Riek's Crayfish (Euastacus rieki)

Description

• The Riek’s Crayfish is a medium sized, spiny crayfish that can grow up to 150 mm in length.
• Its body is brown or green, with orange-red joints and green-blue claws.
• It grows very slowly and lives a long time.
• It’s hard to tell this species apart from other species without looking inside its body.
• It can make long deep complicated burrows in the sides of streams and wetlands.
• It mates in autumn and carries its eggs under its tails through winter, even when its habitat is covered in snow.
• It lives in cold, high-altitude environments and can’t survive in warmer temperatures.
• It eats both plants and animals and can also feed the roots of plants in their burrows while there is snow covering the ground.

Find out more about the Riek’s Crayfish on Canberra NatureMapr.

Where to find them

The Riek’s Crayfish is only found in the high areas of the protected Namadgi National Park in the ACT and the Snowy Mountains area of NSW. However, these places aren’t actively managed to protect the Riek’s Crayfish. It was once thought to live in north-eastern Victoria, but recent research showed that the crayfish there are from a different group. The Riek's Crayfish usually live around 1,000–1,600 m above sea level, but have been seen as low as 560 m.

The crayfish lives in small to medium streams and wet areas near the edges of the water. It can be found in natural environments like grassy plains and eucalyptus forests, but also in places changed by humans like grazing lands and pine plantations. In winter, most of its home is covered in snow or ice. The Riek’s Crayfish dig deep burrows near creeks that reach the water table, and sometimes burrows under rocks or plants along the edge of streams.

Conservation threats

Because the Riek’s Crayfish live in cool, high places and need access to permanent, clean water, the main threat to their survival is the decline of their habitat. Competition with the Common Yabby (Cherax destructor), trampling from horses and deer, and human activity all affect the habitat of the Riek’s Crayfish.

Other threats include:

• climate change impacting water availability
• bushfires destroying plants that provide cover
• post-fire sediment and pollution reducing water quality
• threats from invasive species such as foxes, which prey on the crayfish

Conservation status

• National – Endangered (Nature Conservation Act 2014).
• Australian Capital Territory – Endangered (Nature Conservation Act 2014)

Conservation actions

Conservation aims to increase healthy, wild populations of Riek’s Crayfish in the ACT, including to:

• protect the species from being collected
• protect their habitats in the ACT
• include the species and its habitat needs in the ACT Ecological Guidelines and management plans
• manage the species’ habitat by taking actions after fires and protecting waterways from pollution
• control predators around known crayfish habitats, especially after fires
• improve the long-term health of crayfish populations
• research more about the species’ ecology, habitat, and role in the ecosystem
• find ways to manage threats such as droughts, fire and pests
• raise community awareness and support for crayfish and freshwater fish conservation
• involve local research groups and Indigenous communities to promote knowledge sharing.

Strategies and plans