It's electrifying.

I'’m thinking about fish and wondering whether to strike seafood off the shopping list in my contribution to the regeneration of declining fish stocks, as we are warned this week that within fifty years there will be no fish left to fish. And so I remembered a fascinating piece I had read in W. G Sebald'’s discursive journal of his travels on the East Anglian coast, The Rings of Saturn.

At this point of the journey, he'’s discussing glut and famine in the North Sea herring industry over the centuries, vital to the economies of the British east-coast fishing communities from Buckie to Lowestoft, and to parallel communities in his home country of Germany.

Sebald'’s brief survey of the industry leads to a consideration of the herring itself. Known in the north-east of Scotland as '‘the silver darlings', herring in life shimmer with shades of iridescent blues and greens and orange. Once dead their colours change - the back becomes blue, while the gills, filled with blood, are now red.

Here'’s the bit of the story that intrigues me. Not only does its colour change once it's on the fishmongers slab, the herring begins to glow, a glow that lasts for several days, fading as the fish decays. In 1870, intrigued by this property, two English scientists, wonderfully named Herrington and Lightbown - and you couldn'’t really make those names up - did investigate this phenomenon further, in the hope that the glowing herring might provide the key to an organic, and therefore renewable, source of light. Their experiments came to nothing. As, apparently, will the 'silver darlings'’.