The Tasmanian giant crab, ''Pseudocarcinus gigas'' (sometimes known as the giant deepwater crab, giant southern crab or queen crab) is a very large

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of crab that resides on rocky and muddy bottoms in the oceans off Southern Australia.Levings, A.H. & P.C. Gill (2010). ''Seasonal Winds Drive Water Temperature Cycle and Migration Patterns of Southern Australian Giant Crab Pseudocarcinus gigas.'' In: G.H. Kruse, G.L. Eckert, R.J. Foy, R.N. Lipcius, B. Sainte-Marie, D.L. Stram, & D. Woodby (eds.), Biology and Management of Exploited Crab Populations under Climate Change. . doi:10.4027/bmecpcc.2010.09 It is the only species in the genus ''Pseudocarcinus''.

Habitat

The Tasmanian giant crab lives on rocky and muddy bottoms in the oceans off Southern Australia on the edge of the continental shelf at depths of . It is most abundant at in the summer and in the winter. The seasonal movements generally follow temperature as it prefers . The full temperature range where the species can be seen appears to be .

Description

The Tasmanian giant crab is one of the largest crabs in the world, reaching a mass of and a carapace width of up to . Among crabs only the

Japanese spider crab The Japanese spider crab (''Macrocheira kaempferi'') is a species of marine crab that lives in the waters around Japan. It has the largest known leg-span of any arthropod. It goes through three main larval stages along with a prezoeal stage to gr ...

(''Macrocheira kaempferi'') can weigh more. Male Tasmanian giant crabs reach more than twice the size of females, which do not exceed . Males have one normal-sized and one oversized claw (which can be longer than the carapace width), while both claws are normal-sized in the females. This crab is mainly whitish-yellow below and red above; the tips of the claws are black. Small individuals are yellowish-and-red spotted above.

Behaviour

The Tasmanian giant crab feeds on carrion and slow-moving species, including gastropods,

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...

s (

anomura Anomura (sometimes Anomala) is a group of decapod crustaceans, including hermit crabs and others. Although the names of many anomurans include the word ''crab'', all true crabs are in the sister group to the Anomura, the Brachyura (the two grou ...

and brachyura) and starfish. Cannibalism also occurs. They breed in June and July, and the female carries the 0.5–2 million eggs for about four months. After hatching, the planktonic larvae float with the current for about two months before settling on the bottom. The species is long-lived and slow-growing; juveniles moult their carapace every three-four years and adult females about once every nine years. This greatly limits the breeding frequency, as mating is only possible in the period immediately after the old carapace has been shed, and the new is still soft.

Fishery

The Tasmanian giant crab has been commercially fished in

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

n waters since 1992 and a minimum size was established in Australia in 1993. Fishing is typically by pots in water deeper than . Following concerns surrounding the sustainability of catch numbers, the total allowable catch was adjusted in 2004 to . Twenty-five operators competed for the catch in 2005, delivering a total catch valued at about A$2 million. The Tasmanian giant crab is very long-lived and slow-growing, making it vulnerable to overfishing. Before export, they are sometimes kept alive in tanks with water that is .

References

External links

* {{DEFAULTSORT:crab, giant, Tasmanian Tasmanian giant crab Crustaceans of Australia Edible crustaceans Commercial crustaceans Marine fauna of Tasmania Tasmanian giant crab