Risso Dolphin washed ashore Great Yarmouth beach
© HM Coastguard Gorleston
Risso Dolphin washed ashore Great Yarmouth beach

Marine experts are trying to discover why strange looking dolphins are beginning to turn up dead hundreds of miles from their deep sea haunts. Two bull-headed Risso's dolphins have washed ashore, the first time in 50 years the mysterious-looking creatures have been found in the southern reaches of the North Sea.

The Zoological Society of London has retrieved the dolphin carcasses from near Great Yarmouth over the weekend and will be conducting post mortems to discover how the creatures had died.

Rumours have emerged that the dolphins may have fallen victim to a great white shark attack because they were scarred, but skin gouges are a common sign on these type of marine mammals because of injuries they receive eating their favourite food, squid.

What concerns conservationists is the way the dolphins were found in a southern stretch of the North Sea when, by rights, they should be hunting squid and octopus around the western Scottish and Irish coastlines.

HM Coastguard at Gorleston posted pictures of one the dead dolphins on its Facebook page, explaining how it always passes on all details of what are historically known as "fishes royal" - which include porpoises, whales, dolphins and sturgeon - to the Natural History Museum in London to determine the cause of death.

A spokesperson from the museum explained today: "The animal was a juvenile male and appeared to be very thin.

"Risso's dolphins are not usually found in this area, and are more at home in deeper waters, and therefore it's poor condition may be linked to it being out of its usual habitat."

"The animal was retrieved this morning by colleagues at our partner organisation ZSL and post mortem will be carried out this week at ZSL."

Risso's dolphins, named after the 19th Century naturalist Giuseppe Risso, have a truly global range, stretching from Australia to the Arabian Ocean and the north east Atlantic.

They can grow up to 13ft in length and weigh more than 1,000lb, making them the largest of all dolphin species. One of their strangest features is their round, bulbous heads.

They are protected under various international conservation agreements but are hunted in Japan and parts of the Far East.

They have also suffered from plastic pollution.

Checks to see if tissue samples show signs of contamination will form a major part of the impending post mortem.

Sarah Dolman, policy manager for Whale and Dolphin Conservation, said the species' status around the UK coastline is uncertain because their exact number remains unknown.

She said: "We await the results of the post mortem as they could highlight conservation problems and the reasons why these individuals became stranded so far south in the North Sea."