Murray crayfish once thrived in the southern Murray-Darling Basin. The species was found everywhere from the headwaters of the Murray and Murrumbidgee Rivers in the Australian Alps all the way down to Wellington in South Australia.
For thousands of years, First Nations people managed harvesting sustainably. But crayfish stocks crashed after European settlement. This was partly due to commercial and recreational harvest, which began in the late 1860s. At its peak in 1955, 15 tonnes of Murray crayfish were taken from the river in New South Wales and sent to markets in Melbourne and Sydney.
In South Australia, the commercial fishery was unsustainable by the 1960s and the species was no longer targeted. In the 1980s, Murray crayfish became a protected species in the state. But the damage was done.
Over-harvesting was not the only problem. Murray crayfish prefer free-flowing, oxygen-rich water, so they suffered from efforts to regulate river flows using dams and weirs. Poor water quality, including pollution from pesticides and other agricultural chemicals, made matters worse.
Murray crayfish disappeared from South Australia sometime in the past 40 years. Targeted surveys over a five-year period couldn’t find them anywhere in the state.
But that all changed in the winter of 2023 when our reintroduction program began. Now we’re preparing for the third release of crayfish and there are positive signs many crays from earlier releases are still going strong.
A species in need of support
Like many species from the highly threatened Euastacus genus, Murray crayfish grow slowly. It takes almost ten years for a female to reach sexual maturity, and she only produces a small number of eggs. Dispersal is also limited. This makes it hard for the population to recover in both number and range.
Following a recent assessment, the species Euastacus armatus is expected to soon be listed as vulnerable to extinction under Australia’s conservation laws.
Conservation actions such as reintroductions will be necessary to aid recovery of the species.
A long time coming, shaped by adversity
The idea of returning Murray crayfish to the river in South Australia is not new.
Two University of Adelaide ecologists, the late Keith Walker and Mike Geddes, first suggested it in the 1990s. They even conducted trials involving crayfish in cages to show sections of the river would be suitable for the species.
Then in 2007, the reintroduction idea was floated again. It was one of the main recommendations in a report identifying gaps in knowledge of the species.
But the idea really gathered momentum after disaster struck. Widespread flooding across the southern Murray-Darling Basin in 2010–11 led to a “hypoxic blackwater” event. This is where leaf litter and debris from the floodplain wash into the river, depleting levels of oxygen and causing mass deaths of both fish and crayfish.
This inspired further research into crayfish genetics, recovery potential and preferred habitat. It guided a 2019 strategy outlining how the species could be successfully reintroduced. A trial five-year reintroduction program in the New South Wales range of the species helped refine the strategy.
Then another Murray blackwater event in 2022–23, in NSW and Victoria, forced crayfish out of the water and up the riverbanks.
Vision of dying crayfish leaving the water, only to be consumed by predators or poached by people, prompted the community to respond. Guided by fisheries agencies and a fishing conservation charity, they rescued crays and held them safely in aquaculture facilities until they could be released back into the wild.
Many of these crayfish were later returned to the river where they came from. But a small number were held for release into SA as part of our new reintroduction program.
In a truly collaborative effort, a small environmental not-for-profit organisation, Nature Glenelg Trust, worked in partnership with a natural resource management agency, First Nations community, fisheries agencies from three states and a private aquaculture facility to turn the idea into reality.
The team responsible for releasing Murray crayfish back into South Australia. Photo: Nick Whiterod
Positive signs from crayfish releases
Murray crayfish were first released back into South Australia in winter 2023. It was a big moment for people who have long championed the species’ return.
A further 200 crayfish were released during winter 2024.
During each release, some of the crayfish were tagged with trackers. This has provided world-first movement and activity information. It shows all tagged crayfish being regularly detected, indicating they are flourishing.
Field surveys each season at the reintroduction site have also found the species alive and well, representing the first Murray crayfish found in the state for more than 40 years.
Releasing a tagged Murray crayfish. Photo: Nick Whiterod
Returning a totemic and iconic species
The reintroduction of Murray crayfish into a closely guarded location in South Australia’s Riverland is both culturally and ecologically significant.
It signals the return of a important totem to the Erawirung people of the region, and provides a way to reconnect with the species.
Reestablishing a population of the species in South Australia, where hypoxic blackwater events have not been as severe, also provides insurance against extinction.
The species is considered a keystone species, meaning it plays a disproportionately large role in the ecosystem. So returning it to the river may have even greater ecological benefits.
Coauthor Sylvia Zukowski is managing the reintroduction program. Photo: Nick Whiterod.
The first of many steps
Reintroduction programs require ongoing commitment if they are to be successful. Extra crayfish will need to be added to the reintroduced population over the coming years.
The reintroduced population will continue to be monitored to ensure numbers are increasing and the range expanding. It will remain protected from fishing by local fisheries authorities.
If successful, further reintroductions may be undertaken into other parts of South Australia.
