Biology:Dungeness crab

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Short description: Species of crustacean

Dungeness crab
DungenessCrab.jpg
Dungeness crab measuring 17 cm (6.7 in)
Scientific classification edit
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Malacostraca
Order: Decapoda
Suborder: Pleocyemata
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)[2] makes up one of the most important seafood industries in the range it inhabits along the west coast of North America.[3] It typically grows 20 cm (7.9 in) across and inhabits eelgrass beds and sandy bottoms.[4] Its common name comes from the Dungeness Spit in the Strait of Juan de Fuca, Washington, United States, which shelters a shallow bay inhabited by the crabs.[3]

Description

The carapace widths of mature Dungeness crabs may reach 10 inches, or 25.4 centimeters, but are typically 6–7 inches, or approximately 15–18 centimeters.[4]

Dungeness crabs have a wide, long, hard shell, which they must periodically molt to grow; this process is called ecdysis. They have five pairs of legs, which are similarly armored, the foremost pair of which ends in claws the crab uses both as defense 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. M. magister prefers to eat clams, other crustaceans and small fish, but is also an effective scavenger. Dungeness crabs can bury themselves completely in the sand if threatened.[citation needed]

  • The Common Crab of the Pacific Coast. (Male.) Cancer magister, James Dwight Dana. From The Fisheries and Fisheries Industries of the United States

  • Large Dungeness Crab.jpg

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

Life cycle and ecology

Mature female crabs generally molt in late spring, although exact timing varies with location. Mating occurs immediately after the female has molted and before the new exoskeleton hardens.[5] Males are attracted to potential mates by pheromones present in the urine of females.[citation needed] Upon locating an available female, the male initiates a protective premating 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.[6] Mating occurs only after the female has molted, and the female signals her readiness to molt by urinating on or near the antennae of the male.[citation needed] 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.[citation needed] Young crabs are free-swimming after hatching, and go through five zoeal larval stages and one megalops stage before settling to the bottom in their first juvenile stage. The free-swimming stages take three months to a year. [7] Sexual maturity is reached after about 12 molts or two years.[6]

Juvenile crabs develop in eelgrass beds and estuaries where salinity levels tend to be low. The hyposaline conditions of the estuaries are lethal to some of the crab's symbionts, such as Carcinonemertes errans which consumes a brooding female's live eggs. Dungeness crabs surveyed in Coos Bay were less likely to be infected by C. errans and have fewer worms present on their carapace when inhabiting less saline waters farther inland.[8]

Distribution

The Dungeness crab is named after the Dungeness Spit in the Strait of Juan de Fuca, Washington, United States, which shelters a shallow bay inhabited by the crabs.[3] Its typical range extends from Alaska's Aleutian Islands to Point Conception, near Santa Barbara, California ,[7] while it is occasionally found as far south as Magdalena Bay, Baja California Sur, Mexico.[9]

A genetic analysis of adult Dungeness crabs indicated that there is one population across the California Current System, but it is likely that interannual variation in physical oceanographic conditions (such as ocean circulation patterns) influence larval recruitment among regions, causing genetic diversity to change through time.[10]

Culinary use

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

The Dungeness crab is considered a delicacy in the United States and Canada.[11][12] Long before the area was settled by Europeans, Indigenous peoples throughout the crustacean's range had the crab as a traditional part of their diet and harvested them every year at low tide.[13] The flesh has what is considered to be a delicate flavor and slightly sweet taste.[14] Today they are an integral part of the cuisines of California, British Columbia, and the Pacific Northwest and traditionally feature in dishes like Crab Louie or Cioppino.

