Animal Diversity Web

Geographic Range

This species is found in the rivers, streams, and reservoirs that drain into Bass Straight including the Arthur River System (DELM 1999).

• Biogeographic Regions
• australian
  • native

Habitat

The species can be found mostly in dark, slow moving rivers. They feed around large rotting logs and other submerged structures (DELM 1999).

• Aquatic Biomes
• rivers and streams

Physical Description

Giant freshwater crayfish commonly reach 120 mm in carapace length, although they may get up to 400 mm (Bliss 1982). They do not grow to this size quickly, but can live around 30 years (DELM 1999). This is the largest known freshwater invertebrate, commonly reaching 500g and occasionally reaching 3 kg (Smithton 1999).

They have a dorso-ventrally flattened body with powerfully developed pinchers on their first set of walking legs. Their abdominal legs are longer, adapted for swimming. Females also attach their eggs to these legs (Altevogt, et al 1972).

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• Range mass

  3000 (high) g

  105.73 (high) oz

• Average mass

  500 g

  17.62 oz

• Range length

  400 (high) mm

  15.75 (high) in

• Average length

  120 mm

  4.72 in

Reproduction

This species of crayfish reaches reproductive maturity late in its life. Males reach maturity at about 9 years and females do not reach maturity until about 14 years. Even after they reach maturity, females only breed every two years. They mate and spawn in the autumn and the eggs will hatch the next summer. The eggs remain attached to the female until May. This long reproductive process has a large impact on the species because a female spends much of her mature life with eggs attched to her (DELM 1999).

Behavior

This species of crawfish can live for 30 years because of its lack of natural predators at full maturity. The species is too large for predators such as bass which are predators of smaller species of crawfish. When hiding is needed the crawfish backs into murky banks and under submerged obstructions (IWC 1998).

Food Habits

The Tasmanian Giant Crayfish is omnivorous. It will harvest fungi and bacteria that grows on rotting wood that it supposedly sets aside. It eats leaves and insects that fall into the water, as well as animal flesh (IWC 1998).

Economic Importance for Humans: Positive

This species is considered a gourmet dish in countries such as Australia. It was heavily fished for the past 20 years and is no longer allowed to be caught and eaten (Smithton 1999).

Conservation Status

A few of the reasons for the decline of this species are its long reproductive process, loss of habitat, and the fact that it matures very slowly (DELM 1999).

• IUCN Red List

  Endangered
  More information

• IUCN Red List

  Endangered
  More information

Contributors

Bill McClain (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.

References

Altevogt, R., P. Rietschel, E. Thenius. 1972. The Crustacea. H Grzimek, ed. Grzimek's Animal Life Encyclopedia Volume 1: Lower Animals. New York: Van Nostrand Reinhold Company.

Bliss, D. 1982. Shrimps, Lobsters, and Crabs. New York: Columbia University Press.

Department of Environment and Land Management, June 20, 1999. "Giant Freshwater Lobster" (On-line). Accessed July 14, 2000 at http://www.parks.tas.gov.au/esl/lobster.html.

International Wildlife Coalition, 1998. "Tasmanian Giant Freshwater Crayfish" (On-line). Accessed February 27, 2000 at http://www.iwc.org/volunteers/archives/Jan99/spec_pg7.htm.

Smithton, August 1, 1999. "Tasmanian Giant Freshwater Lobster" (On-line). Accessed February, 15 2000 at http://www.smithton.tco.asn.au/wildlife/lobster/lobster.html.