London river was declared 'biologically dead' in 1957; decades later it is filled with sharks and seals

In 1957, parts of London's famous River Thames were in such bad shape that scientists declared them 'biologically dead'. The water had been starved of oxygen and decades of sewage and industrial pollution had made it extremely difficult for aquatic life to survive. About 70 years later, the waters are now brimming with sharks, seals, seahorses, eels and many other aquatic organisms. According to a January 2026, health check of the river, published by the Zoological Society of London, its remarkable recovery is continuing.Animals in ThamesOne of the most attention-grabbing headlines about the river this year has been the arrival of sharks. At least five shark species are currently known to use the Thames Estuary, including tope and starry smoothhounds. Scientists believe the estuary may provide important nursery habitat for young sharks.ZSL’s latest figures estimate that the Greater Thames Estuary supported about 2,987 grey seals and 599 harbour seals in 2024. Grey seal numbers have risen sharply since systematic monitoring began in 2013, although the picture for harbour seals is less encouraging. Their population peaked at 796 in 2017 before falling back below its 2013 level. Indiv...