About one-quarter of the crab's weight is meat.[15] Dungeness crabs can typically be purchased either live or cooked. A humane way to kill a live crab is to: 1) stun the crab by submerging it in ice water for several minutes, 2) flip the carb onto its back, and 3) drive the tip of a small pick about an inch below the center of its mouth. However, many cook live crabs by simply dropping them into boiling salt water.[16] The crab then is allowed to cook for 15 minutes, after which time the crabs are removed and placed into cold water to cool and then cleaned. Cleaning the crab consists of removing the shell, scooping out the gills and intestines, and separating the legs and claws from the body. When removing the shell there will be a yellow substance, this is called crab fat and is used in many dishes.[17] Another method of preparing crab is called half backing. Half backing is done by flipping the crab upside down and chopping it in half (from head to "tail"), after which the guts and gills can be scooped or hosed out. Many consider half backing to be superior to cooking the entire crab, because the meat is not contaminated by the flavor or toxins of the guts. Furthermore, half backed crabs boil faster or can be quickly steamed instead of boiled.[16] Some common tools for removing crab meat from the shell are a crab cracker and a shrimp fork.[17]

Sustainability

Seafood Watch has given the Dungeness crab a sustainable seafood rating of "Good Alternative" to overfished species or fish that is farmed in ways that harm other marine life or the environment.[18] In 2014, 53 million pounds, worth $170 million, were harvested.[19]

A 2020 study funded by NOAA showed that larval crabs are being affected by ocean acidification caused by lowered pH levels resulting in a higher concentration of hydrogen ions.[20][21]

Celebrations of the Dungeness Crab

In 2009, after lobbying from schoolchildren at Sunset Primary School in West Linn, Oregon, and citing its importance to the Oregon economy, the Oregon Legislative Assembly designated the Dungeness crab as the state crustacean of Oregon.[22]

The annual Dungeness Crab and Seafood Festival is held in Port Angeles, Washington each October.[23]

