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Illustration by: Emily Stefansson

Scientific Name Cancer productus

Common Name(s) Red Rock Crab, Red Crab

Hatitats Rocky low intertidal to 260’ deep

Distribution Alaska USA to Baja Mexico

Abundance in Puget Sound Common

Scientific Name Cancer gracilis

Common Name(s) Slender crab, Graceful crab

Hatitats Sand-mud, intertidal to 470’ deep



Scientific Name Carcinus maenas

Common Name(s) European green crab

Hatitats Multiple substratum, intertidal

Distribution Global


Field Guide for the Salish Sea Intertidal Predatory Crabs

Emily StefanssonLizzie Wackenhut

© 2008 Western Washington University

Illustration by: Lizzie Wackenhut

Scientific Name SynomymsCancer productus None

Taxonomy (Phylum, Subphylum, Class, Order, Family)Arthropoda, Crustacea, Malacostraca, Decapoda, Cancridae

Similar speciesCancer gracilis (Slender Crab)

Distinguishing CharactersTips of the claws are black, whereas the tips of C. gracilis are white.

Natural History InformationLike all other Cancers it is a carnivorous species that possesses heavy powerful claws for breaking open barnacles and other bivalves, which it most commonly preys upon.

Scientific Name SynomymsCancer gracilis None


Similar speciesCancer productus (Red Rock Crab)

Distinguishing CharactersTips of its claws are white, as well as the tips of its carapace teeth, whereas Cancer productus has black tipped claws and no white on its carapace teeth.

Natural History InformationThe larvae and juveniles of this species are often found clinging to jellyfish, both stealing food from the jellies and eating parasitic amphipods. The adults typically prey on barnacles and bivalves.

Scientific Name SynomymsCarcinus maenas None

Taxonomy (Phylum, Subphylum, Class, Order, Family)Arthropoda, Crustacea, Malacostraca, Decapoda, Portunidae

Similar speciesCarcinus aestuarii

Distinguishing CharactersIts carapace possesses bumps that are not present on the Carcinus aestuarii carapace.

Natural History Information Infamous as a voracious predator it eats everything from bivalves, crabs, isopods, snails, and polychaetes to algae. Originally native to the North East Atlantic it has spread all over the globe and is a prominent invasive of the west coast of the United States.




Robert Potts © California Academy of Sciences

Illustration by: Lizzie Wackenhut

Scientific Name Hemigrapsus nudus

Common Name(s) Purple shore crab

Hatitats Under rocks, intertidal

Distribution Alaska to Bahia de Tortuga, Mexico


Scientific Name Pachygrapsus crassipes

Common Name(s) Striped shore crab

Hatitats Upper to mid intertidal

Distribution East Pacific coast, Japan and Korea

Abundance in Puget Sound Rare

Scientific Name Cancer oregonensis

Common Name(s) Pygmy rock crab

Hatitats Low intertidal to subtidal

Distribution Alaska to Los Angeles, CA USA





Scientific Name Synomyms Hemigrapsus nudus Pseudograpsus nudus, Heterograpsus nudusTaxonomy (Phylum, Subphylum, Class, Order, Family)

Arthropoda, Crustacea, Malacostraca, Decapoda, GrapsoideaSimilar species

Pachygrapsus crassipes (Striped Shore Crab)Distinguishing Characters

Chelipeds have distinct dark purple spots, whereas Pachygrapsus crassipes has no spotting on its chelipeds. Natural History Information

It osmoregulates and can therefore tolerate a wide range of hypo to hyperosmotic waters.

Scientific Name SynomymsPachygrapsus crassipes None

Taxonomy (Phylum, Subphylum, Class, Order, Family)Arthropoda, Crustacea, Malacostraca, Decapoda, Grapsoidea

Similar speciesHemigrapsus nudus (Purple Shore Crab)

Distinguishing CharactersDistinct transverse lines on the carapace and legs, whereas Hemigrapsus nudus is completely lacking in stripes on its body.

