King crab

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King crabs
Spiny king crab md.jpg
Paralithodes californiensis
Scientific classification

Samouelle, 1819

King crabs are a taxon of crab-like decapod crustaceans chiefly found in cold seas. Because of their large size and the taste of their meat, many species are widely caught and sold as food, the most common being the red king crab (Paralithodes camtschaticus).

King crabs are generally thought to be derived from hermit crab-like ancestors within the Paguridae, which may explain the asymmetry still found in the adult forms.[2] This ancestry is supported by several anatomical peculiarities which are present only in king crabs and hermit crabs.[3] Although some doubt still exists about this theory, king crabs are the most widely quoted example of carcinisation among the Decapoda.[3] The evidence for this explanation comes from the asymmetry of the king crab's abdomen, which is thought to reflect the asymmetry of hermit crabs, which must fit into a spiral shell. Although formerly classified among the hermit crabs in the superfamily Paguroidea, king crabs are now placed in a separate superfamily, Lithodoidea.[1]

This is not without controversy as there is a widespread consensus in the scientific community that king crabs are derived from hermit crabs and closely related to pagurid hermit crabs, and therefore a separate superfamily in the classification poorly reflects the phylogenetic relationship of this taxon.[3][4]

Species of the king crab, including Neolithodes diomedeae, use a species of sea cucumbers often referred to as sea pigs (Scotoplanes Sp. A) as hosts and can be found on top of and under Scotoplanes. The Scotoplanes reduce the risk of predation for the N. diomedeae, while the Scotoplanes are not harmed from being hosts, which supports the consensus that the two organisms have a commensal relationship.[5]


Lithodes longispina

Around 121 species are known, in 10 genera:[6]


Glyptolithodes is found chiefly in the Southern Hemisphere, but extending as far north as California, although all its closest relatives live in the Northern Hemisphere. Its single species, G. cristatipes was originally placed in the genus Rhinolithodes.


Red (P. camtschaticus) and blue (P. platypus) king crabs are some of the most important fisheries in Alaska, however populations have fluctuated in the past 25 years and some areas are currently closed due to overfishing. The two species are similar in size, shape and life history.[7][8][9] Habitat is the main factor separating the range of blue and red king crabs in the Bering Sea.[10] Red king crabs prefer shallow, muddy or sandy habitats in Bristol Bay and Norton Sound,[10][11] while blue king crabs prefer the deeper areas made up of cobble, gravel and rock that occur around the Pribilof, St. Matthew,[12][13] St. Lawrence, and the Diomede Islands.

Red king crabs have an 11-month brood cycle in their first reproductive year and a 12-month cycle thereafter.[9] Both red and blue king crabs have planktotrophic larvae that undergo 4 zoeal stages in the water column and a non-feeding intermediate glaucothoe stage which seeks appropriate habitat on the sea floor.

Red king crabs make up over 90% of the annual king crab harvest. This crab is in the collection of the Children's Museum of Indianapolis.

Paralithodes camtschaticus[edit]

The red king crab, Paralithodes camtschaticus, is a very large species, sometimes reaching a carapace width of 11 in (28 cm) and a leg span of 6 ft (1.8 m). Its natural range is the Bering Sea around the Kamchatka Peninsula area, between the Aleutian Islands and St. Lawrence Island. It can now also be found in the Barents Sea and the European Arctic, where it was intentionally introduced and is now becoming a pest.[14][15]

Paralithodes platypus[edit]

The blue king crab, Paralithodes platypus, lives near St. Matthew Island, the Pribilof Islands, and the Diomede Islands, Alaska, and there are populations along the coasts of Japan and Russia.[13] Blue king crabs from the Pribilof Islands are the largest of all the king crabs, sometimes exceeding 18 lb (8 kg) in weight.[16]

See also[edit]


