the grey seal

The grey seal (Halichoerus grypus) is the larger of Britain's two species of breeding seal . The coat color varies from grey to brown to silver, often with blotche). Males (bulls) can be distinguished from females by the pattern of darker and lighter fur color. In males, the continuous background color is dark, but in females is it light. Juveniles are born with a creamy white natal coat. The nostrils are parallel, and the 'Roman' nose is characteristic, especially in males the scientific name derives from the Greek for 'hooked-nose sea-pig' Grey seals feed on a wide range of fish species, and also take crustaceans, cephalopods and the occasional seabird. When feeding they typically dive to depths of 30 to 70 metres. In autumn females congregate at traditional pupping sites, called rookeries. At birth the pups weigh 14 kilograms, but as the mother's milk contains 60 percent fat, they rapidly put on weight and develop the blubber layer essential for maintaining body temperature when at sea. Males come ashore at the pupping sites to mate; they compete for sole access to a group of females, and successful dominant males can secure access to up to as many as ten females. After mating the seals disperse. The pups stay in the rookery surviving on their blubber reserves until after the moult, they then go to sea and may disperse over large distances The grey seal is found on both sides of the north Atlantic in temperate and sub arctic waters. Three distinct populations occur; the western Atlantic population, the north-eastern or Baltic population which is endangered, and the eastern Atlantic population which is centred around British coasts, particularly around Scotland

Grey seals are coastal mammals and live in large groups. When they are not in the water they are found on rocky ledges, beaches or on pack ice (Jefferson et al, 2008).


These haul out sites and are usually quiet areas very close to the water's edge, with good access to the open sea (Pomeroy et al, 2000).


The seals rely on haul out sites to rest, breed, moult and give birth.

Grey seals can dive down to 300 metres for up to 30 minutes, although they are more likely to dive for 1–10 minutes, with an average depth of 60 metres or less (Jefferson et al, 2008).


To rest in the sea, the animals position themselves vertically in the water column with their head poking out of the water (Jefferson et al, 2008). Off the British coasts and in the Baltic Sea, their journeys out to sea are usually less than 50km from their haul out sites and last 2–5 days (Sjöberg et al, 1995; McConnell et al, 1999).

Feeding

Grey seals use almost the whole water column to obtain their food - they feed from the ocean floor to the surface and in between. The seals even take seabirds. Their prey includes:

whiting

smelt

skate

lumpfish

pollock

cod

haddock

plaice

salmon

cephalapods

molluscs (Jefferson et al, 2008)

Their food requirements depend on the size of the animal and the nutritional richness of the prey. It is estimated that on average, 7kg of cod or 4kg of sand eels per day are consumed (Special Committee on Seals (SCOS), 2009).



Up to 70 percent of the grey seals' diet can consist of sand eels (Perrin, 2009).


Individuals normally forage within 100km of their haul out site, but tracking has shown that they can feed up to several hundred kilometres away (SCOS, 2009).