Purple Shore Crab

At a glance

Purple Shore Crab (Hemigrapsus nudus) is a crustacean present across the CatchRules coverage area but without species-specific bag, size, or season rules tracked in our regulatory dataset.

Confirmed by 12,495 research-grade iNaturalist observations, with British Columbia, Washington, and California the top jurisdictions by observation count.

Notable details

• The species name 'nudus' means naked — its walking legs are smooth and hairless, unlike the Yellow Shore Crab.
• It prefers rocky, wave-exposed habitats with higher salinity than its close relative the Yellow Shore Crab.
• Reddish-purple mottling on its carapace and pale-tipped claws make it easy to spot among intertidal rocks.
• An omnivore, it scrapes algae and diatoms from rock surfaces and also eats small invertebrates.
• Females brood fertilized eggs under the abdomen until the larvae hatch as free-swimming zoea.

Where Purple Shore Crab are seen

• British Columbia4,594 iNat obs
• Washington3,375 iNat obs
• California2,649 iNat obs
• Oregon1,544 iNat obs
• Alaska333 iNat obs

Background

The purple shore crab, Hemigrapsus nudus, is a common crab of the family Varunidae. It can be found sheltering under rocks in inter-tidal areas along the west coast of North America, from Alaska to Baja California in Mexico. This crab primarily eats sea lettuce and other green algae, and occasionally scavenges dead animals.

Background excerpt adapted from Wikipedia's Purple Shore Crab article (CC BY-SA). Visit Wikipedia for the full entry.

Other crabs/lobsters/shrimp on CatchRules

• Northern Kelp CrabPugettia producta
• Pacific Sand CrabEmerita analoga
• Pacific Rock CrabRomaleon antennarium
• Pacific Hairy Hermit CrabPagurus hirsutiusculus