Cancer pagurus
Cancer pagurus
The crab (Cancer pagurus ) is in the Eastern Atlantic and the North Sea common crab of the family of crabs ( Cancridae ). The species is considered a delicacy and is intensively fished.
Features
Crabs possess the typical crab physique with a significantly shortened Pleon, the abdomen, struck firmly under the cephalothorax. The maximum length of the carapace is approximately 20 cm, the maximum width of around 30 cm.
The carapace is granulated broad oval and very fine; flattened with a light, central elevation. On its front side edge (English latero - anterior margin ) of carapace has 9 or 10 blunt, square teeth, which are separated from each other with distinct pits. The color is uniform reddish- brown, in young animals, the color can tend toward purple.
Crabs have developed powerful scissors that are designed the same way as a rule. The tip of the scissors finger ( dactylus ) is conspicuously colored black.
Distribution and habitat
The crab has its natural distribution in the shelf of the East Atlantic and the North Sea, from northern Morocco to northern Norway to about 70 ° N. Older finds prove his spread in the northern Mediterranean, on the coasts of Spain, France, Italy and the Balkans.
The species is found as Benthont at depths from 6 to 100 meters, which is intertidal to subtidal. There, the crab lives on sandy and rocky bottoms.
Nutrition
The nocturnal crab is primarily a carnivore. It feeds on a variety of crustaceans, fish, molluscs, echinoderms, but also on carrion. So untern others, the congregation beach crab ( Carcinus maenas ), the Great beach snail ( Littorina littorea ) and the European oyster ( Ostrea edulis) are eaten.
Reproduction and life cycle
Sexual maturity occurs at Carapaxbreiten 11-13 centimeters. Copulation takes place in spring and summer, or in autumn, after the female has skinned. Even before this shed couples show a pronounced affinity; Males accompany females 3 to 12 days prior to mating and up to 12 days thereafter. The males transmit the seed packets and the female they kept in their seed bags ( seminal receptacle ). The external fertilization of eggs can be up to 14 months after copulation. Most seed packets are enough for a second egg masses for which therefore no moulting or mating are required.
Fertilized eggs attached to the female under her abdomen ( pleon ), where they may remain for up to nine months. During this time, the female goes into greater depths and stops eating. It digs a pit or goes under stones. For this reason, the proportion of berried females in traps is extremely low. Before the eggs hatch, the female goes back to lower lows.
The larvae hatch as zoea and first living in the water column. After about 2 months they are 2.5 mm wide and go over to a benthic lifestyle. Up to a carapace width of about 6-7 inches, which is reached at about 3 years, remain young crabs in the intertidal zone of the coast. Between 4 and 8 years, the carapace width of males increases annually by about 1 cm, in females, this increase in width is somewhat smaller, at 0.5 inches per year. With increasing age, slows the molting frequency and thus the growth; stronger in males than in females.
Use
The crab is fished with traps or usually limited with trawlers. In 2008, almost 60,000 tonnes were landed in 2009 decreased the amount to about 40,000 tons. The crab is the only crab in the North Sea, which is fished on a larger scale.
On the North Sea island of Helgoland are the animals themselves, but marketed in particular the scissor as " Knieperteich ". Their flesh is eaten as a salad Knieperteich.
Taxonomy
The first description of pocket as cancer Cancer pagurus was carried out by Carolus Linnaeus in the tenth edition of Systema Naturae. The crab is the type species of the genus Cancer. Synonyms are Cancer fimbriatus Olivi, 1792 and Cancer luederwaldti Rathbun, 1930.