Dr Nick Whiterod with a Murray cray – which primarily inhabits the Murray and Murrumbidgee River catchments – and (right) Rob McCormack with the endangered Simple Crayfish, which is found in the Northern Rivers region of NSW. Photos: Nick Whiterod & Rob McCormack.
From the alpine streams of Kosciuszko to the coastal creeks south of Batemans Bay, southern NSW is home to some of the most threatened freshwater animals on the planet.
And the call is out to help protect them.
Australia’s Spiny Crayfish – members of the Euastacus genus – have existed for millions of years, helping keep waterways clean and healthy from the Daintree in Far North Queensland to South Australia while surviving ice ages, drought cycles and geological upheaval.
But the pace of change they now face may prove too much.
Rob McCormack, founder of the Australian Crayfish Project, describes them as “climate refugia specialists – relicts from a time long past when Australia was cooler and wetter”.
Many species inhabit cool, shaded streams and alpine bogs, sheltering beneath rocks, logs and in underground burrows. For some, a single creek or mountain catchment represents their entire range.
“Such a limited range makes them highly vulnerable to a single extreme weather event,” he said.
In just two years following the 2019-2020 Black Summer bushfires, 33 of the 52 to 56 formally described species were added to Australia’s national threatened species list, taking the number from three to 36.
Scientists warn some could disappear within a decade without urgent action.
Dr Nick Whiterod, a researcher at the Coorong Lower Lakes Murray Mouth Research Centre in South Australia, who has spent close to 20 years studying Spiny Crayfish, says about 10 described species occur across southern NSW.
“And genetic work we’ve done has indicated there could actually be new species we don’t know too much about yet – we may be dealing with 20 or so species across this area,” he said.
Southern NSW’s species range from the iconic Murray Crayfish (Euastacus armatus) – the world’s second-largest freshwater crayfish, recently listed as vulnerable – to smaller, lesser-known species inhabiting coastal streams near Batemans Bay and Bega, escarpment creeks and the icy headwaters of the Snowy Mountains.
Among the most precarious is the Fitzroy Falls Spiny Crayfish (Euastacus dharawalus), considered Australia’s most critically endangered crayfish and confined to a 12-kilometre stretch of stream in the Southern Tablelands.
Riek’s Crayfish (Euastacus rieki) and the Alpine Spiny Crayfish (Euastacus crassus) cling to the high country, where they depend on cold, clear, flowing water and healthy alpine wetlands.
Little seen and easily overlooked, many Spiny Crayfish spend much of their lives hidden beneath rocks and in underground burrows.
The Black Summer bushfires changed that.
Across Australia, the fires affected more than 40,000 kilometres of waterways and, for many species, the damage didn’t end when the flames went out.
Many Spiny Crayfish survived the fires themselves by retreating to underground burrows, but the greatest damage came afterwards.
“It’s not the fire itself for aquatic animals – it’s really those downstream impacts,” Dr Whiterod said.
“A bushfire comes through, it burns, then you have a huge rainfall event and it washes debris, nutrients, heavy metals and hydrocarbons into the water.
“Those impacts can travel tens of kilometres downstream and persist.”
Fire damage and sediment-laden water at Mannus Creek near Tumbarumba in southern NSW. Photo: Luke Pearce.
Post-fire erosion choked refuge pools with sediment, stripped away canopy shade that keeps water cool and opened streams to feral pigs and horses, Dr Whiterod explained.
And all of it is unfolding against a backdrop of climate change.
Rising temperatures, reduced snow cover and prolonged drought are already pushing some species beyond their limits, while extreme events such as fire and flood are resetting the cycle before populations have a chance to recover.
For Dr Whiterod, it is the cumulative weight of those threats – and the speed of change – that makes the situation so precarious.
“In the past, there might have been a bushfire that wiped out a species from half its range, but then there weren’t necessarily other threats – they could take the time to recover,” he said.
“Nowadays you have a bushfire, and all those other threats are still at play.”
The crayfish themselves are also slow to bounce back. They are among the slowest-growing and longest-lived invertebrates in Australia’s freshwater systems, often taking seven to nine years to reach maturity, with adults living for decades.
Illegal collection adds further pressure. Taking a Fitzroy Falls Spiny Crayfish, for instance, can carry a two-year jail term and a $220,000 fine.
In another documented case, a person was found with 15 threatened Lamington Spiny Crayfish intended for consumption – an act likely to set that stream ecosystem back a decade or more.
But these ancient crustaceans are far more than curious creatures hidden away in remote waterways.
They are keystone species, cleaning up dead plant and animal material, cycling nutrients and providing food for fish, turtles, platypus, birds and reptiles.
In many ways, the health of a Spiny Crayfish population reflects the health of the entire ecosystem around it.
WWF-Australia conservation scientist Dr Stuart Blanch draws a stark comparison.
“Our spinys are the canaries in the coal mine for many species living in the delicate ecosystems of our mountain streams,” he said.
“Like Greater Gliders, coral reefs and Emperor Penguins, the survival of spinys depends on transitioning away from fossil fuels and stabilising global temperature increases to no more than 1.5°C.
“Spiny Crayfish have been around for millions of years. We can’t let these overlooked and underappreciated creatures disappear on our watch.”
Dr Whiterod also describes them as “ecosystem engineers” – miniature bulldozers that rearrange rocks, wood and sediment to create habitat for other small creatures.
Recovery work is already underway in southern NSW.
The Totally Cray Cray project, led by South East Local Land Services and involving the University of Wollongong, NSW Fisheries and local landholders, has focused on protecting the Fitzroy Falls Spiny Crayfish by fencing cattle out of streams, restoring habitat and removing invasive Common Yabbies.
Though native to Australia, yabbies do not naturally occur east of the Great Dividing Range and were introduced to the area only about a decade ago.
They now compete aggressively with the native crayfish for habitat and food.
Nationally, conservationists are calling for stronger protection, expanded enforcement powers, habitat restoration and investment in captive breeding programs and translocations – techniques that have already shown promise with the Murray Crayfish.
Farmers and landholders with streams on their properties can have a real impact by fencing waterways, protecting streamside vegetation and preserving habitat.
Dr Whiterod said there were countless examples of landholders who effectively watched over a local population – their own “pet crayfish” in the waterway out the back.
For residents curious about whether Spiny Crayfish inhabit local creeks, he recommends contacting Local Land Services or catchment management groups.
“What we do in the next decade will help shape how well these Spiny Crayfish are going to survive into the future,” he said.
“If we don’t do anything, they’re going to be hard pressed to survive.
“But if we can start turning that around – drawing attention to them and implementing conservation actions – we can give them the best chance.”
Original Article published by Edwina Mason on About Regional.
