Astacopsis gouldiTasmanian giant freshwater lobster(Also: giant freshwater crayfish)

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Geographic Range

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

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).

  • 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).

Contributors

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

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

native range

the area in which the animal is naturally found, the region in which it is endemic.

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.