Marine mammals thriving in Thames
Ten years of public sightings show that large marine mammals are regularly found in the River Thames.
The Zoological Society of London (ZSL) has received records of 2,732 animals over that period.
Seals were the most common animal seen, with many spotted around London's Canary Wharf, probably because many people spot them from its skyscrapers.
In addition, the public reported 444 porpoises and dolphins on the river, and 49 whales.
Joanna Barker, ZSL's European conservation projects manager, said: "Many people looking into the Thames see a murky, dirty environment.
"But, actually, beneath the waves, it is full of life. We have a huge range of fish and invertebrates, and also top predators."
Just 50 years ago, the Thames was so polluted it was declared "biologically extinct", too dirty for anything to survive there.
But the public sightings confirm that the river is springing back to life. And many animals are venturing further into the English capital's waterway.
Seals were seen as far upstream as Teddington and Hampton Court Palace, in south west London.
And dolphins and porpoises were spotted at Teddington Lock, with large pods spotted close to Kew Gardens and Deptford.