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.[2][3] It is the only species in the genus Pseudocarcinus.[4]
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 20–820 metres (66–2,690 ft).[2][3] It is most abundant at 110–180 metres (360–590 ft) in the summer and 190–400 metres (620–1,310 ft) in the winter.[3] The seasonal movements generally follow temperature as it prefers 12–14 °C (54–57 °F).[3] The full temperature range where the species can be seen appears to be 10–18 °C (50–64 °F).[5]
The Tasmanian giant crab is one of the largest crabs in the world, reaching a mass of 17.6 kg (39 lb) and a carapace width of up to 46 cm (18 in).[6] Among crabs only the Japanese spider crab (Macrocheira kaempferi) can weigh more.[5] Male Tasmanian giant crabs reach more than twice the size of females,[7] which do not exceed 7 kg (15 lb).[6] Males have one normal-sized and one oversized claw (which can be longer than the carapace width[5]), while both claws are normal-sized in the females.[6] This crab is mainly whitish-yellow below and red above; the tips of the claws are black.[8] Small individuals are yellowish-and-red spotted above.[5]
The Tasmanian giant crab feeds on carrion and slow-moving species, including gastropods, crustaceans (anomura and brachyura) and starfish.[3][7] Cannibalism also occurs.[3] They breed in June and July, and the female carries the 0.5–2 million eggs for about four months.[7] After hatching, the planktonic larvae float with the current for about two months before settling on the bottom.[5] The species is long-lived and slow-growing; juveniles moult their carapace every three-four years and adult females about once every nine years.[5][6] 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.[6]
The Tasmanian giant crab has been commercially fished in Tasmanian waters since 1992 and a minimum size was established in Australia in 1993.[7] Fishing is typically by pots in water deeper than 140 m (460 ft).[6] Following concerns surrounding the sustainability of catch numbers, the total allowable catch was adjusted in 2004 to 62.1 tonnes (137,000 lb).[9] Twenty-five operators competed for the catch in 2005, delivering a total catch valued at about A$2 million.[9] The Tasmanian giant crab is very long-lived and slow-growing, making it vulnerable to overfishing.[7] Before export, they are sometimes kept alive in tanks with water that is 10–14 °C (50–57 °F).[3]
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. It is the only species in the genus Pseudocarcinus.