Crabs 1, 2

Macrocheira kaempferi, the giant spider crab, Japanese spider crab

Macrocheira kaempferi, Giant spider crab

Above is Macrocheira kaempferi, the giant spider crab, Japanese spider crab. The leg span can reach four metres, but the body diameter is usually less than 40 cm. It can weigh as much as 20 kg, and is found in the Pacific Ocean around Japan, usually between 300 - 400 metres deep. It eats carrion and shellfish. Its life span is thought to be as much as 100 years. Eggs are laid in spring in water around 50 metres deep. The crab is a delicacy in Japan and is eaten both raw and cooked - it is delicious.

Many spider crabs attach seaweed and sponges to their body so that they blend into the background.

Below is Carcinoplax longimanus, it is found around japan, to the South China Sea, and around South Africa.

Carcinoplax longimanus

Velvet swimming crab, Necora puber

velvet swimming crab, Necora puber

The Velvet swimming crab, above, is also known as the Devil crab and the Lady crab. It is found on rocks from the shoreline down to 100 m in the North Sea off Norway, down to the north Atlantic coast off north Africa, and in the Mediterranean. Larger individuals tend to be found in deeper waters.

It is the largest swimming crab found in British waters. The carapace is up to 10 cm wide, and its body is covered in short velvety dark brown hairs, hence its common name, although the upper shell is actually blue. Both of its large pincers are the same size. Its last pair of legs is flattened to aid swimming. It is fast moving, aggressive, and will nip swimmers or bathers if disturbed. Its eyes are red and on short stalks. It hunts actively, but will also scavenge. It feeds on seaweed, molluscs and other crustaceans. Juveniles feed on barnacles and small crabs. The Velvet crab is sexually mature after its first year, and can live for another 9 years.

The Velvet crab is fished commercially in some areas. In British waters the crabs are caught in crab pots, and most are exported to mainland Europe. In 2009 2,300 tonnes of Velvet crabs were landed in Scottish ports.

British hermit crab, Pagurus sp.

British hermit crab, Pagurus sp.

The British hermit crab, Pagurus sp. above. There are around 170 species in the Pagurus genus, and all are hermit crabs. The abdomen of a hermit crab does not have a hard shell, so this means that the crab must find another shell for protection. Usually they choose a snail shell.

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