Conondale spiny crayfish (Euastacus hystricosus)

Also known as: Conondale spiny cray
KingdomAnimalia
PhylumArthropoda
ClassCrustacea
OrderDecapoda
FamilyParastacidae
GenusEuastacus (1)
SizeOccipital carapace length: up to 13.9 cm (2)

The Conondale spiny crayfish is classified as Endangered (EN) on the IUCN Red List (1).

The Conondale spiny crayfish (Euastacus hystricosus) is a large freshwater crayfish found only in Queensland, Australia (1) (3) (4) (5). Like other members of the genus Euastacus, it is characterised by its spiny appearance (2) (3) (4), with the spines of this species being particularly numerous, large and sharp (2) (4) (6).

The Conondale spiny crayfish has a dark green body, with a paler underside, dull reddish legs joints, and large, reddish-brown, pincer-like claws (4) (7). The spines on the abdomen are reddish or whitish, with darker tips (7). However, Euastacus species can be quite variable in appearance, sometimes making identification difficult (8).

As in other crayfish species, the body of the Conondale spiny crayfish is protected by a hard carapace. The abdomen is divided into six segments and ends in a tail fan, which is composed of a central flap (telson) and surrounding flaps known as uropods. Crayfish have five pairs of appendages on the thorax, the first pair being modified into the large claws (chelae), with the remainder, known as ‘pereiopods’, being used for feeding and walking. Further appendages on the abdomen, known as ‘pleopods’ or ‘swimmerets’, are used in swimming and also by the female for brooding eggs (9) (10).

On its head, a crayfish bears a pair of compound eyes, several feeding appendages, and two pairs of antennae, the smaller, central pair of which are known as ‘antennules’ (9) (10).

The Conondale spiny crayfish is endemic to southeast Queensland, Australia. It is known from streams in the Brisbane and Mary River Catchments, on and around the Maleny Plateau in the Conondale and nearby Blackall Ranges (1) (3) (4) (5).

Although this species occurs in a number of streams, it is restricted to the few headwater areas above elevations of 475 metres, and therefore has a highly restricted and fragmented distribution (1) (5).

Like other Euastacus species, the Conondale spiny crayfish prefers heavily shaded, well oxygenated waters. It is a freshwater species that inhabits cool, clear, flowing headwater streams in mountains, in both rainforest and wet sclerophyll forest (1) (2) (5).

There is relatively little specific information available on the biology of the Conondale spiny crayfish. However, like other Euastacus species, it digs burrows under logs and rocks, both above and below the water level (1) (3) (5) (6) (9). Juvenile Conondale spiny crayfish are generally found in shallower water, away from the deep areas preferred by larger individuals and by predators such as eels and large shrimps (6).

The Conondale spiny crayfish may be active during the day in deeper, darker areas of water, but it is more commonly active at night, particularly in smaller, shallower, clear streams (6). As in other freshwater crayfish, its diet is likely to include a variety of plant and animal matter, as well as detritus (9).

Unlike many marine species, freshwater crayfish do not have a long, planktonic larval stage. Instead, they produce large eggs which are incubated on the pleopods of the female before hatching into miniature versions of the adult (9) (10). In the Conondale spiny crayfish, females reach maturity at an occipital carapace length of about six centimetres (2).

The Conondale spiny crayfish has a highly fragmented distribution, and the mountain streams it inhabits are declining in quality due to the destruction of surrounding rainforest habitat and the effects of introduced species. Feral pigs cause damage by rooting and by destroying crayfish burrows, while other non-native species, such as cats, foxes and the cane toad (Bufo marinus), may also affect Conondale spiny crayfish populations (1) (5).

A further threat to the habitat of this species comes from climate change, which may result in increased temperatures, altered water regimes, more severe weather events and the loss of suitable cool, highland habitat (1) (5). As the Conondale spiny crayfish depends on a quite restricted habitat in cool, mountainous areas, even a slight increase in temperature could significantly reduce its range (1). Its restricted distribution also puts it at increased risk from localised events such as bushfires and unsuitable forest management practices (1).

Being a large species that is likely to appeal to recreational fishers, the Conondale spiny crayfish is also potentially under threat from illegal fishing pressure, despite being protected by a ‘no take’ policy (1) (5) (6). The taking of large, mature adults may seriously impact on the population structure and reproductive success of this species (1) (5).

There are no specific conservation measures currently targeted at the Conondale spiny crayfish (1) (5). However, it is found within several national parks and state forests, and all Euastacus species are officially ‘no take’ species in Queensland, although illegal poaching does occur (1) (5).

Recommended conservation measures for this large freshwater crayfish include research into its populations, biology, habitat requirements and life history, and further investigations into its response to various threats (1) (5).

In 2005, the Australian Crayfish Project (ACP) was started with the aim of surveying, identifying and documenting all of Australia’s freshwater crayfish species, including the Conondale spiny crayfish. It is hoped that the information generated by this project will help in the conservation of freshwater crayfish species and their habitats throughout Australia (8).

Find out more about freshwater crayfish conservation in Australia:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

  1. IUCN Red List (June, 2011)
    http://www.iucnredlist.org/
  2. Coughran, J. (2008) Distinct groups in the genus Euastacus? Freshwater Crayfish, 16: 123-130.
  3. Riek, E.F. (1969) The Australian freshwater crayfish (Crustacea: Decapoda: Parastacidae), with descriptions of a new species. Australian Journal of Zoology, 17(5): 855-918.
  4. Riek, E.F. (1951) The freshwater crayfish (family Parastacidae) of Queensland. Records of the Australian Museum, 22(4): 368-388.
  5. Coughran, J. and Furse, J.M. (2010) An Assessment of Genus Euastacus (49 Species) Versus IUCN Red List Criteria. A Report Prepared for the Global Species Conservation Assessment of Lobsters and Freshwater Crayfish for the IUCN Red List of Threatened Species. Environmental Futures Centre, Griffith University, Queensland, Australia. Available at:
    http://iz.carnegiemnh.org/crayfish/IAA/docs/Coughran_and_Furse_2010.pdf
  6. Australian Aquatic Biological Pty Limited (2009) The Conondale Spiny Cray Euastacus hystricosus. AAB Newsletter, 3: 8.
  7. Riek, E.F. (1956) Additions to the Australian freshwater crayfish. Records of the Australian Museum, 24(1): 1-6.
  8. Australian Aquatic Biological Pty Limited - Australian Crayfish Project (June, 2011)
    http://www.aabio.com.au/crayfish.html
  9. Identification and Ecology of Australian Freshwater Invertebrates (June, 2011)
    http://www.mdfrc.org.au/bugguide/index.htm
  10. Campbell, A. and Dawes, J. (2004) Encyclopedia of Underwater Life. Oxford University Press, Oxford.