Australia’s spiny crayfish (Euastacus) are facing a rapid decline due to the compounding effects of climate change, bushfires, and habitat degradation. According to ecologist Dr. Nick Whiterod of the Coorong Lower Lakes and Murray Mouth Research Centre and Adelaide University, the number of these species on the country’s threatened species list has surged from three in 2019 to 36 today, with many more expected to follow.
Why are spiny crayfish considered endangered?
The primary threat to the 52 unique species of Australian spiny crayfish is climate change, which is drying out creeks and raising water temperatures to lethal levels. According to Dr. Whiterod, these ancient creatures, which diverged from other crayfish lineages approximately 100 million years ago, are struggling to adapt to the rapid environmental shifts of the last two centuries. The 2019–2020 bushfires were particularly devastating, scorching the habitat of an estimated 40% of the species. When the canopy is stripped away by fire, water temperatures rise, and runoff from ash-filled soil further compromises the delicate creek ecosystems where these crayfish reside.
Spiny crayfish can live for up to 50 years. However, they must survive at least five years before they reach maturity and are capable of reproducing. According to researcher Rob McCormack, a research associate with the Carnegie Museum of Natural History, the survival rate for a juvenile to replace an adult in the wild is estimated at 1,000 to 1.
What is the role of spiny crayfish in river systems?
Spiny crayfish act as the “engines” that drive river systems, providing an essential food source for other animals within their habitat, according to Rob McCormack. Because they are long-lived, populations can persist in the same pool for generations. However, this stability is now at risk. Dr. Stuart Blanch, a conservation scientist at WWF-Australia, describes these crayfish as “the canaries in the coalmine” for mountain stream ecosystems. He notes that their long-term survival depends on global efforts to transition away from fossil fuels and stabilize temperature increases to no more than 1.5C.
How can we protect these ancient species?
Experts are calling for a coordinated national effort to manage the threats facing the genus. Currently, populations face pressure from feral pigs, foxes, and poachers, in addition to the overarching threat of climate change. Ecologist Ollie Scully, who has documented these creatures in the Sunshine Coast hinterland, emphasizes that while they are not as widely known as more charismatic wildlife, they are “incredibly captivating.” Because spiny crayfish are sensitive to drought and fire, major die-offs can occur quickly. Without intervention, many populations may lose their ability to recover from these increasingly frequent climate-driven events.
Frequently Asked Questions
- Are spiny crayfish the same as yabbies? No. According to Rob McCormack, while the yabby is a well-known freshwater crayfish, the spiny crayfish belong to the genus Euastacus and are a “different kettle of fish.”
- Why are their claws sometimes missing? Spiny crayfish can drop their claws in self-defense, a necessary tactic when facing predators like the metre-long eels found in Queensland creeks, according to Ollie Scully.
- What is the biggest threat to their survival? While they face predation and poaching, Dr. Nick Whiterod identifies climate change—which causes water temperatures to rise and creeks to dry out—as the main driver of their extinction risk.
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