Re-establishing Murray crayfish in South Australia

Updated March 2026

The Murraylands and Riverland Landscape Board, in collaboration with a number of partner organisations, have undertaken an ambitious trial to re-establish the Murray crayfish in the South Australian portion of the Murray River. As an iconic native species and of cultural significance to First Nation’s communities, protecting the future of the Murray crayfish is of vital importance.

How did the Murray crayfish become extinct in South Australia?

For the last 40 years, the iconic Murray crayfish (Euastacus armatus) has been virtually extinct in South Australia. Altered flows caused by river regulation reduced the scale of suitable Murray crayfish habitat. In addition, over-fishing by commercial and recreational fishers and pollution also resulted in the decline of the species.
While Murray crayfish do live successfully in locations along the River Murray upstream, human intervention is required to successfully re-establish the population in South Australia. This is because Murray crayfish have a very limited range, so it is unlikely that they will spread downstream naturally.

Where did the released Murray crayfish come from?

As a result of the 2022-23 flood events, a number of Murray crayfish were rescued from black water affected sites interstate. Many of these crays were returned to the location from which they were found, but around 200 were retained for release in South Australia. Between being rescued and released, the crays were maintained in aquarium facilities in Mildura and Victor Harbor.

Both male and female crayfish were released, ranging in size from about 8cm up to about 30cm in length. Including crays of both sexes and in various life stages maximises the likelihood that the released cray will reproduce and develop a self-sustaining community.

What happened since the first Murray crayfish release?

Each year since 2023, approximately 200 adult crayfish and 400-500 juveniles have been translocated from captivity to healthy upstream population sites.

After each release, the Murraylands and Riverland Landscape Board and Nature Glenelg Trust work with a number of partner organisations to monitor the released crayfish to determine their survival rate and learn more about their habits.

Around 30 of the released crayfish are fitted with radio tracking devices which help researchers monitor their movements. The tracking devices are glued to the carapace (shell) of mature crayfish and remain there for approximately 12 months until they moult. Monitoring of these tracked crayfish are undertaken by rangers from the River Murray & Mallee Aboriginal Corporations (RMMAC) River Ranger team as well as recapture monitoring using baited hoop nets.

What has monitoring data shown so far?

Data from radio tracking has provided insights into the behaviour of Murray crayfish in their environment and has shown a high survival rate, indicating that this species can be successfully re-introduced to suitable sites in the River Murray in South Australia.

Since September 2024, Murray crayfish have consistently been recaptured at reintroduction sites, including egg-bearing females. 
Radio tacking data has also indicated a few individuals moving up to 2 km upstream, and up to 10km downstream.

What should I do if I find a Murray crayfish?

If you happen to find a Murray crayfish while fishing or exploring the river, you should return it to the river and don’t tell people where you found it. You’ll be playing a role in helping to preserve the future of this iconic species for future generations.

Murray crayfish are recognised a protected species under South Australian law. Protected species must be returned to the water immediately. Anyone who takes or causes harm to a protected species may face heavy fines.

Who was involved in the project to release Murray crayfish back into the South Australian Murray River?

This initiative is a partnership between Nature Glenelg Trust, and the Murraylands and Riverland Landscape Board through funding from the landscape levies, with support from New South Wales DPI, OzFish, North West Aquaculture, Victoria Fisheries Authority, River Murray & Mallee Aboriginal Corporation (RMMAC) and PIRSA.