Japanese Spider Crab

The Japanese Spider Crab (Macrocheira kaempferi), is the largest living arthropod. Fully grown, the Japanese Spider Crab can reach a leg span of almost 13 ft, a body size of up to 15 inches and a weight of up to 44 pounds. It is believed to have a life expectancy of up to 100 years. The crab’s natural habitat is on the bottom of the Pacific Ocean (some 1000 to 1300 feet deep) around Japan.

The crab has an orange body, but it has white spots on its thin legs. In male specimens, the limbs on which the claws are located become longer than its other limbs, and a large male, when spread out, can widen them to more than 10 feet. The width of the oval-shaped and vertically rounded shell can reach up to 12 inches, and can be up to 16 inches long. Its compound eyes are situated on the front, and two thorns stick out between them. Younger specimens feature hair and thorns on the shell, and their frontal horns are longer, but these gradually atrophy as the crab ages.

The Japanese Spider Crab is caught using small trawling nets, and is often eaten salted and steamed. It is caught in the Sagami, Suruga, and Tosa bays and also around the Izu Islands. Catching of the crab is forbidden during the spring, when it lays its eggs. It is considered a specialty around Suruga Bay, but numbers of the crab have diminished over recent years, and there are efforts to protect them. In Wakayama Prefecture, the crabs are caught when they move to shallower waters in the spring. The Japanese Spider Crab is also used for research and ornamental purposes. It has a gentle disposition and is often reared in aquaria.

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