The Zoological Society of London explain how they carried out the annual seal survey:
The number of seals in the Greater Thames Estuary has increased from 685 to 938 individuals since last year, according to the Zoological Society of London (ZSL).
Conservationists and volunteers took to the skies, boarded boats, and tip-toed across marshland for the second year of the annual seal survey.
The Greater Thames Estuary is home to harbour seals and grey seals. Despite their close proximity to the capital, these populations are some of the least understood in the UK. But having witnessed declines of up to 90 per cent in some Scottish harbour seal populations, conservationists are now keen to keep a close eye on the smaller of the two species in the Greater Thames Estuary.
A survey has found hundreds of seals are living in the Thames. It is the first survey of its kind that has been conducted. It is thought the seals' presence is a bonus to London's marine life.
Funmi Olutoye reports:
There are around 500 harbour seals and 200 of the larger grey seals in the Thames Estuary, according to the Zoological Society of London (ZSL) said.
ZSL's conservation scientist Joanna Barker said:
More than 700 seals have been recorded in the Thames Estuary.
In the first ever count by air, land and sea, the Zoological Society of London found hundreds of grey and harbour seals along the Thames and in small creeks and rivers.