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 ...

crab Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...

that resides on rocky and muddy bottoms in the oceans off

Southern Australia The term Southern Australia is generally considered to refer to the states and territories of Australia of New South Wales, Victoria, Tasmania, the Australian Capital Territory and South Australia. The part of Western Australia south of lati ...

.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

on the edge of the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

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 A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tor ...

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 g ...

(''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 Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures, c ...

and slow-moving species, including

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

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 ...

s (

anomura Anomura (sometimes Anomala) is a group of Decapoda, 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 ...

and brachyura) and

starfish Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea (). Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. Starfish ...

Cannibalism Cannibalism is the act of consuming another individual of the same species as food. Cannibalism is a common ecological interaction in the animal kingdom and has been recorded in more than 1,500 species. Human cannibalism is well documented, b ...

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 Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucia ...

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 Specific definitions of sustainability are difficult to agree on and have varied in the literature and over time. The concept of sustainability can be used to guide decisions at the global, national, and individual levels (e.g. sustainable livi ...

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 Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in th ...

. Before export, they are sometimes kept alive in tanks with water that is .

References

External links

* {{DEFAULTSORT:crab, giant, Tasmanian

Tasmanian giant crab The Tasmanian giant crab, ''Pseudocarcinus gigas'' (sometimes known as the giant deepwater crab, giant southern crab or queen crab) is a very large species of crab that resides on rocky and muddy bottoms in the oceans off Southern Australia.Levin ...

Crustaceans of Australia Edible crustaceans Commercial crustaceans Marine fauna of Tasmania