Fauna
Invertebrate

Asian Shore Crab

Hemigrapsus sanguineus

Also known as Japanese Shore Crab, Pacific Shore Crab

Asian shore crabs are highly adaptable intertidal predators recognizable by their square carapaces with alternating light and dark bands on their legs. Females produce up to 50,000 eggs per clutch multiple times a season, fueling rapid expansion along non-native coastlines. Their aggressive foraging disrupts native ecosystems by outcompeting local crab species and consuming high quantities of young mollusks.

InvasiveIntertidalCrustacean
Asian Shore Crab reference1 / 7
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Not EvaluatedConservation statusIUCN Red List categoriesLCNTVUENCREWEXNot Evaluated — not placed on the risk ladderRed List categories, explained →
Key facts
Diet & preyBlue Mussels, Acorn Barnacles, Green Algae
Predators
  • Gulls
  • Striped Bass
  • Tautog
ThreatsCoastal pollution, extreme cold winters
HabitatsRocky intertidal zones, estuaries, artificial harbor structures
Life span3–5 years
Classification
  1. OrderDecapoda
  2. FamilyVarunidae
  3. GenusHemigrapsus
  4. SpeciesHemigrapsus sanguineus
Range & activity
Range data is not available yet.
Safe observation
Interaction riskLow
  1. Low
  2. Moderate
  3. High
  4. Very high
Why interaction risk is low
Pinch defensively with small but sharp claws; observe without picking them up.
Why it is dangerous
Pincers can exert surprisingly strong pressure, pinching skin if handled carelessly.
How to recognize a risky encounter
Recognizable by three distinct square teeth on each side of the carapace and banded legs.
What to do
Observe without handling, or pick up gently from behind the carapace sides if necessary.
Responsible observation
  • Look under rocks: Turn over intertidal stones at low tide where dense populations shelter.
  • Check the claws: Look for distinct red spots on the fleshy bulb at the base of the pincers.
  • Practice rock care: Return moved rocks carefully to their original positions to protect native life.
Related species
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