Pocket cancer
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Cancer pagurus |
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| Systematics | ||||||||||||
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| Cancer pagurus | ||||||||||||
| Linnaeus , 1758 |
The crab ( Cancer pagurus ) is a common in the eastern Atlantic and the North Sea crab from the family of crabs (Cancridae). The species is considered a delicacy and is intensively fished.
features
Edible crabs have the body structure typical of crabs with a significantly shortened pleon , the abdomen, which is firmly attached under the cephalothorax. The maximum length of the carapace is around 20 cm, the maximum width around 30 cm.
The carapace is broadly oval and very finely granulated; flattened with a slight, central elevation. On its anterior lateral margin (latero-anterior margin) the carapace has 9 or 10 blunt, square teeth, which are separated from one another with clear pits. The color is uniformly reddish-brown, in young animals the color can tend towards purple .
Edible crabs have powerfully developed claws , which are usually designed in the same way. The tip of the scissor finger (Dactylus) is strikingly black.
distribution and habitat
The edible crab has its natural distribution in the shelf of the Eastern Atlantic and the North Sea, from northern Morocco to northern Norway at around 70 ° N. Older finds also attest to its distribution in the northern Mediterranean , on the coasts of Spain, France, Italy and the Balkans.
The species is found as a benthont at depths of 6 to 100 meters, i.e. eu littoral to sublittoral. There the edible crab lives on sandy and rocky ground.
nutrition
The nocturnal edible crab is predominantly a carnivore . It feeds on various crustaceans, fish, mollusks, echinoderms, but also on carrion . The common beach crab ( Carcinus maenas ), the large periwinkle ( Littorina littorea ) and the European oyster ( Ostrea edulis ) are eaten.
Reproduction and life cycle
Sexual maturity occurs with carapace widths of 11 to 13 centimeters. Mating takes place in spring to summer, or in autumn after the female has molt. Even before this molt, couples show a pronounced affinity; Males accompany females 3 to 12 days before mating and up to 12 days afterwards. The males transfer the packets of seeds and the females keep them in their seed pockets ( Receptaculum seminis ). External fertilization of the eggs can take place up to 14 months after mating. Usually the seed packets are sufficient for a second egg clutch, for which no molting or copulation are necessary.
The female attaches fertilized eggs under her abdomen (pleon), where they can remain for up to nine months. During this time the female goes to greater depths and no longer eats. It digs a pit or goes under stones. For this reason, the proportion of egg-bearing females in traps is extremely low. Before the larvae hatch, the female goes back to shallower depths.
The larvae hatch as zoea and initially live in the pelagic region . After about 2 months they are 2.5 mm wide and change into a benthic way of life. Young edible crabs remain in the intertidal zone of the coast up to a carapace width of approx. 6 to 7 centimeters, which is reached at around 3 years of age . Between the ages of 4 and 8, the carapace width of males increases annually by about 1 cm, in females this increase in width is somewhat less and is 0.5 cm per year. With increasing age, the moulting frequency and thus growth slows down; stronger in males than in females.
use
The crayfish is usually caught with traps or, to a limited extent, with trawlers . In 2008 almost 60,000 tons were landed, in 2009 the amount fell to around 40,000 tons. The crab is the only crab in the North Sea that is fished on a large scale.
On the North Sea island of Helgoland , the animals themselves, but especially the scissors, are marketed as " Knieper ". Their meat is eaten as a knee salad, for example.
Taxonomy
The first description of the edible crab as Cancer pagurus was made by Carl von Linné in the 10th edition of the Systema Naturae . The edible crab is a type of the genus Cancer . Synonyms are Cancer fimbriatus Olivi, 1792 and Cancer luederwaldti Rathbun, 1930.
swell
literature
- Alfred Kaestner: Textbook of special zoology . Ed .: Hans-Eckhard Gruner. 4th edition. tape 1 : invertebrates; 4th part: Arthropoda (without Insecta). Gustav Fischer Verlag, Jena Stuttgart New York 1993, ISBN 3-334-60404-7 , p. 1015 f .
Individual evidence
- ↑ a b c d e Species Fact Sheets Cancer pagurus. Food and Agriculture Organization of the United Nations (FAO), accessed February 25, 2012 .
- ↑ a b c d e f Kaestner, 1993; s. literature
- ↑ a b c J.D. Nations: The genus Cancer (Crustacea: Brachyura): systematics, biogeography and fossil record . In: Natural History Museum of Los Angeles County Science Bulletin . tape 23 , p. 1–104 ( pdf 10.5Mb [accessed February 25, 2012]).
- ↑ a b c d e Ken Neal, Emily Wilson: BIOTIC Species Information for Cancer pagurus. Marine Life Information Network (MarLIN), accessed February 25, 2012 .
- ^ E. Edwards: Mating behavior in the European Edible Crab (Cancer pagurus L.) . In: Crustaceana . tape 10 , no. 1 , 1966, p. 23-30 , doi : 10.1163 / 156854066X00045 .
- ^ Alan E. Howard: The distribution and behavior of ovigerous Edible Crabs (Cancer pagurus), and consequent sampling bias . In: J. Cons. Int. Explor. Mer . tape 40 , 1982, pp. 259-261 , doi : 10.1093 / icesjms / 40.3.259 .
- ↑ DA Hancock, E. Edwards: Estimation of annual growth in the Edible Crap (Cancer pagurus L.) . In: J. Cons. Int. Explor. Mer . tape 31 , 1967, p. 246-264 , doi : 10.1093 / icesjms / 31.2.246 .
- ↑ Susi Eising, Martina Görlach, Odette Teubner: The great book of seafood . Gräfe and Unzer Verlag, 2005, ISBN 3-7742-6967-X , p. 63 .
- ^ Carl von Linné: Systema Naturae . 10th edition. tape 1 . Salvius, 1758 ( p. 627 [accessed February 25, 2012]).
