Cancer Pagurus - Distribution and Ecology

Distribution and Ecology

Cancer pagurus is abundant throughout the northeast Atlantic as far as Norway in the north and northern Africa in the south, on mixed coarse grounds, mud and sand from the shallow sublittoral to depths of about 100 metres (330 ft). It is frequently found inhabiting cracks and holes in rocks but occasionally also in open areas. Smaller specimens may be found under rocks in the littoral zone. Unconfirmed reports suggest that C. pagurus may also occur in the Mediterranean Sea and Black Sea.

Adult C. pagurus are nocturnal, hiding buried in the substrate during the day, but foraging at night up to 50 metres (160 ft) from their hideouts. 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. The main predator of Cancer pagurus is the octopus, which will even attack them inside the crab pots that fishermen use to trap them.

Compared to other commercially important crab species, relatively little is known about diseases of Cancer 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". Other microscopic pathogens include fungi, microsporidians, paramyxeans and ciliates. Cancer pagurus is also targeted by metazoan parasites, including trematodes and parasitic barnacles. A number of sessile animals occasionally settle as epibionts on the exoskeleton of C. pagurus, including barnacles, sea anemones, serpulid polychaetes such as Janua pagenstecheri, bryozoans and saddle oysters.