Murray cod monitoring

Found throughout the Murray-Darling Basin, the Murray cod (Maccullochella peelii) is Australia's largest freshwater fish. It is central to First Nations culture and has significant economic, recreational and environmental value.

Historically, the Murray cod was one of the most abundant fish species in the River Murray, but populations declined throughout the 1900s due to the impacts of river regulation, habitat loss, overfishing and invasive species.

To address this issue, the Sustaining Riverland Environments (SRE) program, funded by the Murray-Darling Basin Authority and managed by the South Australian Department for Environment and Water, is undertaking considerable research and management actions aimed at reversing the decline of this iconic species. Activities include re-snagging, fishway construction, investigations of weir pool lowering and restoration of flowing creeks, which will complement the delivery of water for the environment to boost numbers of Murray cod in the South Australian River Murray.

To provide effective management interventions, SRE is also undertaking research to gain better understanding of the species, including its habitat use and movement in the lower River Murray. 

The project is being led by a collaborative team from the South Australian Research and Development Institute (SARDI) Aquatic Sciences Division and CSIRO, Australia’s national science agency, who are aiming to tag, release and monitor 100 Murray cod. 

Fish are humanely implanted with small acoustic tags under anaesthesia, before they are released and monitored using an extensive network of acoustic receivers throughout the river. These receivers will record the unique ID of fish that swim within detection range.

Since the project commenced in mid-2025, 50 Murray cod have been tagged between Overland Corner (Lock 3) and Murtho (Lock 6), with fish ranging between 450 and 1,200 mm in length and weighing between 1.3 and 30 kg. In 2026, the team is planning to tag an additional 50 Murray cod. 

The movements of tagged fish will be monitored until 2028, with data providing natural resource managers with the knowledge to better support Murray cod into the future by evaluating: 

• how the fish interact with key anabranches at Chowilla Game Reserve, Pike Floodplain, Bookmark Creek and Katarapko Floodplain
• how the fish respond to environmental water delivery and manipulation of water levels in weirs
• key barriers to fish movement
• if the fish are utilising areas where re-snagging has been undertaken.  

What to do if you catch a tagged Murray cod

In addition to the acoustic tags, monitored fish have a ‘dart’ tag located near their dorsal fin, with a telephone number and unique id listed. We ask anglers to note the ID number and, after releasing the fish, contact us on the telephone number (1800 119 194) to report the recapture. We can then provide you with a small thank you reward, and the original capture information for the identified fish.

Angler recapture data provides useful supplementary information to the project’s formal acoustic tag data.