Australian redclaw crayfish ravaging African river ecosystem
Redclaw crayfish native to northern Australia are destroying fish populations and plants across Zambia's upper Zambesi River.
The crayfish is known as yabbies to many Australians. They escaped from fish farms and the aquarium trade across Africa from the 1990s onwards.
In Zambia's Barotse floodplains, they dominate shallow pools. They eat native fish, small animals and plants, and hollow out riverbanks.
Some Australian species are normally poor invaders overseas because they evolved in isolation. Redclaws thrive in harsh conditions.
They survived Australia's harsh wet-dry cycles by burrowing deep and sleeping for months. A single female produces thousands of eggs yearly.
Locally adapted predators in Australia keep them in check. Overseas, native fish and crustaceans lack this natural defence.
Redclaws spread 6 kilometres per year. During floods, they spread 49 kilometres.
They are now approaching Botswana's Okavango Delta and are in South Africa's Kruger National Park.
- Cherax quadricarinatus
- Scientific name
- 6 kilometres, 49 kilometres in floods
- Annual spread
- Thousands
- Eggs per female yearly
Why it mattersIt reveals how climate-tough species thrive as global warming intensifies extreme weather. It also shows how escaped farmed animals can transform ecosystems.
AustraliaRedclaws are also classed as invasive in parts of Western Australia, showing how Australian species can harm local waterways when they escape containment.
✓ Claims checked against the source. checked 3 h ago
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