Intertidal Predatory Crabs

Home , Cancer (genus), Cancer productus, Cancridae, Carcinus, Carcinus aestuarii, Grapsoidea

Emily Stefansson Field Guide for the Salish Sea Lizzie Wackenhut Intertidal Predatory Crabs 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 Distribution Alaska USA to Baja Mexico Abundance in Puget Sound Common Illustration by: Lizzie Wackenhut

Scientific Name Carcinus maenas Common Name(s) European green crab Hatitats Multiple substratum, intertidal Distribution Global Abundance in Puget Sound Common Illustration by: Emily Stefansson

Scientific Name Synomyms Cancer productus None Taxonomy (Phylum, Subphylum, Class, Order, Family) Arthropoda, Crustacea, Malacostraca, Decapoda, Cancridae Similar species Cancer gracilis (Slender Crab) Distinguishing Characters Tips of the claws are black, whereas the tips of C. gracilis are white. Natural History Information Like 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 Synomyms Cancer gracilis None Taxonomy (Phylum, Subphylum, Class, Order, Family) Arthropoda, Crustacea, Malacostraca, Decapoda, Cancridae Similar species Cancer productus (Red Rock Crab) Distinguishing Characters Tips 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 Information The 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 Synomyms Carcinus maenas None Taxonomy (Phylum, Subphylum, Class, Order, Family) Arthropoda, Crustacea, Malacostraca, Decapoda, Portunidae Similar species Carcinus aestuarii Distinguishing Characters Its 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.

© 2008 Western Washington University Emily Stefansson Field Guide for the Salish Sea Lizzie Wackenhut Intertidal Predatory Crabs Scientific Name Hemigrapsus nudus Common Name(s) Purple shore crab Hatitats Under rocks, intertidal Distribution Alaska to Bahia de Tortuga, Mexico Abundance in Puget Sound Common Illustration by: Lizzie Wackenhut

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 Robert Potts © California Academy of Sciences

Scientific Name Cancer oregonensis Common Name(s) Pygmy rock crab Hatitats Low intertidal to subtidal Distribution Alaska to Los Angeles, CA USA Abundance in Puget Sound Common

Scientific Name Synomyms Hemigrapsus nudus Pseudograpsus nudus, Heterograpsus nudus Taxonomy (Phylum, Subphylum, Class, Order, Family) Arthropoda, Crustacea, Malacostraca, Decapoda, Grapsoidea Similar 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 Synomyms Pachygrapsus crassipes None Taxonomy (Phylum, Subphylum, Class, Order, Family) Arthropoda, Crustacea, Malacostraca, Decapoda, Grapsoidea Similar species Hemigrapsus nudus (Purple Shore Crab) Distinguishing Characters Distinct transverse lines on the carapace and legs, whereas Hemigrapsus nudus is completely lacking in stripes on its body. Natural History Information Lives 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 Synomyms Cancer oregonensis None Taxonomy (Phylum, Subphylum, Class, Order, Family) Arthropoda, Crustacea, Malacostraca, Decapoda, Cancridae Similar species Lophopanopeus bellus (Black-Clawed Crab) Distinguishing Characters Dark 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.

© 2008 Western Washington University Emily Stefansson Field Guide for the Salish Sea Lizzie Wackenhut Intertidal Predatory Crabs Scientific Name Cancer magister Common Name(s) Dungeness crab Hatitats Low intertidal to subtidal (759’) Distribution Alaska to Santa Barbara, CA USA Abundance in Puget Sound Common Illustration by: Emily Stefansson & Lizzie Wackenhut

Scientific Name Cancer antennarius Common Name(s) Brown rock crab, Pacific rock crab Hatitats Upper intertidal Distribution Alaska USA to Baja Mexico Abundance in Puget Sound Rare Illustration by: Emily Stefansson & Lizzie Wackenhut

Scientific Name Lophopanopeus bellus Common Name(s) Black-clawed crab Hatitats Low intertidal to subtidal (264’) Distribution B.C. Canada to Baja Mexico Abundance in Puget Sound Common

Scientific Name Synomyms Cancer magister None Taxonomy (Phylum, Subphylum, Class, Order, Family) Arthropoda, Crustacea, Malacostraca, Decapoda, Cancridae Similar species Cancer productus (Red Rock Crab), Cancer antennarius (Brown Rock Crab) Distinguishing Characters Carapace 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 Synomyms Cancer antennarius None Taxonomy (Phylum, Subphylum, Class, Order, Family) Arthropoda, Crustacea, Malacostraca, Decapoda, Cancridae Similar species Cancer productus (Red Rock Crab), Cancer magister (Dungeness Crab) Distinguishing Characters 11 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 Information Males of this species place a spermatophore inside the female during mating, which can then be used for multiple spawnings.

Scientific Name Synomyms Lophopanopeus bellus None Taxonomy (Phylum, Subphylum, Class, Order, Family) Arthropoda, Crustacea, Malacostraca, Decapoda, Xanthidae Similar species Cancer oregonensis (Pygmy Rock Crab) Distinguishing Characters Carapace 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.

© 2008 Western Washington University Emily Stefansson Field Guide for the Salish Sea Lizzie Wackenhut Intertidal Predatory Crabs Scientific Name Hemigrapsus oregonensis Common Name(s) Green shore crab, Hairy shore crab Hatitats High to low intertidal Distribution Alaska USA to Baja Mexico Abundance in Puget Sound Very common

Scientific Name Synomyms Hemigrapsus oregonensis None Taxonomy (Phylum, Subphylum, Class, Order, Family) Arthropoda, Crustacea, Malacostraca, Decapoda, Grapsidae Similar species Hemigrapsus nudus (Purple Shore Crab) Distinguishing Characters Carapace 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 Information This 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.