Seals are large marine predators, at the top of the marine food chain. There are 33 species of seal, walrus and sealion world-wide, of which two species, the common and grey seal, inhabit British waters.

Seals belong to the order Pinnipedia, which means "flap-footed", and refers to their webbed limbs. Within this order there are three different families:

• Phocidae - the true, or eared seals;
• Otaridae - fur seals and sea lions; and
• Odobenidae - walrus.

seal facts

• The largest pinniped in the world is the elephant seal which can grow up to 4-5 metres long, whilst the smallest is the Baikal seal which is only up to 1.3 metres in length.
• Many seals are hunted for their fur, shot as pests, and affected by pollution. Some species such as monk seals are particularly rare
• Unlike other marine mammals, seals have not become totally independent of land - they are mammals that have become aquatic and adapted to life in the ocean, yet still mate and give birth on land.
• The hind flippers of true seals point backwards and the fore limbs are small. The limbs are shorter than in terrestrial mammals because most of the bones are contained within the general body contour; the limbs that are present are the equivalent of our hands and feet, and are used as paddles for swimming. On land however, the true seals find it difficult to move about quickly.
• True seals lack external earflaps - one of the distinguishing features that separate true seals from the sea lions and fur seals.
• All seals are carnivores and most species feed on a range of prey, switching from one source to another as season or availability dictates. They tend to feed on prey that is rich in fat, and the diet may include fish, shrimps, crabs, squid, octopus, molluscs and other invertebrates.

threats
plague
In 2002, like in 1988, large numbers of dead and dying common seals were reported in the North Sea. Common seals throughout the region quickly caught the phocine distemper virus (PDV). The virus is very similar to canine distemper and measles in humans. which are both infectious through aerial droplets. Grey seals appear to be more resistant to the disease, but the toll on the common seal populations has been huge.
fur trade
European sealers have had a great impact on seals, with some populations such as the Antarctic fur seal being driven almost to extinction because of the demands for their pelts. Demand for fur coats dropped off in the 1980s, following high profile welfare campaigns. But now that populations have recovered, the pressure for renewed and increased hunts is rising. Seal hunts are currently undertaken by Canada, Namibia and Norway.
fisheries
The issue of seals competing with man for declining fish stocks has become serious in recent years. Seals are perceived by some as causing damage to fishing gear, to the catch of fish and to farmed fish. It is very difficult to find convincing arguments to support this. Seals are also accidentally captured and drowned in fishing gears - particularly gill-nets and pelagic trawls.
pollution
Chemical pollutants and heavy metals are a significant threat because seals bioaccumulate high levels of pollutants in their blubber. Litter, especially plastics, is present in the marine environment in very high quantities. Seals are very inquisitive and can get trapped in plastic strapping bands, or discarded fishing net, which may eventually cut deep into the flesh as the animal grows. The MCS Beachwatch campaign monitors levels of litter on UK beaches every year, and regularly records hazardous debris in large quantities on our shores.