The Thames has a "healthy" seal population according to Zoological Society London conservation scientist Joanna Barker:
More than 700 seals have been found in the Thames Estuary in the first ever survey carried out by air, land and water, says the Zoological Society of London (ZSL).
Volunteers and conservationists recorded 708 grey and harbour seals along the Thames Estuary.
The aerial survey meant researchers could count seals on the outer sandbanks of the estuary, where colonies of up to 120 seals were found in undisturbed spots.
Two threatened species of far-north seals will be granted protections under the Endangered Species Act, US officials announced.
The National Oceanic and Atmospheric Administration ordered "threatened" listings for populations of ringed seals and bearded seals in the waters off northern Alaska, in parts of Russia and other regions of the Arctic.
Both types of seals depend on sea ice and snow, which is becoming scarce in the Arctic region during the non-winter months, NOAA officials said in a written statement.