''Metacarcinus anthonyi'', the yellow rock crab or yellow crab, is a species of edible

crab Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek language, Greek), which typically have a very short projecting tail-like abdomen#Arthropoda, abdomen, usually hidden entirely under the Thorax (arthropo ...

native to the

Pacific coast Pacific coast may be used to reference any coastline that borders the Pacific Ocean. Geography Americas North America Countries on the western side of North America have a Pacific coast as their western or south-western border. One of th ...

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

Distribution

''Metacarcinus anthonyi'' occurs from

Magdalena Bay Magdalena Bay () is a long bay in Comondú Municipality along the western coast of the Mexico, Mexican States of Mexico, state of Baja California Sur. It is protected from the Pacific Ocean by the unpopulated sandy barrier islands of Isla Magda ...

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

north to

Humboldt Bay Humboldt Bay (Wiyot language, Wiyot: ''Wigi'') is a natural bay and a multi-basin, bar-built coastal lagoon located on the rugged North Coast (California), North Coast of California, entirely within Humboldt County, California, Humboldt County, ...

Northern California Northern California (commonly shortened to NorCal) is a geocultural region that comprises the northern portion of the U.S. state of California, spanning the northernmost 48 of the state's List of counties in California, 58 counties. Northern Ca ...

, although it is uncommon further north than San Pedro. It lives in rocky areas at depths of up to . Only the juveniles live in the

intertidal zone The intertidal zone or foreshore is the area above water level at low tide and underwater at high tide; in other words, it is the part of the littoral zone within the tidal range. This area can include several types of habitats with various ...

. Some fossils of ''M. anthonyi'' are also known from central and southern California, dating from the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

Description

Male yellow rock crabs can reach 165 mm carapace width, while females reach 148 mm. The

carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...

is oval, fairly broad, and widest at the 9th of 10 forward-curving anterolateral teeth. Like other California Cancridae crabs, ''M. anthonyi'' has black-tipped claws. ''M. anthonyi'' can be distinguished from ''

Romaleon antennarium ''Romaleon antennarium'' (formerly ''Cancer antennarius''), commonly known as the Pacific, brown or California rock crab, is a crab of the genus '' Romaleon'' found on the western coast of North America. Description ''Romaleon antennarium'' has ...

'' by its lack of red spotting on its underside. ''M. anthonyi'' also tends not to decorate itself and tends not to have hairy legs. It can vary in coloration from yellow to brown with the juvenile crabs tending to be darker than adults. ''Metacarcinus anthonyi'' is one of only two species that regularly reach the

minimum landing size The minimum landing size (MLS) is the smallest fish measurement at which it is legal to keep or sell a fish. The MLS depends on the species of fish. Sizes also vary around the world, as they are legal definitions which are defined by the local regu ...

for crabs in Southern California – the other being ''

Cancer productus ''Cancer productus'', one of several species known as red rock crabs, is a crab of the genus ''Cancer'' found on the western coast of North America. This species is commonly nicknamed the Pearl of the Pacific Northwest. Description ''Cancer p ...

'' – and is the subject of commercial

fisheries Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life or, more commonly, the site where such enterprise takes place ( a.k.a., fishing grounds). Commercial fisheries include wild fisheries and fish farm ...

. ''R. antennarium'' is also caught throughout Southern California commercially

Ecology and life cycle

''Metacarcinus anthonyi'' is an ecologically important species. It is prey for many fish including the

scorpion fish The Scorpaenidae (also known as scorpionfish) are a family of mostly marine fish that includes many of the world's most venomous species. As their name suggests, scorpionfish have a type of "sting" in the form of sharp spines coated with venom ...

barred sand bass The barred sand bass (''Paralabrax nebulifer'') is a species of fish in the family Serranidae, the sea basses and groupers. It is native to California and Baja California, where it lives in the coastal waters of the eastern Pacific Ocean. Descrip ...

and other rock fishes. ''M. anthonyi'' is also prey for

sea otters The sea otter (''Enhydra lutris'') is a marine mammal native to the coasts of the northern and eastern North Pacific Ocean. Adult sea otters typically weigh between , making them the heaviest members of the weasel fa ...

, a threatened species. ''M. anthonyi'' is both a

scavenger Scavengers are animals that consume Corpse decomposition, dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a he ...

and a

predator Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

eating anything that the large

claw A claw is a curved, pointed appendage found at the end of a toe or finger in most amniotes (mammals, reptiles, birds). Some invertebrates such as beetles and spiders have somewhat similar fine, hooked structures at the end of the leg or Arthro ...

s can crush including

echinoderm An echinoderm () is any animal of the phylum Echinodermata (), which includes starfish, brittle stars, sea urchins, sand dollars and sea cucumbers, as well as the sessile sea lilies or "stone lilies". While bilaterally symmetrical as ...

snail A snail is a shelled gastropod. The name is most often applied to land snails, terrestrial molluscs, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gas ...

s and

clam Clam is a common name for several kinds of bivalve mollusc. The word is often applied only to those that are deemed edible and live as infauna, spending most of their lives halfway buried in the sand of the sea floor or riverbeds. Clams h ...

s. ''Metacarcinus anthonyi'' reaches

sexual maturity Sexual maturity is the capability of an organism to reproduce. In humans, it is related to both puberty and adulthood. ''Puberty'' is the biological process of sexual maturation, while ''adulthood'', the condition of being socially recognized ...

after 10–12 molts.

Mating In biology, mating is the pairing of either opposite-sex or hermaphroditic organisms for the purposes of sexual reproduction. ''Fertilization'' is the fusion of two gametes. '' Copulation'' is the union of the sex organs of two sexually repr ...

typically takes place in June, and occurs shortly after the females have molted. Before molting, females release a

pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...

which induces

courtship Courtship is the period wherein some couples get to know each other prior to a possible marriage or committed romantic, ''de facto'' relationship. Courtship traditionally may begin after a betrothal and may conclude with the celebration of marri ...

behavior in the males.

Taxonomy

''Metacarcinus anthonyi'' was first described by Mary J. Rathbun in 1897, under the name ''Cancer anthonyi''. The

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

commemorates

Alfred Webster Anthony Alfred Webster Anthony (December 25, 1865 – May 14, 1939) was an American mining engineer and a collector of natural history specimens. He discovered several new subspecies and species and several new descriptions were made from his collections. ...

, a naturalist working in

San Diego San Diego ( , ) is a city on the Pacific coast of Southern California, adjacent to the Mexico–United States border. With a population of over 1.4 million, it is the List of United States cities by population, eighth-most populous city in t ...

Fishery

''Metacarcinus anthonyi'' is harvested by sport and commercial fishermen in California, mostly from

Morro Bay Morro Bay (''Morro'', Spanish for "Hill") is a seaside city in San Luis Obispo County, California, United States. Located on the Central Coast of California, the city's population was 10,757 as of the 2020 census, up from 10,234 at the 2010 ...

south. The California rock crab fishery is made up of three species - the yellow rock crab (''C. anthonyi''), the brown rock crab ('' C. antennarius''), and the red rock crab ('' C. productus''). Rock crab landings for 1999 were 790,000 pounds and have averaged 1.2 million pounds per year from 1991-1999.

References

{{Taxonbar, from=Q6822385 Cancroidea Crustaceans of the eastern Pacific Ocean Crustaceans described in 1897 Taxa named by Mary J. Rathbun