On World Animal Day (Sat 4 Oct), join us at a very special event as we celebrate the life of Christine Townend, cofounder of Animal Liberation in 1976, and Animals Australia in 1980. Christine spent two decades helping animals in India where she and her husband Jeremy also founded two animal shelters. In 2019 she was awarded the Order of Australia for her contributions to animal protection. A resident of Leura, Christine died on 15 August 2025. Raising the Bar for Nature, at the Planetary Health Centre, will be a night of poetry, art and celebration with delicious plant based food. Bookings essential here (link in profile): https://bit.ly/4migZuD
Early bird registrations and call for submissions are now open for our groundbreaking conference and community expo bringing together the Australian Bushfire Building Conference and the Asbestos & Hazardous Materials Management Conference from the 20-22 November. Visit the Full Cycle 2025 website to purchase your ticket, or register your interest in partnering, speaking, sharing research, exhibiting or running workshops (link in profile): https://www.fullcycleconference.com.au/
Katoomba`s Against the Grain compresses sawdust into briquettes. They`re heating homes across the Blue Mountains and dramatically reducing landfill waste. Read more in our Katoomba Area Local News (link in profile): https://www.katoombalocalnews.com/turning-sawdust-into-gold/
What a glorious Spring day! We spent most of it outside: enjoying Tai Chi in the sunshine; with an outdoor stall at the Sustainability Festival; and at Bushcare - where we welcomed new members to the group, and finally cleared our way through what once seemed like an impenetrable wall of weed.
We`re excited about tomorrow: Tai Chi at 8am Book here (link in profile): https://bit.ly/47WI2YO, the @bluemtns_sustainability_fest from 10am at the Cultural Centre and throughout Katoomba and Leura, and Bushcare from 1.30pm (link in profile): https://bit.ly/420ofE4 (NB. Lis will be heading straight to Planetary Health Bushcare after her talk!)
Check out how Blue Mountains City Council`s environment team worked with students from Kindlehill School at the Planetary Health Centre to demonstrate how to stop erosion on a slope using natural materials. This technique slows stormwater flows, builds soil and reduces water pollution downstream. Our `How to Do Cool Things` playlist on our YouTube channel has lots of other helpful videos too! (link in profile) #erosion #stormwater #repair #regeneration #erosioncontrol #planetaryhealth #watermanagement...
There is a little bit of magic happening on Wednesdays at the Planetary Health Centre as young volunteers from @kindlehill_high_school, and Council staff, work together to create a demonstration site for the wider community. This hands-on program is inspiring all involved, including teacher Sarah Daniel. In her reflection on their Bushcare session, reprinted here, she was reminded of Arundhati Roy’s words that ‘another world is not only possible, she is on her way.’
Read more in Katoomba Area Local News (Link in profile): https://www.katoombalocalnews.com/another-world-is-possible/
If you`re feeling overwhelmed, this Saturday offers inspiring opportunities to `re-set` mind, body and spirit with morning Tai Chi, Qigong and breakfast at the Planetary Health Centre at 8am; the Sustainability Festival at the Cultural Centre from 10am; and Planetary Health Bushcare to fully reconnect with nature and help regenerate habitat for wildlife at 1.30pm. Reserve your spot for Tai Chi here: https://bit.ly/47WI2YO and Bushcare here: https://bit.ly/420ofE4
Cardiac arrest is a leading cause of death in Australia but Community Defibrillators are easy to use and may help you save someone`s life. Learn how in this video: https://www.youtube.com/watch?v=sIdPTT4r0T4&t=60s
Our Planetary Health Bushcare Group had a ball today at the annual Bushcare Picnic and we were thrilled that our youngest member, Arthur van der Meer, was presented with the Junior Bushcare Award. Our inspiring Bushcare Officer Karen Hising, also leads the Narrowneck Bushcare Group which was recognised for 5 years of service to the Bushcare Program. We`re looking forward to our next Bushcare afternoon on Saturday 6 September from 1.30-4.3pm. All welcome.
You can now read the latest Planetary Health newsletter here (link in profile): https://bit.ly/41u8ftQ
Lots of great stories, events and videos! You can subscribe via the Planetary Health website (link in profile): https://www.bluemountainsplanetaryhealth.com.au/
This year, the Australian Bushfire Building and Asbestos & Hazardous Materials Management conferences are joining forces with the Blue Mountains Planetary Health Initiative for Full Cycle 2025, to increase collaboration across sectors, from design to disposal. This vital conference and community expo will explore approaches to reducing risks in a changing climate: from multi-hazards like fire, flood, heatwave and extreme humidity, to hazardous materials like mould, microplastics, PFAS, asbestos and engineered stone. Registration will be live in the coming weeks. In the meantime, visit the Full Cycle 2025 website for more information and to sign up to the mailing list (link in profile) https://www.fullcycleconference.com.au/
Native bee researcher Kit Prendergast installed a thousand bee hotels in the Jarrah forests of Western Australia following the Black Summer bushfires. Did this intervention work? Read her article here.
