MARINE experts suspect a large shark is patrolling the waters off the North-East coast.

A probe is under way after 45 dead porpoises - many with chunks ripped out of them - were discovered along the coastline in recent weeks.

Decapitated seals have also been found, along with remnants of other large fish.

After examining the kills, marine authorities say a Mako shark could be responsible.

Makos are mackerel sharks that are capable of swimming at up to 60mph and can also leap out of the water.

Short-finned Makos average 5 to 8ft (1.5 to 2.5 metres) but can reach 12ft (3.7 metres) long, weighing about 1,000 pounds (450 kg).

Short-finned Makos are found worldwide in temperate and tropical seas, ranging from the surface to relatively deep waters and are occasionally found inshore.

Graeme Richardson, a leading marine medic in the North-East, said: "The large number of dead porpoise found means that it is possible a shark is out there.

"The Natural History Museum, along with other agencies, is now carrying out full autopsy on many of the mammals in a bid to investigate what has been happening."

Medics, along with staff from Sunderland Lifeboat Station, were called to Seaham Beach in County Durham on Friday and Saturday after reports of attacks.

Norman Conn, secretary of Seaham Environmental Association and owner of Riggs Angling shop in Seaham, said: "It is quite common for porpoises and other sea creatures to be washed up at this time of year, although there seem to be more than usual this year."