Natural History InformationLives very high in the intertidal and is semi-terrestrial, spending about half of its time out of water. Feeds of small intertidal invertebrates especially limpets, dead organisms and algae.

Scientific Name SynomymsCancer oregonensis None


Similar speciesLophopanopeus bellus (Black-Clawed Crab)

Distinguishing CharactersDark red, round carapace, approximately 2 inches wide with several teeth on each side, whereas only 3 teeth are present on L. bellus; hairy legs; black-tipped claws.

Natural History Information Males of this species carry females around before molting as a courtship behavior, and continue to do so until their shells have hardened, even after mating.




Illustration by: Emily Stefansson & Lizzie Wackenhut

Scientific Name Cancer magister

Common Name(s) Dungeness crab

Hatitats Low intertidal to subtidal (759’)

Distribution Alaska to Santa Barbara, CA USA


Scientific Name Cancer antennarius

Common Name(s) Brown rock crab, Pacific rock crab

Hatitats Upper intertidal


Abundance in Puget Sound Rare

Scientific Name Lophopanopeus bellus

Common Name(s) Black-clawed crab

Hatitats Low intertidal to subtidal (264’)

Distribution B.C. Canada to Baja Mexico





Illustration by: Emily Stefansson & Lizzie Wackenhut

Scientific Name SynomymsCancer magister None


Similar speciesCancer productus (Red Rock Crab), Cancer antennarius (Brown Rock Crab)

Distinguishing CharactersCarapace is red-brown to purple with 10 teeth on each side; up to 9 inches wide and widest at tenth tooth; claws have white tips (unlike black tips of C. productus and C. antennarius).

Natural History Information The larvae of this species usually attach to the bells of jellyfish, gaining protection from predators, as well as transportation to suitable habitats. This species is also very important in the commercial fishing industry, accounting for over 99 percent of harvested crabs.

Scientific Name SynomymsCancer antennarius None


Similar speciesCancer productus (Red Rock Crab), Cancer magister (Dungeness Crab)

Distinguishing Characters11 teeth on each side of the carapace, whereas C. productus has 10 teeth; carapace is widest at eighth tooth, usually no more than 5 inches wide; rough, hairy legs (unlike C. magister and C. productus); long antennae; black-tipped claws.

Natural History InformationMales of this species place a spermatophore inside the female during mating, which can then be used for multiple spawnings.

Scientific Name SynomymsLophopanopeus bellus None

Taxonomy (Phylum, Subphylum, Class, Order, Family)Arthropoda, Crustacea, Malacostraca, Decapoda, Xanthidae

Similar speciesCancer oregonensis (Pygmy Rock Crab)

Distinguishing CharactersCarapace variable color, ranging from purple to orange to white, approximately 1.5 inches wide; 3 teeth on each side of carapace; black-tipped claws; no hair on legs (unlike C. oregonensis).

Natural History Information Females usually have two broods of young each year, each containing anywhere from 6,000 to 36,000 eggs.




Scientific Name Hemigrapsus oregonensis

Common Name(s) Green shore crab, Hairy shore crab

Hatitats High to low intertidal


Abundance in Puget Sound Very common




Scientific Name SynomymsHemigrapsus oregonensis None

Taxonomy (Phylum, Subphylum, Class, Order, Family)Arthropoda, Crustacea, Malacostraca, Decapoda, Grapsidae

Similar speciesHemigrapsus nudus (Purple Shore Crab)

Distinguishing CharactersCarapace wider than long, somewhat rectangular, and usually no more than 2 inches wide; hairs present on legs, unlike H. nudus; usually green to gray in color, but sometimes white or spotted when young.

Natural History InformationThis species can withstand hypoxic conditions much better than other species of shore crabs. It also often has a parasitic isopod (Portunion conformis), which can only be seen through dissection.




field guide for the salish sea - home | western washington university

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