Saturday, January 23, 2010

The Mystery of the Eels

What is happening to the eels? Once a staple diet in London their numbers in the river Thames has crashed a whopping 98% over the last five years.

I was just reading in the Wandle Valley Trail guide how there "are large numbers of eels" in the lower reaches of that river near where it meets the Thames when the BBC reported the opposite.

Or maybe the Wandle did have a large number, but for some reason they have gone.

It's a bit of a mystery. There are so few eel fishermen that its hard to blame them, but then what?

One problem is that the eel is still little understood. There has been a project to track its migration across the Atlantic the the supposed spawning grounds of the Sargasso Sea, but they have been tracked "only" 1,300 km of the 5,o00 km journey.

It's an animal that has puzzled scientists way back to the days of Aristotle. There was another program on the BBC about him which asked why he fell from favour and the answer was the eel (its been quite a week for the eel).

Aristotle tried to understand the wildlife on the island of Lesbos and undertook a series of dissections which he then documented in a very vigorous way. It was to be one of the cornerstones of our understanding of the biological world.

But he was confused about the humble eel as he couldn't find any reproductive organs. It wasn't his fault - they only grow on the long migration to the spawning ground. But he was left scrambling for notions of the their origin and came up with some bizarre concept involving self generation from mud.

It was, with the benefit of 21st Century hind-sight, complete nonsense, and for that reason he became scarred as the man that got eels wrong. But he got a huge lot right, and as can be seen the eel is still causing the scientists to wonder and theorise. I was certainly impressed by how he moved the science forward, transforming how we look at the world, and can forgive him this blip given the swamp of ignorance he was trying to escape from.

There was a final eel reference this week in that most modern of tv channels, YouTube, when keep turning left's Dylan Winter's got to Arthur Ransome's Secret Water hide-out Witch's Quay.

As Nancy Blacket would put it, Great Congers!


tillerman said...

My granddaughter was a Pike but now she's an Eel.

Theo Pike (The Wandle Trust) said...

I'm not entirely sure about the situation in the Thames, but a recent Environment Agency survey of the Wandle revealed good numbers of eels from Wandsworth all the way to Carshalton. Eels only spread upstream on a basis of population density, so that's a good sign for the whole river.

Along with the River Mole, the Wandle is apparently one of the eel's strongholds in the south of England. Certainly during our monthly community river cleanups we regularly find eels hiding inside motorbikes, old tyres and other rubbish!


Pat said...

I feel that it seems eel for our understanding of the waterways that there eely hasn't been enough eelementary research to peel back a great deel of eelgnorance.

Yes, and I know what the fictional tramp engineer Glencannon did when the fishmonger offered him something 'eely fresh for a meel. I feel reel pain, so I'll seel it.

JP said...

Thanks Theo, that's good to know. I might get in touch as have some questions to ask about when the next clean up is and also about development (boo hiss etc)

Pat; ho ho ho! eely good!

Pat said...

Come to peel out one more reel eel memory, one of Guy Gilpatrick's minor characters said his congers were "Congreely Fresh!"