
The Shore crab (Hemigrapsus sanguineus) is native to the Western Pacific and inhabits rocky intertidal habitats. Non-native populations occur in Northern Europe, the Mediterranean Sea, and the Northwest Atlantic. Shore crabs were first observed in North America in New Jersey in 1988 and have since become established along the East Coast (North Carolina to Nova Scotia), causing ecological changes to rocky intertidal communities.
Description
How to identify shore crabs:
Square-shaped carapace (shell) up to 2 inches in width
3 spines on each side of eyes
Color variable (e.g., light to dark green, purple, orange, brown, and red)
Eight walking legs with distinct light and dark bands on legs and red spots on claws
Habitat and Distribution
Shore crabs are native to the Western North Pacific. Non-native populations exist in Northern Europe, the Mediterranean Sea, and Northwest Atlantic. Shore crabs prefer natural and artificial intertidal rocky habitats but also may occur in salt marshes, subtidal habitats, and marinas. Shore crabs occur throughout New York’s marine coastal environments.
Spread

Shore crabs were likely introduced through ballast water.
Ecological Impacts
The shore crab has caused ecological changes within rocky intertidal communities along the East Coast of the U.S.
Predation: Shore crabs consume invertebrates (e.g., blue mussels, snails, barnacles) and algae
Competition: Shore crabs also compete with native species for food and shelter. For example, research from Long Island, NY, suggests that shore crabs outcompete native, black-fingered mud crabs (Panopeus herbstii). Shore crabs have also largely displaced the non-native green crab (Carcinus maenas ) between Long Island, NY, and Cape Ann, MA.
Management
The shore crab is a prohibited species under New York State Invasive Species Regulation 6 NYCRR Part 575. Prohibited species cannot be knowingly possessed with the intent to sell, import, purchase, transport or introduce. In addition, no person shall sell, import, purchase, transport, introduce or propagate prohibited invasive species.
How You Can Help
Clean, drain, and dry your watercraft and equipment thoroughly before visiting other waterbodies.
Inspect and remove debris and mud from boats, trailers, and equipment.
Dispose of all debris and bait in trash cans or at disposal stations.
Drain all water-holding compartments including live wells, bait wells, and bilge areas. If possible, visit a decontamination station and disinfect compartments with hot water (140°F) for at least 30 seconds.
Dry boats, trailers, and all equipment before use in another water body. A minimum of 5–7 days of drying time in dry, warm conditions is recommended.
Do not dump aquarium contents in any waterbodies, drainage ditches, or sewers.
Use certified bait that is non-invasive and disease free.
Learn how to identify shore crabs and report any encounters.
If you think you have found a shore crab:

DO NOT RELEASE IT ALIVE.
Take several photos of it from different angles and dispose of the specimen.
Email the photos, noting where it was caught (coordinates preferred), [email protected], OR
Submit a report through iMapInvasives
Additional Resources
National Estuarine and Marine Exotic Species Information System - information on marine and estuarine invertebrates and algae introduced to the United States - species profile for shore crab
Eight-year record of Hemigrapsus sanguineus (Asian Shore Crab) invasion in western Long Island Sound estuary - research paper outlining the invasion history of shore crabs to Long Island Sound