Once dead, London’s Thames river is now teeming with seals, porpoises, and even a whale or two

http://qz.com/483977/once-dead-londons-thames-river-is-now-teeming-with-seals-porpoises-and-even-a-whale-or-two/

by Cassie Werber
Aug. 20, 2015

In 1957, the Thames—the huge river that flows though the city of London—was declared biologically dead. And for most of London’s history, its river has been more of a hazard than a habitat. Effluent from Victorian sewers flowed into it. Chemicals from the prolific 19th-century laundries that lined the banks killed off most of the fish, and pretty much anything else that formerly lived in what came to be called the Great Stink.

Yet now it’s teaming not just with fish but with marine mammals including seals and porpoises—and even the occasional whale.

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The change began in the 1990s, with the passing of regulations relating the water industry and the treatment of waste water in urban areas, which imposed a duty on sewage companies to maintain adequate collecting systems and treatment plants. In 1996, the government’s Environment Agency gained oversight of the river.

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The creatures do not stay confined to the outer reaches of the Thames, where it meets the sea, but venture far upstream. Seals were reportedly sighted as far upstream as Hampton Court Palace, the report said, with the highest concentration around the financial hub of Canary Wharf. Harbour porpoises and bottlenose dolphins were also spotted but made it a little less far upstream. Whales were sited in the river reaches nearer the sea—though one errant northern bottlenose whale made it as far as Battersea Bridge, very close to the Houses of Parliament, and died during a rescue operation.

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