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.
The KTOWN pickers - Katoombans Taking On Waste Now - are clearing litter from local tracks and streets and stopping it from entering our waterways and eventually our water supply. Read more in Katoomba Area Local News (link in profile): https://www.katoombalocalnews.com/ktown-katoombans-taking-on-waste-now/
This Saturday will be the first meeting of the Upper Mountains Seed Saving and Gardening Group at the Planetary Health Centre, starting at 10am. Register your interest here (link in profile): https://bit.ly/3LalNFy
It will be followed by the Planetary Health Bushcare group at 1.30pm. Register your interest here (link in profile): https://bit.ly/49k8PPo
Global poisoning by a tsunami of toxins that are flooding the planet is fast becoming the biggest threat to life on earth. Extreme weather events like fire and flood accelerate this chemical pollution. To address this the Planetary Health Centre`s Full Cycle 2025 conference from 20-22 Nov is bringing together leading experts in managing extreme weather events as well as those who are working on reducing the risk of hazardous materials like asbestos and PFAS. According to keynote speaker Julian Cribb:
"The poisoning of our planet through human chemical emissions is arguably the largest human impact of all upon the Earth. In volume, it is four to five times greater than our climate emissions (which are a part of it), and three times more lethal than the estimated climate death-toll. It is the mega-threat least understood by society, monitored by science or regulated by government. It has mainly occurred over the last 50 years, due to a massive global surge in chemical use and materials extraction.
Scientific assessment has identified more than 350,000 man-made chemicals. The US Department of Health estimates 2000 new chemicals go on the market every year and the Smithsonian says 1000 new compounds are now being synthesised every hour. The UN Environment Program warns about a third of these “are persistent, able to accumulate in humans and animals and are toxic”.
The World Health Organisation estimates that 13.7 million people — one in every four — die each year from diseases caused by “air, water and soil pollution, chemical exposures, climate change and ultraviolet radiation”, caused by human activity.
Human chemical emissions are thus responsible for the largest mass killing in history.
Learn more and register for the conference here (link in profile): www.fullcycleconference.com.au
There will be a free community expo on Saturday 22 November at the Planetary Health Centre in Katoomba.
Conference volunteers receive free registration. Email planetaryhealthevents@bmcc.nsw.gov.au if you’d like to volunteer at this critically important event.
T`ai-chi and Qigong routines can increase mobility and strength, improve immunity and help build an inner calm. To get the greatest health impact you need to practice them on a regular basis, so we`re thrilled to now be offering a 6-week block of classes to take you into summer starting 9am this Saturday 1 November and running until Sat 6 December. Bookings essential here (link in profile): https://bit.ly/4qrw4Nx This Saturday, 1 November, the activity is also the first in a full day of Skill Share activities at the Centre that includes Seed Saving and Gardening from 10am, and Planetary Health Bushcare from 1.30pm. You can book in for Bushcare here (link in profile): https://bit.ly/49k8PPo Contact Lis on 0407 437 553 for more information.
Rotarians 4 Planetary Health will be meeting again at the Planetary Health Centre at 6pm on Monday 27 October. Register at this link if you`d like to attend! (link in profile) https://events.humanitix.com/rotarians-4-planetary-health-l7bb4qhr?
