A RIVER RUNS THROUGH the village in western Scotland where I grew up. After heavy rain, it tears under the stone bridge I crossed each day on my way to school, earning its name, the White Cart, on its short journey to the sea. It starts as a burn bubbling its way through the peaty uplands of Eaglesham Moor about ten miles from Glasgow, slipping between heather and cotton grass and pillows of sphagnum moss. Despite its proximity to Scotland’s largest city, the moor is still a wild, waterlogged place, with humps of glacier-scoured volcanic rock protruding from peatland ten meters thick. Wide skies and fleeting weather reflect in the pools, lochans, and reservoirs, turning the moor from air and light into sudden darkness. Up there, the White Cart skirts tracts of managed forest, loops through pastureland, descends through villages that have morphed into Glaswegian suburbs. Deeper into the city, it runs beside sandstone tenements and postwar industrial estates, emerging for a dignified course beside the Georgian symmetry of Pollok House. In the ancient burgh of Paisley, it almost clips the runways of Glasgow Airport before debouching into a soft curve of the River Clyde on its way to the ocean and the sea lochs of the west coast. Its twenty-mile run hosts salmon, otters, kingfishers, and the memories of children. But not, for a good long while, pearl mussels.
People have dived for pearls for thousands of years in the Persian Gulf and Indian Ocean. Enslaved people were dispatched to clear the Caribbean of its pearl beds. The range of the pearl-bearing mussel, Margaritifera margaritifera, once stretched from the Arctic to Portugal, from Russia to the northeastern seaboard of North America. In the late seventeenth century, the topographer William Camden described the White Cart as being well known for its large, fine pearls. A local historian boasted that the river had once concealed pearls so distinctive, they were “taken notice of by some of the most famous jewellers in Europe.”
But over the past century, the pearl-bearing mussels that thrived in the cold, fast-flowing rivers of Scandinavia, Russia, France, and Scotland have largely disappeared. The last report of live pearl mussels in the White Cart was made by a fisherman in 1887. A small cohort survives in remote rivers in the Highlands, the North East, and the Western Isles in Scotland, but in the industrialized Lowlands, they are long extinct.
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