Page last updated at 11:58 GMT, Wednesday, 1 July 2009 12:58 UK

Prehistoric bloodsucker in Thames

Ashe Hurst and Oscar Bridge holding a lamprey
It may look like a stick - but Oscar's find is one of earth's oldest creatures

An ancient blood-sucking fish has been found in the Thames by a 13-year-old boy.

The sea lamprey, an eel-like creature with a sucker-shaped mouth surrounded by teeth, predates the dinosaurs.

But they only venture into fresh water to breed if it is very clean, which is why experts said Oscar Bridge's find is significant.

In the 1960s the Thames was so polluted scientists declared it "biologically extinct" after a survey.

Oscar was taking part in a sponsored clear-up of a riverbank near Fulham's Craven Cottage stadium when he made the discovery.

The fact they are coming back is a really good sign
Chris Coode, Thames21

He said: "All of a sudden I saw this thing and thought, 'what's that?'

"I picked it up and it looked like an eel," he said.

"I did get a shock when I saw the mouth."

He added: "I really like animals - especially creepy ones like that."

What Oscar had found proved to be a 15.5in (40cm) long sea lamprey, one of the most ancient creatures on earth.

Like the shark and the crocodile, sea lampreys have barely changed over thousands of millennia.

The parasitic creature attaches its circular mouth to larger creatures before sucking out their insides.

Sea lamprey found in the River Wear
Lampreys are extremely selective with their spawning sites

Chris Coode is river programmes manager for Thames21, the charity that organised the clean-up.

He said: "We have only found one or two in the 15 years we have been cleaning up the Thames.

"The fact they are coming back is a really good sign.

"The Thames is now one of the cleanest city rivers in Europe."

He added: "The lamprey was dead, but it is not a bad thing - because they die immediately after spawning."

On Sunday lampreys were found in the River Wear, County Durham.

The fish was once considered a delicacy - and King Henry I, who lived in the 11th Century, was reputed to have died from eating too many.

However, Oscar said: "It absolutely stank - a horrible fishy smell."

Print Sponsor

Rare fish 'proves water quality'
28 Jun 09 |  Wear
Call for Thames pollution warning
27 Sep 07 |  London
A tale of two rivers
20 Apr 01 |  UK News

The BBC is not responsible for the content of external internet sites

Has China's housing bubble burst?
How the world's oldest clove tree defied an empire
Why Royal Ballet principal Sergei Polunin quit


Americas Africa Europe Middle East South Asia Asia Pacific