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.
This Saturday the Blue Mountains Peace Symposium will start at 10am with powerful and moving presentations by Dharug man Chris Tobin and Japanese journalist and teacher Harumi Hayakawa. Join Harumi over lunch to make origami cranes for peace, hope and healing in memory of Sadako Sasaki. "At just two years old, she was exposed to radiation in Hiroshima. At twelve, she developed leukaemia. While in hospital, she heard the legend: if you fold 1,000 paper cranes, your wish will come true. Her wish was to recover. She folded cranes with hope and determination—but sadly, she passed away at just twelve. Her story touched hearts around the world, and the paper crane has since become a global symbol of peace." (Harumi Hayakawa) The Symposium is being held at the Planetary Health Centre: 33-39 Acacia St Katoomba (former Katoomba Golf Club) View the full program and reserve your spot here (link in profile): https://events.humanitix.com/blue-mountains-peace-symposium
We`re setting up lots of cosy warm indoor spaces for the Peace Symposium and `Community Picnic` this Sat 2nd August and we`re thrilled that RosyRavelston Books will be there with their `books that change the world`! The Blue Mountains Peace Collective presented them with this poster designed by Melbourne-based Japanese artist Hiroyasu Tsuri, also known as TWOONE@t_w_o_o_n_e. @ican_australia commissioned this artwork to commemorate the 80th anniversary of the US bombing of Hiroshima and Nagasaki in Japan and the first nuclear test on First Nations land in New Mexico, USA, in 1945. It depicts symbols of peace and survival in the wake of nuclear devastation. View the full program for the Symposium and book your tickets here (link in profile): https://events.humanitix.com/blue-mountains-peace-symposium
Sixteen-year-old HART Youth Ambassador, Matilda Emmerich will be displaying her oil painting and poem “Where Hope Sits" and discussing her experience of having it banned at 11.30am this Saturday 2nd August at the Blue Mountains Peace Symposium at the Planetary Health Centre in Katoomba. Artwork and poem can be seen here: https://www.hartyouth.com/art
Places are limited so bookings essential here (link in profile): https://events.humanitix.com/blue-mountains-peace-symposium
Rotarians from throughout the District gathered at the Planetary Health Centre on Sunday to launch Greater Blue Mountains Rotary and its first fundraising campaign to purchase Rooming-in Cribs for Blue Mountains Hospital. Bringing together the expertise and resources of the former Blackheath, Katoomba and Central Blue Mountains Clubs, this exciting new collaboration reflects Rotary International’s theme for 2025-26: “Unite for Good”. The Planetary Health Centre has been collaborating with Rotary to deliver our monthly Skill Share program, and Rotarian Jennifer Scott AM will speak about Rotary’s international work for people, planet and peace at the Blue Mountains Peace Symposium next Saturday 2nd August. Bookings essential here (link in profile): https://events.humanitix.com/blue-mountains-peace-symposium
For more information about Greater Blue Mountains Rotary and how you can get involved email planetaryhealth@bmcc.nsw.gov.au or ring 0407 437 553
We’re thrilled to announce that the Environmental choir Ecopella will be performing at the Planetary Health Symposium and Community Picnic at 12.30pm next Saturday 2nd August at the Planetary Health Centre in Katoomba. They’re passionate, satirical and creative. This image is the cover of one of their CDs. You can view the full program and reserve your spot for the day here (link in profile): https://events.humanitix.com/blue-mountains-peace-symposium
How do we respond to a world at war? Join the community conversation at the Peace Symposium`s midday forum at the Planetary Health Centre on Sat 2 August. In his book 1984, Orwell wrote: "War, it will be seen, not only accomplishes the necessary destruction, but accomplishes it in a psychologically acceptable way." "The primary aim of modern warfare is to use up the products of the machine without raising the general standards of living." This poster will be one of a number on display at the Symposium. View the full program and book here (link in profile): https://events.humanitix.com/blue-mountains-peace-symposium
It`s just over a week to the Blue Mountains Peace Symposium and Community Picnic on Sat 2 Aug at the Planetary Health Centre. View the full program and book here (link in profile): https://events.humanitix.com/blue-mountains-peace-symposium
A huge thank you to @kindlehill_high_school and their fabulous students who`ve been visiting the Planetary Health Centre on Wednesdays to help us regenerate the bushland and develop our site. They`ve reduced the risk of fire around the Centre by replacing flammable vegetation with gravel; they`ve planted citrus trees for our edible winter garden; and they`ve spent two visits regenerating bushland. Today alone they`ve removed 250 privet plants! Such great work to restore habitat for wildlife and help us build a demonstration site for the community. #volunteers #community #bushcare #ediblegarden #disasterriskreduction #habitat #regeneration...
Our free Winter Tai Chi was so popular last month we`re offering it again for free on Sat 2nd August. It will be the first activity of the day as part of our Peace Symposium and Community Picnic at the Planetary Health Centre. Bookings essential here as places are limited(link in profile):
In 1986, the Blue Mountains celebrated the International Year of Peace with a Peace March in Hazelbrook. Join us for the Peace Symposium and Community Picnic at the Planetary Health Centre on Saturday 2nd August. 2025 has been declared the International Year of Peace and Trust because of the urgent need to reestablish these and reinvigorate a global culture of peace in our current turbulent times. This poster was created by Don McGregor, one of the founders of the Blue Mountains Peace Collective, and will be on display at the Symposium. You can view the program and purchase tickets for the Symposium here (link in profile): https://events.humanitix.com/blue-mountains-peace-symposium
The Lawson men’s circle meets on a Thursday night and fills a void where once male initiation and elder-mentorship might have been, helping men with self awareness and self growth. Read more in Mid Mountains Local News (link in profile): https://www.midmtnslocalnews.com/lawson-mens-circle/
Tickets now available here for the Blue Mountains Peace Symposium on 2nd August. A day of internationally renowned speakers, forums, live entertainment and family activities to grow an urgent groundswell for peace (link in profile): https://events.humanitix.com/blue-mountains-peace-symposium
Andy Klotz and other members of the Hawkesbury Herpetological Society recently managed to photograph the rarely seen and endangered Litoria littlejohni, also known as the Northern Heath Frog or Orange-bellied Tree Frog. We interviewed Andy to learn more about the Littlejohni and how they managed to find its small local population in Woodford.
