Common shore crab (Carcinus maenas)

GenusCarcinus (1)
SizeCarapace width: 80 mm (2)

The common shore crab is common and widespread (2).

As its name suggests, the common shore crab is one of the commonest crabs on the British shore, and anyone who has gone rock-pooling is likely to have encountered one (3). This species is usually dark green in colour, although young individuals may have whitish blotches. The carapace of the common shore crab is wider than it is long, and the first pair of walking limbs ('pereopods') have pincers (2).

The common shore crab is found around the coasts of Britain and Ireland (4). It is also common around the coasts of north-west Europe (2).

The common shore crab occurs on the shore from the high water mark down to depths of around 60 metres (4), and can inhabit estuaries (2).

The diet of the common shore crab includes invertebrates such as worms, molluscs and crustaceans. Small molluscs and barnacles are taken by young crabs (2).

Breeding peaks in summer, and mating can only take place shortly after the female common shore crab moults; the male finds a female before she is due to moult, and carries her around underneath his body for a number of days (2). After the moult, copulation occurs. The female creates a cavity by burrowing in the sand; she lays the eggs whilst positioned over this cavity, attaches them to her walking legs and carries them around for several months (2). After hatching, the common shore crab larvae are planktonic for 2-3 years. They then settle as young crabs, and reach maturity after around a year (2).

The common shore crab is not currently threatened.

No conservation action has been targeted at the common shore crab.

For more on the common shore crab, see:

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:

  1. National Biodiversity Network Species Dictionary (January, 2003)
  2. Fish, J.D. and Fish, S. (1996) A Student's Guide to the Seashore. Second Edition. Cambridge University Press, Cambridge.
  3. Buczacki, S. (2002) Fauna Britannica. Hamlyn, London.
  4. Pizzolla, P.F, 2002. Carcinus maenas. Common shore crab. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. (November, 2002)