Save our eels

The migration of European eels is one of the miracles of nature. They start life in the great deeps of the Sargasso sea in the north-west of the Atlantic ocean as tiny, flat creatures, like almost transparent willow leaves, which drift 3,700 miles on the Gulf Stream to Britain and mainland Europe. The journey can take more than three years. When they approach Europe they make their first metamorphosis into ‘glass eels’: thin rods, shorter than a finger, which are also virtually transparent. These in turn have their own metamorphosis into elvers, which are essentially tiny eels. They swim upstream, close to the bank to avoid the river’s current, and slowly change into ‘yellow eels’. At this point they distribute themselves into streams and ponds, lakes and meres — anywhere where there is water. Here they will stay for anything between ten and 30 years, slowly putting on weight as they feed on worms, insects and other fish, dead and alive.

After staying put for decades, suddenly, around the time of a harvest moon, the eel carries out its final metamorphosis. Its skin becomes thicker and its eyes larger and bluer in readiness for the depths of the sea. Its yellowish-brown colour disappears, its back turns black and its sides turn -silver. Then, wherever it is — lake, ditch, pond or stream — it makes its way to the nearest main river by the fastest possible means. This can even entail wriggling across country; eels can survive out of water for three to four hours. Its stomach dissolves, for it will feed no more during its last journey, which may take six months to a year. Eventually, it returns to the Sargasso — so-called because of its floating weed, sargassum — where the eel will mate, spawn and die.