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

Native fish recovery post environmental water delivery in the lower Darling River 2020-2022 - PRESENTATION CANCELLED (#63)

Ivor Stuart 1 , Paula D'Santos 2 , Meaghan Duncan 3 , Iain Ellis 4 , Ben Fanson 5 , Katherine Harrisson 5 , Laura Michie 3 , Clayton Sharpe 6 , Jason Thiem 3 , Dylan van der Muelen 7
  1. Charles Sturt University, Albury, NSW, Australia
  2. Environment, Energy and Science, EES, Buronga, NSW
  3. Department of Primary Industries, Narrandera Fisheries Centre, Narrandera, NSW
  4. Department of Primary Industries, NSW Fisheries, Buronga, NSW
  5. DEWLP, Arthur Rylah Institute, Heidelberg, VIC
  6. NSW Parks & Wildlife, Buronga, NSW
  7. NSW DPI Fisheries, Batemans Bay, NSW

Since the 2018-2020 devastating fish deaths on the lower Darling River (LDR), a series of environmental flows have been implemented to sustain and recover native fish populations. The fish recovery hydrograph is designed to incorporate four key elements: (i) a late winter/spring increase in discharge to inundate Murray cod spawning and rearing habitats, (ii) a spring and early summer sharp increase in discharge to 1500 ML d -1 to enhance survival of larval Murray cod and, (iii) to stimulate golden perch spawning and dispersal, and (iv) a gradual recession summer/autumn recession to a lotic winter baseflow. Monitoring between 2020-2022 has included boat electrofishing, larval and juvenile netting and acoustic tagging. Results demonstrate recruitment of Murray cod and golden perch in the LDR with the later species originating from spawnings upstream of the Menindee Lakes. We highlight that Murray cod populations can be recovered and protected with lotic baseflows, perennial flowing conditions, hydraulic complexity and prevention of protracted cease-to-flow conditions.  While to maintain golden perch populations in the southern MDB, protection of flow events from the northern Murray Darling Basin into the Menindee Lakes with subsequent downstream dispersal of recruits must occur. Our fish recovery hydrograph provides a much-needed template to support post fish-death population recovery and highlight a pathway to rebuild the resilience of the LDR ecosystem.