Standard Talk (15 mins) Australian Society for Fish Biology Conference 2022

Dispersal of early life-history golden perch in the northern Murray-Darling Basin. (#28)

Laura Michie 1 , Katherine Harrisson 2 3 , David Crook 1 , Meaghan Duncan 1 , Ivor Stuart 3 4 , Clayton Sharpe 5 , Iain Ellis 6 , Gavin Butler 7 , Jason Thiem 1
  1. Department of Primary Industries, Narrandera Fisheries Centre, Narrandera, NSW, Australia
  2. Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, Victoria, Australia
  3. Arthur Rylah Institute for Environmental Research, Department of Environment, Land, Water and Planning, Heidelberg, Melbourne, Victoria, Australia
  4. Gulbali Institute for Agriculture, Water and Environment, Charles Sturt University, Albury, NSW, Australia
  5. NSW Water & Wetlands Conservation Branch, National Parks and Wildlife Service, Buronga, NSW, Australia
  6. Murray-Darling Unit, NSW Department of Primary Industries, Buronga, NSW, Australia
  7. Department of Primary Industries, Grafton Fisheries Centre, Grafton, NSW, Australia

Dispersal of fish, whether active or passive, plays an important role in driving species distributions, supporting successful recruitment and promoting gene flow and genetic diversity between sub-populations. In this study we sampled larval and young-of-year (YOY) golden perch over ~1800 km in the Barwon-Darling River, the Lower Darling Baaka River (LDBR), the Menindee Lakes system and three northern tributary inputs to the Barwon-Darling (the Moonie, Culgoa and Warrego Rivers) to identify patterns of movement and quantify spatial distances travelled by early life-history golden perch in the region. The natal origins of YOY golden perch captured in the Menindee lakes and LDBR could be classified to three distinct upstream regions based on strontium isotope ratios (87Sr/86Sr) measured at the otolith core. The majority (56%) had performed no significant dispersal having been spawned in the Darling River in the immediate upstream vicinity of the Menindee Lakes. The remaining fish had dispersed longer distances, having originated from upstream stretches of the Barwon-Darling mainstem and its tributaries, with 5 individuals (3.4%) having dispersed >1600 km from their natal region. Using genetic analysis of the kinship relationships (siblings) between YOY and larval golden perch, individuals captured in the Menindee Lakes and the LDBR (Spring 2020) were able to be linked to larval cohorts captured in March 2020 in the Moonie, Culgoa, Warrego, Barwon and Darling Rivers. Our results demonstrate vast connectivity between sub-catchments of the northern Murray-Darling Basin and highlight the complexity of golden perch early life-history dispersal. Developing our understanding of dispersal strategies in fish, and the factors that may impact these processes such as hydraulic and geomorphic diversity within river systems, is an essential step towards effectively implementing coordinated management strategies for their protection over appropriate spatial scales.