Population demographics of golden perch (

Abstract

An understanding of population demographics and life history processes is integral to the rehabilitation of fish populations. In Australia's highly modified Murray-Darling Basin, native fish are imperilled and fish deaths in the Darling River in 2018-19 highlighted their vulnerability. Golden perch (Macquaria ambigua) is a long-lived percichthyid that was conspicuous in the fish kills. To guide population rehabilitation in the Darling River, pre-fish kill age structure, provenance and movement of golden perch were explored using otolith microstructure and chemistry ( 87 Sr/ 86 Sr). Across the Lower and Mid-Darling River, recruitment was episodic, with dominant cohorts associated with years characterised by elevated discharge. There was substantial variability in age structure, recruitment source and movement patterns between the Lower and Mid-Darling River. In the Mid-Darling River, tributaries were an important recruitment source, whereas in the Lower Darling fish predominantly originated in the Darling River itself. Downstream movement of juveniles, upstream migration of adults and return movements to natal locations were important drivers of population structure. Restoring resilient golden perch populations in the Darling River will be reliant on mitigating barriers to movement, promoting a connected mosaic of recruitment sources and reinstating the hydrological and hydraulic factors associated with spawning, recruitment and dispersal. Globally, increasing water resource development and climate change will necessitate such integrated approaches to the management of long-lived migratory riverine fishes.

Using multiple lines of evidence to assess recovery potential of a warm water fish population in a cold water impacted river

“…In rivers and streams, dissolved 87Sr/86Sr are an artefact of catchment geology and are increasingly being used to discern the natal habitats and movements of numerous diadromous and freshwater fishes in the southern MDB (e.g. Thiem et al, 2022;Zampatti et al, 2022).…”

Mass fish kills catalyse improved water and fisheries management

“…The performance and limitations of the different aerators are outlined, along with recommendations that can improve the way they are used in future events. Studies by Zampatti et al (2022) and Thiem et al (2022) use otolith microstructure and chemistry to explore the ages, provenance and large-scale movements of three potamodromous species that perished in the 2018-19 Lower Darling-Baaka fish kills, namely the golden perch (Macquaria ambigua), Murray cod and silver perch (Bidyanus bidyanus). Their research shows that restoring resilient populations of these species will require reinstating the hydrological and hydraulic factors associated with spawning, recruitment and dispersal, while removing barriers to large-scale movements that have disconnected different natal regions.…”

Living with hypoxia: Residence and site fidelity by golden perch (Macquaria ambigua) in habitats affected by methane seeps and chronic hypoxia

“…Most fish exhibit strong site attachment to spatially limited home ranges for extended periods (Crook, 2004; Koster et al., 2017; O'Connor et al., 2005; Zampatti et al., 2018) and nearly half of individuals do not make among‐tributary movements during their lifetimes (Barrow et al., 2021). Nonetheless, large‐scale movement by adult golden perch is common during high‐flow periods, with a considerable proportion of individuals migrating 10s–100s of km in both upstream and downstream directions (Koster et al., 2014, 2017; Llewellyn, 2014; Marshall et al., 2016; O'Connor et al., 2005; Thiem et al., 2020; Zampatti et al., 2021), and a smaller proportion of fish moving distances of >1,000 km upstream during high flows (Llewellyn, 2014; Reynolds, 1983). Our study aims to investigate the influence of local water chemistry and river flow on golden perch movement and condition in the affected reach of the Condamine River, and to improve our understanding of the risks that methane seeps and chronic hypoxia may pose for fauna in affected ecosystems.…”