Around 65 species of crab occur in the waters of the British Isles.
[1][Note 1] All are marine, with the exception of the introduced Chinese mitten crab, Eriocheir sinensis, which occurs in fresh and brackish water.
They range in size from the deep-water species Paromola cuvieri,[3] which can reach a claw span of 1.2 metres (3 ft 11 in),[4] to the pea crab, which is only 4 mm (0.16 in) wide and lives inside mussel shells.
Around 77% of the catch is landed in the United Kingdom, 19% in Ireland, 4% in the Channel Islands, and 1% in the Isle of Man.
[Note 2] 62 species have been directly observed in the waters of the British Isles:[1][Note 3] Three deep-water species have also been recorded near the British Isles, and are likely to occur in the area.