5510 x 3807 px | 46,7 x 32,2 cm | 18,4 x 12,7 inches | 300dpi
Data acquisizione:
25 dicembre 2009
Ubicazione:
Birsay Bay North West Mainland Orkney Highland Scotland
Altre informazioni:
The grey seal is the larger of the two species of seal that breed around the coast of the British Isles. It is found across the North Atlantic Ocean and in the Baltic Sea. There are two centres of population in the North Atlantic; the largest is in Canada, the other lies mostly in Scottish coastal waters. Populations in all three major centres are increasing, although numbers are still relatively low in the Baltic. Grey seals come ashore on remote islands and coastlines to give birth to their pups in the autumn, to moult in spring, and at other times of the year to haul out between trips to forage for food at sea. Female grey seals give birth to a single white-coated pup, which moults and is abandoned by its mother about 3 weeks later. About 40% of the world population of grey seals can be found in Britain and over 90% of British grey seals breed in Scotland, the majority in the Hebrides and in Orkney. There are also breeding colonies in Shetland, on the North and East coasts of mainland Britain and in Southwest Britain. Although the number of pups born at colonies in the Hebrides has remained approximately constant since 1992, the total number of pups born throughout Britain has grown steadily since the 1960s, when records began. Adult male grey seals may weigh up to 350 kg and grow to over 2.3 m in length. Females are smaller at a maximum of 250 kg in weight and 2 m in length. Grey seals are long-lived animals. Males will live for over 20 years and begin to breed from about age 10. Females often live for over 30 years and begin to breed at about age 5. Grey seals feed mostly on fish that live on or close to the seabed. Their diet is largely composed of sandeels, whitefish (cod, haddock, whiting, ling), and flatfish (plaice, sole, flounder, dab), although this varies seasonally and from region to region. Food requirements depend on the size of the seal and oiliness of the prey but an average figure is 7 kg of cod or 4 kg of sandeels per day.