Thank you to everyone who popped by for the @ediblegardentrailbluemountains today! It was a great day discussing gardens, ponds, frogs, seeds, composting seats, wicking beds and how to restore the hydrological cycle! Next Saturday will be our Skill Share Saturday. We`ll be kickstarting a 6-week block of Tai Chi & Qigong at 9am, launching our Seed Saving and Gardening Group at 10am and running our monthly Bushcare Group at 1.30pm. You can book in for Tai Chi here (link in profile): https://events.humanitix.com/tai-chi-and-qigong-six-week-block-spring-2025-qaw2ts2v and to Bushcare here (link also in profile): https://events.humanitix.com/planetary-health-bushcare-spring-summer-2025
The Planetary Health Centre is on the Edible Garden Trail today! Last week we launched the Upper Mountains Seed Savers and Gardening Group. Come along to learn more, enjoy a coffee in our garden, and pick up a free Vegetable and Flower Sowing Guide. We`re open from 10am. You can find us at 33-39 Acacia St Katoomba. Tickets for the Edible Garden Trail available here (link in profile): https://events.humanitix.com/blue-mountains-edible-garden-trail-2025
The Planetary Health newsletter is now out. Read about three days of innovation at the upcoming Full Cycle Conference in Nov, the Edible Garden Trail this weekend, and a six week block of Tai Chi and Qigong classes at the Planetary Health Centre (link in profile): https://bit.ly/47jbFBz
Today is an Extreme Bushfire Danger Day! Have you heard about the extraordinary fire resistant paint developed by Professor Yeoh and his team at UNSW? Professor Yeoh will be presenting at our Full Cycle Conference on Thurs 20 November. He is world renowned in the field of fire safety and his innovations are helping to keep people and property safe. Importantly among these innovations has been the development and commercialisation of FSA FIRECOAT paint (sold at Bunnings), which creates a protective insulating ‘char’ on a building when it’s exposed to flames. It is water based and non toxic. Watch it in action in this video (link in profile): https://www.youtube.com/watch?v=SkA1RlxMjWQ
Join us at the Conference to learn more about Professor Yeoh’s work during three days of innovation and exploration in which leading speakers from around Australia will share how we can reduce the risks of natural hazards and hazardous materials. Places are limited so register here now (link in profile): https://www.fullcycleconference.com.au/
With new modelling suggesting a hot summer with increasing fire risk it`s worth making time now to learn more about how we can reduce the risk of disaster by registering to attend the Full Cycle Conference that`s bringing together the Bushfire Building and Asbestos & Hazardous Materials Management Conferences in Katoomba on 20-22nd Nov. Group discounts apply if you register now here (link in profile): www.fullcycleconference.com.au
• Emma Whale from the NSW Reconstruction Authority will discuss how state-wide and place-based disaster adaptation planning is helping reduce risk;
• David Sanderson, the inaugural Judith Neilson Chair in Architecture at UNSW, will share the results of a landmark enquiry on how our response to disasters requires a change in housing policy and local government empowerment;
• Owen Price, Director of The Centre for Environmental Risk Management of Bushfires at UOW will compare the patterns of housing loss in the NSW and Californian wildfires;
• Guan Heng Yeoh from UNSW will share how he developed the award winning FIRECOAT fire resistant paint;
• Everson Kandare from RMIT University will discuss the development of fireproof cladding made from molasses-cultured mycelium - a fungal biomass;
• Alan Green from the Sustainable Buildings Research Centre UOW will introduce Heatwave and Multi-Hazard Resilience Star Rating Tools for retrofitting houses;
• Emma Bacon from Sweltering Cities and Dr Kim Loo from Doctors for the Environment will discuss heat waves and social justice;
• Andrew Bovis from Integrated Water Solutions will discuss the potential use of treated blackwater as an independent water source for landscape hydration and fire fighting;
• Sara Jane Wilkinson from UTS will launch the Bushfire Retrofitting Toolkit for older Australians and do a session on green roofs and walls to reduce disaster risk and increase biodiversity;
• Melissa Knothe Tate will discuss research on tackling PFAS contamination;
Thank you to everyone who participated in our inaugural Blue Mountains Food Security Fair today. It was an inspiring and thought provoking day with lots learnt, many connections made, amazing food consumed and stunning weather! We look forward to doing it again next year!
The inaugural Blue Mountains Food Security Fair kicks off at 9am today at the Planetary Health Centre in Katoomba. Pop in to listen to a talk, watch a demo, grab a coffee and sweet treat from Good Fat Pastry, a delicious lunch from Bibi`s Kitchen, fresh mushrooms from EarthRising Mushroom Farm, locally acclimatised vegetable seeds from Mid Blue Mountains Seed Savers, and edible native plants from Muru Mittigar Ltd You can view the full program here (link in profile): https://bit.ly/4nOSJle The Planetary Health Centre is at 33-39 Acacia St (former Katoomba Golf Course).
The Fair is a World Animal Day event and has been supported by a sEEd grant from the Australian Association of Environmental Educators.
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.
