Cancer antennarius is found in intertidal waters off of the Pacific coast of North America. Areas between San Francisco, California and Baja California, Mexico are where the crab is most abundant, though Sequim, Washington marks the northern range limit (Carroll, 1989).
Biogeographic Regions: pacific ocean (Native )
Adults can have a carapace width of up to 155 mm, though females never exceed a width of 145 mm. The carapace is widest at the eighth, of nine, anterolateral teeth. The dorsal coloration is usually a deep red or brown, although this can vary to shades of orange or gray. The ventral side is white, with characteristic red spotting. The powerful claws are black-tipped, and the walking legs are almost always hairy. The latter trait is more common in females. The first antennae of C. antennarius are located between the eye stalks, and are distinctively long compared to others in this genus. As with all members of the Cancer genus, males have a more slender, pointed abdomen than do the females (Carroll, 1989; Mohler et al., 1997).
Other Physical Features: ectothermic ; bilateral symmetry
Catalog Number: USNM 2033
Collection: Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology
Sex/Stage: male; female;
Preparation: Alcohol (Ethanol)
Collector(s): W. Stimpson
Locality: San Francisco, California, United States, North Pacific Ocean
The habitat of C. antennarius ranges from the low intertidal zone to depths in excess of 100 meters. The animal is found on both sandy and rocky substrates, though the rocky environment seems to be preferred. During low tide, C. antennarius is often seen under rocky overhangs and deep within crevices (Carroll, 1989).
Aquatic Biomes: benthic ; coastal
Cancer antennarius feeds by means of scavenging and predation. The animal's diet consists of a variety of bivalves, snails and echinoderms, as well as other crustaceans such as hermit crabs. I have personally kept a number of these animals, and have fed them a diet of shrimp and squid. This mixture seems to be quite suitable for the animal in an aquarium setting. C. antennarius is quite sensitive to the odor of food in the water, and this ability serves as a major means of locating food.
Animals that prey upon adult C. antennarius include sea otters, sharks, octopuses, and large sea bass. The animal is most vulnerable to attack after it has molted. At this time, the shell is soft, and the animal has little protection against predators. Juvenile members of this species are preyed upon by a variety of benthic fishes, including, but not limited to, scorpionfish, cabezon, sand bass, and rockfishes. The polychaete worm Iphitime holobranchiata is known to infest the gills of this particular rock crab, and the infestation is sometimes lethal (Carroll, 1989).
Life History and Behavior
Mating most commonly occurs in the spring and fall. The process is carried out after the female molts, and while her shell is in a soft condition. Mating is stimulated by the release of a female pheromone. The males latch onto the females, and stay in that position until the shell of the female has hardened. During the courtship, a spermatophore is placed within the female. The sperm within this packet can be utilized for multiple spawnings. The spermatophore hardens within the female's reproductive tract, thus preventing other males from fertilizing her eggs. The eggs are extruded eleven weeks after the mating, and are fertilized internally as the female releases them. After a period of 7-8 weeks, the larvae hatch from the orange-colored mass of eggs. The larvae progress through six stages of growth, and are planktonic while doing so. Ocean currents cause the larvae to become widely distributed over the continental shelf. It is not until the last stage of larval growth that the animal moves inshore (Carroll, 1989).
Molecular Biology and Genetics
Barcode data: Cancer antennarius
Below is the sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen.
Other sequences that do not yet meet barcode criteria may also be available.
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Download FASTA File
Statistics of barcoding coverage: Cancer antennarius
Public Records: 16
Specimens with Barcodes: 16
Species With Barcodes: 1
The only known conservation efforts surrounding Cancer antennarius are centered in the fishing industry. State agencies impose catch limits on the crab, both for quantity and size (Carroll, 1989).
US Federal List: no special status
CITES: no special status
Relevance to Humans and Ecosystems
There is no known negative impact.
With a taste that is reportedly similar to that of the Dungeness crab, Cancer antennarius is fished both commercially and recreationally. The industry is minor, however, when compared to the fishery of Cancer magister, the Dungeness crab. Most fishing of C. antennarius is centered in California, and localized overfishing does occur (Carroll, 1989).
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