Crabby giants: Puget Sound King Crab and Tasmanian Giant Crab

Late last year, S.E.A. Aquarium welcomed some crabby new residents. Say Hi to the Puget Sound King Crab (Lopholithodes mandtii) and Tasmanian Giant Crab (Pseudocarcinus gigas).

Puget Sound King Crab: built like a tank

As its name suggests, this crab is found in Puget Sound (a semi-enclosed body of water along the northwestern coast of the U.S. state of Washington), but its range extends all the way from southern Alaska to central California.

Found in subtidal areas to depths of 135 metres, an adult Puget Sound King Crab can grow to about 25 centimetres across, with a box-like carapace that’s covered in bumps and wart-like tubercles.

Underside of a Puget Sound King Crab. Fun fact: Like all other crab species, Puget Sound King Crabs have eight legs but only six are visible. The remaining two are hidden inside the crab’s carapace! Image source

Its primary defense against predation is to pull its legs toward its body, fitting tightly against the carapace like a tank. Its left claw or chelae (pronounced “kee-lee”) has strong, molar-like dentitions for crushing prey such as barnacles, urchins, sea stars, while it uses its spoon-like right chelae for cutting.

Image source

Tasmanian King Crab: one of the world’s largest crabs

The Tasmanian Giant Crab lives on rocky and muddy bottoms in the cold waters (10–18 degrees Celsius) off Southern Australia, on the edge of the continental shelf at depths of 20–820 metres.

Males are typically more than twice the size of females. They weigh up to 17.6 kilograms, with a carapace that can reach over 40 centimetres wide. Their oversized right claw is elongated, sharp and arcs over its regular-sized left claw. Oversized claws are only found in male crabs.

The Tasmanian Giant Crab is a long-lived and slow-growing species. Juveniles moult their carapace every three to four years and adult females about once every nine years. This greatly limits the breeding frequency, as mating is only possible during the period after moulting while the new shell is still soft.

These crabs breed in June and July, and the female carries about half a million to two million eggs for about four months. After hatching, the planktonic larvae float with the current for about two months before settling on the bottom.

Be sure to check them out the next time you’re at S.E.A. Aquarium!

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