Dungeness crab

Dungeness crab
Dungeness crab measuring 17 cm (6.7 in)
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Order:	Decapoda
Infraorder:	Brachyura
Family:	Cancridae
Genus:	Metacarcinus
Species:	M. magister
Binomial name
Metacarcinus magister (Dana, 1852) [1]
Synonyms
Cancer magister Dana, 1852 [1]

The Dungeness crab, Metacarcinus magister (formerly Cancer magister), is a species of crab that inhabits eelgrass beds and water bottoms on the west coast of North America. It typically grows to 20 cm (7.9 in) across the carapace and is a popular seafood. Its common name comes from the port of Dungeness, Washington.

Description

Close-up of the head: the two eyes sit on eyestalks, with an antennule on either side of the rostrum (centre, above the mouth).

The carapace width of mature Dungeness crabs may reach 25 centimetres (9.8 in) in some areas off the coast of Washington, but are typically under 20 centimetres (7.9 in).^[2] They are a popular delicacy, and are the most commercially important crab in the Pacific Northwest, as well as the western states generally.^[3] The annual Dungeness Crab and Seafood Festival is held in Port Angeles each October.^[4]

Dungeness crabs have a wide, long, hard shell, which they must periodically moult to grow; this process is called ecdysis. They have five pairs of legs, which are similarly armoured, the foremost pair of which ends in claws that the crab uses both as defence and to tear apart large food items. The crab uses its smaller appendages to pass the food particles into its mouth. Once inside the crab's stomach, food is further digested by the "gastric mill", a collection of tooth-like structures. Metacarcinus magister prefers to eat clams, other crustaceans and small fish, but is also an effective scavenger. Dungeness crabs can also bury themselves completely in the sand if threatened.

Life cycle and ecology

Mature female crabs generally moult between May and August, and mating occurs immediately after the female has moulted and before the new exoskeleton hardens.^[5] Males are attracted to potential mates by pheromones present in the urine of female Dungeness crabs. Upon locating an available female, the male initiates a protective pre-mating embrace that lasts for several days. In this embrace, the female is tucked underneath the male, oriented such that their abdomens touch and their heads face each other. Mating occurs only after the female has moulted, and the female signals her readiness to moult by urinating on or near the antennae of the male. The female extrudes the eggs from her body several months later; however, they remain attached under her abdomen for three to five months until they hatch. Young crabs are free-swimming after hatching, and go through five larval stages before reaching maturity after about ten moults or two years.

Distribution

The Dungeness crab is named after Dungeness, Washington,^[6] which is located approximately five miles north of Sequim and 15 miles (24 km) east of Port Angeles. Its range extends from Alaska's Aleutian Islands to Point Conception, California.^[7]

Dungeness crab have recently been found in the Atlantic Ocean, far from their known range, raising concern about their possible effects on the local wildlife.^[8]

Harvesting

Dungeness crab ready to eat at Fisherman's Wharf, San Francisco

About one-quarter of the crab's weight is meat.^[9] The flesh has what is considered to be a delicate flavour that is slightly sweet. Dungeness crabs can typically be purchased either live or cooked. Larger crabs are valued for the higher meat-to-shell ratio. Live crabs are cooked simply by dropping into boiling salt water, waiting for a boil to return and then allowing it to continue for 15 minutes. After which time the crabs are removed and placed into cold water and then cleaned. Two common tools for removing crab meat from the shell are a crab cracker and a shrimp fork. Sometimes, a cleaver, mallet or small hammer is used for cracking.^[10]

Sustainability

Seafood Watch has given the Dungeness crab a sustainable seafood rating of 'Best Choice'.^[11]

"State crustacean" designation in Oregon

In 2009, based on lobbying from schoolchildren at Sunset Primary School in West Linn, Oregon, and citing its importance to the Oregon economy, the Oregon State Legislature designated the Dungeness crab as the state crustacean of Oregon.^[12]

References

1. ^ ^{a b} Peter K. L. Ng, Danièle Guinot & Peter J. F. Davie (2008). "Systema Brachyurorum: Part I. An annotated checklist of extant Brachyuran crabs of the world" (PDF). Raffles Bulletin of Zoology 17: 1–286. http://rmbr.nus.edu.sg/rbz/biblio/s17/s17rbz.pdf. 
2. ^ "2006-2007 Fishing in Washington Rule Pamphlet" (PDF). Washington Department of Fish and Wildlife. p. 130. Archived from the original on June 17, 2009. http://replay.web.archive.org/20090617120725/http://wdfw.wa.gov/fish/regs/2006/06regs_6.pdf. 
3. ^ "Species Fact Sheet. Cancer magister Dana, 1852". FAO. January 22, 2004. http://www.fao.org/figis/servlet/FiRefServlet?ds=species&fid=3461. 
4. ^ "Dungeness Crab and Seafood Festival". http://www.crabfestival.org. 
5. ^ "Dungeness Crab Biology". Fisheries and Oceans Canada. http://www.pac.dfo-mpo.gc.ca/fm-gp/commercial/shellfish-mollusques/crab-crabe/bio-eng.htm. Retrieved April 20, 2011. 
6. ^ "The Dungeness Crab". Dungeness community website. http://www.dungeness.com/crab/. Retrieved August 28, 2006. 
7. ^ "Seafood Watch Dungeness Crab Report" (PDF). Monterey Bay Aquarium. http://www.montereybayaquarium.org/cr/cr_seafoodwatch/content/media/MBA_SeafoodWatch_DungenessCrabReport.pdf. Retrieved June 10, 2010. 
8. ^ Andrea Cohen (August 9, 2006). "Crab nabbed; circumstances fishy". MIT News Office. http://web.mit.edu/newsoffice/2006/crab.html. 
9. ^ Saekel, Karola (November 18, 1998). "For Bay Area Crab Lovers, The Boats Are Coming In". San Francisco Chronicle. http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/1998/11/18/FD27781.DTL. Retrieved October 7, 2008. 
10. ^ "Online video teaching how to crack and clean Dungeness crab". http://us.video.aol.com/video.index.adp?pls=video.category.762.1133840&startid=1133840&mode=1. 
11. ^ "Seafood Recommendations: Dungeness Crab". Seafood WATCH. http://www.montereybayaquarium.org/cr/SeafoodWatch/web/sfw_factsheet.aspx?fid=16. Retrieved December 19, 2009. 
12. ^ "House Joint Resolution 37, 2009 (Enrolled)". Oregon State Legislature. http://www.leg.state.or.us/09reg/measures/hjr1.dir/hjr0037.en.html. Retrieved October 23, 2009. 

Further reading

External identifiers for Metacarcinus magister
EOL	4257742
ITIS	98675
NCBI	29965
WoRMS	440388
Also found in: Wikispecies, ADW

• Media related to Metacarcinus magister at Wikimedia Commons
• Dixon, Kirsten (2003). The Winterlake Lodge Cookbook: Culinary Adventures in the Wilderness. Anchorage: Alaska Northwest Books. ISBN 9780882405629. OCLC 51855528. 
• Hibler, Jane (1991). Dungeness Crabs and Blackberry Cobblers: The Northwest Heritage Cookbook. New York, NY: Knopf. ISBN 9780394577456. OCLC 24430394.