flow pulses, but there is a lack of understanding of how these fish actually respond to them.

This research aims to understand three main focus points: 1 – How golden perch use floodplain lakes in terms of habitat, feeding, and behaviour. 2 – How and when they move and if they move between the lakes, creek and river. 3 – When young fish are born and their early life histories. Using acoustic tags, I will monitor adult fish movements and analyse ear bones (otoliths) to determine the origins and age of juveniles. I will also examine food webs and water quality to understand what supports growth and survival. 

About this project

The research is being conducted to answer the question of environmental flow success on golden perch breeding, movement and survival. The river’s natural flow has been altered, which drastically reduces floodplain connectivity, which in turn disrupts the ecological processes of native fish. The solution to this is to use Eflows to establish connectivity and prompt spawning events. Golden Perch movement, spawning, and recruitment – particularly in off-channel floodplain lakes such as Tala and Yanga in the lower Murrumbidgee. It remains unclear whether these lakes function as breeding habitats, productive nurseries or temporary refuges. This research addresses that knowledge gap by integrating fish movement tracking, recruitment assessment, and habitat analysis. Acoustic telemetry will quantify how adults and juveniles move between lakes, creeks and the river and whether they respond to environmental flow events. This is performed by inserting tags underneath the fishies’ skin. Receivers around the lake will pick up each individual as it passes by, giving an indication of movement behaviour. Otolith ageing and microchemistry will determine the origin and dispersal pathways of young-of-year fish. This analysis gives the age of the fish to the day and can be used to compare with flow records to show when spawning has occurred and where it occurred in comparison with flows. Concurrent sampling of water quality, productivity, and food webs will identify the ecological conditions that support growth and survival. By linking hydrology, connectivity and life-history processes, this project will provide evidence-based recommendations to optimise environmental water delivery for Golden Perch population persistence.

Expected outcomes

Native fish populations in the Murray Darling Basin have declined due to river regulation and reduced floodplain connectivity. Environmental water is delivered to restore ecological processes, yet its effectiveness for species such as Golden Perch remains uncertain – particularly in floodplain lakes. Understanding whether these lakes function as spawning sites, nurseries, or refuges is critical for improving water management. This research will link fish movement, recruitment, and habitat productivity to environmental flows, providing evidence-based recommendations to optimise water delivery and support long-term population persistence in a highly regulated and water-limited river system.