Канцелярский краб (Cancer pagurus): описание и биология.

Species of crustacean

Cancer pagurus, commonly known as the edible crab or brown crab, is a species of crab found in the North Sea, North Atlantic Ocean, and perhaps the Mediterranean Sea. It is a robust crab of a reddish brown colour, having an oval carapace with a characteristic "pie crust" edge and black tips to the claws. A mature adult may have a carapace width up to and weigh up to C. pagurus is a nocturnal predator, targeting a range of molluscs and crustaceans. It is the subject of the largest crab fishery in Western Europe, centred on the coasts of the British Isles, with more than 60,000 tonnes caught annually.

The carapace of C. pagurus adults is a reddish brown colour, while in young specimens it is purple brown. It occasionally bears white patches, and is shaped along the front edge into nine rounded lobes, A fold of the carapace extends ventrally to constitute a branchial chamber where the gills lie. The first pereiopod is modified into a strong cheliped (claw bearing leg); the claw's fingers, the dactylus and propodus, are black at the tips. are held under the female's abdomen up to eight months until they hatch. The first juvenile stage is characterised by a well developed abdomen, which in time becomes reduced in size and folded under the sternum. Juveniles settle to the sea floor in the intertidal zone, where they stay until they reach a carapace width of , and then migrate to deeper water.

C. pagurus is abundant throughout the northeast Atlantic as far as Norway in the north and North Africa in the south, on mixed coarse grounds, mud, and sand from the shallow sublittoral to depths around Unconfirmed reports suggest that C. pagurus may also occur in the Mediterranean Sea and Black Sea. Their diet includes a variety of crustaceans (including the crabs Carcinus maenas and Pilumnus hirtellus, the porcelain crabs Porcellana platycheles and Pisidia longicornis, and the squat lobster Galathea squamifera) and molluscs (including the gastropods Nucella lapillus and Littorina littorea, and the bivalves Ensis, Mytilus edulis, Cerastoderma edule, Ostrea edulis, and Lutraria lutraria). It may stalk or ambush motile prey, and may dig large pits to reach buried molluscs.

Compared to other commercially important crab species, relatively little is known about diseases of C. pagurus. Its parasites include viruses, such as the white spot syndrome virus, various bacteria that cause dark lesions on the exoskeleton, and Hematodinium like dinoflagellates that cause "pink crab disease". A number of legal restrictions apply to the catching of C. pagurus. Catching "berried" crabs (females carrying eggs) is illegal, Different minimum sizes are employed in different geographical areas, to reflect differences in the crab's growth rate across its range. Recent studies have shown that edible crabs are negatively affected by electromagnetic fields emitted from sub sea power cables around offshore wind farms.

Around one third of the weight of an adult edible crab is meat, of which one third is white meat from the claws (see declawing of crabs), and two thirds is white and brown meat from the body. As food, male edible crabs are referred to as cocks and females as hens. Cocks have more sweet white meat; hens have more rich brown meat. Dishes include dressed crab (crab meat arranged in the cleaned shell, sometimes with decoration of other foodstuffs), soups such as bisque or bouillabaisse, pâtés, mousses, and hot soufflés.

According to the rules of the International Code of Zoological Nomenclature, Cancer pagurus was first described by Carl Linnaeus in 1758, in the tenth edition of his Systema Naturae, which marks the starting point of zoological nomenclature. It was chosen to be the type species of the genus Cancer by Pierre André Latreille in 1810. The specific epithet pagurus is a Latin word, deriving from the πάγουρος (pagouros), which, alongside κάρκινος (karkinos), was used to refer to edible marine crabs; neither classical term can be confidently assigned to a particular species. Although the genus Cancer formerly included most crabs, it has since been restricted to eight species.