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Crab

Harbour Crab

Liocarcinus depurator

Polybius depurator (Linnaeus, 1758) · Polybiidae WoRMS 1750291

Reference photos

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A swimming crab of fine muddy sand and gravel, found on all British and Irish coasts from the lower shore down to over 300 m. The shell is broader than long, about 51 mm wide, with five pointed teeth along each front side edge and rows of hairs across it. The body is pale reddish-brown, and the give-away is the violet-tinted paddle on the last pair of legs. Although it is a swimming crab it normally crawls on the seabed, and only really swims in extremis.

Depth

Lower shore and sublittoral, recorded from 5 m down to over 300 m

Size

Shell about 51 mm wide and 40 mm long, with males recorded to 56 mm across

Habitat

Fine muddy sand, muddy gravel and clean sand, on the lower shore and in the sublittoral

Behaviour

Mostly active at night; although a swimming crab, it normally crawls on the seabed and only really swims in extremis. Lives singly.

Diet

I eat

  • Polychaete worms, crustaceans, molluscs, brittlestars and fish make up most of the diet
  • Both a predator and a scavenger, taking a wide range of small invertebrates and carrion
  • Animals living in the sediment: at high densities it can significantly reduce the infauna

Where you'd find it

Found around most of Britain and Ireland, though less often in the Celtic Sea and the waters west of Ireland.

ChannelCeltic SeaNorth SeaIrish SeaW of IrelandW of Scotland
Often seenNow and thenWhere PEBL filmsBased on marine survey records (OBIS). Blank seas can mean nobody has looked there, not that the animal is absent.

Sources

Open-access references behind this page. Every statement on this page was read out of one of them; anything that could not be traced to a source was taken off the page rather than left standing. Each link was checked on the date shown, and confirmed then to be about this species.

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