European shore crab

Carcinus maenas

The European shore crab is a 10-legged eating machine. It could devastate our shores and everything living there.

About the European shore crab

This crab is native to European coasts. Its range runs from Iceland and Norway to Mauritania, West Africa. It prefers shallow, protected bays to exposed shores. This is a hardy species, it can survive in:

  • temperatures from −2°C to 33°C
  • environments from nearly fresh water to the ocean
  • shallow waters down to 60m.

Why this is a problem for New Zealand

The European shore crab eats everything, including plants, algae, shellfish, crabs (even their own species), worms, and carrion.

They:

  • can form dense colonies (up to 200 per square metre)
  • are aggressive and highly effective predators
  • displace native and fisheries species
  • can damage shellfish aquaculture
  • can collapse wild-harvest shell fisheries.

How they could get here

This pest is most likely to arrive in New Zealand in ballast water from ships. MPI has strict measures in place to limit the chances of ballast water from international vessels containing unwanted pests.

It could also hitchhike on the hull of a boat. Boats visiting our waters need to keep their hulls clean. Even if you don't travel overseas, keeping your boat hull clean can stop pests spreading.

How to identify the European shore crab

The features that make this crab unique.

  • Three rounded "teeth" or lobes between the eyes.
  • Five forward-facing spines on each side of the carapace (shell).
  • An adult carapace of up to 8cm wide.
  • Legs are smooth, spineless, and lack swimming paddles.
  • Adult colour varies from green on top and yellowish underneath, to mottled red and orange above and orange or partly red underneath.
orange coloured crab green mottled coloured crab green crab with orange underneath legs
Adult European shore crabs vary in colour. Left: CC 4.0 Hans Hillewaert ; Middle: MPI; Right: A M Arias, Marine Biosecurity Porthole.

If you think you've found a European shore crab

  • take a photo
  • collect a crab in a plastic bag and refrigerate it (if you can)
  • record location and landmarks
  • call 0800 80 99 66

Note: This information is a summary of the European shore crab's global distribution and potential impacts on New Zealand.

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