The eels are in trouble. A little story seeped out last week: the eel population in the Thames has fallen by 98 per cent in the past five years. There are now only a few loyal creatures left in the river's murky waters.
Every three years or so, the eels make an Odyssean journey from the Sargasso Sea to the rivers of Europe. (It's like their version of the Grand Tour.) The Thames used to be a resting place, cradling them after their exhausting travels. But it seems they've had enough of us, even though they were the adventurous souls who recolonised the river after its "biological death" in the 1960s.
It's a sad tale, the disappearing eels, rendered only a little less so by the existence of an ebullient conservationist whose life's work is to look after them. Dr Matthew Gollock, the Thames conservation project manager of the Zoological Society of London, seems baffled by their absence. "Eels are mysterious creatures at the best of times, but we are very concerned about the rapid disappearance," he says.
Mysterious creatures! I don't think of an eel as being mysterious. Slippery, I suppose, with a sort of Peter Mandelson-like ability to slide around silently, popping up when you least expect it to strike fear into your very soul. (Have you noticed the Mandelson Slide? It's as though he's on tiny wheels.) But mysterious?
I ask Gollock to explain. "We don't know a massive amount about them," he says wistfully.
Gollock became obsessed with the creatures while doing his PhD - on eels and parasites. "I get gooey whenever I see them," he says, which is remarkable when you consider that eels, in all their gimlet-eyed glory, usually make people shudder. "I'm quite a champion of animals that people don't support. I'm not really one for cute and cuddly."
No, he is not. But Gollock is a champion, in all senses. Hearing him talk about eels made me think I should devote my life to the cause. "People turn their nose up at eels, but they're so tenacious!" He talks about their "spirit" - the strange, awesome compulsion they have to slither thousands of miles across the seas to London, where they while away 20 years or so of life before going all the way back again. They swim 4,000 miles to die. To die! They deserve medals just for that.
Unsurprisingly, we have had a hand in the sorry saga. The natural, unpredictable changes in eel behaviour have been compounded by human activity - man-made dams and the effects that climate change has had on oceanic currents have contributed to keeping them away. But I wonder whether, if we all had a bit more Gollock in us - the surging enthusiasm, the love of the uncuddly, the lifelong commitment to an unpopular creature - we wouldn't be in such a God-awful mess on our little planet. Eels, if you're listening, come home. Or could we do a swap? We'll send Mandelson Sargasso-wards if you come back. He'll swim - or slide - it in no time. And I'm sure we could arrange an absurdly long job title and a few peerages for you all, if you like.