A rare Arctic seal is making its home in the docks at Hartlepool, England.

Whiskers in Hartlepool harbour

But the 2.5m long mammal is no stranger to the North Sea coast. It appears to be "Whiskers", the seal which washed up in Lincolnshire in spring 1998.

He was nursed back to health before his eventual release in the Shetland Islands that autumn. He has seen the same vet this time for stomach and breathing problems.

But instead of heading north to the Arctic, Whiskers headed south and is delighting fishermen and birdwatchers by bobbing about in the waters of Hartlepool's Fish Quay.

Bearded Seals (scientific name Erignathus barbatus) usually stray no further south than Iceland or north Norway. One reached the Norfolk coast in 1892 and there is also a record from France's North Sea coast in the past.

They are the largest of the true seals, with adult males growing up to 3.4m long (11ft) and reaching weights of well over a quarter of a ton. They mainly feed on crabs, shrimps, clams and snails which they catch in shallow Arctic seas.

Helped by their thick blubber layers, they are extremely hardy and range as close to the North Pole as 85 degrees North. The females give birth to their pups on ice floes in April and May.

The most recent available estimates of their populations were about 300,000 living in the western Laptev Sea, Barents Sea and northernmost Atlantic and over 250,000 in the rest of the Arctic Ocean, the northernmost Pacific and the Bering and Okhotsk Seas.