Sunday 25 January 2015
The freshwater pearl mussels of the Lake District have a perilous start to life. Every summer each of the half a million adult mussels on the river Ehen in the wilds of Ennerdale in Cumbria release up to four million larvae. Most of these simply wash out to sea and oblivion, but a few will latch on to the gills of the passing Atlantic salmon or Arctic char who visit the river to spawn.
The tiny mussels, less than a tenth of a millimetre long, will harmlessly “live on the gill” of the fish for up to 18 months as it heads out into the depths of the Atlantic. When the fish finally makes it back to spawn in the river, the mussels drop off to burrow into the clean, sandy and gravelly riverbed and go on, potentially, to live for 100 years. And, like the oyster, freshwater mussels occasionally produce a pearl. Or at least that’s what should happen. A century of habitat degradation, over extraction of water and even poaching, have made its life even more perilous
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