References

Notes

  1. ↑ 1.0 1.1 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". Raffles Bulletin of Zoology 17: 1–286. http://rmbr.nus.edu.sg/rbz/biblio/s17/s17rbz.pdf. 
  2. ↑ the naming convention recognised by WoRMS
  3. ↑ 3.0 3.1 3.2 "Dungeness Crab Species Profile, Alaska Department of Fish and Game". https://www.adfg.alaska.gov/index.cfm?adfg=dungenesscrab.main. 
  4. ↑ 4.0 4.1 "Dungeness Crab. Cancer magister". Washington Department of Fish and Wildlife. https://wdfw.wa.gov/species-habitats/species/cancer-magister#conservation. 
  5. ↑ Government of Canada, Fisheries and Oceans Canada (2016-12-19). "Dungeness Crab". https://www.dfo-mpo.gc.ca/species-especes/profiles-profils/dungeness-crab-crabe-dormeur-eng.html. 
  6. ↑ 6.0 6.1 "Dungeness Crab Report". Pacific States Marine Fishery Commission, 2011. https://www.psmfc.org/crab/2014-2015%20files/DUNGENESS_CRAB_REPORT_2012.pdf.
  7. ↑ 7.0 7.1 "Seafood Watch Dungeness Crab Report". Monterey Bay Aquarium. http://www.montereybayaquarium.org/cr/cr_seafoodwatch/content/media/MBA_SeafoodWatch_DungenessCrabReport.pdf. 
  8. ↑ Dunn, Paul H.; Young, Craig M. (2013-12-20). "Finding refuge: The estuarine distribution of the nemertean egg predator Carcinonemertes errans on the Dungeness crab, Cancer magister". Estuarine, Coastal and Shelf Science 135: 201–208. doi:10.1016/j.ecss.2013.10.012. Bibcode: 2013ECSS..135..201D. 
  9. ↑ "Dungeness Crab of California and Its Close Relatives". https://www.wildlife.ca.gov/Fishing/Ocean/Dungeness-Crab#26430382-dungeness-crab. 
  10. ↑ Jackson, Tyler M.; Roegner, G. Curtis; O'Malley, Kathleen G. (2018). "Evidence for interannual variation in genetic structure of Dungeness crab (Cancer magister) along the California Current System". Molecular Ecology 27 (2): 352–368. doi:10.1111/mec.14443. PMID 29193425. https://repository.library.noaa.gov/view/noaa/53524. 
  11. ↑ "Dungeness Crab Season in Full Swing". December 9, 2018. https://www.sea2table.com/blog/tales-from-the-dock/dungeness-crab-season-in-full-swing/. 
  12. ↑ "22 Must-Try Foods from British Columbia | Food Network Canada". https://www.foodnetwork.ca/shows/great-canadian-cookbook/photos/must-try-british-columbia-recipes/. 
  13. ↑ "Crabs | Traditional Animal Foods of Indigenous Peoples of Northern North America - Animals - Marine Invertebrates - Crustaceans". http://traditionalanimalfoods.org/marine-invertebrates/crustaceans/page.aspx?id=6518#dung-b. 
  14. ↑ Gary Rainer Puetz (2008). Cooking with the Seafood Steward. Arnica Publishing. ISBN 978-0-9801942-5-8. https://books.google.com/books?id=cw570PaLseoC&pg=PT57. 
  15. ↑ 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. 
  16. ↑ 16.0 16.1 Kring, Lorna (2015-06-09). "How to Buy, Clean, and Cook Crabs the Right Way" (in en-US). https://foodal.com/knowledge/how-to/crabs-ultimate-guide-to-buying-preparing-and-cooking/. 
  17. ↑ 17.0 17.1 "How to Cook Live Dungeness Crab: Step by Step" (in en). 2020-11-20. https://fathomseafood.com/blogs/news/how-to-cook-live-dungeness-crab-step-by-step. 
  18. ↑ "Monterey Bay Aquarium Seafood Watch Dungeness Crab Report." Monterey Bay Aquarium, 4 Nov 2019. https://www.seafoodwatch.org/globalassets/sfw-data-blocks/reports/c/mba_seafoodwatch_dungeness_crab_report.pdf.
  19. ↑ "Dungeness Crab Report 2014". Pacific States Marine Fisheries Commission. http://www.psmfc.org/crab/2014-2015%20files/DUNGENESS%20CRAB%20REPORT2014.pdf. 
  20. ↑ Bednaršek, Nina; Feely, Richard A.; Beck, Marcus W.; Alin, Simone R.; Siedlecki, Samantha A.; Calosi, Piero; Norton, Emily L.; Saenger, Casey et al. (May 2020). "Exoskeleton dissolution with mechanoreceptor damage in larval Dungeness crab related to severity of present-day ocean acidification vertical gradients". Science of the Total Environment 716: 136610. doi:10.1016/j.scitotenv.2020.136610. PMID 31982187. Bibcode: 2020ScTEn.716m6610B. https://pearl.plymouth.ac.uk/bitstream/10026.1/16753/1/Bednarsek%20et%20al%202020%20PDF.pdf. 
  21. ↑ Richerson, Kate; Punt, André E.; Holland, Daniel S. (2020). "Nearly a half century of high but sustainable exploitation in the Dungeness crab (Cancer magister) fishery". Fisheries Research (Elsevier) 226: 105528. doi:10.1016/j.fishres.2020.105528. ISSN 0165-7836. 
  22. ↑ "House Joint Resolution 37, 2009 (Enrolled)". Oregon State Legislature. http://www.leg.state.or.us/09reg/measures/hjr1.dir/hjr0037.en.html. 
  23. ↑ "Dungeness Crab & Seafood Festival – Embrace Your Inner Crab!". https://landing.crabfestival.org/. 

Further reading

  • Dixon, Kirsten (2003). The Winterlake Lodge Cookbook: Culinary Adventures in the Wilderness. Anchorage, AK: Alaska Northwest Books. ISBN 978-0-88240-562-9. OCLC 51855528. 
  • Hibler, Jane (1991). Dungeness Crabs and Blackberry Cobblers: the Northwest Heritage Cookbook. New York, NY: Knopf. ISBN 978-0-394-57745-6. OCLC 24430394. 


Wikidata ☰ Q1936093 entry



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