Scientific name: Homarus gammarus
Common names: Clawed lobster, European lobster
The earliest records of lobster fishing in Scotland date back to the 12th century when lobster was caught by hand using 'crooks' and hoop nets. With the introduction of baited traps (creels), exploitation on a more commercial basis developed, and today there are important creel fisheries for the European lobster in many areas around the Scottish coast. Landings by Scottish vessels have increased substantially in recent years, from 290 tonnes in 2001 to about 940 tonnes with a value of over £11.4 million in 2009. In recent years, the majority of lobster landings have come from the East Coast, South East, Hebrides, Orkney and South Minch assessment units.
Biology and lifecycle
The European lobster is found all around the coast of Scotland, typically on hard ground in relatively shallow waters and on the fringes of kelp beds. The diet of the adults consists mainly of benthic invertebrates such as crabs, molluscs, sea urchins, polychaete worms and starfish, but may also include fish and plants. The majority of lobsters are caught in waters shallower than 30 m but they may be found as deep as 150 m. Substrate and suitable shelter are thought to affect the size and population density, with larger lobsters being found on more exposed grounds. Lobsters do not undertake extensive migrations and will only move a few miles along the shore. Despite this, a recent study on the genetic variation of lobsters reported very low levels of genetic variation amongst lobster populations in Europe.
The growth rate of lobster is highly variable. Individuals recruiting into the fishery at the minimum landing size of 87 mm carapace length (CL) can be anywhere between 4 and 12 years old. In common with other crustaceans, lobster shed their shell (moult) in order to grow. The main moulting period is in June-July. Juveniles moult more frequently and grow faster than older animals. Mating occurs just after moulting while the female's shell is still soft. Size at maturity in females varies across Scotland; females mature at smaller sizes in the South East than in the Hebrides.
Female lobsters produce between 10 and 15 thousand eggs. Once fertilised the eggs develop internally for up to a year after which they are carried under the 'tail' for 9 to 11 months until they hatch. 'Berried' female lobsters have much reduced feeding and growth rates and low catchability during the egg bearing phase.
Lobsters can grow very old and the potential reproductive life span of a female lobster is in excess of 40 years. Amongst the largest reported lobsters in the UK are a female of 157 mm CL, thought to be about 72 years old, and an 11 lb (5 kg) lobster from the Hebrides estimated 190 mm CL.