In 1974, a salmon was found in the River Thames, England, for the first time since 1833. The 8-lb 4½-oz female, discovered entangled in the protective nets around West Thurrock power station,* was a major surprise. It was sent to the British Museum for positive identification. Victorian era sewage and factory waste polluted the once-thriving salmon river, and by 1849 all salmon had disappeared. On 7 Jul 1855, Michael Faraday wrote in The Times about the putrid state of the Thames. From 1961, improved sewage treatment and limits on industrial discharges gradually brought about a cleaner river. The salmon’s life cycle requires a high standard of water quality, so the species reflects the environmental quality.« The Great Stink of London: Sir Joseph Bazalgette and the Cleansing of the Victorian Metropolis, by Stephen Halliday. - book suggestion.