European Lobster

Homarus gammarus is a large crustacean, with a body length up to 60 centimetres (24 in) and weighing up to 5–6 kilograms (11–13 lb), although the lobsters caught in lobster pots are usually 23–38 cm (9–15 in) long and weigh 0.7–2.2 kg (1.5–4.9 lb). Like other crustaceans, lobsters have a hard exoskeleton which they must shed in order to grow, in a process called ecdysis (molting). This may occur several times a year for young lobsters, but decreases to once every 1–2 years for larger animals.

The first pair of pereiopods is armed with a large, asymmetrical pair of feet. The larger one is the "crusher", and has rounded nodules used for crushing prey; the other is the "cutter", which has sharp inner edges, and is used for holding or tearing the prey. Usually, the left claw is the crusher, and the right is the cutter.

Homarus gammarus is found across the north-eastern Atlantic Ocean from northern Norway to the Azores and Morocco, not including the Baltic Sea. It is also present in most of the Mediterranean Sea, only missing from the section east of Crete, and along only the south-west coast of the Black Sea. The northernmost populations are found in the Norwegian fjords Tysfjorden and Nordfolda, inside the Arctic Circle.

Adult H. gammarus live on the continental shelf at depths of 0–150 metres (0–492 ft), although not normally deeper than 50 m (160 ft). They prefer hard substrates, such as rocks or hard mud, and live in holes or crevices, emerging at night to feed.

The diet of H. gammarus mostly consists of other benthic invertebrates. These include crabs, molluscs, sea urchins, starfish and polychaete worms.

The three clawed-lobster species Homarus gammarus, H. americanus and Nephrops norvegicus are hosts to the three known species of the animal phylum Cycliophora; the species on H. gammarus has not been described.

Homarus gammarus is susceptible to the disease gaffkaemia, caused by the bacterium Aerococcus viridans. Although it is frequently found in American lobsters, the disease has only been seen in captive H. gammarus, where prior occupation of the tanks by H. americanus could not be ruled out.

Female H. gammarus reach sexual maturity when they have grown to a carapace length of 80–85 millimetres (3.1–3.3 in), whereas males mature at a slightly smaller size. Mating typically occurs in summer between a recently moulted female, whose shell is therefore soft, and a hard-shelled male. The female carries the eggs attached to her pleopods for up to 12 months, depending on the temperature. Females carrying eggs are said to be "berried" and can be found throughout the year.

Homarus gammarus is traditionally "highly esteemed" as a foodstuff and was mentioned in "The Crabfish" a seventeenth century English folk song. It may fetch very high prices and may be sold fresh, frozen, canned or powdered. Both the claws and the abdomen of H. gammarus contain "excellent" white meat, and most of the contents of the cephalothorax are edible. The exceptions are the gastric mill and the "sand vein" (gut). The price of H. gammarus is up to three times higher than that of H. americanus, and the European species is considered to be more flavorful.