  1. ^ a b Sammy De Grave; N. Dean Pentcheff; Shane T. Ahyong; et al. (2009). "A classification of living and fossil genera of decapod crustaceans" (PDF). The Raffles Bulletin of Zoology. Suppl. 21: 1–109. Archived from the original (PDF) on 2011-06-06.
  2. ^ The origin of king crabs: hermit crab ancestry under the magnifying glass
  3. ^ a b c Jonas Keiler; Stefan Richter; Christian S. Wirkner (2013). "Evolutionary morphology of the hemolymph vascular system in hermit and king crabs (Crustacea: Decapoda: Anomala)". Journal of Morphology. 274 (7): 759–778. doi:10.1002/jmor.20133. PMID 23508935.
  4. ^ Arthur Anker; Gustav Paulay (2013). "A remarkable new crab-like hermit crab (Decapoda: Paguridae) from French Polynesia, with comments on carcinization in the Anomura" (PDF). Zootaxa. 3722 (2): 283–300. doi:10.11646/zootaxa.3722.2.9.
  5. ^ Barry JP, Taylor JR, Kuhnz LA, De Vogelaere AP. Symbiosis between the holothurian Scotoplanes sp. A and the lithodid crab Neolithodes diomedeae on a featureless bathyal sediment plain. Mar Ecol. 2017;38:e12396.
  6. ^ Patsy A. McLaughlin; Tomoyuki Komai; Rafael Lemaitre; Dwi Listyo Rahayu (2010). Martyn E. Y. Low; S. H. Tan (eds.). "Annotated checklist of anomuran decapod crustaceans of the world (exclusive of the Kiwaoidea and families Chirostylidae and Galatheidae of the Galatheoidea)" (PDF). Zootaxa. Suppl. 23: 5–107. Archived from the original (PDF) on 2012-01-22. |chapter= ignored (help)
  7. ^ G. C. Jensen; D. A. Armstrong (1989). "Biennial reproductive cycle of blue king crab, Paralithodes platypus, at the Pribilof Islands, Alaska and comparison to a congener Paralithodes camtschatica". Canadian Journal of Fisheries and Aquatic Sciences. 46 (6): 932–940. doi:10.1139/f89-120.
  8. ^ A. K. Klitin; S. A. Nizyaev (1999). "The distribution and life strategies of some commercially important Far Eastern lithodid crabs in the Kuril Islands". Biologiya Morya. Vladivostok. 25 (3): 221–228.
  9. ^ a b B. G. Stevens; K. M. Swiney (2006). "Timing and duration of larval hatching for blue king crab Paralithodes platypus Brandt, 1850 held in the laboratory" (PDF). Journal of Crustacean Biology. 26 (4): 495–502. doi:10.1651/S-2677.1. Archived from the original (PDF) on 2012-03-19.
  10. ^ a b North Pacific Fishery Research Council (2005). "Essential Fish Habitat Assessment Report for the Bering Sea and Aleutian Islands King and Tanner Crabs" (PDF). NOAA Fisheries Report. Archived from the original (PDF) on 2010-05-28. Retrieved 2009-12-06.
  11. ^ J. Soong; T. Kohler (2005). Norton Sound Winter Red King Crab Studies (PDF). Fisheries Data Series. Alaska Department of Fish and Game.
  12. ^ J. Zheng; M. C. Murphy; et al. (1997). "Application of a catch-survey analysis to blue king crab stocks near Pribilof and St. Matthew Islands" (PDF). Alaska Fishery Research Bulletin. 4 (1): 62–74.
  13. ^ a b Ivan Vining; S. Forrest Blau; Doug Pengilly (2001). "Evaluating changes in spatial distribution of blue king crab near St. Matthew Island" (PDF). In Gordon H. Kruse; Nicolas Bez; Anthony Booth; Martin W. Dorn; Sue Hills; Romuald N. Lipcius; Dominique Pelletier; Claude Roy; Stephen J. Smith; David Witherell (eds.). Spatial processes and management of marine populations. University of Alaska Sea Grant College Program Report. pp. 327–348. ISBN 978-1-56612-068-5.
  14. ^ Lars Bevanger (August 9, 2006). "Norway fears giant crab invasion". BBC News.
  15. ^ Alex Kirby (September 29, 2003). "King crabs march towards the Pole". BBC News.
  16. ^ "King Crab 101". Fisherman's Express. 2000.

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